IEEE 802.16m to the Rescue: Meeting the Exploding Mobile Internet Data Demand
http://www.ieee802.org/16/tgm/docs/80216m-08_003r1.pdf ) which is a major amendment ( full backward compatibility) to the WiMAX Release 1.o(IEEE802.16e-2005) standard will offer significantly greater capacity, coverage and performance, and lower latency in order to meet the ITU-R requirements for an IMT -Advanced 4G technology (http://www.telecomabc.com/i/imt-advanced.html) solution. With remarkable design improvements in the advanced air interface architecture (new blocks inside Layer 1 and 2), 802.16m will be able to easily provide the necessary capacity that operators will demand to further grow their urban networks as well as to reliably deliver data at extremely high speeds (e.g. up to 120Mbps down and 60Mbps up using a 4×2 MIMO/TDD 5:3 configuration) to users. As an example, in today’s WiMAX Network deployments, user devices connect to a single channel frequency utilizing a 5msec frame structure with time-division duplexed (TDD) DL and UL information using a 10MHz bandwidth. With 802.16m, user devices will be able to connect to two different channel frequencies (multi-carrier) at the same time utilizing the following possible combinations: 1) two independent 20msec super-frames each using a 10MHz bandwidth, 2) two independent 20msec super-frames each using a 20MHz bandwidth, and 3) one 20msec super-frame using a 20MHz bandwidth and the other 20msec super-frame using a 10MHz bandwidth – Hence, 20MHz (doubles today’s data transfer rates), 40MHz (quadruples today’s data transfer rate), and 30MHz (triples today’s data transfer rate), respectively. More so, the two carriers (radio frequencies) are not necessarily in adjacent bands. If they are in adjacent bands, then the guard bands can be used to transfer data. Digging deeper, a 20msec super-frame is divided into four 5msec radio frames with each radio frame further sub-divided into eight 0.617msec sub-frames. Each of the eight sub-frames per radio frame contains legacy zones for existing 802.16e devices and high-speed zones for new 802.16m devices. Within each of the four radio frames, a variety of DL/UL combinations ( 6/2, 5/3. etc.) can be achieved using various TDD, FDD and HFDD schemes which makes it possible to reduce the one-way air-link latency from 18.5sec (802.16e) to 5msec (802.16m). Utilizing critical features such multi-hop relay architecture, multi-carrier operation, self-configuration, multi-antenna schemes (Single – User and Multi-User MIMO), interference mitigation, enhanced multi-cast broadcast, increased VoIP capacity, improved cell-edge throughput, increased vehicular speeds (up to 500km/hr) and so forth, 802.16m is poised as the broadband internet connectivity technology of choice well into this decade.