This document summarizes a proposed price-based spectrum sharing scheme for wireless cellular networks. It describes a system model where two wireless networks share radio frequency spectrum by allowing traffic overflow from a home network to a neighboring network when the home network reaches capacity. A dynamic pricing algorithm is proposed where prices increase as traffic loads rise to encourage users to reduce call durations and deter additional traffic. Performance evaluations using MATLAB simulations analyze how the scheme impacts traffic channel utilization, network revenue, and quality of service. The scheme aims to improve spectrum utilization and address scarcity issues during busy traffic periods.
Improvement of crankshaft MAC protocol for wireless sensor networks: a simula...IJECEIAES
Due to the dramatic growth in the use of Wireless Sensor Network (WSN) applications ranging from environment and habitat monitoring to tracking and surveillance, network research in WSN protocols has been very active in the last decade. With battery-powered sensors operating in unattended environments, energy conservation becomes the key technique for improving WSN lifetimes. WSN Medium Access Control (MAC) protocols address energy awareness and reduced duty cycles. The focus of this study is to investigate, through simulation, the effect of variations in various factors that influence the performance results of WSNs. Using MiXiM framework with OMNeT++ simulator, this simulation study proposes modifications in Crankshaft MAC protocol in order to improve its performance. The impact of duration and number of slots, degree of connectivity among the nodes, mobility speed and mobility update interval and also, the impact of sending data packets without preambles are investigated. Based on the simulation results, an improved version of the Crankshaft protocol for WSN is suggested and a comparative study of the performances of the original and improved protocol is presented. The results clearly indicate the superiority of the improved protocol over its original version.
Enhancing Opportunistic Routing for Cognitive Radio NetworkIRJET Journal
This document proposes an enhancement to opportunistic ad-hoc on-demand distance vector (AODV) routing called EOAODV. In traditional AODV and opportunistic routing, the next hop node is selected based only on expected transmission count (ETC), which can drain the energy of nodes that get selected frequently. EOAODV selects the next hop based on both ETC and the residual energy of nodes, to avoid overusing certain nodes. It describes EOAODV's algorithm which calculates routes based on ETC and energy residue. Nodes with the least ETC and higher energy will be selected as next hops to maximize throughput while balancing energy usage across nodes.
1. The document proposes an optimal Threshold Offloading (TO) algorithm to efficiently offload mobile data traffic from macrocells to femtocells in LTE networks. The TO algorithm considers the tradeoff between network signaling overhead from user mobility and femtocell offloading capability.
2. An analytical model is developed to quantify the performance of the TO algorithm and validate it through simulations. The results show that the TO algorithm can significantly reduce signaling overhead with minor reduction in femtocell offloading capability.
3. The paper provides network operators guidelines to set optimal offloading thresholds according to their management policies, offering a systematic approach based on the mathematical analysis.
Teletraffic Analysis of Overflowed Traffic with Voice only in Multilayer 3G W...IRJET Journal
This document presents a study analyzing the traffic overflow performance of a three-layered wireless mobile network with microcells, macrocells and satellite cells handling voice-only traffic. The three-layered hierarchical network structure is described, with microcells overlaid by macrocells and macrocells overlaid by satellite cells. An existing call admission control scheme is evaluated that prioritizes voice calls, including handling call blocking probabilities, channel utilization, and call dropping probabilities across the different cell layers under varying traffic parameters. Analytical models are developed and numerical calculations are performed to analyze the performance of the call admission control scheme in the three-layered network handling overflowed voice traffic.
This document discusses load balancing in cellular networks through paging techniques. It first provides background on cellular networks and hierarchical network structures. It then reviews existing work related to reducing paging costs, communication between users, location updates, and paging strategies for 3G mobile networks. The existing frequency reuse system is described as having problems like frequency reuse, flooding, delays, and interference. The proposed system introduces soft frequency reuse, which employs zone-based frequency reuse factors and power restrictions to reduce interference between cell areas. Load balancing of paging requests across network tiers can minimize delays and costs through techniques like hierarchical pipelining, sequential, and blanket paging schemes.
A Novel Approach to Fairly Grant Channel Access to Secondary Users in Cogniti...IJSRED
This document proposes a channel access scheduling approach for secondary users in cognitive radio networks. It introduces a scheduling manager that coordinates channel access between secondary users. The scheduling manager considers metrics like quality of service and waiting time to determine which secondary user gets channel access. Simulation results show the proposed approach improves network throughput and fairness in channel allocation. It aims to address the issue of coordinating channel access for multiple heterogeneous secondary users within a cognitive radio network.
Professor Mark Beach's presentation (without videos) on the University of Bristol's Massive MIMO activities as given at the IET's 'Towards 5G Mobile Technology – Vision to Reality' event, January 25th 2017.
Ne xt generation dynamic spectrum access cognitive2006surveyyoooh
This document summarizes a survey on next generation/dynamic spectrum access/cognitive radio wireless networks. It discusses the inefficiency of fixed spectrum assignment in current wireless networks and introduces cognitive radio technology as the key enabler of opportunistic spectrum access. The document defines cognitive radio, outlines its physical architecture and cognitive capabilities, and describes the main functions of cognitive radio networks including spectrum sensing, management, mobility, and sharing. It also discusses the challenges these functions pose for upper layer protocols and the need for cross-layer design in cognitive radio networks.
Improvement of crankshaft MAC protocol for wireless sensor networks: a simula...IJECEIAES
Due to the dramatic growth in the use of Wireless Sensor Network (WSN) applications ranging from environment and habitat monitoring to tracking and surveillance, network research in WSN protocols has been very active in the last decade. With battery-powered sensors operating in unattended environments, energy conservation becomes the key technique for improving WSN lifetimes. WSN Medium Access Control (MAC) protocols address energy awareness and reduced duty cycles. The focus of this study is to investigate, through simulation, the effect of variations in various factors that influence the performance results of WSNs. Using MiXiM framework with OMNeT++ simulator, this simulation study proposes modifications in Crankshaft MAC protocol in order to improve its performance. The impact of duration and number of slots, degree of connectivity among the nodes, mobility speed and mobility update interval and also, the impact of sending data packets without preambles are investigated. Based on the simulation results, an improved version of the Crankshaft protocol for WSN is suggested and a comparative study of the performances of the original and improved protocol is presented. The results clearly indicate the superiority of the improved protocol over its original version.
Enhancing Opportunistic Routing for Cognitive Radio NetworkIRJET Journal
This document proposes an enhancement to opportunistic ad-hoc on-demand distance vector (AODV) routing called EOAODV. In traditional AODV and opportunistic routing, the next hop node is selected based only on expected transmission count (ETC), which can drain the energy of nodes that get selected frequently. EOAODV selects the next hop based on both ETC and the residual energy of nodes, to avoid overusing certain nodes. It describes EOAODV's algorithm which calculates routes based on ETC and energy residue. Nodes with the least ETC and higher energy will be selected as next hops to maximize throughput while balancing energy usage across nodes.
1. The document proposes an optimal Threshold Offloading (TO) algorithm to efficiently offload mobile data traffic from macrocells to femtocells in LTE networks. The TO algorithm considers the tradeoff between network signaling overhead from user mobility and femtocell offloading capability.
2. An analytical model is developed to quantify the performance of the TO algorithm and validate it through simulations. The results show that the TO algorithm can significantly reduce signaling overhead with minor reduction in femtocell offloading capability.
3. The paper provides network operators guidelines to set optimal offloading thresholds according to their management policies, offering a systematic approach based on the mathematical analysis.
Teletraffic Analysis of Overflowed Traffic with Voice only in Multilayer 3G W...IRJET Journal
This document presents a study analyzing the traffic overflow performance of a three-layered wireless mobile network with microcells, macrocells and satellite cells handling voice-only traffic. The three-layered hierarchical network structure is described, with microcells overlaid by macrocells and macrocells overlaid by satellite cells. An existing call admission control scheme is evaluated that prioritizes voice calls, including handling call blocking probabilities, channel utilization, and call dropping probabilities across the different cell layers under varying traffic parameters. Analytical models are developed and numerical calculations are performed to analyze the performance of the call admission control scheme in the three-layered network handling overflowed voice traffic.
This document discusses load balancing in cellular networks through paging techniques. It first provides background on cellular networks and hierarchical network structures. It then reviews existing work related to reducing paging costs, communication between users, location updates, and paging strategies for 3G mobile networks. The existing frequency reuse system is described as having problems like frequency reuse, flooding, delays, and interference. The proposed system introduces soft frequency reuse, which employs zone-based frequency reuse factors and power restrictions to reduce interference between cell areas. Load balancing of paging requests across network tiers can minimize delays and costs through techniques like hierarchical pipelining, sequential, and blanket paging schemes.
A Novel Approach to Fairly Grant Channel Access to Secondary Users in Cogniti...IJSRED
This document proposes a channel access scheduling approach for secondary users in cognitive radio networks. It introduces a scheduling manager that coordinates channel access between secondary users. The scheduling manager considers metrics like quality of service and waiting time to determine which secondary user gets channel access. Simulation results show the proposed approach improves network throughput and fairness in channel allocation. It aims to address the issue of coordinating channel access for multiple heterogeneous secondary users within a cognitive radio network.
Professor Mark Beach's presentation (without videos) on the University of Bristol's Massive MIMO activities as given at the IET's 'Towards 5G Mobile Technology – Vision to Reality' event, January 25th 2017.
Ne xt generation dynamic spectrum access cognitive2006surveyyoooh
This document summarizes a survey on next generation/dynamic spectrum access/cognitive radio wireless networks. It discusses the inefficiency of fixed spectrum assignment in current wireless networks and introduces cognitive radio technology as the key enabler of opportunistic spectrum access. The document defines cognitive radio, outlines its physical architecture and cognitive capabilities, and describes the main functions of cognitive radio networks including spectrum sensing, management, mobility, and sharing. It also discusses the challenges these functions pose for upper layer protocols and the need for cross-layer design in cognitive radio networks.
1) Researchers at the University of Bristol presented on their 128-antenna massive MIMO testbed that can support up to 22 users in real-time.
2) The testbed uses a centralized digital signal processing approach with FPGA-based MIMO processing to perform linear decoding and precoding on uplink and downlink signals.
3) Experimental results showed the system achieving 145.6 bits/s/Hz of summed rate for 22 users, each transmitting 256-QAM signals over multiple spatial streams.
NetSim(http://www.tetcos.com/ ) Simulator provide Cognative Radio network
follow this link for more Details
http://www.tetcos.com/
Cognitive radio (CR) is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly move into vacant channels while avoiding occupied ones
Performance Investigation of OFDM-FSO System under Diverse Weather Conditions...IJECEIAES
Free space optical (FSO) communication systems which are deployed for last mile access, being considered as a suitable alternative technology for optical fiber networks. It is one of the emerging technologies for broadband wireless connectivity which has also been receiving growing attention due to high data rate transmission capability with low installation cost and license free spectrum. However, the widespread use of FSO technology has been hampered by the randomly time varying characteristics of propagation path mainly due to atmospheric turbulence, sensitivity to diverse weather conditions and the nonlinear responsivity of laser diode. This paper presents the performance investigation of an OFDM-FSO system over atmospheric turbulence channels under diverse weather conditions of Bangladesh. The channel is modeled with gamma-gamma distribution using 16-QAM modulation format and 4×4 multiple transceiver FSO system. All possible challenges are imposed on the system performance such as atmospheric attenuation, turbulence, pointing error, geometric loss etc. The refractive index structure parameter and atmospheric attenuation coefficient for different weather conditions are calculated by using the data, collected from Bangladesh Meteorological Department. The acquired results can be fruitful for scheming, forecasting and assessing the OFDM-FSO system’s ability to transmit wireless services over turbulent FSO links under actual conditions of Bangladesh.
IMPROVED PROPAGATION MODELS FOR LTE PATH LOSS PREDICTION IN URBAN & SUBURBAN ...ijwmn
To maximize the benefits of LTE cellular networks, careful and proper planning is needed. This requires the use of accurate propagation models to quantify the path loss required for base station deployment. Deployed LTE networks in Ghana can barely meet the desired 100Mbps throughput leading to customer dissatisfaction. Network operators rely on transmission planning tools designed for generalized environments that come with already embedded propagation models suited to other environments. A challenge therefore to Ghanaian transmission Network planners will be choosing an accurate and precise propagation model that best suits the Ghanaian environment. Given this, extensive LTE path loss measurements at 800MHz and 2600MHz were taken in selected urban and suburban environments in Ghana and compared with 6 commonly used propagation models. Improved versions of the Ericson, SUI, and ECC-33 developed in this study predict more precisely the path loss in Ghanaian environments compared with commonly used propagation models.
ROUTING PROTOCOLS PERFORMANCE IN MOBILE AD-HOC NETWORKS USING MILLIMETER WAVEIJCNCJournal
Self-Organized networks (SONs) have been studied for many years, and have attracted many researchers due to their substantial applications. Although the performance of such networks in the lower band networks (sub-6 GHz band frequencies) has been well studied, there are only sparse studies on SON in higher frequency bands, such as the millimeter wave (mmWave) band ranges between 28GHz and 300GHz. mmWave frequencies have attracted many researchers in the past few years because of its unique features
and are now considered as an important part of the next generation of wireless communications namely (5G).In this paper, we study the performance of some well-known routing protocols in the case of mmWave Mobile Ad hoc Networks (MANET) using the ns-3 mmwave module that was developed recently. SONs are within the goals for the next release of the 3GPP New Radio (NR) standardization process (Release-16) for the 5G, which makes the study of the behavior of such frequency bands for these networks an important activity towards achieving such goal. Mathematical and simulation results show a great improvement in the routing protocols delivery rates and power consumption when using mmWave compared to the sub6GHz band frequencies.
Dynamic Topology Re-Configuration in Multihop Cellular Networks Using Sequent...IJERA Editor
Cellular communications has experienced explosive growth in the past two decades. Today millions of people around the world use cellular phones. Cellular phones allow a person to make or receive a call from almost anywhere. Likewise, a person is allowed to continue the phone conversation while on the move. Cellular communications is supported by an infrastructure called a cellular network, which integrates cellular phones into the public switched telephone network. The cellular network has gone through three generations.The first generation of cellular networks is analog in nature. To accommodate more cellular phone subscribers, digital TDMA (time division multiple access) and CDMA (code division multiple access) technologies are used in the second generation (2G) to increase the network capacity. With digital technologies, digitized voice can be coded and encrypted. Therefore, the 2G cellular network is also more secure. The third generation (3G) integrates cellular phones into the Internet world by providing highspeed packet-switching data transmission in addition to circuit-switching voice transmission. The 3G cellular networks have been deployed in some parts of Asia, Europe, and the United States since 2002 and will be widely deployed in the coming years. The high increase in traffic and data rate for future generations of mobile communication systems, with simultaneous requirement for reduced power consumption, makes Multihop Cellular Networks (MCNs) an attractive technology. To exploit the potentials of MCNs a new network paradigm is proposed in this paper. In addition, a novel sequential genetic algorithm (SGA) is proposed as a heuristic approximation to reconfigure the optimum relaying topology as the network traffic changes. Network coding is used to combine the uplink and downlink transmissions, and incorporate it into the optimum bidirectional relaying with ICI awareness. Numerical results have shown that the algorithms suggested in this thesis provide significant improvement with respect to the existing results, and are expected to have significant impact in the analysis and design of future cellular networks.
Cognitive radio network_MS_defense_presentationIffat Anjum
The document appears to be a student thesis that discusses medium access control (MAC) protocols for coexisting cognitive radio networks (CCRNs). It proposes a new distributed and quality of service aware MAC protocol called WF-MAC. WF-MAC aims to enable fair channel sharing among multiple CCRNs while maintaining QoS sensitivity and maximizing spectrum utilization. It achieves this through a two dimensional learning mechanism for channel selection based on perception and availability prediction.
Coordinated Multipoint Transmission and Reception in LTE-Advanced (1)Mariem NAIJA
This document presents a performance analysis of downlink Coordinated Multipoint (CoMP) transmission. It aims to simulate a basic tri-sector macro-cell, and CoMP scenarios using both shared and dedicated spectrum to decrease inter-cell interference and increase cell-edge throughput. The analysis was conducted using a simulation tool and evaluated the results of a basic macro cell deployment alongside CoMP deployments using shared and dedicated spectrum. It concludes the study and discusses perspectives for future work.
GPSFR: GPS-Free Routing Protocol for Vehicular Networks with Directional Ante...ijwmn
Efficient and practical communications between large numbers of vehicles are critical in providing high level of safety and convenience to drivers. Crucial real-time information on road hazard, traffic conditions and driver services must be communicated to vehicles rapidly even in adverse environments, such as “urban canyons” and tunnels. We propose a novel routing protocol in vehicular networks that does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. This GPS-Free Geographic Routing (GPSFR) protocol uses the estimated relative position of vehicles and greedily chooses the best next hop neighbor based on a Balance Advance (BADV) metric which balances between proximity and link stability in order to improve routing performance. In this paper, we focuses primarily on the complexity of routing in highways and solves routing problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage to only 27% that of GPSR in the dense network. Consequently, GPSFR outperforms GPSR in terms of higher data delivery ratio, lower delay, less sensitivity of the network density and route paths’length
Multi Channel Protocols In Cognitive Radio NetworksMuhammad Mustafa
Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum, user behaviour and network state. this presentation discusses main approaches and protocols of multichannel cognitive radio networks.
Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Mi...IJECEIAES
The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.
The document discusses the IEEE 802.22 standard for cognitive radio wireless regional area networks (WRANs). It describes how cognitive radio technology can help address the spectrum crunch by efficiently utilizing vacant TV bands and other licensed spectrum. The standard defines the MAC and PHY layer specifications for a cognitive radio system, including spectrum sensing, mobility, sharing, and a superframe structure to manage communication in available TV channels while avoiding interference with primary users. The goal is to provide wireless connectivity over distances of up to 30 km using the cognitive radio capabilities defined in the 802.22 standard.
Coordinated Multipoint (CoMP) Transmission for LTE-Advanced Networks in Dense...Beneyam Haile
The document discusses evaluating the performance of Coordinated Multipoint (CoMP) transmission for LTE-Advanced networks in dense informal settlements. It describes:
1) Simulating a CoMP scheme using quantized co-phasing among three macro cells in a dense informal settlement area in Dar es Salaam, Tanzania.
2) Results showing the overall SINR, SNR, and spectral efficiency performance improved as the CoMP threshold increased, selecting more UEs for CoMP.
3) A tradeoff between energy efficiency and spectral efficiency based on transmission power, with energy savings possible without large spectral efficiency losses.
IRJET- Statistical Tuning of Hata Model for 3G Communication Networks at 1.85...IRJET Journal
This document summarizes a study that statistically tunes the Hata propagation model for 3G networks at 1.857GHz in Port Harcourt, Nigeria. Drive tests were conducted at three urban sites to collect field measurements of path loss. The measured data was compared to predictions from standard models including Hata, COST 231, and LEE. Hata was identified as the best fitting standard model. To improve accuracy, Hata's parameters were statistically optimized using linear regression on the measured data. The optimized Hata model reduced mean absolute percentage error from 15.0% to 13.35% compared to the standard Hata model, demonstrating its improved path loss prediction for the environment.
A Review on Cooperative Communication Protocols in Wireless World ijwmn
Future generations of cellular communications requires higher data rates and a more reliable
transmission link with the growth of multimedia services, while keeping satisfactory quality of service, .
MIMO antenna systems have been considered as an efficient approach to address these demands by
offering significant multiplexing and diversity gains over single antenna systems without increasing
bandwidth and power. Although MIMO systems can unfold their huge benefit in cellular base stations,
but they may face limitations when it comes to their deployment in mobile handsets.
To overcome this drawback, relays (fixed or mobile terminals) can cooperate to improve the overall
system performance in cellular networks. Cooperative communications can efficiently combat the severity
of fading and shadowing through the assistance of relays. It has been found that using relays the capacity
and coverage of cellular networks can be extended without increasing mobile transmit power or
demanding extra bandwidth.
INVESTIGATION OF RADIO FREQUENCY LICENSED SPECTRUM UTILIZATION IN NIGERIA: A ...ijwmn
This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of - 110dBm, a threshold of -95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investigated sub bands; only one band was completely occupied with spectrum occupancy of 100%. 12 bands were partially occupied while 11 were completely free. The average spectrum occupancy for the whole band was obtained as 11.64%. This showed good location for dynamic spectrum access and cognitive radio deployment, especially in Television White Space (TVWS).
Spectrum sharing in cognitive radio networks IJECEIAES
Cognitive radio networks are the next step to tackle scarcity in wireless networks given the increasing demand of radioelectric spectrum where the proposed solution is to share said resource to improve this situation. In the present article, a review of the current state of spectrum sharing in cognitive radio networks. To achieve this purpose, the articles published over the last 4 years on the matter were reviewed including topics such as mobile networks and TV. Some studies and simulations proposed to share the spectrum is shown. The current state of the studies reveals that there has been significant progress in this research area yet it is necessary to continue similar studies and set in motion different schemes.
NetSim Webinar on Cognitive Radio NetworksSANJAY ANAND
Why use a Network Simulator for research ?
Introduction to NetSim
Cognitive Radio Basics
Designing Cognitive Radio networks using NetSim
Modifying Cognitive Radio source C code in NetSim
How to develop custom metrics?
Q & A
This document summarizes research on improving the capacity of cellular systems using fractional frequency reuse (FFR). It discusses how frequency reuse is used to increase the number of users that can be served but causes interference, particularly for cell edge users. Fractional frequency reuse is proposed to solve this problem by allocating different frequency sets to cell center and edge users to reduce interference. The document also reviews different types of interference (co-channel and adjacent channel) and how power control can help reduce interference in cellular systems.
Capacity Improvement of Cellular System Using Fractional Frequency Reuse (FFR)IJEEE
Today wireless communication is mostly used rather than wired communication, due to remote location reach ability, less fault occurrence, less time to commissioning and low cost etc. But wireless network has less frequency spectrum to cover the whole world. To improve the capacity of cellular system in a limited spectrum without major technological changes, frequency is reused in cells. But it offers interferences mostly for cell edge users. To solve the problem of spectral congestion and user capacity, fractional frequency reuse is used. This paper gives idea about different frequency reuse factors, fractional frequency reuse and super cell with sectoring to improve the capacity of cellular system.
The document discusses the history and development of 3G mobile communication technology, specifically UMTS. It provides details on:
- The evolution from 1G to 2G mobile networks and the need for 3G to support higher data rates and multimedia services.
- The standardization of UMTS through ETSI and ITU, focusing on the two selected radio transmission technologies - UTRA FDD and TDD.
- The architecture of 3G UMTS networks, including frequency reuse techniques used to maximize capacity within limited spectrum availability.
1) Researchers at the University of Bristol presented on their 128-antenna massive MIMO testbed that can support up to 22 users in real-time.
2) The testbed uses a centralized digital signal processing approach with FPGA-based MIMO processing to perform linear decoding and precoding on uplink and downlink signals.
3) Experimental results showed the system achieving 145.6 bits/s/Hz of summed rate for 22 users, each transmitting 256-QAM signals over multiple spatial streams.
NetSim(http://www.tetcos.com/ ) Simulator provide Cognative Radio network
follow this link for more Details
http://www.tetcos.com/
Cognitive radio (CR) is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly move into vacant channels while avoiding occupied ones
Performance Investigation of OFDM-FSO System under Diverse Weather Conditions...IJECEIAES
Free space optical (FSO) communication systems which are deployed for last mile access, being considered as a suitable alternative technology for optical fiber networks. It is one of the emerging technologies for broadband wireless connectivity which has also been receiving growing attention due to high data rate transmission capability with low installation cost and license free spectrum. However, the widespread use of FSO technology has been hampered by the randomly time varying characteristics of propagation path mainly due to atmospheric turbulence, sensitivity to diverse weather conditions and the nonlinear responsivity of laser diode. This paper presents the performance investigation of an OFDM-FSO system over atmospheric turbulence channels under diverse weather conditions of Bangladesh. The channel is modeled with gamma-gamma distribution using 16-QAM modulation format and 4×4 multiple transceiver FSO system. All possible challenges are imposed on the system performance such as atmospheric attenuation, turbulence, pointing error, geometric loss etc. The refractive index structure parameter and atmospheric attenuation coefficient for different weather conditions are calculated by using the data, collected from Bangladesh Meteorological Department. The acquired results can be fruitful for scheming, forecasting and assessing the OFDM-FSO system’s ability to transmit wireless services over turbulent FSO links under actual conditions of Bangladesh.
IMPROVED PROPAGATION MODELS FOR LTE PATH LOSS PREDICTION IN URBAN & SUBURBAN ...ijwmn
To maximize the benefits of LTE cellular networks, careful and proper planning is needed. This requires the use of accurate propagation models to quantify the path loss required for base station deployment. Deployed LTE networks in Ghana can barely meet the desired 100Mbps throughput leading to customer dissatisfaction. Network operators rely on transmission planning tools designed for generalized environments that come with already embedded propagation models suited to other environments. A challenge therefore to Ghanaian transmission Network planners will be choosing an accurate and precise propagation model that best suits the Ghanaian environment. Given this, extensive LTE path loss measurements at 800MHz and 2600MHz were taken in selected urban and suburban environments in Ghana and compared with 6 commonly used propagation models. Improved versions of the Ericson, SUI, and ECC-33 developed in this study predict more precisely the path loss in Ghanaian environments compared with commonly used propagation models.
ROUTING PROTOCOLS PERFORMANCE IN MOBILE AD-HOC NETWORKS USING MILLIMETER WAVEIJCNCJournal
Self-Organized networks (SONs) have been studied for many years, and have attracted many researchers due to their substantial applications. Although the performance of such networks in the lower band networks (sub-6 GHz band frequencies) has been well studied, there are only sparse studies on SON in higher frequency bands, such as the millimeter wave (mmWave) band ranges between 28GHz and 300GHz. mmWave frequencies have attracted many researchers in the past few years because of its unique features
and are now considered as an important part of the next generation of wireless communications namely (5G).In this paper, we study the performance of some well-known routing protocols in the case of mmWave Mobile Ad hoc Networks (MANET) using the ns-3 mmwave module that was developed recently. SONs are within the goals for the next release of the 3GPP New Radio (NR) standardization process (Release-16) for the 5G, which makes the study of the behavior of such frequency bands for these networks an important activity towards achieving such goal. Mathematical and simulation results show a great improvement in the routing protocols delivery rates and power consumption when using mmWave compared to the sub6GHz band frequencies.
Dynamic Topology Re-Configuration in Multihop Cellular Networks Using Sequent...IJERA Editor
Cellular communications has experienced explosive growth in the past two decades. Today millions of people around the world use cellular phones. Cellular phones allow a person to make or receive a call from almost anywhere. Likewise, a person is allowed to continue the phone conversation while on the move. Cellular communications is supported by an infrastructure called a cellular network, which integrates cellular phones into the public switched telephone network. The cellular network has gone through three generations.The first generation of cellular networks is analog in nature. To accommodate more cellular phone subscribers, digital TDMA (time division multiple access) and CDMA (code division multiple access) technologies are used in the second generation (2G) to increase the network capacity. With digital technologies, digitized voice can be coded and encrypted. Therefore, the 2G cellular network is also more secure. The third generation (3G) integrates cellular phones into the Internet world by providing highspeed packet-switching data transmission in addition to circuit-switching voice transmission. The 3G cellular networks have been deployed in some parts of Asia, Europe, and the United States since 2002 and will be widely deployed in the coming years. The high increase in traffic and data rate for future generations of mobile communication systems, with simultaneous requirement for reduced power consumption, makes Multihop Cellular Networks (MCNs) an attractive technology. To exploit the potentials of MCNs a new network paradigm is proposed in this paper. In addition, a novel sequential genetic algorithm (SGA) is proposed as a heuristic approximation to reconfigure the optimum relaying topology as the network traffic changes. Network coding is used to combine the uplink and downlink transmissions, and incorporate it into the optimum bidirectional relaying with ICI awareness. Numerical results have shown that the algorithms suggested in this thesis provide significant improvement with respect to the existing results, and are expected to have significant impact in the analysis and design of future cellular networks.
Cognitive radio network_MS_defense_presentationIffat Anjum
The document appears to be a student thesis that discusses medium access control (MAC) protocols for coexisting cognitive radio networks (CCRNs). It proposes a new distributed and quality of service aware MAC protocol called WF-MAC. WF-MAC aims to enable fair channel sharing among multiple CCRNs while maintaining QoS sensitivity and maximizing spectrum utilization. It achieves this through a two dimensional learning mechanism for channel selection based on perception and availability prediction.
Coordinated Multipoint Transmission and Reception in LTE-Advanced (1)Mariem NAIJA
This document presents a performance analysis of downlink Coordinated Multipoint (CoMP) transmission. It aims to simulate a basic tri-sector macro-cell, and CoMP scenarios using both shared and dedicated spectrum to decrease inter-cell interference and increase cell-edge throughput. The analysis was conducted using a simulation tool and evaluated the results of a basic macro cell deployment alongside CoMP deployments using shared and dedicated spectrum. It concludes the study and discusses perspectives for future work.
GPSFR: GPS-Free Routing Protocol for Vehicular Networks with Directional Ante...ijwmn
Efficient and practical communications between large numbers of vehicles are critical in providing high level of safety and convenience to drivers. Crucial real-time information on road hazard, traffic conditions and driver services must be communicated to vehicles rapidly even in adverse environments, such as “urban canyons” and tunnels. We propose a novel routing protocol in vehicular networks that does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. This GPS-Free Geographic Routing (GPSFR) protocol uses the estimated relative position of vehicles and greedily chooses the best next hop neighbor based on a Balance Advance (BADV) metric which balances between proximity and link stability in order to improve routing performance. In this paper, we focuses primarily on the complexity of routing in highways and solves routing problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage to only 27% that of GPSR in the dense network. Consequently, GPSFR outperforms GPSR in terms of higher data delivery ratio, lower delay, less sensitivity of the network density and route paths’length
Multi Channel Protocols In Cognitive Radio NetworksMuhammad Mustafa
Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum, user behaviour and network state. this presentation discusses main approaches and protocols of multichannel cognitive radio networks.
Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Mi...IJECEIAES
The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.
The document discusses the IEEE 802.22 standard for cognitive radio wireless regional area networks (WRANs). It describes how cognitive radio technology can help address the spectrum crunch by efficiently utilizing vacant TV bands and other licensed spectrum. The standard defines the MAC and PHY layer specifications for a cognitive radio system, including spectrum sensing, mobility, sharing, and a superframe structure to manage communication in available TV channels while avoiding interference with primary users. The goal is to provide wireless connectivity over distances of up to 30 km using the cognitive radio capabilities defined in the 802.22 standard.
Coordinated Multipoint (CoMP) Transmission for LTE-Advanced Networks in Dense...Beneyam Haile
The document discusses evaluating the performance of Coordinated Multipoint (CoMP) transmission for LTE-Advanced networks in dense informal settlements. It describes:
1) Simulating a CoMP scheme using quantized co-phasing among three macro cells in a dense informal settlement area in Dar es Salaam, Tanzania.
2) Results showing the overall SINR, SNR, and spectral efficiency performance improved as the CoMP threshold increased, selecting more UEs for CoMP.
3) A tradeoff between energy efficiency and spectral efficiency based on transmission power, with energy savings possible without large spectral efficiency losses.
IRJET- Statistical Tuning of Hata Model for 3G Communication Networks at 1.85...IRJET Journal
This document summarizes a study that statistically tunes the Hata propagation model for 3G networks at 1.857GHz in Port Harcourt, Nigeria. Drive tests were conducted at three urban sites to collect field measurements of path loss. The measured data was compared to predictions from standard models including Hata, COST 231, and LEE. Hata was identified as the best fitting standard model. To improve accuracy, Hata's parameters were statistically optimized using linear regression on the measured data. The optimized Hata model reduced mean absolute percentage error from 15.0% to 13.35% compared to the standard Hata model, demonstrating its improved path loss prediction for the environment.
A Review on Cooperative Communication Protocols in Wireless World ijwmn
Future generations of cellular communications requires higher data rates and a more reliable
transmission link with the growth of multimedia services, while keeping satisfactory quality of service, .
MIMO antenna systems have been considered as an efficient approach to address these demands by
offering significant multiplexing and diversity gains over single antenna systems without increasing
bandwidth and power. Although MIMO systems can unfold their huge benefit in cellular base stations,
but they may face limitations when it comes to their deployment in mobile handsets.
To overcome this drawback, relays (fixed or mobile terminals) can cooperate to improve the overall
system performance in cellular networks. Cooperative communications can efficiently combat the severity
of fading and shadowing through the assistance of relays. It has been found that using relays the capacity
and coverage of cellular networks can be extended without increasing mobile transmit power or
demanding extra bandwidth.
INVESTIGATION OF RADIO FREQUENCY LICENSED SPECTRUM UTILIZATION IN NIGERIA: A ...ijwmn
This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of - 110dBm, a threshold of -95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investigated sub bands; only one band was completely occupied with spectrum occupancy of 100%. 12 bands were partially occupied while 11 were completely free. The average spectrum occupancy for the whole band was obtained as 11.64%. This showed good location for dynamic spectrum access and cognitive radio deployment, especially in Television White Space (TVWS).
Spectrum sharing in cognitive radio networks IJECEIAES
Cognitive radio networks are the next step to tackle scarcity in wireless networks given the increasing demand of radioelectric spectrum where the proposed solution is to share said resource to improve this situation. In the present article, a review of the current state of spectrum sharing in cognitive radio networks. To achieve this purpose, the articles published over the last 4 years on the matter were reviewed including topics such as mobile networks and TV. Some studies and simulations proposed to share the spectrum is shown. The current state of the studies reveals that there has been significant progress in this research area yet it is necessary to continue similar studies and set in motion different schemes.
NetSim Webinar on Cognitive Radio NetworksSANJAY ANAND
Why use a Network Simulator for research ?
Introduction to NetSim
Cognitive Radio Basics
Designing Cognitive Radio networks using NetSim
Modifying Cognitive Radio source C code in NetSim
How to develop custom metrics?
Q & A
This document summarizes research on improving the capacity of cellular systems using fractional frequency reuse (FFR). It discusses how frequency reuse is used to increase the number of users that can be served but causes interference, particularly for cell edge users. Fractional frequency reuse is proposed to solve this problem by allocating different frequency sets to cell center and edge users to reduce interference. The document also reviews different types of interference (co-channel and adjacent channel) and how power control can help reduce interference in cellular systems.
Capacity Improvement of Cellular System Using Fractional Frequency Reuse (FFR)IJEEE
Today wireless communication is mostly used rather than wired communication, due to remote location reach ability, less fault occurrence, less time to commissioning and low cost etc. But wireless network has less frequency spectrum to cover the whole world. To improve the capacity of cellular system in a limited spectrum without major technological changes, frequency is reused in cells. But it offers interferences mostly for cell edge users. To solve the problem of spectral congestion and user capacity, fractional frequency reuse is used. This paper gives idea about different frequency reuse factors, fractional frequency reuse and super cell with sectoring to improve the capacity of cellular system.
The document discusses the history and development of 3G mobile communication technology, specifically UMTS. It provides details on:
- The evolution from 1G to 2G mobile networks and the need for 3G to support higher data rates and multimedia services.
- The standardization of UMTS through ETSI and ITU, focusing on the two selected radio transmission technologies - UTRA FDD and TDD.
- The architecture of 3G UMTS networks, including frequency reuse techniques used to maximize capacity within limited spectrum availability.
PERFORMANCE ANALYSIS OF THE LINK-ADAPTIVE COOPERATIVE AMPLIFY-AND-FORWARD REL...IJCNCJournal
This paper analyzes the performance of cooperative amplify-and-forward (CAF) relay networks that
employ adaptive M-ary quadrature amplitude modulation (M-QAM)/M-ary phase shift keying (M-PSK)
digital modulation techniques in Nakagami-m fading channel. In particular, we present and compared the
analysis of CAF relay networks with different cooperative diversity and opportunistic routing strategies
such as regular Maximal Ratio Combining (MRC), Selection Diversity Combining (SDC), Opportunistic
Relay Selection with Maximal Ratio Combining (ORS-MRC) and Opportunistic Relay Selection with
Selection Diversity Combining (ORS-SDC). We advocate a simple yet unified numerical approach based on
the marginal moment generating function (MGF) of the total received SNR to compute the average symbol
error rate (ASER), mean achievable spectral efficiency, and outage probability performance metrics.
Advanced antenna techniques and high order sectorization with novel network t...ijwmn
Mobile operators commonly use macro cells with trad
itional wide beam antennas for wider coverage in th
e
cell, but future capacity demands cannot be achieve
d by using them only. It is required to achieve max
imum
practical capacity from macro cells by employing hi
gher order sectorization and by utilizing all possi
ble
antenna solutions including smart antennas. This pa
per presents enhanced tessellation for 6-sector sit
es
and proposes novel layout for 12-sector sites. The
main target of this paper is to compare the perform
ance
of conventional wide beam antenna, switched beam sm
art antenna, adaptive beam antenna and different
network layouts in terms of offering better receive
d signal quality and user throughput. Splitting mac
ro cell
into smaller micro or pico cells can improve the ca
pacity of network, but this paper highlights the
importance of higher order sectorization and advanc
e antenna techniques to attain high Signal to
Interference plus Noise Ratio (SINR), along with im
proved network capacity. Monte Carlo simulations a
t
system level were done for Dual Cell High Speed Dow
nlink Packet Access (DC-HSDPA) technology with
multiple (five) users per Transmission Time Interva
l (TTI) at different Intersite Distance (ISD). The
obtained results validate and estimate the gain of
using smart antennas and higher order sectorization
with
proposed network layout.
Advanced antenna techniques and high order sectorization with novel network t...ijwmn
Mobile operators commonly use macro cells with traditional wide beam antennas for wider coverage in the
cell, but future capacity demands cannot be achieved by using them only. It is required to achieve maximum
practical capacity from macro cells by employing higher order sectorization and by utilizing all possible
antenna solutions including smart antennas. This paper presents enhanced tessellation for 6-sector sites
and proposes novel layout for 12-sector sites. The main target of this paper is to compare the performance
of conventional wide beam antenna, switched beam smart antenna, adaptive beam antenna and different
network layouts in terms of offering better received signal quality and user throughput. Splitting macro cell
into smaller micro or pico cells can improve the capacity of network, but this paper highlights the
importance of higher order sectorization and advance antenna techniques to attain high Signal to
Interference plus Noise Ratio (SINR), along with improved network capacity. Monte Carlo simulations at
system level were done for Dual Cell High Speed Downlink Packet Access (DC-HSDPA) technology with
multiple (five) users per Transmission Time Interval (TTI) at different Intersite Distance (ISD). The
obtained results validate and estimate the gain of using smart antennas and higher order sectorization with
proposed network layout.
Wimax technology has reshaped the framework of broadband wireless internet
service. It provides the internet service to unconnected or detached areas such as east South
Africa, rural areas of America and Asia region. Full duplex helpers employed with one of
the relay stations selection and indexing method that is Randomized Distributed Space Time
are used to expand the coverage area of primary Wimax station. The basic problem was
identified at cell edge due to weather conditions (rain, fog), insertion of destruction because
of multiple paths in the same communication channel and due to interference created by
other users in that communication. It is impractical task for the receiver station to decode
the transmitted signal successfully at the cell edges, which increases the high packet loss and
retransmissions. But Wimax is a outstanding technology which is used for improving the
quality of internet service and also it offers various services like Voice over Internet
Protocol, Video conferencing and Multimedia broadcast etc where a little delay in packet
transmission can cause a big loss in the communication. Even setup and initialization of
another Wimax station nearer to each other is not a good alternate, where any mobile
station can easily handover to another base station if it gets a strong signal from other one.
But in rural areas, for few numbers of customers, installation of base station nearer to each
other is costlier task. In this review article, we present a scheme using R-DSTC technique to
choose and select helpers (relay nodes) randomly to expand the coverage area and help to
mobile station as a helper to provide secure communication with base station. In this work,
we use full duplex helpers for better utilization of bandwidth.
Promoting fractional frequency reuse performance for combating pilot contami...IJECEIAES
Massive multiple-input multiple-output (MIMO) improves spectrum efficiency by increasing the capacity of the wireless structure. Therefore, massive MIMO is promising for fifth generation (5G) wireless communications. In massive MIMO, channel estimation is a crucial part that should achieve reliable performance. Pilots are sent from the end-users to be used for estimating the channel. However, the problem of interference in pilot contamination affects the performance for cell-edge users. Specifically, pilot contamination appears when the same pilot sequence is utilized at the same time by more than one terminal. This lead to an inaccurate estimation of the channel. Consequently, the decoded data will not be reliable. For mitigating these pilot contamination effects, an enhanced fractional frequency reuse (eFFR) scheme is proposed that uses an algorithm in the allocation of pilot sequences to end users’ devices based on the locations of the users from the target base station (BS). The simulation results exhibit that the proposed scenario outweighs the traditional FFR within both signal to interference, and noise ratio (SINR), and capacity. Consequently, the suggested scenario enhances the performance of more than 80% of the cell terminals and the other 20% of the terminals have a slightly lower performance compared to the FFR.
Coverage and Capacity Performance Degradation on a Co-Located Network Involvi...Onyebuchi nosiri
The document investigates the performance effects of noise rise caused by spurious emission from a co-located jammer on the coverage radius and system capacity of a CDMA2000 and WCDMA network. Measurements were taken to evaluate the impact of increasing noise rise on these parameters. The results showed that as noise rise increased due to spurious emission, the coverage radius and number of supported users decreased, reducing system capacity. A noise rise of 2dB represented a 15 user reduction and 33% lower capacity. The study concludes noise rise degradation impacts must be controlled to maintain desired coverage area and capacity performance.
Coverage and Capacity Performance Degradation on a Co-Located Network Involvi...Onyebuchi nosiri
Abstract—Coverage and capacity performance in a cellular network determines the system potentials. If the coverage radius is limited, end users suffer poor service quality, if the system capacity reduces, fewer subscribers will be accommodated. This paper investigated the performance effects of the noise rise caused by the spurious emission from a co-located jammer involving downlink frequency of CDMA2000 and uplink frequency of WCDMA operating at 1.9GHz. Measurements were carried out to evaluate the impact on the coverage radius and the system capacity.
IRJET- Optimization of Frequency Spectrum through Beam ReplicationIRJET Journal
The document discusses optimizing frequency spectrum usage in GSM networks. It proposes transmitting information as beams that are duplicated across antennas or radio frequency modules to cover 360 degrees, rather than using multiple sectors with different frequencies. This reduces spectrum consumption compared to conventional sectoring methods. The method replicates broadcast control channels and transceivers across all beams transmitting the same information, allowing coverage with fewer resources. It aims to more efficiently use spectrum allocated for GSM as subscribers shift to newer technologies.
This document analyzes the capacity of MIMO wireless channels when accounting for impairments from physical transceiver hardware limitations. It is shown that when including the effects of transceiver impairments like non-linearities, phase noise, and quantization noise, the capacity of MIMO channels reaches a finite limit as SNR increases, rather than increasing without bound. This results in a zero multiplexing gain, unlike the ideal case without impairments. However, the relative capacity increase from MIMO over single-antenna channels remains at least as large when including impairments. Various figures are presented showing the capacity and multiplexing gain for different channel models and transceiver configurations. The document concludes by stating the analysis provides insights into understanding
Spectrum Sensing with VSS-NLMS Process in Femto/Macrocell EnvironmentsIJECEIAES
Handover is a process that allows a mobile node to change its attachment point. A mobile node connected to a network can, in order to improve the quality of service, have the need to leave it to connect to a cell either of the same network or of a new network. The present paper introduce three techniques using adaptive Variable Step-Size Least Mean Square (VSSLMS) filter combined with spectrum sensing probability method to detect the triggering of handover in heterogeneous LTE networks. These techniques are Normalized LMS (NLMS), Kwong-NLMS and Li-NLMS. The simulation environment is composed of two femtocells belonging to a macrocell. Five User Equipements (UEs) are positioned in one femtocell and are assumed closest to its circumference. Simulation results show that sensing probability with Li-NLMS algorithm has a better performance compared with classical NLMS and Kwong-NLMS
Dynamic Spectrum Allocation in Wireless sensor NetworksIJMER
Radio frequency spectrum is considered the most expensive and scarce resource among all wireless
network resources, and it is closely followed by the energy consumption, especially in low energy, battery powered
wireless sensor network devices. These days, there is a tremendous growth in the applications of wireless sensor
networks (WSNs) operating in unlicensed spectrum bands (ISM). Moreover, due to the rapid growth of wireless
devices that are designed to be operated in unlicensed spectrum bands, these spectrum bands have been overcrowded.
The problem with overcrowded spectrum or scarcity of spectrum can be solved by Dynamic Allocation of Spectrum.
In this paper we have presented the implementation and analysis of dynamic spectrum allocation in Wireless Sensors
Networks using the concept of Cognitive Radio Ad Hoc Network.
EFFICIENT ANALYSIS OF THE ERGODIC CAPACITY OF COOPERATIVE NON-REGENERATIVE RE...ijwmn
This paper proposes a novel efficient method to analyze the ergodic channel capacity of cooperative amplify-and-forward relay systems. This is accomplished by employing a very tight approximate moment generating function of the end-to-end signal-to-noise ratio that is applicable to various fading environments, including mixed and composite fading channels. Three adaptive source transmission policies are considered: constant power with optimal rate adaptation, optimal joint power and rate adaptation, and fixed rate with truncated channel inversion. Closed-form expressions for ergodic capacity under these policies are derived for Nakagami-m fading with independent but not identically distributed statistics. The accuracy of the proposed approximate method is validated through existing results and Monte Carlo simulations.
EFFICIENT ANALYSIS OF THE ERGODIC CAPACITY OF COOPERATIVE NON-REGENERATIVE RE...ijwmn
In this paper, we proposed a novel efficient method of analyzing the ergodic channel capacity of the
cooperative amplify-and-forward (CAF) relay system. This is accomplished by employing a very tight
approximate moment generating function (MGF) of end-to-end signal-to-noise ratio of 2-hop multi-relay
system, which is In this paper, we proposed a novel efficient method of analyzing the ergodic channel
capacity of the cooperative amplify-and-forward (CAF) relay system. This is accomplished by employing a
very tight approximate moment applicable to myriad of fading environments including mixed and
composite fading channels. Three distinct adaptive source transmission policies were considered in our
analysis namely: (i) constant power with optimal rate adaptation (ORA); (ii) optimal joint power and rate
adaptation (OPRA); and (iii) fixed rate with truncated channel inversion (TCIFR). The proposed frame
work based on the novel approximate MGF method is sufficiently general to encapsulate all types of fading
environments (especially for the analysis of the mixed fading case)and provides significant advantage to
model wireless system for mixed and composite fading channel. In addition to simplifying computation
complexity of ergodic capacity for CAF relaying schemes treated in literature, we also derive closed form
expressions for the above three adaptive source transmission policies under Nakagami-m fading with i.n.d
statistics. The accuracy of our proposed method has been validated with existing MGF expressions that are
readily available for specific fading environments in terms of bounds, and via Monte Carlo simulations.
IRJET- BER Reduction of Distributed Spatial Modulation in Cooperative Relay N...IRJET Journal
This document summarizes a research paper on reducing bit error rate (BER) of distributed spatial modulation in cooperative relay networks for cellular systems. The key points are:
1) Distributed spatial modulation (DSM) is proposed to overcome limitations of spatial modulation for mobile terminals by using multiple cooperative relays to form a virtual antenna array.
2) In DSM, source information is broadcast to relays and one relay is selected to forward the information to the destination, reducing transmit power.
3) A DSM-OFDM protocol is proposed where only one relay transmits per OFDM subcarrier while others transmit zero power.
4) Simulation results show the proposed DSM-OFDM scheme achieves
B ENCHMARKING OF C ELL T HROUGHPUT U SING P ROPORTIONAL F AIR S CHEDULE...ijwmn
The proportional fair (PF) scheduling algorithm com
promises between cell throughput and fairness. Many
research findings have been published by various re
searchers about PF algorithm based on mathematical
model and simulations. In this paper we have taken
the practical route to analyse the algorithm based
on
three types of subscription. In this benchmarking s
tudy, the user subscriptions are differentiated as
Gold,
Silver and Bronze schemes and they are provisioned
with certain throughputs. Apart from subscriptions
plans, the channel condition also plays a major rol
e in determining the throughput. So in order to ens
ure
fairness among different subscriptions even in the
bad channel conditions and to deliver the provision
ed
throughputs certain priorities are attached with th
e subscriptions. As per the subscription plans Gold
subscribers are assigned with 50% of the speed offe
red by the network as maximum based on CAT3 speed
(100 Mbps in DL and 50 Mbps in UL), Silver is assig
ned with 25% of the max speed and Bronze is
assigned with 12% of the max speed. The priorities
assigned to subscribers determines the fairness in
the
unfavourable channel conditions - Bronze (high), Si
lver and Gold (medium). In this paper, an
benchmarking tests have been performed with all of
three types of subscribers for nearly two hours in
the
live single cell network without any heterogeneous
cells influencing it. Furthermore, the results are
compared with the simulation results.
MOBILITY AND ROUTING BASED CHANNEL ESTIMATION FOR HYBRID MILLIMETER-WAVE MIMO...IJCNCJournal
Recently, technological developments have enhanced, the use of Millimeter-wave (mm-Wave) Multiple Input Multiple Output (MIMO) system in various communication applications and wireless sensor networks as channel estimation efficiency can be immensely improved with the help of this technological developments in Millimeter-wave MIMO system and wireless sensor network as well. Moreover, they can improve quality of communication services to a great extent. However, cell interference in Millimeter-wave (mm-Wave) MIMO system can produce a massive impact on spectral efficiency. Therefore, a Routing Enabled Channel Estimation (RECE) technique is presented in this article to minimize interference between cells. The proposed Channel Estimation technique improves channel capacity as well as spectral efficiency. Moreover, Normalized Mean Square Error (NMSE) is minimized heavily using proposed RECE technique. Here, main aim of this article is to reduce cell interference and channel estimation inside a cell by using route selection, beam selection, and spatial frequency estimation. Here, different scenarios and parameters are considered to evaluate performance efficiency of proposed RECE technique in terms of spectral efficiency, NMSE and SNR and compared against varied traditional channel estimation techniques. Moreover, it is clearly evident from performance results that the proposed channel estimation technique performs better than the other two methods.
Mobility and Routing based Channel Estimation for Hybrid Millimeter-Wave MIMO...IJCNCJournal
This document summarizes a research paper that proposes a Routing Enabled Channel Estimation (RECE) technique for hybrid millimeter-wave MIMO wireless sensor networks. The technique aims to reduce interference between cells to improve spectral efficiency and capacity. It uses route selection, beam selection, and spatial frequency estimation to minimize interference within a cell. The performance of the proposed RECE technique is evaluated based on metrics like spectral efficiency, normalized mean square error, and SNR and is shown to outperform other traditional channel estimation methods. The mathematical modeling of the proposed technique is also presented.
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A price based spectrum sharing scheme in wireless cellular networks
1. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
1
A Price Based Spectrum Sharing Scheme in Wireless Cellular
Networks
Sadath Kalolo (Corresponding author) 1
*, Anael Sam1
, Dina Machuve1
and Justinian Anatory2
1
The Nelson Mandela African Institute of Science and Technology, P.O Box 447 Arusha, Tanzania
Emails: *kalolos@nm-aist.ac.tz, anael.sam@nm-aist.ac.tz, dina.machuve@nm-aist.ac.tz
2
University of Dodoma, P.O Box 259, Dodoma, Tanzania
Email: anatory@engineer.com
Abstract
Radio frequency spectrum scarcity has become a high priority research area over the past few years. The huge
increase of network subscribers with multimedia applications coupled with underutilization of radio frequency
spectrum motivates the search for other measures to address the scarcity of radio frequency spectrum. This work
investigates on a price based spectrum sharing scheme for connection-oriented traffic in wireless cellular
networks as a solution to address the scarcity of radio frequency spectrum. Dynamic pricing approach is applied
with traffic overflows into neighbor networks. Performance evaluations of the scheme at steady state using
MATLAB simulations reveal significant gains to the quality of service. Application of the scheme to highly
loaded network traffic improves both network revenue and traffic channel utilizations.
Keywords::::Pricing, spectrum sharing, traffic overflows, Quality of service, channel utilizations, Wireless
cellular networks.
1. Introduction
The wireless cellular industry is growing fast coupled with an increase in bit rates and multimedia applications.
The global mobile cellular subscriptions stand at 6.8 billion users in 2013 with a global penetration rate of 96%,
128% in developed countries, and 89% in the developing countries(ITU 2013). In Tanzania, the mobile cellular
subscription was about 27.4 million in December 2012 with a penetration rate of 61%(TCRA 2012). This growth
demands for extra radio frequency spectrum capacities especially during busy hour periods.
Various approaches are used to optimize radio frequency utilization in wireless cellular networks including cell
split and frequency reuse, overlapping of cell layers, and dynamic channel allocation techniques (Rappaport
2009), (Garg 2007) &(Katzela and Naghshineh 1996). However, even with the high level of frequency reuse, as
with the introduction of micro, pico and femto cells, during busy hour periods the networks are overwhelmed
with high volumes of traffic resulting into congestions. Furthermore, repeated use of most of these methods ends
up with network complexity and an increase in radio frequency interference.
Wireless cellular network traffic is heterogeneous with spatial and temporal fluctuations. The demand for
wireless radio resources differs significantly between peak and off-peak hours. Radio frequency spectrum
utilization varies in the range of 15% to 85% in the band below 3 GHz (Akyildiz, Lee et al. 2006). Currently,
most wireless cellular networks offer cheaper or even free off-peak calls as a marketing incentive, in an attempt
to effectively utilize the available network capacity. However, this approach lacks flexibility to take into account
the actual network load by increasing the price when higher demands are anticipated (Bouroche 2003). Variation
of prices according to utilization assists to lighten network congestion and potentially yields more revenue to
network operator (Fitkov-Norris and Khanifar 2000)&(Viterbo and Chiasserini 2001).
Radio frequency (RF) spectrum sharing exploits the differences in traffic loadings between networks (Heinonen,
Pirinen et al. 2008). Sharing are feasible in three different cases depending on the objective; Sharing as a last
option, always connected to the base station that has the greatest of unused resources, and as a secondary user.
For networks with primary and secondary traffic routes, extra capacities are obtained by allowing incoming
traffic to overflow from primary channel groups to secondary channel groups (Iversen 2005). Alternative path
routing of overflow traffic widely improves the performance of hierarchical networks and IP networks (Huang,
Ko et al. 2008).
In Tanzania, wireless cellular networks’ traffic is disrupted by frequent power cut-off due to power shortage and
rationing. The growth of the industry, use of multimedia applications and frequent power rationing motivates the
search for other RF management strategies to address the problem of RF scarcity and quality of service. This
work investigates a price based spectrum sharing scheme for connection- oriented traffic in wireless cellular
network that applies dynamic pricing strategies with traffic overflows into neighbor networks at busy hour
periods. The rest of the paper is organized as follows; section II presents the state of art of RF spectrum
optimization and utilizations. Section III presents the system and traffic model of the network. Section IV
presents the network simulations and the results. Section V concludes our work paving directions for further
research.
2. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
2
2. State of Art
RF spectrums are assigned to wireless cellular networks exclusively on long term basis. In Tanzania seven
companies are licensed to offer wireless cellular network services(TCRA 2011), four of which operates GSM
technology while the remaining operate CDMA technology services. Absolute RF Channel Numbers (ARFCNs)
are assigned to GSM operators both in the 900 MHz and 1800 MHz bands. Furthermore, all GSM operators are
also licensed with UMTS/WCDMA services in 2100 MHz band. Wireless cellular network operators implement
a combination of traffic channels from the above frequency bands to support multi band terminals. Mobile
networks evolve from macro cell systems to micro, pico and femto cell systems in the search for more capacity
to accommodate more network users. Two categories of channel allocations are noted to be in use currently; the
baseband hoping (fixed channel assignment) and frequency hopping (dynamic channel assignment). Baseband
hoping are mainly used in rural areas sites are far from each other and each radio transceiver is assigned a fixed
frequency while frequency hopping schemes are commonly used in towns and cities. Cells in rural areas are
grouped into bigger clusters with a 4 × 3 cell cluster being in common use. In cities and towns a tight frequency
reuse pattern is used due to high traffic loads in these areas with a 1 × 1 cell cluster being in common use. To
avoid frequency collision, RF hopping techniques are used with appropriate parameter settings including; the
mobile allocation (MA), hopping sequence numbers (HSN), and mobile allocation index offset (MAIO).
However, some of the cells are poorly utilized while others are over utilized. Table 1 presents some of traffic
channel utilizations per cell extracted randomly from a wireless cellular operator as observed in our study.
Table 1: Traffic channel utilizations per cell
S/N
Sample Traffic Channel (TCH) Utilization per cell
Site No. Average TCH utilization (%) Site No. Average TCH utilization (%)
1 Site 1 122.4 17 Site 17 58.6
2 Site 2 6.6 18 Site 18 206.2
3 Site 3 19.3 19 Site 19 197.3
4 Site 4 115.2 20 Site 20 152.2
5 Site 5 118.7 21 Site 21 64.1
6 Site 6 91.3 22 Site 22 4.3
7 Site 7 131.4 23 Site 23 78.0
8 Site 8 106.4 24 Site 24 145.5
9 Site 9 114.1 25 Site 25 60.0
10 Site 10 154.4 26 Site 26 43.1
11 Site 11 138.6 27 Site 27 45.5
12 Site 12 73.6 28 Site 28 67.8
13 Site 13 142.2 29 Site 29 3.6
14 Site 14 103.7 30 Site 30 184.0
15 Site 15 74.8 31 Site 31 129.2
16 Site 16 160.4 32 Site 32 237.1
3. System Model
We consider two wireless cellular networks each operating the same radio access technology to allow RF
spectrum sharing when such requirement arises. Each network operator is basically assigned with a certain
amount of absolute RF channel numbers (ARFCNs). The home network and the neighbor network together
constitute a n + n server/ traffic channels loss system (M/M/n/n queue), where n = n + n . Mobile stations
are randomly distributed in the area of study and are randomly assigned to their home network from which they
buy services regularly. Sequential (ordered) hunting is done when mobile stations arrive at the base transceiver
stations such that home network traffic channels are always utilized first. When incoming traffic load exceeds the
capacity of the base transceiver station, extra traffic load overflows into neighbor wireless cellular network. This
depends on the availability of traffic channels at that operator.
We assume a pure chance traffic type I is offered into a system that works as a loss system (Blocked calls are
cleared). The call arrivals follow the standard poison modulated process with mean arrival rates of λ and
service times that are exponentially distributed with mean service rate of µ . Fig. 1 presents a two dimensional
Markov Chain used to represent the system evolution. Fig. 2 presents a traffic model where blocked calls in the
home network overflows into a neighbor network with available traffic channels n . Calls that overflow into the
neighbor network do not return to their home network even when the traffic channels are released. Overflowing
traffic is not pure chance traffic type I any more but burst. If all available traffic channels in the neighbor
network are also occupied, arriving calls are blocked and cleared.
3. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
3
Figure 1: A two dimensional Markov Chain
Figure 2: Traffic model
1.1 A price based spectrum sharing algorithm
We propose a scheduler that is decentralized and works at the base station controller/radio network controller.
The scheduler iterates through the base transceiver stations assessing their traffic channel utilization status, thus
providing base information for price adjustments based on the current traffic load. When traffic load is low, the
price is lowered to motivate more network users to place their calls into the network. As traffic load increases
arrangements are made such that when the home network capacity is used up, the extra traffic load overflows
into traffic channels available at the neighbor network. The limitation of the traffic channels at the neighbor
network operator will cause a steady increase in call pricing accordingly to deter additional traffic and suite the
available capacity.
1.2 The demand function
We use the demand function appearing in (Viterbo and Chiasserini 2001), where in (1) p is the call price per
time unit. Q is the quality of service index for call success probability (Q = 1 − P ) and P is the call blocking
probability. The parameters α and β are related to the user population characteristics.
, ) = ! "#$%&)
(1)
The demand in the time span ∆t is assumed to equal the actual traffic generated in the time span of ∆t, thus,
∆). ! "#$% *+)
= ∆). ,. 1 − -.) (2)
Where, , =
/0
10
, for 0 ≤ i ≤ n − 1
89 =
:0
*+
. ! "#0$% *+)
(3)
for 0 ≤ i ≤ n − 1
4. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
4
Assuming that p = p;, p , p , … . p= ) is the price vector that represents the cost per time unit of a call started
when the system is in a given state. Network users react to the changes in price per time unit by reducing their
number and duration of calls. Significant reaction is expected when network users access the RF traffic channels
from the neighbor network since these traffic channels are charged at slightly higher prices than the charges of
home network. If t> = and t>?@ are the minimum and maximum call duration of a call per time unit, then the
call duration in state i, 0) is given by (4).
:0
= ):AB! CD #0 #E)
(4)
for 0 ≤ i ≤ n − 1)
Where,
K> = ln
t>?@ t> =⁄ )
p= − p;)
The average call termination rate when the system is in state i, 0) is obtained by (5).
µ9 = I; + I + ⋯ + I9 (5)
for 1 ≤ i ≤ n
1.3 Call blocking
Analysis of the two dimensional Markov Chain is limited by state explosions as the number of traffic channels is
increased. We therefore obtain the blocking probability for the home network is at steady state and approximate
the overflow traffic using Fredericks and Hayward’s approximation method. Considering a single dimension
markov chain with n + 1 states and using cut equations we obtain the call blocking for the home network as in
(6).
p n ) = E n , a) = P = L∑ ∏
OPQR
1P
S
T
=R
ST; U ∏
OPQR
1P
=R
T (6)
The overflow traffic is given by (7).
w = a. E n , a) =
OPQR
1P
L∑ ∏
OPQR
1P
S
T
=R
ST; U ∏
OPQR
1P
=R
T 7)
The mean and peakedness of overflow traffic are obtained by (8) below (Iversen 2005).
Mean, w =
/0QR
10
L∑ ∏
/0QR
10
X
9T
YR
XT; U ∏
/0QR
10
YR
9T
Peakedness, z = 1 − [
OPQR
1P
L∑ ∏
OPQR
1P
S
T
=R
ST; U ∏
OPQR
1P
=R
T +
]PQR
^P
=R$ [
]PQR
^P
$_
]PQR
^P
`∑ ∏
]PQR
^P
a
PbR
cR
abE
d
QR
∏
]PQR
^P
cR
PbR
e
(8)
We apply Fredericks and Hayward’s approximation method (Iversen 2005) to approximate the overflow traffic
blocking as in (9).
E n, a, z)~E
=
g
,
?
g
, 1)~E
=
h
,
?
g
) (9)
Thus, the overflow traffic blocking is given by (10).
wi =
OPQR
1P
L∑ ∏
OPQR
1P
S
T
=R
ST; U ∏
OPQR
1P
=R
T E j
=k
hk
,
l
hk
m (10)
And system traffic congestion (STC) is obtained by (11).
STC = `∑ ∏
λPQR
µP
S
T
=R
ST; d ∏
λPQR
µP
=R
T E j
=k
hk
,
l
hk
m (11)
1.4 Traffic channel utilizations
We assume a sequential assignment of traffic channels to incoming traffic. The traffic carried by the iqr
channel
is the difference between the traffic lost from i − 1)qr
channel and the traffic lost from iqr
channel. Traffic
carried by the iqr
channel is independent of the number of channels after the iqr
channel in the hunting order. In
the home network traffic channel utilizations is obtained by (12).
s9 =
/0QR
10
L∑ ∏
/0QR
10
X
9T
YR
XT; U L∏
/0QR
10
X
9T − ∏
/0QR
10
X
9T U (12)
for: 0 ≤ k ≤ n
For the spectrum shared network the traffic channel utilizations when the system is in state i, j) is given by (13).
s9 =
/0QR
10
L∑ ∏
/0QR
10
X
9T
YR
XT; U w j
Yk
xk
,
y
xk
m L∏
/0QR
10
X
9T − ∏
/0QR
10
X
9T U (13)
For 0 ≤ z ≤ { and 0 ≤ | ≤ {
1.5 Network revenue
We assume that g = g , g , … , g~, … . g=R
) is the revenue vector representing the total revenue per time unit of
the network when a system is in a given state. The revenue per time unit when the system is state i, 0) is given
5. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
5
by (14).
•9 = ∑ 9
9
; for 0 ≤ i ≤ n (14)
And the total network revenue is obtained by the following equation.
€9 = ∑ 1 − -•9)9
9T; ∗ •9 (15)
for 0 ≤ i ≤ n
In a spectrum shared network when the system is in state i, j), the total network revenue is obtained using (16).
€9 = ∑ 1 − ƒ„…) ∗ •9
9
9T; (16)
for 0 ≤ i ≤ n
4. Simulations
We apply linear pricing vector (dynamic prices) to the demand function and allow extra incoming traffic load to
overflow into a neighbor network. We further assume that eight traffic channels (TCHs) are available from the
home network cell and traffic channels from the neighbor network are available in intervals of one traffic
channels. We also assume the variation of call holding periods from a maximum of 180 seconds to a minimum of
60 seconds. The ratio of the constants β and α in the demand function is assumed to equal four (
β
α† = 4) as used
in (Viterbo and Chiasserini 2001). We allow the dynamic price to vary from 0.7 to 1.4 units per second and for
the purpose of simplification, in all experiments we ignore the hand-off traffic. We use MATLAB simulations to
calculate the probability of blocking iteratively until the steady state is reached. The parameters obtained at
steady state are then used to compute various performance measures of the scheme.
4.1 Simulation Results
Dynamic pricing with spectrum sharing schemes produces lower call blocking probability of incoming calls
when traffic overflows into a neighbor network. Fig. 3 presents the comparative results of call blocking
probabilities (system traffic congestions) for a dynamic pricing with and without spectrum sharing.
Figure 3: Call blocking for a dynamic priced network with and without spectrum sharing
Traffic overflow causes poor traffic channel utilization in the system. This is explained by the burstness of the
traffic that overflows into the neighbor network (Peakedness = Variance Mean⁄ being greater than one).
However, when traffic load is high the traffic channel utilizations for dynamic prices with spectrum sharing
exceed dynamic prices without spectrum sharing. This suggests the applications of the scheme to highly traffic
loaded network scenarios. Fig. 4 presents the simulations results for traffic channel utilization.
10
-0.4
10
-0.2
10
0
10
0.2
10
-12
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
p (Traffic Load)
Pb(BlockingProbability)
Call blocking - dynamic pricing
without sharing
Sharing, N2=1
Sharing, N2=2
Sharing, N2=3
6. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
6
Figure 4: Traffic channel utilization for a dynamic priced network with and without spectrum sharing
A small increase to the total network revenue is observed when dynamic pricing with traffic overflows into the
neighbor network is applied as compared to dynamic pricing without spectrum sharing. Fig. 5 presents
simulation results for the total network revenue in the network. However, the change in the network revenue
generated for successive increase of neighbor network traffic channels is minimal.
Figure 5: Total network revenue for a dynamic priced network with and without spectrum sharing
5. Conclusions
We have presented a price based spectrum sharing scheme for connection oriented traffic in wireless cellular
networks. Dynamic prices are applied with traffic overflows into neighbor networks. Performance evaluation
using MATLAB simulations reveals significant gains in the quality of services offered and an improvement of
traffic utilizations when sharing are opted in a highly traffic loaded network. Gain in the network revenue is also
observed when spectrum sharing is allowed. The application of the scheme to the connectionless oriented traffic
is left as a direction for further research.
References
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Bouroche, M. (2003). Meeting QoS Requirements in a Dynamically Priced Commercial Cellular Network,
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10
-0.4
10
-0.2
10
0
10
0.2
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
p (Traffic Load)
TrafficChannelUtilization
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Without sharing
Sharing, N2=1
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Sharing, N2=3
10
-0.4
10
-0.2
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10
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1
p (Traffic Load)
R(NetworkRevenue)
Total network revenue - dynamic pricing
without sharing
with spectrum sharing N2 =3
7. Journal of Information Engineering and Applications www.iiste.org
ISSN 2224-5782 (print) ISSN 2225-0506 (online)
Vol.3, No.8, 2013
7
Iversen, V. B. (2005). "Teletraffic engineering and network planning." COM, DTU.
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Viterbo, E. and C. F. Chiasserini (2001). Dynamic pricing for connection-oriented services in wireless networks,
IEEE.
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those inseparable from gaining access to the internet itself. Printed version of the
journals is also available upon request of readers and authors.
IISTE Knowledge Sharing Partners
EBSCO, Index Copernicus, Ulrich's Periodicals Directory, JournalTOCS, PKP Open
Archives Harvester, Bielefeld Academic Search Engine, Elektronische
Zeitschriftenbibliothek EZB, Open J-Gate, OCLC WorldCat, Universe Digtial
Library , NewJour, Google Scholar