22-07-2014, 12:37 PM
FOURTH GENERATION WIRELESS TECHNOLOGY
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INTRODUCTION TO WIRELESS SYSTEM
Wireless telecommunication history can be classified into different generations of network. Each generation has been a giant stride which revolutionized the field of mobile communication:
First generation (1G) in 1980 where all the systems where based on analog radio signal technology. Voice was considered to be the main traffic, Various 1G standards defined were Advance Mobile Phone System(AMPS), Nordic Mobile Telephone (NMT), Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA).
Second generation (2G) wireless communications systems, In 1990, 1G was replaced by 2G which provided rich set of services such as high voice quality and global mobility based on the digital radio signal technology. Here also voice was considered to be the main traffic, 2G includes standards such as Global System For Mobile Communications (GSM), General Packet Radio System (GPRS). Both 1G and 2G are based on circuit switched technology for data communication at low speed.2G was a huge success.
(2.5G) which is an intermittent between 2G and 3G. It is based on both circuit switched and packet switched technologies providing high data rate with low power consumption. It uses the infrastructure of Global System for Mobile communications (GSM) and Code division multiple access (CDMA) to provide its making their appearance in late 2002 and in 2003, are designed for voice and paging services, as well as interactive media use such as teleconferencing, Internet access, and other services.
Third generation (3G) In the present generation which includes standards from 2.5G to 3G and also some other technologies such as WiMAX (Worldwide Interoperability for Microwave Access). It is totally based on the packet switching technology providing broad range of high quality services to the end user to meet the demand of high data rate and increasing rate of network users. The problem with 3G wireless systems is bandwidth-these systems provide only WAN coverage ranging from 144 kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications).
Segue to 4G ( Fourth generation of communication) the "next dimension " of wireless communication. The 4G wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr. Frequency band is 2 - 8 GHz. it gives the ability for world wide roaming to access cell anywhere This idea was beyond the imagination of ordinary mobile user promising “connect anytime, anyhow, anywhere” .This ubiquitous network access will be achieved by seamlessly integrating the available and new networks using a core IP based network layer. This vision is called as the" Magic Technology"
Mobility Management
This layer provides quality and uniform services to the mobile/stationary terminal across various heterogeneous networks. It provides features of low handover latency and packet loss during the provision of real-time and non-real time services to the end user
moving across different networks. To achieve this, it performs tasks such as binding update (updating the care-off address of the mobile user), location
management, common control signaling (signaling required to perform wireless network discovery),address assignment, handover control mechanism and so forth.
Physical Layer
This layer consist of the core IPV6 network of 4G and other heterogeneous access networks such as GSM (Global System for Mobile communications), CDMA( Code Division Multiple Access) and WLAN in their physicalview. This layer is composed of two sub-layers namely:
Convergence layer
This layer provides common control signaling mechanism across the core and other heterogeneous networks at the physical level. It also allows different radio access networks to transparently use the independent network services such as mobility management, resource management and QoS management.
Operation, Administration, Maintenance and Provisioning
This layer spans across all the layers of the network architecture and provides the functionalities of network controlling, network monitoring and fault detection. It also maintains the repudiation between various services and resources of several heterogeneous and core networks
OFDM (Orthogonal Frequency Division Multiplexing)
An FDM is the available band width is subdivided into a number of narrower band channels each user is allocated a unique frequency carrier in which to transmit and receive, OFDM reduces the amount of crosstalk in signal transmissions, 803.11a WLAN, 802.16 and WiMAX technologies use OFDM. OFDM technology has been incorporated into LTE because it enables high data bandwidths to be transmitted efficiently while still providing a high degree of resilience to reflections and interference. The access schemes different between the uplink and downlink, OFDMA used in the downlink; while SC-FDMA(Single Carrier - Frequency Division Multiple Access) is used in the uplink. SC-FDMA is used in view of the fact that its peak to average power ratio is small and the more constant power enables high RF power amplifier efficiency in the mobile.
4.2 IPv6(INTERNET PROTOCOL VERSION 6)
IPv6 support is essential in order to support a large number of wireless-enabled devices.
By increasing the number of IP addresses, IPv6 removes the need for Network Address Translation (NAT), a method of sharing a limited number of addresses among a larger group of devices, although NAT will still be required to communicate with devices that are on existing IPv4 networks.
In the context of 4G, IPv6 also enables a number of applications with better multicast, security, and route optimization capabilities.
With the available address space and number of addressing bits in IPv6, many innovative coding schemes can be developed for 4G devices and applications that could aid deployment of 4G networks and services.
Mobile IPv6 have been proposed to reduce the handoff Mobile latency and the number of lost packets.
The field “Traffic Class” and “Flow Label” in IPv6 header enables the routers to secure the special QoS for packet series with marked priority.
Number of bit= 32bits, 8 octet .
4.3 VoIP AND VoLTE
• VoIP(Voice Over IP ) : A methodology and group of technologies for the delivery of voice communication and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, IP communications, and broadband phone service.
• VoLTE (Voice Over LTE): This approach is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE. This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy Circuit Switch voice network to be maintained
Main Features LTE
• Peak download rates up to 299.6 Mbit/s and upload rates up to 75.4 Mbit/s depending on the user equipment category (with 4x4 antennas using 20 MHz of spectrum). Five different terminal classes have been defined from a voice centric class up to a high end terminal that supports the peak data rates. All terminals will be able to process 20 MHz bandwidth.
• Improved support for mobility, exemplified by support for terminals moving at up to 350 km/h (220 mph) or 500 km/h (310 mph) depending on the frequency band.
• OFDMA for the downlink, SC-OFDM for the uplink to conserve power
• Support for both FDD and TDD communication systems as well as half-duplex FDD with the same radio access technology
• Support for all Frequency band currently used by IMT systems by ITU-R
• Supports at least 200 active data clients in every 5 MHz cell.
• Simplified architecture : The network side of E-UTRAN is composed only of eNode (BTS).
• Packet switch radio interface.
• Support for cell sizes from tens of meters radius (Femto and Pico cell) up to 100 km (62 miles) radius Macro cells. In the lower frequency bands to be used in rural areas, 5 km (3.1 miles) is the optimal cell size, 30 km (19 miles) having reasonable performance, and up to 100 km cell sizes supported with acceptable performance. In city and urban areas, higher frequency bands (such as 2.6 GHz in EU) are used to support high speed mobile broadband. In this case, cell sizes may be 1 km (0.62 miles) or even less.
• Support for MBSFN (Multicast-Broadcast Single Frequency Network). This feature can deliver services such as Mobile TV using the LTE infrastructure.
• Supply Bandwidths from 1.25-20 MHz
LTE-ADVANCE
• The LTE-Advanced (Release 10) is an evolution of LTE, which is to compliant with the IMT-Advanced requirements and targets.
• It aims to provide peak data rates of up to 1Gbps (for low mobility) and 500 Mbps in DL and UL respectively.
• LTE-Advanced is required to reduce the user- and control-plane latencies as compared to LTE (Release8).
• It targets to achieve peak spectrum efficiency of 30 bps/Hz and 15 bps/Hz in DL and UL respectively.
• LTE-Advanced enhances the cell edge user throughput) in order to achieve a homogeneous user experience in cell.
• It will support the mobility across the cell from 350 km/h to 500 km/h depending on operating frequency band
OFDM WITH (CDMA)
• CDMA (code division multiple access): all users share the same radio frequency at the same time but different codeword, OFDM are different technologies with different capabilities:
• CDMA2000 offers high-performance mobile broadband and voice services today and will continue to be enhanced to provide greater broadband speeds and voice capacity
• OFDM leverages wider-bandwidths up to 20 MHz to provide greater speed and capacity
WiMAX TECHNOLOGY
WiMAX : Worldwide Interoperability for Microwave Access – should be capable of around 40 megabits per second with a range of 30 miles. It is one of the closest technologies to meet the standards of true 4G and as it develop should surpass the 100MB/second which is the 4G standard. Mobile WiMAX allows the use of high speed data transfers and is the main competition for the 4G LTE services provided by cellular carriers
CONCLUSION
The advent of 4G is sure to revolutionize the field of telecommunication domain bringing the wireless experience to a completely new level. It would provide wealth of features and services making the world a smaller place to live. Thus, 4G seems to have the capability to realize. But 4G should also take lesson from the 3G’s failure to capture the imagination of the end-users. Technology should not be developed for technology’s sake rather it should target the end user. Thus, user-centric approach towards 4G’s development is the key to its success. Common consensus on the standards and the technologies for 4G needs to be reached to fasten 4G’s deployment which would be a gradual process. Lot of research work is required to investigate the open issues like design for SDR, QoS parameters and so forth. The threat analysis model provided by ITU is very apt for the complete analysis and planning for security of 4G. It can be used as a reference framework for future research. But still comprehensive research work is required in the field of network security to tackle potential security threats because a ubiquitous "secured” heterogeneous network will appeal more to the today’s consumers
[attachment=66112]
INTRODUCTION TO WIRELESS SYSTEM
Wireless telecommunication history can be classified into different generations of network. Each generation has been a giant stride which revolutionized the field of mobile communication:
First generation (1G) in 1980 where all the systems where based on analog radio signal technology. Voice was considered to be the main traffic, Various 1G standards defined were Advance Mobile Phone System(AMPS), Nordic Mobile Telephone (NMT), Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA).
Second generation (2G) wireless communications systems, In 1990, 1G was replaced by 2G which provided rich set of services such as high voice quality and global mobility based on the digital radio signal technology. Here also voice was considered to be the main traffic, 2G includes standards such as Global System For Mobile Communications (GSM), General Packet Radio System (GPRS). Both 1G and 2G are based on circuit switched technology for data communication at low speed.2G was a huge success.
(2.5G) which is an intermittent between 2G and 3G. It is based on both circuit switched and packet switched technologies providing high data rate with low power consumption. It uses the infrastructure of Global System for Mobile communications (GSM) and Code division multiple access (CDMA) to provide its making their appearance in late 2002 and in 2003, are designed for voice and paging services, as well as interactive media use such as teleconferencing, Internet access, and other services.
Third generation (3G) In the present generation which includes standards from 2.5G to 3G and also some other technologies such as WiMAX (Worldwide Interoperability for Microwave Access). It is totally based on the packet switching technology providing broad range of high quality services to the end user to meet the demand of high data rate and increasing rate of network users. The problem with 3G wireless systems is bandwidth-these systems provide only WAN coverage ranging from 144 kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications).
Segue to 4G ( Fourth generation of communication) the "next dimension " of wireless communication. The 4G wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr. Frequency band is 2 - 8 GHz. it gives the ability for world wide roaming to access cell anywhere This idea was beyond the imagination of ordinary mobile user promising “connect anytime, anyhow, anywhere” .This ubiquitous network access will be achieved by seamlessly integrating the available and new networks using a core IP based network layer. This vision is called as the" Magic Technology"
Mobility Management
This layer provides quality and uniform services to the mobile/stationary terminal across various heterogeneous networks. It provides features of low handover latency and packet loss during the provision of real-time and non-real time services to the end user
moving across different networks. To achieve this, it performs tasks such as binding update (updating the care-off address of the mobile user), location
management, common control signaling (signaling required to perform wireless network discovery),address assignment, handover control mechanism and so forth.
Physical Layer
This layer consist of the core IPV6 network of 4G and other heterogeneous access networks such as GSM (Global System for Mobile communications), CDMA( Code Division Multiple Access) and WLAN in their physicalview. This layer is composed of two sub-layers namely:
Convergence layer
This layer provides common control signaling mechanism across the core and other heterogeneous networks at the physical level. It also allows different radio access networks to transparently use the independent network services such as mobility management, resource management and QoS management.
Operation, Administration, Maintenance and Provisioning
This layer spans across all the layers of the network architecture and provides the functionalities of network controlling, network monitoring and fault detection. It also maintains the repudiation between various services and resources of several heterogeneous and core networks
OFDM (Orthogonal Frequency Division Multiplexing)
An FDM is the available band width is subdivided into a number of narrower band channels each user is allocated a unique frequency carrier in which to transmit and receive, OFDM reduces the amount of crosstalk in signal transmissions, 803.11a WLAN, 802.16 and WiMAX technologies use OFDM. OFDM technology has been incorporated into LTE because it enables high data bandwidths to be transmitted efficiently while still providing a high degree of resilience to reflections and interference. The access schemes different between the uplink and downlink, OFDMA used in the downlink; while SC-FDMA(Single Carrier - Frequency Division Multiple Access) is used in the uplink. SC-FDMA is used in view of the fact that its peak to average power ratio is small and the more constant power enables high RF power amplifier efficiency in the mobile.
4.2 IPv6(INTERNET PROTOCOL VERSION 6)
IPv6 support is essential in order to support a large number of wireless-enabled devices.
By increasing the number of IP addresses, IPv6 removes the need for Network Address Translation (NAT), a method of sharing a limited number of addresses among a larger group of devices, although NAT will still be required to communicate with devices that are on existing IPv4 networks.
In the context of 4G, IPv6 also enables a number of applications with better multicast, security, and route optimization capabilities.
With the available address space and number of addressing bits in IPv6, many innovative coding schemes can be developed for 4G devices and applications that could aid deployment of 4G networks and services.
Mobile IPv6 have been proposed to reduce the handoff Mobile latency and the number of lost packets.
The field “Traffic Class” and “Flow Label” in IPv6 header enables the routers to secure the special QoS for packet series with marked priority.
Number of bit= 32bits, 8 octet .
4.3 VoIP AND VoLTE
• VoIP(Voice Over IP ) : A methodology and group of technologies for the delivery of voice communication and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, IP communications, and broadband phone service.
• VoLTE (Voice Over LTE): This approach is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE. This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy Circuit Switch voice network to be maintained
Main Features LTE
• Peak download rates up to 299.6 Mbit/s and upload rates up to 75.4 Mbit/s depending on the user equipment category (with 4x4 antennas using 20 MHz of spectrum). Five different terminal classes have been defined from a voice centric class up to a high end terminal that supports the peak data rates. All terminals will be able to process 20 MHz bandwidth.
• Improved support for mobility, exemplified by support for terminals moving at up to 350 km/h (220 mph) or 500 km/h (310 mph) depending on the frequency band.
• OFDMA for the downlink, SC-OFDM for the uplink to conserve power
• Support for both FDD and TDD communication systems as well as half-duplex FDD with the same radio access technology
• Support for all Frequency band currently used by IMT systems by ITU-R
• Supports at least 200 active data clients in every 5 MHz cell.
• Simplified architecture : The network side of E-UTRAN is composed only of eNode (BTS).
• Packet switch radio interface.
• Support for cell sizes from tens of meters radius (Femto and Pico cell) up to 100 km (62 miles) radius Macro cells. In the lower frequency bands to be used in rural areas, 5 km (3.1 miles) is the optimal cell size, 30 km (19 miles) having reasonable performance, and up to 100 km cell sizes supported with acceptable performance. In city and urban areas, higher frequency bands (such as 2.6 GHz in EU) are used to support high speed mobile broadband. In this case, cell sizes may be 1 km (0.62 miles) or even less.
• Support for MBSFN (Multicast-Broadcast Single Frequency Network). This feature can deliver services such as Mobile TV using the LTE infrastructure.
• Supply Bandwidths from 1.25-20 MHz
LTE-ADVANCE
• The LTE-Advanced (Release 10) is an evolution of LTE, which is to compliant with the IMT-Advanced requirements and targets.
• It aims to provide peak data rates of up to 1Gbps (for low mobility) and 500 Mbps in DL and UL respectively.
• LTE-Advanced is required to reduce the user- and control-plane latencies as compared to LTE (Release8).
• It targets to achieve peak spectrum efficiency of 30 bps/Hz and 15 bps/Hz in DL and UL respectively.
• LTE-Advanced enhances the cell edge user throughput) in order to achieve a homogeneous user experience in cell.
• It will support the mobility across the cell from 350 km/h to 500 km/h depending on operating frequency band
OFDM WITH (CDMA)
• CDMA (code division multiple access): all users share the same radio frequency at the same time but different codeword, OFDM are different technologies with different capabilities:
• CDMA2000 offers high-performance mobile broadband and voice services today and will continue to be enhanced to provide greater broadband speeds and voice capacity
• OFDM leverages wider-bandwidths up to 20 MHz to provide greater speed and capacity
WiMAX TECHNOLOGY
WiMAX : Worldwide Interoperability for Microwave Access – should be capable of around 40 megabits per second with a range of 30 miles. It is one of the closest technologies to meet the standards of true 4G and as it develop should surpass the 100MB/second which is the 4G standard. Mobile WiMAX allows the use of high speed data transfers and is the main competition for the 4G LTE services provided by cellular carriers
CONCLUSION
The advent of 4G is sure to revolutionize the field of telecommunication domain bringing the wireless experience to a completely new level. It would provide wealth of features and services making the world a smaller place to live. Thus, 4G seems to have the capability to realize. But 4G should also take lesson from the 3G’s failure to capture the imagination of the end-users. Technology should not be developed for technology’s sake rather it should target the end user. Thus, user-centric approach towards 4G’s development is the key to its success. Common consensus on the standards and the technologies for 4G needs to be reached to fasten 4G’s deployment which would be a gradual process. Lot of research work is required to investigate the open issues like design for SDR, QoS parameters and so forth. The threat analysis model provided by ITU is very apt for the complete analysis and planning for security of 4G. It can be used as a reference framework for future research. But still comprehensive research work is required in the field of network security to tackle potential security threats because a ubiquitous "secured” heterogeneous network will appeal more to the today’s consumers