This document summarizes a paper that introduces the complexities involved in dimensioning and planning WiMAX networks. It discusses key WiMAX features that must be considered for optimal network coverage, capacity, and service requirements. It also introduces Fujitsu's WiMAX Network Dimensioning Tool, which uses innovative algorithms for interference margin calculation and capacity analysis. Finally, it provides an overview of the challenges of WiMAX network dimensioning and planning compared to 2G/3G networks.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
A simulation study of wi max based communication system using deliberately cl...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
A simulation study of wi max based communication system using deliberately cl...eSAT Journals
This document summarizes a study on reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems using deliberate clipping. It begins with an introduction to WiMAX technology and OFDM. It then discusses the PAPR problem in OFDM systems and different techniques to reduce PAPR, including signal scrambling and signal distortion methods. It focuses on deliberate clipping as a simple method to limit PAPR by distorting the signal before amplification. The document presents a simulation of an OFDM system using deliberate clipping at the Nyquist sampling rate to investigate its effect on bit error rate performance compared to an unclipped system.
DISCRETE COSINETRANSFORM-II FOR REDUCTION IN PEAK TO AVERAGE POWER RATIO OF O...ijwmn
Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication
and wireless communication systems as it provides enhanced spectral efficiency than Frequency division
multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to
average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reduction
techniques have been used, including techniques based on companding. Incompanding, -Law
companding has potential to reduce the PAPR of OFDMsignals. -Law Companding technique
preserves the dynamic range of samples at low amplitudes.A new method named as precoding which is
having less complexity compared to the other power reduction techniques is proposed to reduce PAPR.
This paper put forward combination of two existing techniques namely -Law Companding Transform
and Discrete Cosine Transform-II precoding technique. The simulation results show that, the proposed
combinedscheme gives better result for PAPR Reduction and results in no distortion.
This document summarizes some key features of the LTE radio interface that enable unprecedented performance in mobile broadband. It discusses features like spectrum flexibility that allow LTE to operate in different frequency bands and bandwidths with both FDD and TDD duplexing. It also describes multi-antenna transmission techniques in LTE including transmit diversity to improve coverage and capacity, and multi-stream transmission to significantly increase peak data rates through multiple parallel data streams. Scheduling, link adaptation, and hybrid ARQ are explained as ways to efficiently utilize radio resources based on varying channel conditions.
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
BER PERFORMANCE ANALYSIS FOR WIMAX PHY LAYER UNDER DIFFERENT CHANNEL CONDITIONSijistjournal
This document summarizes the performance analysis of the physical (PHY) layer of WiMAX under different channel conditions. It provides details on the key components of WiMAX including the OFDM air interface, adaptive modulation and coding, and channel encoding. It also describes the simulation setup used to evaluate the PHY layer performance over varying wireless channel models.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
A simulation study of wi max based communication system using deliberately cl...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
A simulation study of wi max based communication system using deliberately cl...eSAT Journals
This document summarizes a study on reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems using deliberate clipping. It begins with an introduction to WiMAX technology and OFDM. It then discusses the PAPR problem in OFDM systems and different techniques to reduce PAPR, including signal scrambling and signal distortion methods. It focuses on deliberate clipping as a simple method to limit PAPR by distorting the signal before amplification. The document presents a simulation of an OFDM system using deliberate clipping at the Nyquist sampling rate to investigate its effect on bit error rate performance compared to an unclipped system.
DISCRETE COSINETRANSFORM-II FOR REDUCTION IN PEAK TO AVERAGE POWER RATIO OF O...ijwmn
Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication
and wireless communication systems as it provides enhanced spectral efficiency than Frequency division
multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to
average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reduction
techniques have been used, including techniques based on companding. Incompanding, -Law
companding has potential to reduce the PAPR of OFDMsignals. -Law Companding technique
preserves the dynamic range of samples at low amplitudes.A new method named as precoding which is
having less complexity compared to the other power reduction techniques is proposed to reduce PAPR.
This paper put forward combination of two existing techniques namely -Law Companding Transform
and Discrete Cosine Transform-II precoding technique. The simulation results show that, the proposed
combinedscheme gives better result for PAPR Reduction and results in no distortion.
This document summarizes some key features of the LTE radio interface that enable unprecedented performance in mobile broadband. It discusses features like spectrum flexibility that allow LTE to operate in different frequency bands and bandwidths with both FDD and TDD duplexing. It also describes multi-antenna transmission techniques in LTE including transmit diversity to improve coverage and capacity, and multi-stream transmission to significantly increase peak data rates through multiple parallel data streams. Scheduling, link adaptation, and hybrid ARQ are explained as ways to efficiently utilize radio resources based on varying channel conditions.
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
BER PERFORMANCE ANALYSIS FOR WIMAX PHY LAYER UNDER DIFFERENT CHANNEL CONDITIONSijistjournal
This document summarizes the performance analysis of the physical (PHY) layer of WiMAX under different channel conditions. It provides details on the key components of WiMAX including the OFDM air interface, adaptive modulation and coding, and channel encoding. It also describes the simulation setup used to evaluate the PHY layer performance over varying wireless channel models.
This document discusses various topics related to ad-hoc wireless networks including wireless network concepts, radio propagation mechanisms, characteristics of wireless channels, cellular networks, ad hoc networks, medium access control, routing protocols, multicasting, and transport layer protocols for ad hoc networks. It provides classifications and examples of different types of network architectures, protocols, and issues/challenges in ad hoc wireless networks.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
Performance analysis of round trip time in narrowband rf networks for remote ...ijcsit
Networks for remote wireless communications using narrow band radios modem &Routers ((RipEX unit)
,as a means of transmission to communicate between the loins broadcast sites TV/FM.
RTT delay measurement is influenced by different parameters of Narrowband RF Networks.
We illustrate, in this paper, how RTT varies (in remote wireless practical communications application)
versus distance, modulation, baud rates, number of hops and throughput, between source and destination.
Also, we will see how the Forward Error Correction (FEC) affect, in the same time, the RTT according the
factors cited above.
This document discusses the origins and development of ad hoc networks. It describes how packet radio networks (PRNETs) in the 1970s, developed by DARPA, were the first generation of ad hoc networks. PRNETs used multi-hop routing between mobile radio terminals and packet radios to communicate without fixed infrastructure. The document outlines the key components and routing techniques of PRNETs, including point-to-point and broadcast routing. It also discusses how subsequent generations in the 1980s-1990s focused on improving performance, scalability, and developing commercial applications like Bluetooth.
A mobile adhoc network is a collection of wireless mobile nodes that communicate with one another without any fixed networking infrastructure. Since the nodes in this network are mobile, the power management and energy conservation become very critical in mobile adhoc network. The nodes in this network have limited battery power and limited computational power with a small amount of memory. Such nodes must conserve energy during routing to prolong their usefulness and increase network lifetime. This research paper proposes a scheme that takes into consideration the power awareness during route selection. This scheme observes power status of each and every node in the topology and further ensures the fast selection of routes with minimal efforts and faster recovery. The scheme is incorporated with the AODV protocol and the performance has been studied through simulation over NS-2.
Iaetsd survey on cognitive radio networks and itsIaetsd Iaetsd
This document summarizes a survey on cognitive radio networks and their routing mechanisms. It discusses how cognitive radios can dynamically identify unused portions of the spectrum and configure themselves to operate in those spaces to better utilize spectrum resources. It also describes some of the key challenges in designing routing metrics for cognitive radio networks, including how primary users occupying channels can break links in secondary networks, requiring secondary users to either wait, switch channels, or re-route data traffic. Finally, it outlines different cognitive radio network architectures like infrastructure, ad-hoc, and mesh networks and how routing schemes may be either stationary or dynamic depending on how often primary users interrupt secondary transmissions.
This document provides an outline for a lecture on data communication and computer networks. It covers networking fundamentals and each layer of the OSI model, including the physical layer, data link layer, network layer, transport layer, and application layer. For the physical layer, it discusses different transmission media such as twisted pair, coaxial cable, optical fiber, and wireless. It provides details on technologies like Ethernet, DSL, and fiber optic cable. The data link layer section covers terminology and the role of the link layer in transferring data between adjacent nodes.
Optical space division multiplexing uses multiple cores or modes in optical fibers to increase transmission capacity. A history of the technology was provided, noting the progression from single mode fibers to coherent detection and polarization multiplexing. Limits with single mode fibers were discussed, along with ways that multi-core and multi-mode fibers can overcome capacity constraints through spatial multiplexing across fiber cores and modes. Recent demonstrations showed record capacities of 57.6 Tb/s over multi-mode fiber and 24 Tb/s over hollow-core fiber. Integration challenges with spatial division multiplexing were also outlined.
INVESTIGATION OF UTRA FDD DATA AND CONTROL CHANNELS IN THE PRESENCE OF NOISE ...ijngnjournal
In this paper, the main aim is to design and simulate UTRA FDD control channel in the presence of noise and wireless channel by using FDD library/Matlab box set that can be used to design and implement some
systems. Moreover, a test and verification of the library is achieved with different channel models such as Additive White Gaussian Noise (AWGN), fading and moving channel models. FDD library are employed to design whole transmitter and receiver. Then we had tested AWGN channel and some other channel models.
Also we illustrated what are control channels DCCH and the other one as understanding the whole system. Moreover, the standards have been covered as well as implemented the whole transmit and receive chain plus the generation of DPCH, DPCCH channel. we had tested the performance against the AWGN noise.
Then we have studied different channel models that are defined in the standard, used the few of them like the fading channel and moving channel. We have tried to compare the performance in terms of Monte Carlo simulation by producing the BER curves. We have also change some channel parameters like phase, number of multipaths and we have tried to see the performance of the model in the presence of actual channel model.
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Lecture 1 mobile and adhoc network- introductionChandra Meena
This document provides an overview of a course on mobile and ad hoc networks. It lists two textbooks that will be used and states that the goal is to cover fundamental design issues and solutions for network architecture and protocols. It also lists some related websites and outlines the objectives of chapters that will introduce wireless communication technologies, network standards, and multiple access techniques for ad hoc networks.
Analysis of a framework implementation of the transceiver performances for in...IJECEIAES
The greatest advantages of optical fibers are the possibility of extending data rate transmission and propagation distances. Being a multicarrier technique, the orthogonal frequency division multiplexing (OFDM) can be applicable in hybrid optical-wireless systems design owing to its best spectral efficiency for the interferences of radio frequency (RF) and minor multipath distortion. An optical OFDM-RoF-based wireless local area network (W-LAN) system has been studied and evaluated in this work. The outline for integrating an optical technology and wireless in a single system was provided with the existence of OFDM-RoF technology and the microstrip patch antenna; these were applied in the Optisystem communication tool. The design of the proposed OFDM-RoF system is aimed at supporting mm-wave services and multi-standard operations. The proposed system can operate on different RF bands using different modulation schemes like 4.16 and 64QAM that may be associated to OFDM and multidata rates up to 5 Gbps. The results demonstrate the robustness of the integrated optical wireless link in propagating OFDM-RoF-based WLAN signals across optical fibers.
Analysis of WiMAX Physical Layer Using Spatial Multiplexing Under Different F...CSCJournals
WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum and its industry. WiMAX is basically a wireless digital communication system which is also known as IEEE 802.16 standard intended for wireless \"metropolitan area networks\". WiMAX is based upon OFDM multiplexing technique. It was developed in order to provide high speed data rates to the users located in those areas also where broadband wireless coverage is not available. MIMO systems also play an important role in the field of wireless communication by allowing data to be transmitted and received over different antennas. WiMAX-MIMO systems are developed to improve the performance of WiMAX system. This paper analyzes WiMAX-MIMO system for different modulation schemes with different CC code rates under different fading channels (Rician and Nakagami channel). Spatial Multiplexing technique of MIMO system is used for the simulation purpose. Analysis has been done in the form of Signal-to Noise Ratio (SNR) vs Bit Error Rate (BER) plots.
This document summarizes an article from the International Journal of Computer Engineering and Technology that models and simulates the physical layer of the IEEE 802.22 wireless standard over a multipath fading channel. It describes the IEEE 802.22 standard and its use of OFDM and OFDMA to provide resilience against multipath propagation. It then models the physical layer in Simulink, including modulation, channel effects, demodulation and decoding. Finally, it presents simulation results for different modulation schemes and coding rates over multipath channels to analyze the performance of the physical layer under varying conditions.
This document discusses cognitive radio and its radio frequency (RF) challenges. It begins by introducing dynamic spectrum access and the concept of cognitive radio as a way to opportunistically access unused licensed spectrum. It then discusses the key elements of cognitive radio systems, including spectrum sensing to detect unused spectrum and flexible waveforms. It focuses on the interweave approach where secondary users access spectral holes not in use by primary licensed users. Finally, it discusses some of the RF challenges in implementing cognitive radio, particularly wideband spectrum sensing to reliably detect primary user signals across frequency bands.
Soft Frequency Reuse (SFR) in LTE-A Heterogeneous Networks based upon Power R...IJECEIAES
As the traffic demand grows and the RF environment changes, the mobile network relies on techniques such as SFR in Heterogeneous Network (HetNet) to overcome capacity and link budget limitation to maintain user experience. Inter-Cell Interference (ICI) strongly affecting Signal-toInterference plus Noise Ratio (SINR) of active UEs, especially cell-edge users, which leads to a significant degradation in the total throughput. In this paper we evaluate the performance of SFR with HetNet system in order dealing with interferences. Simulation result shows that the power ratio control in SFR HetNet system doesn’t have much effect on total achieved capacity for overall cell.
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Atoll is a radio network design tool for LTE planning. It uses the CrossWave propagation model which takes into account morphology data like buildings and clutter classes to more accurately model radio wave propagation compared to standard propagation models like Hata. CrossWave predictions are tuned using results from calibration campaigns to improve accuracy. Atoll also allows for 3D coverage modeling and optimization of heterogeneous networks with different transmitter layers.
Owp112020 wcdma radio network capacity dimensioning issue1.22Gratien Niyitegeka
This document discusses WCDMA radio network capacity planning. It covers traffic modeling, interference analysis, and dimensioning methods. The key points are:
- WCDMA network capacity is restricted by factors like uplink interference, downlink power, and channel resources.
- Traffic is modeled using parameters like call attempts, call duration, and data rates. Models distinguish between circuit-switched and packet-switched services.
- Interference analysis is important because WCDMA uses the same frequency across cells, causing interference. Uplink interference depends on received power levels and adjacent cell interference.
- Dimensioning methods aim to estimate multi-service capacity while meeting requirements for noise rise and Eb/
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
This document discusses various topics related to ad-hoc wireless networks including wireless network concepts, radio propagation mechanisms, characteristics of wireless channels, cellular networks, ad hoc networks, medium access control, routing protocols, multicasting, and transport layer protocols for ad hoc networks. It provides classifications and examples of different types of network architectures, protocols, and issues/challenges in ad hoc wireless networks.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
Performance analysis of round trip time in narrowband rf networks for remote ...ijcsit
Networks for remote wireless communications using narrow band radios modem &Routers ((RipEX unit)
,as a means of transmission to communicate between the loins broadcast sites TV/FM.
RTT delay measurement is influenced by different parameters of Narrowband RF Networks.
We illustrate, in this paper, how RTT varies (in remote wireless practical communications application)
versus distance, modulation, baud rates, number of hops and throughput, between source and destination.
Also, we will see how the Forward Error Correction (FEC) affect, in the same time, the RTT according the
factors cited above.
This document discusses the origins and development of ad hoc networks. It describes how packet radio networks (PRNETs) in the 1970s, developed by DARPA, were the first generation of ad hoc networks. PRNETs used multi-hop routing between mobile radio terminals and packet radios to communicate without fixed infrastructure. The document outlines the key components and routing techniques of PRNETs, including point-to-point and broadcast routing. It also discusses how subsequent generations in the 1980s-1990s focused on improving performance, scalability, and developing commercial applications like Bluetooth.
A mobile adhoc network is a collection of wireless mobile nodes that communicate with one another without any fixed networking infrastructure. Since the nodes in this network are mobile, the power management and energy conservation become very critical in mobile adhoc network. The nodes in this network have limited battery power and limited computational power with a small amount of memory. Such nodes must conserve energy during routing to prolong their usefulness and increase network lifetime. This research paper proposes a scheme that takes into consideration the power awareness during route selection. This scheme observes power status of each and every node in the topology and further ensures the fast selection of routes with minimal efforts and faster recovery. The scheme is incorporated with the AODV protocol and the performance has been studied through simulation over NS-2.
Iaetsd survey on cognitive radio networks and itsIaetsd Iaetsd
This document summarizes a survey on cognitive radio networks and their routing mechanisms. It discusses how cognitive radios can dynamically identify unused portions of the spectrum and configure themselves to operate in those spaces to better utilize spectrum resources. It also describes some of the key challenges in designing routing metrics for cognitive radio networks, including how primary users occupying channels can break links in secondary networks, requiring secondary users to either wait, switch channels, or re-route data traffic. Finally, it outlines different cognitive radio network architectures like infrastructure, ad-hoc, and mesh networks and how routing schemes may be either stationary or dynamic depending on how often primary users interrupt secondary transmissions.
This document provides an outline for a lecture on data communication and computer networks. It covers networking fundamentals and each layer of the OSI model, including the physical layer, data link layer, network layer, transport layer, and application layer. For the physical layer, it discusses different transmission media such as twisted pair, coaxial cable, optical fiber, and wireless. It provides details on technologies like Ethernet, DSL, and fiber optic cable. The data link layer section covers terminology and the role of the link layer in transferring data between adjacent nodes.
Optical space division multiplexing uses multiple cores or modes in optical fibers to increase transmission capacity. A history of the technology was provided, noting the progression from single mode fibers to coherent detection and polarization multiplexing. Limits with single mode fibers were discussed, along with ways that multi-core and multi-mode fibers can overcome capacity constraints through spatial multiplexing across fiber cores and modes. Recent demonstrations showed record capacities of 57.6 Tb/s over multi-mode fiber and 24 Tb/s over hollow-core fiber. Integration challenges with spatial division multiplexing were also outlined.
INVESTIGATION OF UTRA FDD DATA AND CONTROL CHANNELS IN THE PRESENCE OF NOISE ...ijngnjournal
In this paper, the main aim is to design and simulate UTRA FDD control channel in the presence of noise and wireless channel by using FDD library/Matlab box set that can be used to design and implement some
systems. Moreover, a test and verification of the library is achieved with different channel models such as Additive White Gaussian Noise (AWGN), fading and moving channel models. FDD library are employed to design whole transmitter and receiver. Then we had tested AWGN channel and some other channel models.
Also we illustrated what are control channels DCCH and the other one as understanding the whole system. Moreover, the standards have been covered as well as implemented the whole transmit and receive chain plus the generation of DPCH, DPCCH channel. we had tested the performance against the AWGN noise.
Then we have studied different channel models that are defined in the standard, used the few of them like the fading channel and moving channel. We have tried to compare the performance in terms of Monte Carlo simulation by producing the BER curves. We have also change some channel parameters like phase, number of multipaths and we have tried to see the performance of the model in the presence of actual channel model.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
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Lecture 1 mobile and adhoc network- introductionChandra Meena
This document provides an overview of a course on mobile and ad hoc networks. It lists two textbooks that will be used and states that the goal is to cover fundamental design issues and solutions for network architecture and protocols. It also lists some related websites and outlines the objectives of chapters that will introduce wireless communication technologies, network standards, and multiple access techniques for ad hoc networks.
Analysis of a framework implementation of the transceiver performances for in...IJECEIAES
The greatest advantages of optical fibers are the possibility of extending data rate transmission and propagation distances. Being a multicarrier technique, the orthogonal frequency division multiplexing (OFDM) can be applicable in hybrid optical-wireless systems design owing to its best spectral efficiency for the interferences of radio frequency (RF) and minor multipath distortion. An optical OFDM-RoF-based wireless local area network (W-LAN) system has been studied and evaluated in this work. The outline for integrating an optical technology and wireless in a single system was provided with the existence of OFDM-RoF technology and the microstrip patch antenna; these were applied in the Optisystem communication tool. The design of the proposed OFDM-RoF system is aimed at supporting mm-wave services and multi-standard operations. The proposed system can operate on different RF bands using different modulation schemes like 4.16 and 64QAM that may be associated to OFDM and multidata rates up to 5 Gbps. The results demonstrate the robustness of the integrated optical wireless link in propagating OFDM-RoF-based WLAN signals across optical fibers.
Analysis of WiMAX Physical Layer Using Spatial Multiplexing Under Different F...CSCJournals
WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum and its industry. WiMAX is basically a wireless digital communication system which is also known as IEEE 802.16 standard intended for wireless \"metropolitan area networks\". WiMAX is based upon OFDM multiplexing technique. It was developed in order to provide high speed data rates to the users located in those areas also where broadband wireless coverage is not available. MIMO systems also play an important role in the field of wireless communication by allowing data to be transmitted and received over different antennas. WiMAX-MIMO systems are developed to improve the performance of WiMAX system. This paper analyzes WiMAX-MIMO system for different modulation schemes with different CC code rates under different fading channels (Rician and Nakagami channel). Spatial Multiplexing technique of MIMO system is used for the simulation purpose. Analysis has been done in the form of Signal-to Noise Ratio (SNR) vs Bit Error Rate (BER) plots.
This document summarizes an article from the International Journal of Computer Engineering and Technology that models and simulates the physical layer of the IEEE 802.22 wireless standard over a multipath fading channel. It describes the IEEE 802.22 standard and its use of OFDM and OFDMA to provide resilience against multipath propagation. It then models the physical layer in Simulink, including modulation, channel effects, demodulation and decoding. Finally, it presents simulation results for different modulation schemes and coding rates over multipath channels to analyze the performance of the physical layer under varying conditions.
This document discusses cognitive radio and its radio frequency (RF) challenges. It begins by introducing dynamic spectrum access and the concept of cognitive radio as a way to opportunistically access unused licensed spectrum. It then discusses the key elements of cognitive radio systems, including spectrum sensing to detect unused spectrum and flexible waveforms. It focuses on the interweave approach where secondary users access spectral holes not in use by primary licensed users. Finally, it discusses some of the RF challenges in implementing cognitive radio, particularly wideband spectrum sensing to reliably detect primary user signals across frequency bands.
Soft Frequency Reuse (SFR) in LTE-A Heterogeneous Networks based upon Power R...IJECEIAES
As the traffic demand grows and the RF environment changes, the mobile network relies on techniques such as SFR in Heterogeneous Network (HetNet) to overcome capacity and link budget limitation to maintain user experience. Inter-Cell Interference (ICI) strongly affecting Signal-toInterference plus Noise Ratio (SINR) of active UEs, especially cell-edge users, which leads to a significant degradation in the total throughput. In this paper we evaluate the performance of SFR with HetNet system in order dealing with interferences. Simulation result shows that the power ratio control in SFR HetNet system doesn’t have much effect on total achieved capacity for overall cell.
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Atoll is a radio network design tool for LTE planning. It uses the CrossWave propagation model which takes into account morphology data like buildings and clutter classes to more accurately model radio wave propagation compared to standard propagation models like Hata. CrossWave predictions are tuned using results from calibration campaigns to improve accuracy. Atoll also allows for 3D coverage modeling and optimization of heterogeneous networks with different transmitter layers.
Owp112020 wcdma radio network capacity dimensioning issue1.22Gratien Niyitegeka
This document discusses WCDMA radio network capacity planning. It covers traffic modeling, interference analysis, and dimensioning methods. The key points are:
- WCDMA network capacity is restricted by factors like uplink interference, downlink power, and channel resources.
- Traffic is modeled using parameters like call attempts, call duration, and data rates. Models distinguish between circuit-switched and packet-switched services.
- Interference analysis is important because WCDMA uses the same frequency across cells, causing interference. Uplink interference depends on received power levels and adjacent cell interference.
- Dimensioning methods aim to estimate multi-service capacity while meeting requirements for noise rise and Eb/
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
This document summarizes a presentation on radio network planning for 3G networks. It discusses key concepts in radio network planning like cell configuration, interference management, frequency reuse, and mobile network evolution. It then covers the specific steps in 3G radio network planning, including dimensioning, nominal planning, simulation, and optimization. The document provides examples of link budget calculations and using planning software to simulate network performance and verify the design meets requirements.
This document outlines the process of cellular network planning and optimization. It discusses collecting radio network data through drive testing, analyzing network performance, and proposing solutions to issues or meet key performance indicators. The objectives of optimization are finding and correcting problems, meeting contract quality criteria, and iterative improvement of overall network quality without degrading other areas. Methodologies proposed include problem analysis, drive testing, simulation, and exporting data to map software to identify solutions.
Simulation of IEEE 802.16e Physical LayerIOSR Journals
Abstract : Growth in technology has led to unprecedented demand for high speed Internet access. IEEE
802.16e (Mobile WiMAX) is a wireless communication standard with high data transfer rates and good
performance. It not only is efficient as compared to its counterpart technologies today (Wi-Fi and 3G), but also
lays the foundation for 4G mobile communication. In 4G wireless communication systems, bandwidth is a
precious resource, and service providers are continuously met with the challenge of accommodating more users
within a limited allocated bandwidth. To increase data rate of wireless medium with higher performance,
Mobile WiMAX uses Orthogonal Frequency Division Multiple Access (OFDMA). This paper describes the
simulation of the physical layer of IEEE 802.16e using Simulink in Matlab 7.0 (R2010a). The system
performance is evaluated considering the Signal to noise ratio (SNR) and Bit error rate (BER) parameters.
Keywords: 802.16e, OFDMA, Mobile WiMAX.
BER PERFORMANCE ANALYSIS FOR WIMAX PHY LAYER UNDER DIFFERENT CHANNEL CONDITIONSijistjournal
This paper gives an introduction on the IEEE 802.16 standard – WIMAX or Worldwide Interoperability for Microwave Access. The different parts give details on the architectural specifications of WiMAX networks and also on the working principle of WiMAX networks including its services provided. It also provides brief descriptions on its salient features of this technology and how it benefits the networking industry. A brief outline of the basic building blocks or equipment of WiMAX architecture is also provided. This paper also evaluates the simulation performance of IEEE 802.16 OFDM PHY layer. The Stanford University Interim (SUI) channel model under varying parameters is selected for the wireless channel in the simulation. The performance measurements and analysis was done in simulation developed in MATLAB.
Performance Analysis of Ultra Wideband Communication SystemEditor IJMTER
Ultra-Wideband (UWB) is a radio transmission scheme that uses extremely low power
pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages
over conventional continuous wave radio communications including potential support for high data
rates, robustness to multipath interference and fading. The paper covers Ultra Wide-Band
technology. General description, Challenges, various modulation schemes such as OOK, PAM,
PPM, and BPSK under specified Ultra Wide Band regimes: low Power spectral density, large
spreading ratio and a highly dispersive channel. The capacity and BER performance of a single user
ultra wideband communication is investigated for various modulation schemes and coded, uncoded
methods also simulated. Fading channel like Ricean and Rayleigh are compared. Channelized digital
receiver concept is discussed.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses radio technologies for mobile WiMAX networks, including OFDM, OFDMA, S-OFDMA, smart antenna systems, and frequency reuse strategies. It explains how these technologies improve spectral efficiency, coverage, throughput and quality of service. Specifically, it discusses how OFDM/OFDMA divide the frequency band into multiple subcarriers to increase robustness to interference, how smart antennas like beamforming increase signal strength and throughput, and how frequency reuse optimization is important to maximize spectrum usage while minimizing interference.
The document discusses WiMAX technology and its use of OFDM to address bottleneck problems in high-speed networks. It describes how WiMAX uses OFDM to efficiently allocate bandwidth and share it between connecting nodes based on their data request sizes, in order to prevent data loss. It also provides background on WiMAX architecture and management, and how it can support high-speed point-to-point and point-to-multipoint connections with optimized handover and security features.
An enhanced technique for PAPR reduction in mobile WIMAXIRJET Journal
This document discusses techniques to reduce peak-to-average power ratio (PAPR) in mobile WiMAX systems. Mobile WiMAX uses orthogonal frequency division multiple access (OFDMA) which is susceptible to high PAPR. The document analyzes using discrete sine transform (DST) as a pre-coding technique before OFDM modulation to reduce PAPR. It compares DST to other pre-coding techniques like Hadamard transform and raised cosine pre-coding. The technique works by linearly transforming the input signal block before modulation. This results in a signal with lower PAPR while avoiding non-linear distortion and improved efficiency for broadband wireless services.
Objective is to include the brief insight on 5G network architecture and standard progress, Accumulated it from different paper/journal, vendor’s white paper and different blog.
The document describes an Adaptive Source Provision System (ASPS) proposed to control traffic rates and ensure load balancing in WiMAX networks. The system considers relay stations and uses an adaptive resource management approach. When new users arrive, their data rates are computed and compared to relay station data rates. If a user's rate is lower, the base station's rate is also compared. Connections are switched from congested to non-congested stations to minimize network load and balance traffic. The system aims to improve traffic management and load balancing compared to existing approaches.
WiMax (Worldwide Interoperability for Microwave Access) is a wireless technology that provides broadband connections over long distances using radio signals rather than cables or wires. It uses the IEEE 802.16 standard to deliver high-speed internet access of up to 40 Mbps to fixed locations and 15 Mbps for mobile use within a few kilometers of the base station. WiMax can provide both fixed and mobile broadband access as an alternative to cable and DSL. It has a longer range than WiFi with connections of up to 30 miles using line-of-sight antennas.
Data Transmission Analysis using MW-5000 at 5.8 GHz Frequency IJECEIAES
This document summarizes an experiment on data transmission analysis using a MW-5000 module at 5.8 GHz frequency. The experiment found that the duration for data transmission depends on the length of the message and the baud rate setting. Testing various message lengths at a fixed baud rate of 4800 resulted in similar transmission durations. However, transmitting the same message at different baud rates showed that higher baud rates reduced the transmission duration. Specifically, a message sent at 4800 baud took 1.14 seconds while at 9600 baud it took 0.60 seconds. The document concludes that transmission duration is influenced by message length and baud rate.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
802.16e provides enhancements to 802.16-2004 to support subscriber stations moving at vehicular speeds. It specifies a system for combined fixed and mobile broadband wireless access using Scalable OFDMA technology. Mobile WiMAX supports seamless handoff between base stations, sleep and idle modes for power management, and smart antenna technologies like beamforming. It can offer full mobility and compete with 3G for IP traffic with peak data rates up to 63Mbps download and 28Mbps upload in a 10MHz channel.
Optical switching technologies allow for more efficient routing of data in fiber optic networks. Spectral switching routes different wavelength channels to different output ports, while spatial switching routes light to different fiber locations. Few optical switching technologies have been widely deployed, but some successes include wavelength selective switches used in reconfigurable optical add-drop multiplexer nodes. Optical switching can benefit terrestrial networks, undersea cable systems, and networks supporting 5G/6G by enabling increased data transmission and more flexible routing of traffic. Data center interconnect networks also rely on high-speed optical fiber links with optical switching to share resources between data centers.
This document summarizes research on improving the performance of WiMAX systems using FEC zigzag coding and MIMO techniques. It first provides background on WiMAX and discusses how OFDM, MIMO, and various channel coding schemes like zigzag codes work. It then evaluates the bit-error rate performance of WiMAX systems using zigzag-coded modulation with different code rates and lengths. The results show zigzag coding presents stronger error correction than Reed-Solomon with Convolutional coding. Encoding and decoding of zigzag codes is explained, along with how concatenated zigzag codes provide even stronger error correction through interleaving and turbo processing.
RESOURCE ALLOCATION ALGORITHMS FOR QOS OPTIMIZATION IN MOBILE WIMAX NETWORKSijwmn
This document summarizes research on resource allocation algorithms for quality of service (QoS) optimization in mobile WiMAX networks. It discusses the Swapping Min-Max (SWIM) algorithm and Cooperative Multicast Scheduling (CMS) technique. SWIM performs scheduling for real-time polling service to meet QoS criteria like optimal throughput, latency guarantees, minimal delay jitter and number of bursts. CMS enhances throughput for multicast video by dividing transmission bursts into two phases where selected stations retransmit to nearby members for cooperation. Simulation results show SWIM has less bursts, zero jitter and optimal throughput, while CMS further improves throughput for each multicast group member.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
WRAP is a medium access control (MAC) protocol for wavelength-routed passive optical networks (WR-PONs) that does not require a separate control channel, carrier sensing, or centralized scheduling. Each node has a single tunable transmitter and fixed receiver. Access is regulated through wavelength allocations made by destination nodes in response to requests. Simulations test three allocation algorithms and show the Preferential/Random algorithm provides better performance than alternatives. WRAP performance is also compared to two other applicable protocols, showing WRAP enables high utilization over a wide range of traffic conditions while guaranteeing minimum bandwidth between nodes.
Worldwide Interoperability for Microwave Access (WiMAX) is a new communication technology that
conduits the fissure between fixed and mobile access and offers the same Quality of Service (QoS) to both
types of users. Generally, WiMAX is more vulnerable to the inside and outside attacks due to the absence of
any clear line of defense. The Mobile Subscriber Stations (MSSs) selected to transfer the packets to the
Base Station (BS) are vulnerable to Denial of Service (DoS) attacks like flooding. Recent research has
discovered that DoS attacks can easily be launched by injecting malevolent management frames into the
WiMAX network based on the Privacy and Key Management- ReSPonse (PKM-RSP) and Automatic Repeat
ReQuest (ARQ)-Reset messages. In this paper, an algorithm is proposed to mitigate the flooding attacks
and enhance the security level in the network.
SURVEYING BEST SUITABLE SCHEDULING ALGORITHM FOR WIMAX- WI-FI INTEGRATED HETE...cscpconf
To provide uninterrupted service to all subscribers in a wireless network, we need to incorporate a low cost, flexible Heterogeneous network which will be able to link with any kind
of network for efficient spectrum utilization, hence improved system capacity. In this connection, Wi-Fi/ Wi MAX integrated network seems to be an ideal solution as it is able to
provide easy deployment, high speed data rate and wide range coverage with high throughput, low end to end delay, flat and low jitter. Wi-Fi/ WiMAX integrated network provides Quality of
Service (QoS) that can support all kinds of real-time application in wireless networks that includes priority scheduling and queuing for bandwidth allocation that is based on traffic
scheduling algorithms within wireless networks. In this paper, we have designed a Wi-Fi/ WiMAX integrated network and analyze the performance of different scheduling algorithms for
that integrated network and highlight our findings on the scheduling algorithm which will give the best performance for a heterogeneous network.
Similar to Radio network dimensioning and planning for wimax networks (20)
This document provides guidelines for evaluating radio interface technologies proposed for IMT-Advanced systems. It describes the objectives of IMT-Advanced including supporting a wide range of services across mobile and fixed networks. The document outlines the evaluation methodology, including using system and link level simulations to assess characteristics like spectral efficiency and latency, as well as inspections of submissions. Evaluation groups will use these guidelines to evaluate proposals against requirements for technologies to be considered IMT-Advanced.
This document outlines the requirements, evaluation criteria, and submission templates for candidate radio interface technologies and sets of technologies to be considered for IMT-Advanced standards. It describes the services, spectrum, and technical performance requirements, and provides evaluation guidelines and templates that proponents must use to submit technology proposals. A complete submission includes completed templates describing the technology, an initial self-evaluation of how the technology meets the requirements, and an indication of which requirements and evaluation criteria versions apply. Technologies will be accepted if they meet requirements in at least 3 of 4 test environments.
Comparison of the link budget with experimental performance of a wi max systemPfedya
The document compares the link budget calculations of a WiMAX system to experimental performance measurements in a suburban environment. It describes the configuration of the WiMAX system operating at 3.5 GHz, including the base station parameters, receiver sensitivity, and scenario. It then presents the methodology, which involves measuring path loss to develop a path loss model, using that model to calculate link budgets and expected ranges for different modulations, and validating these by taking actual performance measurements with WiMAX modems. The results of the path loss measurements and link budget calculations are then compared to the experimental performance measurements to validate the link budget approach.
This document outlines minimum requirements for IMT-Advanced radio interface technologies. It discusses requirements in several areas:
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- Peak spectral efficiency should be at least 15 bit/s/Hz for downlink and 6.75 bit/s/Hz for uplink.
- Scalable bandwidth up to 40 MHz is required, with encouragement for support of up to 100 MHz.
- Cell edge user spectral efficiency is defined but specific values are not given.
This thesis investigates closed loop power control schemes for the LTE uplink physical uplink shared channel (PUSCH). Different values of the path loss compensation factor between 0.7-1.0 are evaluated to determine the optimal value. Both ideal and realistic cases accounting for delay, error, and power headroom reporting are simulated. Using a simple upload traffic model, closed loop power control with a fractional path loss compensation factor of 0.8 improved mean bit rate by 63-68% compared to full compensation in both ideal and realistic scenarios. Power headroom reporting triggered by path loss changes provided better performance than periodic triggering.
Admission control for multihop wireless backhaul networks with qo sPfedya
This document proposes several schemes for admission control of connections with quality of service (QoS) requirements over a multihop wireless backhaul network. It first constructs tree topologies connecting wireless backhaul nodes to a wired gateway. It then admits either the best subset of connections while respecting their rate and delay requirements, or admits all connections with appropriate degradation of their QoS requirements. The key contributions are addressing both rate and delay requirements for connections, which has not been done before for wireless backhauls, and providing algorithms for admission control that deterministically guarantee delays.
A study of throughput for iu cs and iu-ps interface in umts core networkPfedya
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Radio network dimensioning and planning for wimax networks
1. 435FUJITSU Sci. Tech. J., 43,4,p.435-450(October 2007)
Radio Network Dimensioning and Planning
for WiMAX Networks
V Bharathi Upase V Mythri Hunukumbure V Sunil Vadgama
(Manuscript received May 7, 2007)
This paper is a high‑level introduction to the complexities involved in dimension‑
ing and planning of Worldwide interoperability for Microwave Access (WiMAX) net‑
works, with specific emphasis on key WiMAX features and planning techniques that
need to be considered for optimal network coverage, capacity, and service require‑
ments. We introduce Fujitsu’s in‑house developed WiMAX Network Dimensioning
Tool, which contains innovative algorithms for interference margin calculation and
capacity analysis. In theory, WiMAX technology allows a huge number of optional
and mandatory features and promises larger coverage and higher data throughput
in comparison to the existing 2G/3G technologies. This paper explains briefly the
challenges involved in network planning due to such features, with a further descrip‑
tion on the step‑by‑step approach to network dimensioning and planning.
1. Introduction
Worldwide interoperability for Microwave
Access (WiMAX) has become synonymous with
the IEEE 802.16 air interface standard.1)
WiMAX
is a broadband wireless access (BWA) technol‑
ogy capable of delivering voice, video, and data
over the microwave RF spectrum to stationary or
moving users. There are two flavours of WiMAX:
Fixed WiMAX and Mobile WiMAX.
IEEE 802.16‑2004 or IEEE 802.16d is a
fixed wireless access technology, optimised for
fixed and nomadic applications in line‑of‑sight
(LOS) and non‑LOS (NLOS) environments. It is
designed to serve as a wireless digital scriber line
(DSL) replacement technology to provide basic
voice and broadband access. This standard is also
a viable solution for wireless backhaul for WiFi
access points or potentially for cellular networks.
IEEE 802.16e is a mobile WiMAX standard
targeted primarily for portable and mobile appli‑
cations in NLOS environments. Mobile WiMAX
systems can also provide fixed and nomadic
access. Mobile WiMAX incorporates features
such as soft/optimised handoff, fractional
frequency reuse, features for better NLOS perfor‑
mance, and indoor penetration.
The WiMAX Forum is an organization
that promotes WiMAX interoperability between
vendors and develops WiMAX system profiles.
The system profiles refer to a set of parameters
on which a WiMAX network will operate, includ‑
ing the frequency band, channel bandwidth, and
duplexing scheme. The profiles do not cover all
possible operational parameters, but instead
prioritise those with wide support from the indus‑
try and those in harmony with various frequency
regulations across regions and countries.
The WiMAX standard supports a wide range
of features, including multiple input multiple
output (MIMO) and adaptive antenna system
(AAS) antenna types, operating frequencies in
the licensed and unlicensed bands, a wide range
of bandwidths, multiple operating modes {time
division duplex (TDD) and frequency division
2. 436 FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
duplex (FDD)}, and fractional frequency reuse.
The support for these advanced features help in
achieving high data throughputs of the order of
70 Mb/s and coverage distances of around 50 km,
depending on the spectrum available.
The challenges in WiMAX network dimen‑
sioning and planning compared to conventional
2G/3G cellular network planning are to evalu‑
ate the implication of each of the optional and
mandatory features and then consider the best
combination of the supported features to suite
the operator’s business model. Section 2 of
this paper gives a high‑level description of the
features and application of WiMAX. Section 3
describes an approach for addressing network
dimensioning and planning for WiMAX network
and gives details of the Fujitsu’s in‑house dimen‑
sioning tool DoORs. Lastly, Section 4 presents
our conclusions.
2. WiMAX technology and
applications
2.1 WiMAX technology
2.1.1 OFDM and OFDMA
The Fixed WiMAX technology speci‑
fies a radio interface that uses orthogonal
frequency‑division multiplexing (OFDM), and the
Mobile WiMAX technology uses a radio interface
based on OFDMA.
In an OFDM system, a very‑high‑rate data
stream is divided into multiple parallel low‑rate
data streams. Each smaller data stream is then
mapped to an individual data sub‑carrier and
modulated using some form of phase shift keying
(PSK) or quadrature amplitude modulation
(QAM). OFDM systems efficiently overcome
the interference and frequency‑selective fading
caused by multipath propagation. The effect
of inter symbol interference (ISI) is suppressed
because the parallel OFDM sub‑carriers have a
longer symbol period than the carrier in a single
carrier system. OFDM delivers better perfor‑
mance in NLOS urban environments due to its
better resistance to multipath interference.
OFDMA is a variation of OFDM, which
provides multiple access to different users by
allocating different sub‑bands from the total
bandwidth. It employs multiple closely spaced
sub‑carriers divided into groups of sub‑carriers
called sub‑channels. The sub‑carriers that form
a sub‑channel need not be adjacent. In the
downlink (DL), a sub‑channel may be intend‑
ed for different receivers. In the uplink (UL),
a transmitter may be assigned one or more
sub‑channels. Figure 1 shows the sub‑carrier
arrangement in OFDM and OFDMA systems.
2.1.2 Sub-channelisation in WiMAX
Sub‑channelisation defines sub‑channels
that can be allocated to subscriber stations (SSs)
depending on their channel conditions and data
requirements. In OFDM, only one SS transmits
in a time slot.
Figure 1
OFDM and OFDMA.
3. 437FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
In OFDMA, several SSs can transmit in
the same time slot over several sub‑channels.
Figure 2 shows the allocation pattern of the
sub‑carriers to SSs in an OFDM and OFDMA
system. By using sub‑channelisation, within the
same time slot, a Mobile WiMAX base station (BS)
can allocate more transmit power to user devices
(subscriber stations) with a lower signal‑to‑noise
ratio (SNR) and less power to user devices with
a higher SNR. Sub‑channelisation also enables
the BS to allocate higher power to sub‑channels
assigned to indoor SSs, resulting in better
in‑building coverage. Sub‑channelisation in the
uplink can save a user device transmit power
because it can concentrate power to only selected
sub‑channels allocated to it. This power‑saving
feature is particularly useful for battery‑powered
user devices, especially in Mobile WiMAX.
With OFDMA, there are two types of
sub‑carrier permutation for sub‑channelisation:
diversity and contiguous. The diversity permu‑
tation draws sub‑carriers pseudo‑randomly
to form a sub‑channel. It provides frequency
diversity and inter‑cell interference averaging.
The diversity permutations include DL fully
used sub‑carrier (DL FUSC), DL partially used
sub‑carrier (DL PUSC), UL PUSC, and additional
optional permutations. The contiguous permu‑
tation groups a block of contiguous sub‑carriers
to form a sub‑channel. The contiguous permuta‑
tions include DL adjacent subcarrier allocation
scheme (DL AMC) and UL AMC, which have the
same structure as each other. AMC permuta‑
tion enables multi‑user diversity by choosing the
sub‑channel with the best frequency response.
In general, diversity sub‑carrier permutations
perform well in mobile applications while contig‑
uous sub‑carrier permutations are well suited
for fixed, portable, or low mobility environments.
These options enable the network designer to
trade‑off mobility for throughput.
2.1.3 Modulation and coding scheme in
WiMAX
WiMAX utilises an adaptive modulation
and coding scheme together with BPSK, QPSK,
and QAM modulation schemes.3)
The adaptive
modulation allows the highest order modulation
to be chosen according to the channel conditions.
As we increase our range, we step down to lower
order modulations, but as we reduce our range,
we can use higher order modulations such as
QAM for increased throughput. The standard
also supports repetition coding of rate 1, 2, 4, or 6.
This can, in theory, be used in combination with
any modulation and coding scheme. Repetition
coding can be used to lower the required receiv‑
er sensitivity and hence increase the cell range.
However, the penalty will be a reduction in capac‑
ity in line with the rate selected because every
transmission will be repeated multiple times.
The network planner needs to consider the use
of repetition coding in line with the deployment
requirements (for coverage or capacity).
Figure 2
Uplink subchannelisation in WiMAX.
4. 438 FUJITSU Sci. Tech. J., 43,4,(October 2007)
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2.1.4 Spectrum
Unlike 2G/3G technologies, where the
operating frequency is fairly defined, the
WiMAX air interface is designed to operate
over a range of frequencies, both in the licensed
band (2.5 to 2.69 GHz and 3.4 to 3.6 GHz) and
in the unlicensed band (5.725 to 5.850 GHz).
The WiMAX Forum has identified several
frequency bands for the initial 802.16 products.
IEEE 802.16 supports a variable channel
bandwidth. The channel bandwidth can be an
integer multiple of 1.25 MHz, 1.5 MHz, and
1.75 MHz with a maximum of 20 MHz. WiMAX
supports two modes of operation: FDD and
TDD. In TDD, the uplink and downlink can be
asymmetrical, which means that the percentage
of downlink subframe to uplink subframe of one
frame can be decided according to the network’s
uplink/downlink capacity requirement.
2.1.5 Fractional frequency reuse
The operating spectrum is the scarc‑
est resource in network deployment. Mobile
WiMAX, which will be deployed like 2G and 3G
cellular networks, supports fractional frequency
reuse. It works by allowing users at a cell centre
to operate on all available sub‑channels, while
users at a cell edge are only allowed to operate
on a fraction of all available sub‑channels. A
fraction of the total available sub‑channels is
allocated in such a way that adjacent cell edges
will operate on different sets of sub‑channels.
Fractional frequency reuse takes advantage of
the fact that a Mobile WiMAX user transmits on
sub‑channels (because in OFDMA, a channel is
divided into sub‑channel segmentation) and does
not occupy an entire channel such as in 3G. In
Figure 3, f1, f2, and f3 represent different sets
of sub‑channels in the same frequency channel.
With the multicell layout shown below for Omni
sites, full load frequency reuse is maintained
for the users close to the centre of the cell and
fractional frequency reuse is implemented for cell
edge users. Fractional frequency reuse maximiz‑
es spectral efficiency for users at the cell centre
and improves signal strength and throughput for
users at the cell edge.
2.2 WiMAX application
1) Fixed WiMAX is considered a cost‑effective
backhauling option for cellular operators
where the cost of backhauling represents a
Figure 3
Fractional frequency reuse.
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significant portion of their recurring costs.
WiMAX can provide point‑to‑point links
of up to 50 km, with data rates capable of
supporting multiple E1/T1s. Fixed opera‑
tors can offer nomadic and portable Internet
usage as an addition to their fixed access
offering to complement their DSL and WiFi
bundle. In developing countries, Fixed
WiMAX can be the most cost‑effective
solution for delivering broadband and VoIP
to residential customers where wired infra‑
structure is lacking.
2) Mobile WiMAX is designed to complement
existing 2G/3G access technologies with
an “Always Best Connected” experience
with voice and data connections. Portable
Internet allows session continuity through‑
out the network. WiMAX can then be
positioned as a complementary solution by
offering higher bandwidth when required,
particularly in dense urban areas. By
integrating WiMAX into their networks,
mobile operators can boost their service
with high bandwidth. Figure 4 shows that
a WiMAX network can be deployed to obtain
service while at home, on the move, in the
office, or in public places.
3. Radio network dimensioning
and planning for WiMAX
3.1 Overview
The objective of the radio network dimen‑
sioning and planning activity is to estimate
the number of sites required to provide cover‑
age and capacity for the targeted service areas
and subscriber forecast. This section describes
a methodology that is suitable for dimension‑
ing and planning of a WiMAX network based on
utilisation of the OFDM and OFDMA PHY of
IEEE 802.16.
Designing, deploying, and managing any
cellular system requires clear objectives to be
identified from the outset. These include defini‑
tion of the service area; the projected number
Figure 4
Mobile WiMAX deployment.
6. 440 FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
of customers; their distribution, spectrum avail‑
ability, growth rate, and system usage; and the
network interconnect agreement, numbering,
and routing policy for inter‑network access and
roaming.
The Quality of Service (QoS) of a WiMAX
network is a critical aspect of radio planning,
which determines the level of service that users
will experience when they access the network for
voice or data communication. This is achieved
by careful planning that helps to successfully
implement different quality and range enhanc‑
ing features supported in WiMAX. The carefully
formulated design criteria such as link‑budgets,
targeted service classes, coverage threshold levels
for different service types, an appropriate propa‑
gation model for the available spectrum and an
appropriate channel allocation strategy will help
in satisfying the technical and business goals.
Figure 5 shows the natural flow of activities
performed in network planning, starting from
gathering the marketing and design require‑
ment input and satisfying the business model to
providing a nominal cell plan using a network
planning tool. The next sections describes the
process for WiMAX network dimensioning and
planning and describes a WiMAX network dimen‑
sioning tool called DoORs developed at Fujitsu
Laboratories of Europe Ltd.
3.2 Cell dimensioning for WiMAX
Radio network dimensioning aims to
estimate the number of required base stations
in accordance with the theoretical approach,
which is the first step of radio network planning.
Network dimensioning process is based on the
Marketing inputs Demand forecast
Link budget, traffic model
DoORs
Radio network infrastructure quantities
Planning tool
Digital Terrain &
Clutter Map
Nominal cell plan
Business modelling
Radio configuration and
site count
Design parameters
Site required for
coverage
Site required for
capacity
License/regulatory
requirements
Figure 5
Network dimensioning and planning processes.
7. 441FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
assumption of uniform distribution of subscribers,
homogenous morphology and ideal site distribu‑
tion. The outputs of the dimensioning phase are
further used in configuring the network planning
tool. Digital map containing height and clutter
information at pixel level is used in the network
planning tool to design a nominal cell plan. The
results of network dimensioning activity essen‑
tially assist in the business planning and budget
planning process for understanding the likely
return on investment, which helps in design‑
ing the tariff strategy as well. The output of this
activity also provides input to the core network
team to plan the network topology and to decide
the number of backhaul links required for the
initial launch of the network.
Since the result of the network dimensioning
will significantly impact the network reliability
and initial implementation cost, each parameter
that is used in the dimensioning process must be
thoroughly considered. Due to the large number
of optional and mandatory features supported
by IEEE 802.16, it may not be possible to obtain
a single set of site count values for the scenario
to be dimensioned. The difference in site count
for the same scenario may be due to assumptions
about the frequency reuse scheme, handover
mode, and multiple antenna diversity gains being
considered and the SNR values (used in calcu‑
lating the receiver sensitivity of the equipment)
assumed for the deployment model.
The main inputs required for network
dimensioning are:
• BS and SS equipment‑specific parameters:
Equipment‑specific parameters include
the BS and SS transmit powers, antenna
gains, feeder losses, BS/SS heights, support‑
ed OFDM/OFDMA equipment‑related
parameter configurations, and other
equipment‑related features. If the equip‑
ment datasheets are available, then
parameter values are straightforward. In
situations where dimensioning is performed
for technology evaluation, the generic or
vendor independent parameter values and
features are used. In the latter case, most
of the parameter values are derived from
IEEE 802.16 standards and the technical
understanding and simulation results.
• Marketing‑specific parameters: The
marketing input includes the areas to be
serviced, equipment penetration in the
market for one year (snapshot analysis) or
a forecast for over 5 to 10 years, services
to be offered to the subscribers, coverage
objective for different clutter categories
(e.g., dense urban, suburban or rural), and
the over-subscription ratio.
• License regulation and propagation model:
Depending on the spectrum allocated to the
area to be planned, an appropriate propaga‑
tion model that suits the allocated spectrum
and the propagation environment must be
selected or modelled. Statistical/empirical
propagation models that implicitly take
into account all environmental influences
regardless of whether they can be separately
recognized are considered for dimensioning.
The accuracy of existing models depends on
the similarities between the environment to
be analysed and the environment to which
the standard models relate. Generally, most
empirical models have model correction
factors that allow the model to be tailored to
particular markets using direct knowledge of
the area’s attenuation factors. Customised
continuous wave (CW) propagation measure‑
ments for a specific area/frequency help
to tailor an accurate propagation model
suitable for that deployment. Widely accept‑
ed propagation models for WiMAX are the
IEEE 802.16 recommended SUI model,
the Modified COST231 Hata model, and
the ECC 33 model. All these models have
correction factors to accommodate the range
of frequencies supported by WiMAX.
Once the design requirements are defined,
the next step is to perform coverage analysis
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and capacity analysis to identify the required
number of infrastructure quantities satisfying
the business model.
3.2.1 Coverage analysis
Coverage analysis fundamentally remains
the most critical step in the design of any
network. Appropriate selection of the propaga‑
tion model and the fade margins for the area
coverage probability are key factors to eliminate
cell design that leads to interference or quali‑
ty degradation in the network. IEEE 802.16
supports some coverage enhancing features such
as UL sub‑channelisation (boosts the uplink
power budget by 8 to 10 dB or more depend‑
ing on the amount of sub‑channelisation used)
and repetition coding (factor of 1, 2, 4, or 6). In
OFDM, the UL sub‑channelisation factor is fixed
to 1, 2, 4, or 6, while it is flexible in OFDMA.
Depending on the deployment model, an appro‑
priate sub‑carrier allocation scheme needs to be
considered. For example, for a nomadic to station‑
ary type of deployment with a BW of 10 MHz,
AMC with a FFT size of 1024 and a guard period
of 1/8 will be most appropriate due to the advan‑
tages the adjacent sub‑carrier allocation schemes
have for nomadic to stationary deployment.
Transmit and receive diversity gains obtained
by using advanced antenna techniques help to
enhance the range and rate. The mobile WiMAX
supports three types of handover modes like hard
handover, FBSS handover and Macro diversity
handover. The macro diversity handover (MDHO)
provides extra gain that helps in range enhance‑
ment. The receiver sensitivity of the equipment
for all the modulation schemes supported by
WiMAX is either obtained from the equipment’s
datasheet or is calculated from the SNR values
of the modulation schemes for a specific antenna
type under specific channel conditions (obtained
from link‑level simulations), along with assumed
equipment noise figures and implementation
losses. The link budget specifies the maximum
path loss between the SS and BS. This gives a
limit to the cell range for different configura‑
tions in order to maintain a balanced uplink
and downlink. The balance must be calculated
accurately for full duplex connection to be
maintained at all times. If the SS can receive
from but not transmit to the BS, the connection
will terminate after a period defined by the
Radio Link Timeout value. The link budget is
a pre‑requisite to any cell plan and is one of the
vital components of network quality. An example
link budget for IEEE 802.16e systems is shown
in Table 1. Table 2 shows the parameters used
for capacity calculation. The link budget serves
to look at the system as a whole and attempts
to represent the system as an average (in
terms of the derived cell ranges), providing the
engineering guidelines to begin cell layout and
design.
3.2.2 Capacity analysis
Capacity analysis involves accessing the
demanded and available traffic for different
service requirements considering the activity
factor, overbooking/contention ratio, and TDD
ratio for the uplink and downlink. IEEE 802.16
supports an adaptive modulation and coding
scheme, which leads to a ring structure for capac‑
ity calculation. The cell throughput calculation
is based on the area of each modulation scheme.
The theoretical throughput calculation per
modulation scheme is done using the following
formula:.
(1)
where M is the modulation gain, which is 2 for
QPSK, 4 for 16‑QAM, and 6 for 64‑QAM; C is the
coding rate (1/2, 3/4, etc.); Rr is a repetition rate of
1, 2, 4 or 6; Rb is the bit rate; and Rs is the symbol
rate.
The bit rate Rb as derived from Equation 1
is the PHY throughput rate, which accounts only
for the pilot overhead. It does not account for the
signalling overhead, which includes the pream‑
ble, FCH, UL/DL MAP and MAC overhead. The
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Table 1
Mobile WiMAX-Link Budget-1/2QPSK Cell edge.
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B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
maximum throughput will need to be adjusted
based on the amount of signalling overhead. The
signalling overhead depends on the number of
active connections and the service type used by
these connections, which makes it a dynamic
parameter. Analysis and studies indicate that
the signalling overhead may vary from 4 to 10%
of the PHY throughput.
Initially the cell radius is determined by
the coverage requirement. If the capacity can be
handled by that radius, then the final number
of cells required for the network is calculated;
however, if the number of sites required for
capacity exceeds the number required for cover‑
age, an iterative process is performed to check if
the cell radius can be shrunk and the required
capacity fulfilled.
3.3 A tool for dimensioning of overall radio
networks for WiMAX
Dimensioning of Overall Radio networks
(DoORs) is a software tool developed by Fujitsu
Laboratories of Europe to support dimension‑
ing of WiMAX and 3G UMTS networks. The
DoORs tool contains a graphical user interface
(GUI) driven front end developed with Visual
Basic software and a spreadsheet based data
repository. The tool provides the capabilities
to simultaneously dimension multiple rollout
phases for different environments such as dense
urban, urban, suburban, and rural topologies.
The WiMAX component of DoORs is compli‑
ant with both IEEE 802.16d for fixed broadband
standards and IEEE 802.16e for mobile broad‑
band standards, supporting a comprehensive set
of optional and mandatory features available in
the standard. The DoORs tool forms a reposi‑
tory of parameter values derived from in‑house
radio link and radio system simulators and from
vendor datasheets. Figure 6 shows the different
inputs that are used in the analytical dimension‑
ing process. The radio link simulator provides
the SNR values for the different channel condi‑
tions and antenna types that are required to
calculate the receiver sensitivity of the BS and
SS equipment. The radio system simulator helps
to cross‑validate the different margins and values
that are derived from analytical calculations.
The tool is enriched with a number of analyti‑
cal models, for example, an intercell interference
margin calculation model and a system through‑
put calculation model, which along with other
parameters are designed to be part of the overall
coverage and capacity analysis to provide the
total site count required for a specific deployment
model.
The DoORs tool can also be used for technol‑
ogy evaluation to analyse the impact of varying
the parameter values on the total site count. For
example, it can be used to evaluate how the total
site count varies when a repetition coding of 2
or 4 is used or evaluate the impact on the total
site count when uplink sub‑channelisation is
enabled or disabled. The tool provides a quick
and accurate site count and a firm ground for
the next step of network planning. A high‑level
description of the features modelled in these tools
is provided in the sub‑sections below.
3.3.1 Design parameters and data
management
The WiMAX standard demonstrates a lot of
flexibility by encompassing variable parameters.
The DoORs tool accommodates these variable
parameters and allows the user to make suitable
selections. Different modes (FDD or TDD) with
bandwidths from 1.25 to 20 MHz and different
site configurations (Omni or 3 or 6 sectors) with
up to 6 carriers per sector can be configured for
Table 2
Additional parameters for capacity calculation.
11. 445FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
any simulation. Thus DoORs enable rapid evalu‑
ation of a many “what‑if” scenarios and serve as
an advantage over manual dimensioning.
Multiple vendor equipment specifications
can be stored and reused. The tool has provi‑
sion for efficient data management where each
set of simulations can be saved as a project file
and retrieved. The output results including
the number of BS sites, the total and average
throughput, and the link budget used for analy‑
sis are available in graphical and spreadsheet
formats.
The propagation models are used for deter‑
mining cell radius from the maximum allowable
path loss (MAPL) value derived in the link
budget calculations. As WiMAX networks are
deployed worldwide, it is expected that different
regions will employ different carrier frequencies.
For example, WiMAX networks in the US and the
Far East will occupy the 2.4 GHz/2.5 GHz band,
while in Europe they will occupy the 3.5 GHz
band. In the global context, the optimum propa‑
gation model will differ from region to region due
to variations in clutter characteristics and the
variations in spectrum utilisation. The DoORs
tool supports three popular empirical propaga‑
tion models, COST231‑HATA, SUI, and ECC 33.
According to the spectrum and terrain in consid‑
eration an appropriate propagation model can be
used.
3.3.2 Interference margin calculator
An estimation of the interference margins
is an important feature because any fully loaded
wireless network tends to be interference limited.
A brief description of the model that is considered
appropriate for analytically modelling interfer‑
ence in a WiMAX network is given below.
Mobile WiMAX employs OFDMA as the
multi‑access technology, and the main source of
interference comes from collisions amongst same
sub‑carrier and time‑slot selections in neighbour‑
ing cells/sectors. The first task in interference
calculation is thus the determination of collision
rates against the cell loading. The sub‑carrier
mapping from logical to physical channels varies
Figure 6
Inputs to the dimensioning tool-DoORs W.
12. 446 FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
with the sub‑carrier allocation scheme. Also, the
method of data burst allocation in the uplink and
downlink sub‑frames impacts the collision rate.
An example of data burst allocations for the 5 ms
PUSC frame is shown in Figure 7.
Due to the nature of data burst allocation
in the PUSC downlink, all the sub‑carriers can
be occupied before the sub‑frame is fully loaded.
Consequently in low traffic conditions sub‑frames
may be only partially occupied in time axis. Thus
the collision rates at the beginning of sub‑frames
can quickly reach 100% well before the downlink
reaches full load condition and the collision rates
drop down in parts of the sub‑frame, yielding a
collision probability (Pcoll) function with several
maxima and minima across the sub‑frame length.
In contrast, in the PUSC uplink, the data bursts
occupy the minimum number of sub‑carriers and
the entire sub‑frame length. Thus the collisions
would increase linearly with the loading for the
uplink. The AMC sub‑carrier allocations for both
the uplink and downlink are similar to the PUSC
uplink sub-carrier allocations scheme, where the
collision rates are linearly proportional to cell
loading.
The interference power I is estimated by
assuming uniform hexagonal cell geometry and
worst-case interference scenario. Three types
of site configurations, omnidirectional, 3‑sector,
and 6‑sector are considered as well as frequency
reuse of 1 and 3. For frequency reuse of 1, use of
fractional frequency reuse is assumed. The inter‑
ference power I is a function of transmit effective
isotropic radiated power (EIRP), the collision
probability, the path loss suffered by each inter‑
fering path, and for directional antennas the
angle of arrival/departure of interfering signals.
Equation (2) below gives the interference power
from the above contributions.
1
= 1
(2)
PTGT represents the EIRP at the transmit‑
Figure 7
Data burst allocations for PUSC downlink and uplink.2)
13. 447FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
ter, Pcoll the collision probability, and PLi the path
loss for the ith
interfering user/BS. The path
loss is calculated using the assigned path loss
model and the cell radii from the link budget.
The Cosg
qi term represents the antenna directiv‑
ity for 3‑sector and 6‑sector deployments. For
3‑sector deployments, g = 1 is assumed, and for
6‑sector deployments (where the roll‑off needs to
be sharper), g = 3 is assumed.
The actual interference margin Im is calcu‑
lated as a “noise rise” as shown by Equation (3)
below, where the noise power N is already known
through link budget calculations.
(3)
3.3.3 Capacity calculator
The system capacity calculator included in
DoORs tool estimates the cell capacities based
on the summation of the throughputs from each
of the 7 adaptive modulation schemes depend‑
ing on the percentage of the total area covered by
each of the schemes. Higher order modulation
schemes require a corresponding higher receive
SNR. The ring boundaries are determined
from MAPL for each of the modulation and
coding rate. The outermost ring corresponds to
the minimum modulation and coding rate (for
example, ½ QPSK modulations in IEEE 802.16e)
and yielding the lowest data rate. The inner‑
most ring corresponds to highest modulation
and coding rate (for example ¾ rate 64 QAM in
IEEE 802.16e) and thus yielding the highest data
rate.
The capacity calculator also considers the
impact of MIMO antenna structures. Both
MIMO‑A and MIMO‑B schemes as defined in
the IEEE 802.16e standard are supported. The
MIMO schemes can enhance coverage or capacity
or a combination of both.
3.4 Cell design and optimisation for
WiMAX
3.4.1 Cell design for WiMAX
Nominal cell planning follows sequentially
after cell dimensioning. Cell design is performed
with the help of a network planning tool using
digital elevation and demographic maps. The
elevation maps provide the height of the area
at pixel level, where each pixel is of the resolu‑
tion of the mapping data (5 m, 20 m, or 50 m).
The demographic map provides the clutter
class of the area at the pixel level. The total
demanded traffic can be distributed uniformly
or non‑uniformly across the target area based on
the clutter category. For example, the demand‑
ed traffic can be distributed over target area
with higher traffic weighting given to clutter
classes such as dense urban and urban, whilst
less traffic weighting given to classes such as
rural and forest, and probably zero weighting
to classes such as marsh and water. Snapshot
traffic estimation and traffic forecast for consecu‑
tive years need to be considered for a successful
network rollout.
The dimensioning process simplifies most
of the BS and SS equipment configuration stage
in the planning tool and moreover provides the
initial cell radii to be used as the starting point
for deciding site positions on the map. The
site positioning not only depends on the inter‑
site distance obtained from dimensioning but
also on other factors like the local regulation
for site locations, availability of land for site
locations, electricity to the BS, and other details.
Generally it is very costly to reposition incorrect‑
ly positioned sites.
An appropriate antenna pattern and tuned
propagation model needs to be used to obtain
close to real‑life predictions for the BS location.
The prediction file contains the path loss values
from the BS to the pixel points around the BS.
These along with the channel allocation to the
sites will help in providing the interference array
that determines the cell radii of the modula‑
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B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
tion schemes. Very high resolution maps with
details of building heights and street widths help
to achieve a near real‑life network plan. With
such high‑resolution data, the radio propagation
pattern, including reflection and diffraction, can
be captured in the planning tool using a 3D ray
tracing propagation model.
Channel allocation is based on the inter‑
cell co‑channel to interference (C/I) ratio. In a
WiMAX system, the co‑channel interference is
based on the probability of collision and varies
depending on factors like the sub‑carrier alloca‑
tion scheme, channel allocation scheme, and cell
loading. An efficient segmentation allocation for
fractional frequency reuse schemes can provide
benefits whenever the spectrum is limited.
The final radio plan consists of the coverage
plans, capacity estimations, interference plans,
power budget calculations; parameter set plans,
channel allocation plans, and other details. Some
example outputs are shown in Figure 8.
3.4.2 Network optimisation
It is impossible to predict the exact
performance of a network once it has been
implemented, so it will always be necessary
to make minor adjustments to the network.
Network optimisation is an important element
of a network’s lifecycle comprising of prelaunch
network optimisation and post launch network
performance optimisation. At the initial network
launch, there is more focus on the network/radio
optimisation to ensure that the network performs
as per the design and is free from configura‑
(a) Site plan for an area (b) The best server signal strength
(b) plot for the area
(d) DL maximum throughput plot
(b) for the area
(c) Best available DL CPE’s for the
(b) area
Figure 8
Example — Network planning outputs.
15. 449FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
tion and implementation faults. The prelaunch
network/radio optimisation is performed on a
cell‑by‑cell basis.
Network performance optimisation involves
finely tuning the network after the configuration
faults are eliminated by selecting appropri‑
ate network parameters to achieve the set QoS
targets. The main focus of WiMAX radio network
optimisation is expected to be on areas such as
the sub‑carrier allocation scheme, neighbour
list definition, zoning definition for the frequen‑
cy reuse of 1 and channel measurements. The
network performance optimisation involves
establishing end‑to‑end key performance indica‑
tors to cover service accessibility, availability,
retainability, and service integrity for monitoring
the network QoS as perceived by the end user. It
is always beneficial to have a proactive perfor‑
mance monitoring system in place to ensure the
set design standards are always met.
The optimisation process is initiated by
collecting and analysing network data from drive
testing on selected routes and also data from
network nodes by using customised software.
The detailed network optimisation and perfor‑
mance process is outside the scope of this paper
and what is provided here is a brief overview.
4. Conclusions
This paper presented the challenges in
WiMAX network deployment and explained
an approach to the network dimensioning
and planning process. It also introduced an
in‑house developed analytical dimensioning tool
called DoORs. The tool provides a user‑friendly
environment for quick and accurate dimension‑
ing that provides a firm ground for the next steps
of network and cell design. It enables rapid
evaluation and selection of many of the basic
parameters and options of the WiMAX radio
interface. Consequently, it reduces the time
needed for the cell design phase and makes the
design is easier to optimise.
References
1) IEEE 802.16 Working Group 16: IEEE Standard
for Local and Metropolitan Area Networks, Part
16: Air Interface for Fixed and Mobile Broadband
Wireless Systems. IEEE STD 802.16e-2005 and
IEEE STD 802.16-2004, approved 28 Feb 2006.
2) Mobile WiMAX — Part I: A Technical Overview
and Performance Evaluation. WiMAX Forum,
2006.
3) WiMAX Deployment Considerations for Fixed
Wireless Access in the 2.5 GHz and 3.5 GHz
Licensed Bands. WiMAX Forum, June 2005.
16. 450 FUJITSU Sci. Tech. J., 43,4,(October 2007)
B. Upase et al.: Radio Network Dimensioning and Planning for WiMAX Networks
Bharathi Upase, Fujitsu Laboratories
of Europe Ltd.
Ms. Upase received the B.E and
M.E degrees in Electronics and
Communication Engineering from
Karnataka University, India in 1992
and 1994, respectively. She joined
SDM College of Engineering, India,
as a Lecturer. From 1998, she was
a consultant in the Wireless Division
of Marconi (UK), mainly working with
a number of wireless operators such as O2 and Vodafone in
the UK and Vodacom in South Africa on wireless network plan-
ning involving cell planning, frequency planning, site survey,
KPI evaluation and optimisation for GSM, GPRS, and WCDMA
networks. She also worked in the product development divi-
sion of Marconi defining requirement specification for modules
in the network planning tool Planet. In 2003 she joined Bechtel
Telecommunication UK, where she was involved in intense drive
testing and KPI evaluation for improved GPRS coverage on
high‑speed rail routes for the Vodafone network. In 2004 she
joined Fujitsu Laboratories of Europe Ltd., where she has been
involved in radio network planning research; assisting Fujitsu
business groups with cell design for Fujitsu’s customers; and
design and development of a radio network dimensioning tool
for WCDMA, HSDPA, wireless LANs, and WiMAX.
E-mail: bharathi.upase@uk.fujitsu.com
Mythri Hunukumbure, Fujitsu
Laboratories of Europe Ltd.
Dr. Hunukumbure received the BSc
degree in Electronic and Telecommu-
nications Engineering from University
of Moratuwa, Sri Lanka in 1998. He
completed MSc and PhD studies at
University of Bristol, U.K. He joined
Fujitsu Laboratories of Europe Ltd.
as a research engineer in 2006. His
research studies have encompassed
the appraisal of code orthogonality and space-time signal
processing technology to 3G mobile systems. He has been
actively involved in the European COST273, IST-Saturn, and
Mobile VCE research programs. At Fujitsu, he is involved with
4G WiMAX related research, mainly concentrating on network
dimensioning and planning for the evolving WiMAX architecture.
E-mail: mythri.hunukumbure@uk.fujitsu.com
Sunil Vadgama, Fujitsu Laboratories
of Europe Ltd.
Mr. Vadgama graduated from University
of Surrey in 1984. Subsequently joined
Philips Research Laboratories (UK),
where his work included the develop-
ment of advanced mobile communica-
tion systems, UMTS, and linearization
of RF power amplifiers. In 1991, he
joined Fujitsu (UK), where he was
initially engaged in the development
of GSM terminals and subsequently on RD of advanced tech-
nologies for IMT2000 base stations. He chaired the Industrial
Steering Committee of the Personal Distributed Environments
(PDE) research group in the Core 3 research programme of the
Mobile Virtual Centre of Excellence in UK from 2003 to 2005.
He is currently Manager of the Wireless Technology Group and
Assistant Division Manager for the Network Systems Research
Division at Fujitsu Laboratories of Europe Ltd and is currently
studying the long-term evolution of 3G, WiMAX, the future 4G,
and ad‑hoc wireless access technologies.
E-mail: sunil.vadgama@uk.fujitsu.com