1. The document discusses relay technologies in IEEE 802.16j Mobile Multi-hop Relay (MMR) Networks.
2. It describes two relay modes (transparent and non-transparent), three relay transmission schemes (amplify and forward, selective decode and forward, demodulation and forward), and two relay pairing schemes (centralized and distributed).
3. The document also discusses characteristics of relay-based networks such as throughput enhancement, coverage increase, and cost reduction. It covers relay placement optimization and relaying techniques including time/frequency domain and cooperative relaying.
The document discusses simulation of relay modes in IEEE 802.16j mobile multi-hop relay (MMR) WiMAX networks. It describes two relay modes defined in IEEE 802.16j - transparent mode and non-transparent mode. Transparent mode is used to increase capacity within the base station coverage area using two hops, while non-transparent mode extends base station coverage using two or more hops. The document outlines the simulation setup and parameters used to simulate both transparent and non-transparent relay modes in an IEEE 802.16j MMR network using the NCTUns simulation tool.
This document provides an overview of the Mobile WiMAX IEEE 802.16m standard. It discusses key enhancements in Mobile WiMAX including improved non-line-of-sight coverage through advanced antenna diversity schemes and hybrid automatic repeat request. It also covers adaptive antenna systems and multiple-input multiple-output technologies to improve coverage. The document focuses on physical layer specifications for 802.16m including flexibility to support heterogeneous users and extending the use of multiple-input multiple-output transmission. It also discusses resource allocation, multi-cell multiple-input multiple-output, and interoperability with legacy WiMAX and other wireless technologies.
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.
WC and LTE 4G Broadband module 3- 2019 by Prof.Suresha VSURESHA V
This document provides an overview of Module 3 which covers the channel structure of LTE. It discusses:
1. The channel structure in LTE includes logical channels, transport channels, and physical channels. Logical channels provide services to higher layers, transport channels to lower layers, and physical channels handle actual transmission.
2. The LTE network architecture consists of the radio access network (E-UTRAN) and core network (EPC). E-UTRAN includes eNodeBs while EPC includes MME, SGW, PGW, and PCRF.
3. The radio interface protocol stack separates into control and user planes. It consists of layers like RRC, PDCP, RLC, MAC
Survivability Issues in Optical Wavalength Division Multiplexing (WDM) NetworkIOSR Journals
This document provides a survey of survivability issues in optical wavelength division multiplexing (WDM) networks. It discusses various protection techniques used in single and multi-domain WDM networks including link-based, path-based, and p-cycle protection. It reviews existing algorithms for survivability against multi-link failures such as LBSR, ESPP, and LSPP. It then proposes a new algorithm that combines p-cycle protection and wavelength assignment with Dijkstra's algorithm to reduce blocking probability. The document concludes that p-cycle protection is an effective technique and the proposed algorithm aims to find the shortest lightpath and optimize resource usage.
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.
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 simulation of relay modes in IEEE 802.16j mobile multi-hop relay (MMR) WiMAX networks. It describes two relay modes defined in IEEE 802.16j - transparent mode and non-transparent mode. Transparent mode is used to increase capacity within the base station coverage area using two hops, while non-transparent mode extends base station coverage using two or more hops. The document outlines the simulation setup and parameters used to simulate both transparent and non-transparent relay modes in an IEEE 802.16j MMR network using the NCTUns simulation tool.
This document provides an overview of the Mobile WiMAX IEEE 802.16m standard. It discusses key enhancements in Mobile WiMAX including improved non-line-of-sight coverage through advanced antenna diversity schemes and hybrid automatic repeat request. It also covers adaptive antenna systems and multiple-input multiple-output technologies to improve coverage. The document focuses on physical layer specifications for 802.16m including flexibility to support heterogeneous users and extending the use of multiple-input multiple-output transmission. It also discusses resource allocation, multi-cell multiple-input multiple-output, and interoperability with legacy WiMAX and other wireless technologies.
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.
WC and LTE 4G Broadband module 3- 2019 by Prof.Suresha VSURESHA V
This document provides an overview of Module 3 which covers the channel structure of LTE. It discusses:
1. The channel structure in LTE includes logical channels, transport channels, and physical channels. Logical channels provide services to higher layers, transport channels to lower layers, and physical channels handle actual transmission.
2. The LTE network architecture consists of the radio access network (E-UTRAN) and core network (EPC). E-UTRAN includes eNodeBs while EPC includes MME, SGW, PGW, and PCRF.
3. The radio interface protocol stack separates into control and user planes. It consists of layers like RRC, PDCP, RLC, MAC
Survivability Issues in Optical Wavalength Division Multiplexing (WDM) NetworkIOSR Journals
This document provides a survey of survivability issues in optical wavelength division multiplexing (WDM) networks. It discusses various protection techniques used in single and multi-domain WDM networks including link-based, path-based, and p-cycle protection. It reviews existing algorithms for survivability against multi-link failures such as LBSR, ESPP, and LSPP. It then proposes a new algorithm that combines p-cycle protection and wavelength assignment with Dijkstra's algorithm to reduce blocking probability. The document concludes that p-cycle protection is an effective technique and the proposed algorithm aims to find the shortest lightpath and optimize resource usage.
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.
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
This document provides an overview of network models, including the OSI and TCP/IP models. It describes the seven layers of the OSI model and the functions of each layer. The four layers of the TCP/IP model are also explained, along with their relationship to the OSI layers. Key topics covered include data encapsulation, peer-to-peer communication between layers, and the responsibilities of the physical, data link, network, transport, and application layers.
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.
WiMAX Features, Characteristics and Application in Wireless Technology Computingijtsrd
WiMAX stands for Worldwide Interoperability for Microwave Access which is also called as IEEE 802.16, the WiMAX technology is basically a wireless broadband communications technology, and it is used to provide higher data rate with increased coverage area. It means that it is based on IEEE 802.16 standard, which provides high speed data over a wide area. This technology can operate Non LOS non line of site . WiMAX is considered as a technology for point to multipoint wireless networking. In this paper it cover about WiMAX, WiMAX feature, it's Characteristics and Application and their architecture of WiMAX. Khushboo Kumari ""WiMAX Features, Characteristics and Application in Wireless Technology Computing"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30204.pdf
Paper Url : https://www.ijtsrd.com/computer-science/computer-network/30204/wimax-features-characteristics-and-application-in-wireless-technology-computing/khushboo-kumari
An Efficient Wireless Backhaul Utilizing MIMO Transmission and IPT ForwardingCSCJournals
Wireless backhaul has been received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high performance network, high throughput, low average delay and low packet loss rate, is highly appreciated to sustain the increasing proliferation in multimedia transmissions. The critical issue reducing the performance of wireless backhaul is the interference occurred in the network due to simultaneous nodes transmissions. In this research, we propose a high performance wireless backhaul using the low interference sensitivity MIMO based nodes. MIMO transmission has a better BER performance over SISO one even with the same transmission rate and bandwidth, which means that MIMO can operate at lower SINR values than SISO and give the same performance. This MIMO robust performance against interference gives us a greater benefit when adopted as a wireless interface in wireless backhaul than SISO. These facts motivated us to use the IEEE 802.11n the current MIMO standard to design a MIMO based wireless backhaul. In addition and to justify our assumptions, we investigate the effect of MIMO channels correlation, a major drawback in MIMO transmission, upon the system performance, and prove the robustness of the scheme under different MIMO channels correlation values. After proving the effectiveness of MIMO as a wireless interface for wireless backhaul, we further improve the performance of this MIMO-backhaul using the high efficient Intermittent Periodic Transmit (IPT) forwarding protocol. IPT is a reduced interference packet forwarding protocol with a more efficient relay performance than conventional method in which packets are transmitted continuously form the source nodes. By using these two techniques (IEEE 802.11n (MIMO) + IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by simply applying IEEE 802.11n to conventionally relayed backhaul. The proposed wireless backhaul will accelerate introduction of picocell based mobile communication systems.
Secure and Service-Oriented Network Control Framework for WiMAX Networks
IEEE 802.16 supports both TDD ( time-division duplex) and FDD (frequency-division duplex)
Multihop communication is needed for deployment of wimax network. Because of multihop
Security is issues associated with wimax network
Issue is how to support different services and applications in WiMAX networks
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.
This document analyzes the performance of Wi-Fi networks under three conditions: no fading, flat fading, and dispersive fading. It simulates these conditions using an IEEE 802.11a WLAN physical layer model in Matlab. The simulation measures packet error rate and bit rate as the signal-to-noise ratio and maximum Doppler shift are varied. With no fading, there is no packet error and bit rate increases with SNR. Under flat and dispersive fading, packet error and bit rates are affected differently based on the maximum Doppler shift. The best performance occurs under flat fading with a lower maximum Doppler shift of 100Hz.
The document provides information about the CCNA certification exam, including the exam number, total marks, duration, passing score, question types, and benefits of obtaining the certification. It also discusses common networking devices, network interface cards, hubs, switches, routers, common network topologies, and the functions of LANs, MANs and WANs. Finally, it introduces the OSI model and its seven layers.
The document provides information about the CCNA certification exam, including the exam number, total marks, duration, passing score, question types, and benefits of obtaining the certification. It also discusses common networking devices, network interface cards, hubs, switches, routers, common network topologies, and the functions of local, metropolitan, and wide area networks. Finally, it introduces the OSI model and its seven layers, describing the function of each layer.
Handover Behaviour of Transparent Relay in WiMAX NetworksIDES Editor
The knowledge on handover behaviour in WiMAX
network is essential for network management and planning
in order to achieve optimum system throughput. In this paper
we have analysed the handover behaviour of transparent relay
in several configurations for the IEEE 802.16j Mobile Multihop
Relay (MMR) WiMAX network. The simulation was
performed using NCTUns tool and adopted the hard handover
mechanism for three different relay network topologies with
varying mobile station speeds. The result shows the handover
for internal network is faster than the external network and
by appropriate relay deployment the system throughput can
be increased up to 14.39%.
The document discusses the OSI model, which defines 7 layers of network communication - physical, data link, network, transport, session, presentation, and application. It describes the functions of each layer, with a focus on the physical and data link layers. The physical layer deals with transmitting raw bits and electrical signaling. The data link layer handles framing, addressing, error checking, and flow control to deliver error-free frames between nodes.
The document discusses Ethernet technologies and concepts. It covers the basic Ethernet frame format, which includes fields for preamble, start-of-frame delimiter, destination address, source address, length/type, data, and frame check sequence. It also describes half-duplex frame transmission using CSMA/CD (carrier sense multiple access with collision detection) and the process stations follow to transmit frames and handle collisions. Additionally, it provides background on the development of Ethernet standards and the logical relationship between Ethernet and the OSI reference model.
This document analyzes the performance of different VoIP codecs over a WiMAX network using the network simulator NS2. The simulation varies parameters like the number of nodes and type of VoIP codec. Performance is evaluated based on metrics like throughput, average delay, and jitter. Results are presented graphically to compare these metrics for different codecs and number of nodes. The document provides background on VoIP codecs, IEEE 802.16 service flow classes, and simulation setup using NS2.
IEEE 802.11n Based Wireless Backhaul Enabled by Dual Channel IPT (DCH-IPT) Fo...CSCJournals
Wireless backhaul has received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high throughput with a minimum delay network is highly appreciated to sustain the increasing proliferation in multimedia transmissions. In this paper, we propose a backhaul network using the Multi-Input Multi-Output (MIMO) IEEE 802.11n standard in conjunction with the Dual Channel Intermittent Periodic Transmit IPT (DCH-IPT) packets forwarding protocol. By using these two techniques (IEEE 802.11n + DCH-IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by the currently used backhaul. The current backhaul is based upon Single-Input Single-Output (SISO) IEEE 802.11a,b,g standards in conjunction with Single Channel Conventional (SCH-Conv) relaying protocol in which packets are transmitted continuously from source nodes using single channel. The proposed backhaul will accelerate introduction of picocell based mobile communication systems.
The document discusses the CCNA certification exam including details about the exam such as number of questions, duration, passing score, and benefits of obtaining the certification. It also provides information about networking devices, topologies, protocols, and the OSI model layers. Key topics covered include switches, routers, network topologies like star and bus, the 7 layers of the OSI model and what each layer is responsible for, and how data is encapsulated as it moves through the layers from physical to application.
The document discusses the CCNA certification exam and provides details about its format, benefits, and requirements. It then covers networking concepts like network devices, topologies, protocols, and the OSI model. Key points include that the CCNA exam tests knowledge of networking fundamentals, has multiple choice and simulation questions, and benefits career advancement. It also defines common network components, topologies, and each layer of the OSI model.
The goal of the carrier today is to offer manageable end-user data services with a measurable QoS (Quality-of-Service) at the minimum cost per bit, using the smallest footprint systems, with the simplest implementation that allows for service-level agreements, operational efficiency, and traffic scalability. This has lead to the emergence of two design principles: the lower the layer at which...
The document discusses the CCNA certification exam including details about the exam such as number of questions, duration, passing score, and benefits of obtaining the certification. It also provides an overview of networking concepts including the purpose of networking, networking devices, network interface cards, hubs, switches, routers, network topologies, LANs/WANs, virtual private networks, bandwidth, the OSI model, and IEEE 802 standards.
The document discusses transparent electronics, which uses invisible electronic circuitry and optoelectronic devices. It describes applications like smart car windshields and solar panel embedded windows. Transparent conducting oxides are key materials that are engineered to be both transparent and conductive through doping and modifying the band gap. Circuits can be made through transparent thin film resistors, capacitors, and transistors. Further research is still needed to improve the accuracy of transparent thin film resistors.
This document provides an overview of network models, including the OSI and TCP/IP models. It describes the seven layers of the OSI model and the functions of each layer. The four layers of the TCP/IP model are also explained, along with their relationship to the OSI layers. Key topics covered include data encapsulation, peer-to-peer communication between layers, and the responsibilities of the physical, data link, network, transport, and application layers.
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.
WiMAX Features, Characteristics and Application in Wireless Technology Computingijtsrd
WiMAX stands for Worldwide Interoperability for Microwave Access which is also called as IEEE 802.16, the WiMAX technology is basically a wireless broadband communications technology, and it is used to provide higher data rate with increased coverage area. It means that it is based on IEEE 802.16 standard, which provides high speed data over a wide area. This technology can operate Non LOS non line of site . WiMAX is considered as a technology for point to multipoint wireless networking. In this paper it cover about WiMAX, WiMAX feature, it's Characteristics and Application and their architecture of WiMAX. Khushboo Kumari ""WiMAX Features, Characteristics and Application in Wireless Technology Computing"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30204.pdf
Paper Url : https://www.ijtsrd.com/computer-science/computer-network/30204/wimax-features-characteristics-and-application-in-wireless-technology-computing/khushboo-kumari
An Efficient Wireless Backhaul Utilizing MIMO Transmission and IPT ForwardingCSCJournals
Wireless backhaul has been received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high performance network, high throughput, low average delay and low packet loss rate, is highly appreciated to sustain the increasing proliferation in multimedia transmissions. The critical issue reducing the performance of wireless backhaul is the interference occurred in the network due to simultaneous nodes transmissions. In this research, we propose a high performance wireless backhaul using the low interference sensitivity MIMO based nodes. MIMO transmission has a better BER performance over SISO one even with the same transmission rate and bandwidth, which means that MIMO can operate at lower SINR values than SISO and give the same performance. This MIMO robust performance against interference gives us a greater benefit when adopted as a wireless interface in wireless backhaul than SISO. These facts motivated us to use the IEEE 802.11n the current MIMO standard to design a MIMO based wireless backhaul. In addition and to justify our assumptions, we investigate the effect of MIMO channels correlation, a major drawback in MIMO transmission, upon the system performance, and prove the robustness of the scheme under different MIMO channels correlation values. After proving the effectiveness of MIMO as a wireless interface for wireless backhaul, we further improve the performance of this MIMO-backhaul using the high efficient Intermittent Periodic Transmit (IPT) forwarding protocol. IPT is a reduced interference packet forwarding protocol with a more efficient relay performance than conventional method in which packets are transmitted continuously form the source nodes. By using these two techniques (IEEE 802.11n (MIMO) + IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by simply applying IEEE 802.11n to conventionally relayed backhaul. The proposed wireless backhaul will accelerate introduction of picocell based mobile communication systems.
Secure and Service-Oriented Network Control Framework for WiMAX Networks
IEEE 802.16 supports both TDD ( time-division duplex) and FDD (frequency-division duplex)
Multihop communication is needed for deployment of wimax network. Because of multihop
Security is issues associated with wimax network
Issue is how to support different services and applications in WiMAX networks
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.
This document analyzes the performance of Wi-Fi networks under three conditions: no fading, flat fading, and dispersive fading. It simulates these conditions using an IEEE 802.11a WLAN physical layer model in Matlab. The simulation measures packet error rate and bit rate as the signal-to-noise ratio and maximum Doppler shift are varied. With no fading, there is no packet error and bit rate increases with SNR. Under flat and dispersive fading, packet error and bit rates are affected differently based on the maximum Doppler shift. The best performance occurs under flat fading with a lower maximum Doppler shift of 100Hz.
The document provides information about the CCNA certification exam, including the exam number, total marks, duration, passing score, question types, and benefits of obtaining the certification. It also discusses common networking devices, network interface cards, hubs, switches, routers, common network topologies, and the functions of LANs, MANs and WANs. Finally, it introduces the OSI model and its seven layers.
The document provides information about the CCNA certification exam, including the exam number, total marks, duration, passing score, question types, and benefits of obtaining the certification. It also discusses common networking devices, network interface cards, hubs, switches, routers, common network topologies, and the functions of local, metropolitan, and wide area networks. Finally, it introduces the OSI model and its seven layers, describing the function of each layer.
Handover Behaviour of Transparent Relay in WiMAX NetworksIDES Editor
The knowledge on handover behaviour in WiMAX
network is essential for network management and planning
in order to achieve optimum system throughput. In this paper
we have analysed the handover behaviour of transparent relay
in several configurations for the IEEE 802.16j Mobile Multihop
Relay (MMR) WiMAX network. The simulation was
performed using NCTUns tool and adopted the hard handover
mechanism for three different relay network topologies with
varying mobile station speeds. The result shows the handover
for internal network is faster than the external network and
by appropriate relay deployment the system throughput can
be increased up to 14.39%.
The document discusses the OSI model, which defines 7 layers of network communication - physical, data link, network, transport, session, presentation, and application. It describes the functions of each layer, with a focus on the physical and data link layers. The physical layer deals with transmitting raw bits and electrical signaling. The data link layer handles framing, addressing, error checking, and flow control to deliver error-free frames between nodes.
The document discusses Ethernet technologies and concepts. It covers the basic Ethernet frame format, which includes fields for preamble, start-of-frame delimiter, destination address, source address, length/type, data, and frame check sequence. It also describes half-duplex frame transmission using CSMA/CD (carrier sense multiple access with collision detection) and the process stations follow to transmit frames and handle collisions. Additionally, it provides background on the development of Ethernet standards and the logical relationship between Ethernet and the OSI reference model.
This document analyzes the performance of different VoIP codecs over a WiMAX network using the network simulator NS2. The simulation varies parameters like the number of nodes and type of VoIP codec. Performance is evaluated based on metrics like throughput, average delay, and jitter. Results are presented graphically to compare these metrics for different codecs and number of nodes. The document provides background on VoIP codecs, IEEE 802.16 service flow classes, and simulation setup using NS2.
IEEE 802.11n Based Wireless Backhaul Enabled by Dual Channel IPT (DCH-IPT) Fo...CSCJournals
Wireless backhaul has received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high throughput with a minimum delay network is highly appreciated to sustain the increasing proliferation in multimedia transmissions. In this paper, we propose a backhaul network using the Multi-Input Multi-Output (MIMO) IEEE 802.11n standard in conjunction with the Dual Channel Intermittent Periodic Transmit IPT (DCH-IPT) packets forwarding protocol. By using these two techniques (IEEE 802.11n + DCH-IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by the currently used backhaul. The current backhaul is based upon Single-Input Single-Output (SISO) IEEE 802.11a,b,g standards in conjunction with Single Channel Conventional (SCH-Conv) relaying protocol in which packets are transmitted continuously from source nodes using single channel. The proposed backhaul will accelerate introduction of picocell based mobile communication systems.
The document discusses the CCNA certification exam including details about the exam such as number of questions, duration, passing score, and benefits of obtaining the certification. It also provides information about networking devices, topologies, protocols, and the OSI model layers. Key topics covered include switches, routers, network topologies like star and bus, the 7 layers of the OSI model and what each layer is responsible for, and how data is encapsulated as it moves through the layers from physical to application.
The document discusses the CCNA certification exam and provides details about its format, benefits, and requirements. It then covers networking concepts like network devices, topologies, protocols, and the OSI model. Key points include that the CCNA exam tests knowledge of networking fundamentals, has multiple choice and simulation questions, and benefits career advancement. It also defines common network components, topologies, and each layer of the OSI model.
The goal of the carrier today is to offer manageable end-user data services with a measurable QoS (Quality-of-Service) at the minimum cost per bit, using the smallest footprint systems, with the simplest implementation that allows for service-level agreements, operational efficiency, and traffic scalability. This has lead to the emergence of two design principles: the lower the layer at which...
The document discusses the CCNA certification exam including details about the exam such as number of questions, duration, passing score, and benefits of obtaining the certification. It also provides an overview of networking concepts including the purpose of networking, networking devices, network interface cards, hubs, switches, routers, network topologies, LANs/WANs, virtual private networks, bandwidth, the OSI model, and IEEE 802 standards.
The document discusses transparent electronics, which uses invisible electronic circuitry and optoelectronic devices. It describes applications like smart car windshields and solar panel embedded windows. Transparent conducting oxides are key materials that are engineered to be both transparent and conductive through doping and modifying the band gap. Circuits can be made through transparent thin film resistors, capacitors, and transistors. Further research is still needed to improve the accuracy of transparent thin film resistors.
IEEE BASE paper on artifical retina using TTF technologyAnu Antony
This document summarizes research on an artificial retina that uses thin-film transistors driven by a wireless power supply. Key points:
- The artificial retina is fabricated on a transparent and flexible substrate to allow implantation on the curved human retina using an epiretinal method. This preserves high image resolution and minimally damages living retinal tissue.
- A wireless power system using inductive coupling, rectification, and voltage regulation was developed and shown to provide enough stable power for the artificial retina's operation, despite some output voltage fluctuations.
- Testing showed the artificial retina could correctly detect illumination profiles as output voltage profiles, even when powered by the unstable wireless source, demonstrating its potential for implant use. However, further development
This document provides an introduction to transparent electronics. It discusses how transparent electronics allows for invisible electronic circuitry and devices with applications in consumer electronics, energy, and transportation. The basic device structure is similar to conventional electronics, but the materials must be transparent in the visible spectrum. The goals of transparent electronics are to discover and implement transparent electronic materials, incorporate these materials into transistor and circuit designs, and achieve application-specific performance requirements. Realizing this technology requires expertise from various fields including materials science, chemistry, physics, and engineering. In the past decade, the available materials for transparent electronics have expanded beyond transparent conducting oxides to include other conducting, dielectric, and semiconducting materials needed for full device fabrication.
This document provides an overview of transparent electronics as presented in a student's seminar report. It includes an introduction to transparent electronics, a brief history covering transparent conductive oxides and thin-film transistors, and how transparent electronic devices work utilizing oxide semiconductors. The document consists of the student's seminar report covering topics such as advancements, applications, markets, and future scope of transparent electronics. It is presented to fulfill the requirements for a Bachelor of Technology degree.
The document discusses transparent electronics and transparent conducting materials. It explains that transparent conductors are neither 100% optically transparent nor metallically conductive due to the contradictory nature of these properties from a band structure perspective. Transparent conducting oxides (TCOs) are commonly used by degenerately doping the material to displace the Fermi level into the conduction band, providing high carrier mobility and low optical absorption. The document also discusses applications of transparent amorphous oxide semiconductors (TAOSs) in displays and chemical detection.
This document discusses transparent electronics using transparent conducting oxides (TCOs). It introduces TCOs such as indium tin oxide which allow for both optical transparency and electrical conductivity. This is achieved through degenerate doping and the Burstein-Moss shift. TCOs find applications in transparent thin-film transistors, resistors, capacitors and indutors which could enable see-through laptops, phones and solar panels. Further advances could lead to solar windows but also environmental challenges.
Artificial retina using thin film transistor reportRam B
The document describes an artificial retina that uses thin-film photodiodes and poly-silicon thin-film transistors. It is fabricated on transparent and flexible substrates to mimic the functions of a natural retina. The artificial retina achieves edge enhancement through a circuit design that processes signals from the photodiodes through current mirrors and load resistances. It can be implanted inside the eye through either epiretinal or subretinal implantation methods to help restore sight for those who have lost vision due to retinal damage or disease.
This document discusses cost-effective deployment of relay stations in WiMAX networks. It first outlines the costs associated with base stations and relay stations, including capital expenditures and operational expenditures. It then discusses challenges in planning relay station placement to both improve quality of service and reduce costs. Specifically, it examines dividing the network into zones based on signal strength and using different modulation and coding schemes in each zone. The goal is to determine optimal relay station locations and configurations to enhance network performance while minimizing overall deployment costs.
The document discusses seamless handovers within WiMAX and between WiMAX and WLAN networks. It provides an overview of these two wireless technologies, including their standards, architectures, and key aspects like WiMAX's point-to-multipoint mode and WLAN's use of 802.11g. The document then examines some main issues for seamless handovers, such as latency and packet loss. It aims to review and compare various solutions for seamless handovers within and between these networks based on certain criteria.
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 compares the next-generation mobile broadband technologies LTE and WiMAX. It describes their quality of service (QoS) structures and how they are designed to support current and future QoS needs to sustain various application requirements. The document provides details on LTE and WiMAX standards, architectures, and QoS support through different bearer types and service flows.
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.
Performance Analysis of Different Combination of Mimo Antenna System using Di...ijtsrd
The wireless communication system like MIMO OFDM Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing , the transmitter and the receiver have to be synchronized to each other in order to make efficient transmission. In this paper, OFDM based on the orthogonality are proposed for timing synchronization for Rayleigh channel using different combination of antenna system. This work simulate by Matlab R2013a tool by using communication block, and result shown between BER verses SNR. Anjali Juneja ""Performance Analysis of Different Combination of Mimo Antenna System using Digital Modulation"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21364.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/21364/performance-analysis-of-different-combination-of-mimo-antenna-system-using-digital-modulation/anjali-juneja
Wireless Mesh Networks Based on MBPSO Algorithm to Improvement Throughput IJECEIAES
1. The document discusses a study that aims to improve throughput in wireless mesh networks using a Modified Binary Particle Swarm Optimization (MBPSO) algorithm.
2. Wireless mesh networks rely on semi-static node configurations and paths that impact performance metrics like packet delivery ratio, end-to-end delay, and throughput. Previous heuristic algorithms were summarized to identify a suitable approach.
3. The study adapts an MBPSO approach to improve throughput. Results showed throughput increased by 5.79% compared to previous work.
IEEE 802 Standard Network’s Comparison under Grid and Random Node Arrangement...Eswar Publications
The IEEE 802 standard well-known as 802.11 called as Wi-Fi network, 802.15.4 called as ZigBee or sensor network and 802.15.1 called as Bluetooth network. The network such as ZigBee, Bluetooth and Wi-Fi works in 2.4 GHz ISM band. All the above networks works in same ISM band of 2.4 GHz, but the performance of the network varies. The performance of simulation depends upon the coverage area, data rates, and power consumption in each network. The heterogeneous network performances is evaluated with static and mobility model in random and grid node placement by varying the traffic loads of one CBR and with five CBR for each network. The
simulation result is compared in terms of jitter, average end to end delay and throughput to analyze the network performance in the 2.4 GHz frequency band. IEEE 802.11 network shows the low jitter and delay value with high throughput compared with sensor network.
In this paper, we examine WiMAX – based network and evaluate the performance for quality of service (QoS) using an idea of IEEE 802.16 technology. In our models, the study used a multiprocessor architecture organized by the interconnection network. OPNET Modeler is used to simulate the architecture and to calculate the performance criteria (i.e. throughput, delay and data dropped) that
slightly concerned in network estimation. It is concluded that our models shorten the time quite a bit for
obtaining the performance measures of an end-to-end delay as well as throughput can be used as an
effective tool for this purpose.
Opnet based simulation and investigation of wimax network using different qo seSAT Publishing House
This document summarizes a study that used the OPNET simulation tool to evaluate the performance of WiMAX networks with different numbers of nodes under various quality of service (QoS) metrics. Three WiMAX network models were created with 15, 25, and 40 nodes. Key performance indicators like initial ranging activity, delay, transmission power, and path loss were analyzed. In general, initial ranging activity and path loss were highest for the medium sized network while delay and transmission power increased with network size. The analysis provided insights into how QoS is impacted by the scale of the WiMAX network.
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.
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.
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.
This document analyzes the performance of routing algorithms for an integrated Wi-Fi/WiMAX heterogeneous network. It begins with an introduction describing the need for such integrated networks to provide uninterrupted wireless service. It then provides overviews of the Wi-Fi (IEEE 802.11n) and WiMAX (IEEE 802.16e) technologies that would be integrated. Several routing algorithms are described, including Bellman-Ford, AODV, DYMO, OLSRv2, RIP, and OSPFv2. The document then discusses how to statistically analyze the performance of the integrated network using these various routing algorithms, focusing on metrics like throughput, packet loss probability, and distortion. The analysis will
The document discusses challenges and security issues related to the Internet of Things (IoT). It notes that while IoT provides many benefits across various industries like healthcare, transportation, and more, it also faces challenges. Key challenges include the large number of devices and sensors requiring unique identification, and the need for proper data storage, management, and processing. Regarding security issues, the document states that IoT devices are vulnerable to attacks due to limited computing resources. It proposes using cloud computing and other techniques to help build a more secure IoT infrastructure.
Performance analysis of IEEE 802.11ac based WLAN in wireless communication sy...IJECEIAES
IEEE 802.11ac based wireless local area network (WLAN) is emerging WiFi standard at 5 GHz, it is new gigabit-per-second standard providing premium services. IEEE 802.11ac accomplishes its crude speed increment by pushing on three distinct measurements firstly is more channel holding, expanded from a maximum of 80 MHz up to 160 MHz modes. Secondly, the denser modulation, now using 256-QAM, it has the ability to increase the data rates up to 7 Gbps using an 8×8 multiple input multiple output (MIMO). Finally, it provides high resolution for both narrow and medium bandwidth channels. This work presents a study to improve the performance of IEEE 802.11ac based WLAN system.
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.
IEEE 802.16 is a standard for fixed wireless broadband access that provides high-speed internet access over long distances (up to 31 miles). It uses point-to-multipoint radio links to connect base stations to multiple subscriber stations and supports services like data, voice, and video. The standard defines the physical and medium access control layers for both licensed and unlicensed frequency bands below 11GHz to support residential and small business broadband connectivity as a cheaper alternative to fiber.
A MODIFIED IEEE 802.15.6 MAC SCHEME TO ENHANCE PERFORMANCE OF WIRELESS BODY A...ijwmn
- The document proposes a modified IEEE 802.15.6 MAC scheme to enhance the performance of wireless body area networks for e-health applications.
- The standard IEEE 802.15.6 MAC scheme is unable to fulfill all the requirements of medical applications in WBANs due to some limitations.
- The proposed MAC scheme modifies the superframe structure, user priorities, and access mechanism of the standard IEEE 802.15.6 to improve reliability, throughput, delay, energy consumption, and fairness.
A MODIFIED IEEE 802.15.6 MAC SCHEME TO ENHANCE PERFORMANCE OF WIRELESS BODY A...ijwmn
The recently released IEEE 802.15.6 standard specifies several physical (PHY) layers and medium access
control (MAC) layer protocols for variety of medical and non-medical applications of Wireless Body Area
Networks (WBAN). Themedical applications of WBAN hasseveral obligatory requirements and constrains
viz. high reliability, strict delaydeadlines and low power consumption.The standard IEEE 802.15.6 MAC
scheme is not able to fulfil the all requirements of medical applications of WBAN. To address this issue we
propose anIEEE 802.15.6-based MAC schemethat is the modification of superframe structure, user
priorities and access mechanism of standard IEEE 802.15.6 MAC scheme. The proposed superframe has
three access phases: random access phases (RAP), manage access phases (MAP) and contention access
phase (CAP). The proposed four user priorities nodes access the channel during RAP using CAMA/CA
mechanism with a large value of contention window. The proposed MAC scheme uses RTS/CTS access
mechanism instead of basic access mechanism to mitigate the effect of hidden and expose terminal
problem. Moreover, we develop an analytical model to evaluate the performance of proposed MAC scheme
and solve the analytical model using Maple. The results show that the modified IEEE802.15.6 MAC
scheme achieve the better performance in terms of reliability, throughput, average access delay, energy
consumption, channel utilization and fairness compared to standard IEEE 802.15.6 MAC scheme in Ehealth applications.
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GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
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10 satishkumar final_paper--105--113
1. Computer Engineering and Intelligent Systems www.iiste.org
ISSN 2222-1719 (Paper) ISSN 2222-2863 (Online)
Vol 2, No.3
Relay Technologies in IEEE 802.16j Mobile Multi-hop Relay (MMR)
Networks
D.Satish Kumar (Corresponding author)
Department of Electrical and Electronics Engineering, Kalignar Karunanidhi Institute of Technology
Coimbatore-641402, Tamilnadu, India.
Tel: +919843723396, Email: satishcoimbatore@yahoo.co.in
Dr.N.Nagarajan
Department of Computer Science and Engineering, Coimbatore Institute of Engineering and Technology
Coimbatore-641109, Tamilnadu, India
Email: swekalnag@gmail.com
Abstract
IEEE 802.16 standard is created to compete with cable access networks. In the beginning end users are immobile and have
a line of sight with base station, now it moved to mobile non line of sight (NLOS) with the new standard IEEE 802.16e
and IEEE 802.16j. The new IEEE 802.16j standard which is an amendment to IEEE 802.16e is mobile multi hop relay
(MMR) specification for wireless networks.
This paper discusses relay modes, relay transmission schemes and relay pairing schemes of IEEE 802.16j. Relay
technologies such as transparent relay modes, non transparent relay mode, relay pairing schemes such as centralized relay
pairing schemes, distributed relay pairing scheme, characterises of relay based networks such as throughput enhancement,
capacity increase, cost reduction , relay techniques such as time domain frequency domain relay techniques and relay
placement are also discussed in this paper. The paper also discusses about integration of IEEE 802.16j with IEEE 802.11.
Keywords: IEEE 802.16j, Relay pairing schemes, relay techniques, Relay modes, WIMAX, NCTUns, etc
Contents
1. Introduction-Wireless Groups.
2. IEEE 802.16j Standard
3. WiMAX Forum.
4. Relay Modes.
a) Transparent Mode
b) Non Transparent Mode
5. Relay Transmission Schemes.
a) Amplify and Forward
b) Selective Decode and Forward.
c) Demodulation and Forward.
6. Relay Pairing Schemes.
a) Centralized Relay Pairing Schemes.
b) Distributed Relay Pairing Schemes
7. Relay Placement.
8. Characteristics of Relay based Networks.
9. Relaying Techniques.
10. Multiple-Input Multiple-Output (MIMO) communication for IEEE 802.16j
11. IEEE 802.16j Protocol Layering.
a) Data/Control Plane.
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2. b) Management Plane.
12. IEEE 802.16j [WIMAX] Integration with IEEE 802.11n [Wi-Fi]
13. Conclusion And Future Works
14. References
1. Introduction-Wireless Groups
Wireless systems for achieving high speed mobile wireless access services can be divided into two groups. The first group
is International Mobile telecommunications-2000 [IMT-2000] which include wideband code division multiple access(W-
CDMA), high speed downlink packet access (HSDPA), high speed uplink packet access (HSUPA), High speed packet
access plus (HSUPA+), LTE/LTE-Advanced specified by 3GPP (3rd generation Partnership project ) , CDMA2000 1x and
Ultra Mobile Broadband (UMB) specified by 3GPP2. The second group consists of IEEE 802.16e, IEEE 802.16j [1], and
IEEE 802.16m [1] standard specified by IEEE 802.16 committee.
The second group is also called as Worldwide interoperability for Microwave access (WiMAX) standard is one of the 4G
(4th generation ) telecommunication technologies that supplies wireless communication of data through different
transmission links like point to multi point. Two groups which play role in the development of IEEE 802.16j standard is,
IEEE 802.16 working group on Broadband wireless Access standard which develop standards and recommended practices
to support the development of broadband Wireless metropolitan area networks and WiMAX forum which certify and
promotes broadband wireless product based on IEEE 802.16 standard.
2. IEEE 802.16J Standard
The new task group IEEE 802.16j-2009 standard [1][2] of IEEE 802.16 Air interface for Broadband Wireless Access was
officially established in March 2006, in order to support mobile multi-hop relay (MMR) specification, mesh mode is
removed in the IEEE 802.16 -2009 standard.. The specification is shown in table 2, it is an amendment of IEEE 802.16e
[3][4][5][6] standard for enhancing coverage throughput as shown in fig 1 and system capacity. It provides multi hop
wireless connectivity where traffic between a base station (BS) and a subscriber station (SS) can be relayed through a relay
station. This system enables mobile stations to communicate with a base station through intermediate relay station.
Multihop relay station (M-RS) is an optional deployment that may be used to provide additional coverage or performance
advantage in an access network. The RS may be fixed in location or, in the case of an access RS, it may be mobile access
RS. Most of the time the RS will act as a BS and should have its own physical cell identifier, and also it should be able to
transmit its own synchronization channels and control information. There should be no difference between cell control in
RS and BS.
The radio link originating or terminating at an MS is named as the access link, but the link between BS and RS or between
pair of RSs is called relay link. Theses access link and relay link can be used for uplink and downlink data transmission.
This standard [7][8][9]defines the physical and the MAC layer specifications for MMR networks. The MAC layer
supports functions such as network entry, bandwidth request, forwarding of PDUs, connection management and Hand
over. The PHY layer adopts orthogonal frequency division multiple access (OFDMA) [1][2][3] as the primary channel
access mechanism for non-line of sight (NLOS) communications in the frequency band below 11 GHz. Where multiple
users are allocated separate set of slots, so that they can communicate in parallel. It supports point to multipoint (PMP)
network topology where resource allocation is performed by BS on a per connection basis and the SSs are treated equally.
MIMO [2] techniques have ability to exploit NLOS channels and increase spectral efficiency compared to single input
single output (SISO) systems. It is able to provide high capacity and data rate without increasing bandwidth. The gain of
MIMO is multiplexing gains, diversity gains and array gains.
Fig 1: IEEE 802.16j Mobile multi hop relay (MMR) network.
The aim of this paper, to the best of our knowledge the first of its kind, is to give an overview of the relay technologies in
IEEE 802.16j along with the different proposed and probable research solutions, starting right from the advent of IEEE
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3. 802.16e technology until today, thus identifying the research directions related to the existing and future technologies of
WiMAX.. In this article, we focus on the mobile WiMAX , IEEE 802.16j mobile multi hop relay (MMR) technology and
will use the acronym ’ “IEEE 802.16j’ instead of Mobile WiMAX IEEE 802.16j mobile multi hop relay (MMR) in the rest
of the paper. The rest of the article is organized as follows. In section I, we briefly recapitulate the different relay modes,
relay transmission schemes, and relay pairing schemes, techniques in IEEE 802.16j’ . In section II we brief discussed
about the different technical issues in Physical layer of IEEE 802.16j’ and present a comparative study of the advantages
of the different Physical layer technical issues. This is followed in section III by a brief discussion about the different
technical issues in MAC-CPS layer of the IEEE 802.16j technology and their relevancy. This is followed in section IV by
a brief discussion about the different technical issues in MAC-Security layer of the IEEE 802.16j technology. Section IV
presents a brief comparative study between IEEE 802.16j and LTE technologies. Conclusions are drawn in Section V.
3. WiMAX Forum
The WiMAX forum [3] was established in 2003 to promote deployment of WiMAX as a broadband wireless access
technology. It initiated several technical specifications and allows certification of WiMAX products. The network
specification involve interaction with other standard organization include IETF, 3GPP, 3GPP2, DSL forum, and OMA.
4. RELAY MODES
Two different relay modes [1] are defined in this standard, transparent mode and Non- transparent mode.
a. Transparent Mode
The transparent relay mode [1] increases the throughput which facilities capacity increases within the Bs coverage area. It
has no support to coverage extension because it does not forward framing information to BS. It is operated in two hop
network topology and supports centralized scheduling only as scheduling is done only in BS. It uses CID based forwarding
scheme and supports embedded and explicit mode of path management.
Fig 2: Non-tranparent mode channel parameters
b. Non transparent relay mode
The Non transparent relay mode [1] as in fig 3 is to increase the coverage extension of BS, here RS generate its own
framing information and forward it to SSs. It operates is 2 or more hops and uses centralized or distributed scheduling
mode, as scheduling is done in BS and RSs. It used CID and Tunnel based forwarding scheme and supports embedded and
explicit mode of path management. The channel parameters are shown in fig 2
Fig 3: Non-tranparent mode of operation.
The transparent relay station does not transmit control message, permeable, FCH (frame control header, and DL/UL-MAP,
as it only increases system throughput. The non transparent relay station transmit control message, permeable, FCH (frame
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4. control header, and DL/UL-MAP, as it increases system throughput and increases cell coverage. Table 1 shows the
difference between transparent and non transparent mode of operation.
5. Relay Transmission Schemes
There are many relay transmission schemes [24[26] proposed, they are Amplify and forward, selective Decode and
forward, Demodulation and forward.
a. Amplify And Forward
Here the relay receives signal from the BS or SSs in the first phase it amplify this signal and forwards it to the SSs or BS
in second phase. This is very simple and short delay relay transmission scheme.
b. Selective Decode and Forward.
Here also the relay receives signal from the BS or SSs in the first phase it decodes the signal and the decoded data is
checked for cyclic redundancy check (CRC) then the decoded data is coded and forwards it to the SSs or BS in second
phase. This scheme avoids error propagation through the channel.
c. Demodulation and Forward.
Here also the relay receives signal from the BS or SSs in the first phase it demodulate the signal without decoding and then
it modulates and forwards it to the SSs or BS in second phase.
TABLE-1
S.No Transparent Mode Non Transparent Mode
Supports Centralized or
Supports Centralized
Distributed scheduling- as
1. scheduling - as scheduling
scheduling done in base and
done only in base station
relay station
Use CID based forwarding Use Tunnel based or CID based
2.
scheme forwarding scheme
3. Use only 2 hops Use 2 or more Hops
Does not provide coverage
4. Provides BS coverage extension.
extension
5. Low Relay station cost. High Relay station cost.
6. Relay Pairing Schemes
Pairing scheme [24] is developed for having collaboration between RSs and BS in data transmission. This will improve
the coverage and throughput of the mobile multi hop relay (MMR) networks. There are two pairing schemes proposed,
Centralized pairing scheme and distributed pairing scheme. The other Relay pairing schemes are Random Relay Pairing
Schemes and Opportunistic Relay Pairing Schemes
a. Centralized Relay Pairing Schemes
In this scheme the BS will act as a control node and collects the channel and location information from all the RSs and SSs
and then make the pairing decision. This information must be formed as a service set and periodically updated in the local
BS to capture dynamic changes of SSs This scheme requires more signaling over head, and can achieve better performance
gains.
b. Distributed Relay Pairing Schemes
In this scheme, RS collects the channel and location information from all the nearby SSs and then makes the pairing
decision. First each RS identify its service set of neighborhood SSs and also the channel conditions between its BS as well
as its SS, those RS with single service set each randomly selects a time slot from the N- slots in the pairing scheme. If
multiple RS choose the same time slot then collusion occurs and those RS will be trying again in the next pairing scheme.
7. Relay Placement
By deploying relay stations [26] in lower SINR cell boundary area the system capacity, throughput per user, and the
system reliability can be enhanced. The Relay placement is formulated as an optimization problem and solved by and
iterative algorithm, under the assumption that MS distribution is uniform. In some cases large geographic area under non
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5. uniformly distributed traffic demand is considered. The locations of BS are determined in the first stage network
deployment. An RS location algorithm is designed to locate RSs.
8. Characteristics of Relay Based Networks.
Relay based networks[15][16][17][18] has small form factor, low cost relays associated with Base stations. Three main
benefits provided from relay based architecture over single {hop architecture are throughput enhancement, coverage
increase and deployment cost.
a. Throughput Enhancement:
It is expected to increase system capacity by deploying RSs in a manner that enables more aggressive spatial reuse.
b. Coverage Enhancement/Extension:
The relay technology is expected to improve the coverage reliability in geographic areas that are severely shadowed from
the BS and/or to extend the range of a BS.
c. Cost Reduction:
Relay based systems have the potential to deliver cost gains over traditional single {hop wireless access systems. Using
RSs, an operator could deploy a network with wide coverage at a lower cost than using only (more) expensive BSs to
provide good coverage and system capacity.
9. Relaying Techniques:
The Relaying techniques[15][16][17][18] [26] include the conventional techniques (i) time domain relaying, (ii) frequency
domain relaying and (iii) hybrid time/frequency domain relaying and the current technique that is interest among the
research community is (iv) co-operative technique.
a. Time Domain Relaying:
In this scheme relays access the Medium in time multiplex. The resources are further divided in time in either the DL or
UL to allow the relay station to receive and transmit data.
b. Frequency Domain Relaying:
Relays are operating on different frequency channels. The main advantage of this scheme is that relays can transmit
and receive data simultaneously.
c. Hybrid Time/Frequency Domain Relaying:
Relays are operating periodically on different frequency channels to forward data. The idea here is to switch between two
frequencies in order to allow the BS to transmit to its client while the relay is forwarding data on another frequency.
d. Cooperative Relaying Techniques:
Such techniques can significantly enhance the performance of relay based systems by multiple RSs cooperatively
transmitting the same data to a SS or the BS, i.e. in the DL or UL. This leads to similar benefits than in MIMO systems
with transmit/receive diversity and spatial multiplexing.
10. Multiple-Input Multiple-Output (MIMO) Communication for IEEE 802.16j.
MIMO- Multiple-Input Multiple-Output techniques have been used in IEEE 802.16d/e/j to improve cell coverage and
increase average user with in the cell. MIMO transmission [26][11[12] is used to increase the data rate of the
communication between a given transmitter-receiver pair and/or improve the reliability of the link. Use of multiple
antennas can improve the achievable rates of users in the network with given frequency. As MIMO technology matures it
is expected that MIMO will be widely used for wireless communication. For Next Generation WiMAX a system is to
support at least up to 8 transmit antennas at the base station, 4 streams and Space-Time Coding. MIMO futures such as
closed-loop MIMO will be included in future WiMAX More specifically, it has been already decided to support closed-
loop MIMO using Channel Quality Information, Precoding Matrix Index and rank feedback in future systems.
The MIMO techniques [32][33] are Single User MIMO ( SU-MOMO) , Multi User MIMO (MU-MIMO) and cooperative
MIMO. The adoption of MIMO techniques often requires a tight design integration of PHY, medium access control
(MAC), and higher layers of IEEE 802.16j. The key MIMO techniques are ; Open-loop transmit diversity in DL, Open-
loop spatial multiplexing in DL, Open-loop transmit diversity in UL, Open-loop spatial multiplexing in UL, Collaborative
spatial multiplexing in UL (UL MU-MIMO), Adaptive beam forming including DL SDMA (DL MU-MIMO), Closed-
loop antenna grouping/selection, Closed-loop codebook-based pre-coding. These above features are included in Release
1.0 and 1.5 of WiMAX forum.
a. Single User MIMO ( SU-MOMO)
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6. In SU-MOMO [32] the transmitter and receiver are equipped with M and N antennas. The channel is Rayleigh or Rician
fading channel. Based on the full or partial availability of Channel State Information (CSI) to receiver and transmitter SU-
MOMO is classified in to open loop SU-MOMO and closed loop MIMO.
b. Open loop SU-MOMO
Open-loop MIMO systems[32] are more desirable in mobility applications because they do not require CSI as 802.16e
support mobility of up to 120 km/h. 802.16e adopts space-time coding (STC) as the main open-loop MIMO scheme. STC
is supported for both the uplink and downlink, for up to four transmit antennas, and for a multiplexing rate up to 4. STC
option allows low complexity decoding, while others are optimized for high complexity decoding. Cyclic delay diversity
(CDD) is another open-loop scheme. Too much CDD delay may reduce the receiver’s channel estimation accuracy due to
the augmented frequency fluctuation.
c. Closed- loop SU-MOMO
Closed-loop systems[33] can achieve better performance than open-loop systems by exploiting CSIT.
d. Multi User MIMO (MU-MIMO)
MU-MIMO [32] allows multiple SSs to spatially share the same time-frequency resource for the improvement of both the
cell spectral efficiency and average user experience.
e. Distributed MIMO and Relay in IEEE 802.16j.
Among BS, RS(s), and SS, a distributed MIMO system is formed with all the transmit antennas of BS and RS on one side
and the receive antennas of the destination SS on the other side.
New MOMO techniques [33] are open-loop multiuser MIMO, and collaborative multicell MIMO. In the multicell MIMO
multiple BSs collaborate to serve multiple SSs in the edge region of the BSs’ cell. A precoding entity in the network
backhaul will decide the precoding vectors used for all SSs in all the BSs. The multicell MIMO system has the potential to
eliminate dominant intercell interferences, while offering multiplexing rate and diversity gain.
11. IEEE 802.16j Protocol Layering
IEEE 802.16j protocol layering[13][14][15][26] consists of Data/Control Plane and Management plane. The Data/Control
Plane defines PHY and MAC layers. The Management plane defines respective management entity of PHY and MAC
layers.
Fig 4: IEEE 802.16j MAC –CPS and SSCS sublayers
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7. Fig 5: IEEE 802.16j protocol layering.
a. Data /Control Plane
The IEEE 802.16j data /control plane as in fig 5 includes the Physical layer (PHY), MAC common part sub layer (MAC-
CPS) and MAC convergence sub layer (MAC-CS). The MAC common part sub layer as in fig 4 includes connection
admission control, Link management, ARQ, scheduler Downlink/uplink burst processing. The MAC convergence sub
layer Network management, configuration management, uplink packet reassembly and downlink packet classifier.
b. Management Plane:
The management plane as in fig 5 includes the corresponding Management entity of Physical layer (PHY), MAC common
part sub layer (MAC-CPS) and MAC convergence sub layer (MAC-CS).
12. IEEE 802.16j [WIMAX] Integration with IEEE 802.11n [Wi-Fi]
WiFi also called as WLAN or IEEE 802.11 provide wireless connectivity to local networks in unlicensed frequency band
and offers low or free of cost internet connectivity, but WiMAX designed for point to multi point (PMP) operates in
licensed and unlicensed band provides broad band internet connectivity to last mile access. In WiFI subscriber stations are
connected through access points (AP), but WiMAX subscriber stations are connected to base station (BS). The IEEE
802.16j standard provides PMP mode for SS outside the BS coverage area and use dedicated relay stations (RS) to support
mobile nodes.
For integration of Wi-Fi with WiMAX different scenarios are considered such as single mode client scenario, Dual mode
client scenario, Backhaul scenario, multi hop heterogeneous scenario, Dual gate way single mode client scenario, Dual
gate way Dual mode client scenario, Mobile / moving Networks scenario.
In single mode client scenario SSs are connected to either BS1 or AP1 that is SS1 to BS1 if it is within the coverage area
of BS1 and SS2 to AP1 if it is within the coverage area of AP1.
In backhaul Scenario the SS1 are connected to internet through point to point backhaul connection (BSi-BSj). In dual
mode SS1 is connected to both WiMAX BS and Wi-Fi AP. In dual gate way mode, a dual gateway will connect to SS and
BS, that is provides coverage area of BS. In multi hop mode an RS can provide coverage extension to SS for both BS and
also AP. In mobile network scenario a mobile gateway can be used by external clients outside the coverage area of Wi-Fi /
WiMAX.
13. Conclusion and Future Works
The new IEEE 802.16j standard which is an amendment to IEEE 802.16e is multi hop relay specification for wireless
networks. Relay technologies such as transparent relay modes, non transparent relay mode, relay pairing schemes such as
centralized relay pairing schemes, distributed relay pairing scheme, characterises of relay based networks such as
throughput enhancement,capacity increase, cost reduction , relay techniques such as time domain frequency domain relay
techniques and relay placement are also discussed in this paper. In future we are planning to solve some of the technical
issues such as Network planning, Relay placement, scheduling services, bandwidth allocation etc.
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Authors
D.SatishKumar received his B.E., degree in Electrical and Electronics Engineering from Bharathiar
University and M.E. degree in Computer Science and Engineering from Manonmaniam Sundharnar
University respectively. He is currently working towards the PhD degree in Computer Science and
Engineering in Anna University of Technology Coimbatore, Tamil Nadu INDIA. His research interests
accumulate in the area of IEEE 802.16j Multi hop Mobile networks, Routing, WIMAX networks,
Network management in wired Networks and Wireless Networks.
Email: - satishcoimbatore@yahoo.co.in
Dr.N.Nagarajan received his B.Tech and M.E. degrees in Electronics Engineering at M.I.T Chennai.
He received his PhD in Faculty of information and communication engineering from Anna University,
Chennai. He is currently working as Principal, Coimbatore Institute of Engineering and Technology,
Coimbatore. He is member of board of study of faculty of information Technology at Anna University
of technology, Coimbatore. His specialization includes optical, wireless Adhoc and sensor networks.
He is guiding assorted research scholars in optical networks and wireless networks.
Email: - swekalnag@rediffmail.com
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