WiMAX MAC Layer Properties The MAC layer is subdivided primarily into three sublayers:
(1) Service specific convergence sublayer (CS) The main purpose of this sublayer is to interface with the higher layers in the WiMAX communication model.
(2) MAC common part sublayer (MAC CPS) This sublayer takes care of core MAC functionalities such as security, management of connections, and access to the physical network.
(3) Privacy sublayer As suggested by the name this manages authentication of IPTV subscribers and encryption of the v ideo content.
WiMAX Transport Layer Properties Standard TCP/IP is generally used at the network and transport layers to ensure delivery of IPTV services.
Transmission Ranges Geographic topologies combined with other factors such as equipment specifications and weather conditions can all have an impact on the distance between a IPTV consumer device and a WiMAX base station. WiMAX has a theoretical maximum speed of approximately 60 Mbps within a coverage area of 6 10 km. This varies between implementations and equipment vendors. Assuming that the contention ratios are correctly planned, these data throughput levels will comfortably allow subscribers within the WiMAX coverage area to access IPTV services. It is important to note that WiMAX can support both line of sight (LoS) and nonline of sight (NLOS).
Mobile WiMAX
IEEE 802.16 cannot be used to provide broadband services in a mobile environment. For this purpose, an amendment to the IEEE Standard 802.16 standard was developed called IEEE 802.16e. Also known as Mobile WiMAX, IEEE 802.16e was approved in 2005 and certified products were released to the market in 2006. It operates in several licensed spectrum bands: 2.5, 3.3, and 3.4 3.8 GHz. Mobile WiMAX incorporates a number of key features that are necessary to transport IPTV services and applications:
. The technology supports peak data speeds of around 32 46 Mbps. These types of speeds if deployed correctly allow delivery of compressed IP based high definition content to mobile handsets.
. It utilizes technologies such as OFDMA and optimized handoffs to allow IPTV viewers access multicast broadcast TV channels in geographical areas that are susceptible to the affects of multipath transmission paths.
. It integrates with multimedia subsystem (IMS), which simplifies interworking between IPTV applications and other IP based services such as high speed Internet access and VoIP. Note that IMS is an emerging technology architecture that allows network operators to accelerate and simplify the deployment of IP based services.
. Mobile WiMAX provides support for advanced quality of services (QoS)mechanisms, which are beneficial to real-time applications such as IPTV.
In addition to the above characteristics, it is important to note that at the time ofwriting the WiMAX forum continues its work on expanding the multicasting capabilities of Mobile WiMAX. This is expected to further enhance the ability of Mobile WiMAX to meet the stringent requirements associated with broadcasting live IP based TV channels to mobile devices.
(1) Service specific convergence sublayer (CS) The main purpose of this sublayer is to interface with the higher layers in the WiMAX communication model.
(2) MAC common part sublayer (MAC CPS) This sublayer takes care of core MAC functionalities such as security, management of connections, and access to the physical network.
(3) Privacy sublayer As suggested by the name this manages authentication of IPTV subscribers and encryption of the v ideo content.
WiMAX Transport Layer Properties Standard TCP/IP is generally used at the network and transport layers to ensure delivery of IPTV services.
Transmission Ranges Geographic topologies combined with other factors such as equipment specifications and weather conditions can all have an impact on the distance between a IPTV consumer device and a WiMAX base station. WiMAX has a theoretical maximum speed of approximately 60 Mbps within a coverage area of 6 10 km. This varies between implementations and equipment vendors. Assuming that the contention ratios are correctly planned, these data throughput levels will comfortably allow subscribers within the WiMAX coverage area to access IPTV services. It is important to note that WiMAX can support both line of sight (LoS) and nonline of sight (NLOS).
Mobile WiMAX
IEEE 802.16 cannot be used to provide broadband services in a mobile environment. For this purpose, an amendment to the IEEE Standard 802.16 standard was developed called IEEE 802.16e. Also known as Mobile WiMAX, IEEE 802.16e was approved in 2005 and certified products were released to the market in 2006. It operates in several licensed spectrum bands: 2.5, 3.3, and 3.4 3.8 GHz. Mobile WiMAX incorporates a number of key features that are necessary to transport IPTV services and applications:
. The technology supports peak data speeds of around 32 46 Mbps. These types of speeds if deployed correctly allow delivery of compressed IP based high definition content to mobile handsets.
. It utilizes technologies such as OFDMA and optimized handoffs to allow IPTV viewers access multicast broadcast TV channels in geographical areas that are susceptible to the affects of multipath transmission paths.
. It integrates with multimedia subsystem (IMS), which simplifies interworking between IPTV applications and other IP based services such as high speed Internet access and VoIP. Note that IMS is an emerging technology architecture that allows network operators to accelerate and simplify the deployment of IP based services.
. Mobile WiMAX provides support for advanced quality of services (QoS)mechanisms, which are beneficial to real-time applications such as IPTV.
In addition to the above characteristics, it is important to note that at the time ofwriting the WiMAX forum continues its work on expanding the multicasting capabilities of Mobile WiMAX. This is expected to further enhance the ability of Mobile WiMAX to meet the stringent requirements associated with broadcasting live IP based TV channels to mobile devices.
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