2 Topics WiMAX Protocol About WiMAX Physical layer MAC layer Fixed / Mobile WiMAX WiMAX vs Wi-Fi WiMAX applications
3 What is WiMAX Worldwide Interoperability for Microwave Access a "last mile" broadband wireless access (BWA) alternative to cable modem, Digital Subscriber Line (DSL) or T1/E1 service. Wireless Metropolitan Area Network (WMAN) Based on IEEE 802.16
4 IEEE 802.16 Standards 802.16.1-2001 (10-63 GHz, line-of-sight, up to 134Mbit/s) 802.16.2 (minimising interference between coexisting WMANs.) 802.16a-2003 (2-11 Ghz, Mesh, non-line-of-sight) 802.16b-2004 (5-6 Ghz) 802.16c (detailed system profiles) 802.16e-2005 (Mobile Wireless MAN) called Mobile WiMAX 802.16m-2011, data rates of 100 Mbit/s mobile & 1 Gbit/s fixed (4G) 802.16-2012, 16p, 16n, current
5 Standar d Family Primary Use Radio Tech Downlink (Mbit/s) Uplink (Mbit/s) Notes WiMAX802.16 Mobile Internet MIMO- SOFDM A 128 (in 20MHz bandwidth ) 56 (in 20MHz bandwi dth) IEEE 802.16m expected to offer peak rates of at least 1 Gbit/s fixed speeds and 100Mbit/s to mobile users. LTE UMTS/ GSM General 4G OFDMA/ MIMO/S C-FDMA 100 (in 20MHz bandwidth ) 50 (in 20 MHz bandwi dth) LTE-Advanced expected to offer peak rates up to 1 Gbit/s fixed speeds and 100 Mb/s to mobile users.
6 Purpose of WiMAX Providing mobile broadband connectivity across cities and countries through a variety of devices. Providing a wireless alternative to cable and DSL for "last mile" broadband access. Providing data, telecommunications (VoIP) and IPTV services. Providing a source of Internet connectivity as part of a business continuity plan.
7 Fixed and Mobile WiMAX Fixed WiMAX is optimised for home/office networks Mobile WiMAX is optimised for mobiles
11 WiMAX as a mobile voice and data network is potentially exponentially more efficient (profitable) than the legacy cellular infrastructure
12 WiMAX Architecture MIB Management Information Base
13 802.16 protocol
14 802.16 protocol stack 802.16 covers data link and physical layer
802.16 MAC Sublayer Protocol Classes of service 1. Constant bit rate service. 2. Real-time variable bit rate service. 3. Non-real-time variable bit rate service. 4. Best-effort service.
17 Physical layer (PHY)
18 PHY cont. BPSK: 1 bit/baud QPSK: 2 bits/baud QAM-16: 4 bits/baud QAM-64: 6 bits/baud Example: a 25 MHz bandwidth, QPSK can deliver 50 Mbps, QAM-16 100 Mbps, QAM-64 150 Mbps Baud (Bd): measure of the symbol rate; the number of distinct symbolic changes (signalling event) made to the transmission medium per second in a digitally modulated signal 25 Bd means that 25 symbols are transmitted per second.
19 PHY cont. TDD (time-division duplex) - use same bandwidth for uplink and downlink - controlled by timing FDD (frequency-division duplex) - use different frequency for uplink and downlink OFDM (orthogonal frequency-division multiplexing) - enhancement of frequency division multiplexing (FDM) - maximise use of bandwidth Also Adaptive Antenna Support (AAS) and MIMO
20 TDD and FDD
16.21 Figure 16.5: Frame structure at the physical layer (TDD) In each time slot, a frame is in the air. The base station fills the data to send to substation in the downstream subframe; the substations fill the data to send to the base station in the upstream subframe.
22 OFDM FDMOFDM OFDM uses bandwidth which is not available for use in FDM
23 WiMAX Antennas
24 Omni directional antenna Omni directional antennas are used for point-to- multipoint configurations. its energy is greatly diffused in broad-casting 360 degrees This limits its range and ultimately signal strength good for situations where there are a lot of subscribers located very close to the base station
25 Sector antennas focusing the beam in a more focused area offers greater range and throughput with less energy Many operators will use sector antennas to cover a 360-degree service area rather than use an omni directional antenna
26 Panel antennas a flat panel of about one foot square often used for point-to-point applications
27 Frequency Plan By reusing frequencies at different base stations, a WiMAX operator can avoid interference from their own network
28 WiMAX vs Wi-Fi
29 WiMAX vs Wi-Fi cont. WiMAX is designed to cover large area (multiple homes/buildings), while Wi-Fi is to cover small area (a home/building)
30 Comparison of WiMAX, WiFi and 3G technology
31 WiMAX applications Broadband Internet Multimedia IP multimedia subsystem (IMS) Cellular Alternative A clear alternative to connect areas without pre- existing physical cable or telephone networks or just areas without BB access
32 Broadband Internet Fixed WiMAX is substitute for T1 Mobile WiMAX has larger coverage than WiFi
WiMax in UK UK Broadband, a subsidiary of PCCW (owned by Hong Kong Telecom) Freedom4 (formerly Pipex Wireless) had the necessary spectrum to launch these wireless networks in the UK, but only Freedom4 opted to do so with a WiMax network in Milton Keynes and Stratford Upon Avon. These WiMax networks were up and running in real world situations years before LTE arrived on the scene. 33 Freedom4s WiMAX Licence Sold For 12.5m. June 29, 2010.
http://www.eur opa- network.com/ wimax/ 34
Why did LTE beat WiMax 35 Most WiMax backers, including Clearwire in the United States (which has already built WiMax networks in many US cities), have signalled their intent to move across to LTE. It was never cost effective for WiMax networks to compete effectively against fixed-line broadband networks. What happened was that LTE came along early enough so that all operators adopted it, said James. No one adopted 16m because there were no economies of scale. Indeed, all WiMax operators have signalled they will move to LTE. WiMax is dead as a mobile technology but it is not dead as a fixed technology. UK Broadband brought Freedom4s spectrum, because it is adjacent to UKBs spectrum. We now have 124MHz of LTE UK Broadbands chief executive, Nicholas James http://www.ukbroadband.com/
Sprint will KILL OFF WiMax in 2015 36 http://www.theregister.co.uk/2014/10/06/spr int_wimax_to_close_in_2015/ Third-ranked US mobile network Sprint appears to be poised to kill off its implementation of its less- regarded 4G technology, WiMax. The spectrum it frees up will all move to LTE.
37 Number of WiMAX subscriber worldwide from 2010 to 2014 (in millions) http://www.statista.com/statistics/277656/number-of-wimax-subscriber-worldwide- since-2010/
39 Reference Tannenbaum Computer Networks Stallings wireless communications & Networks Frank Ohrtman: Wimax overview: http://www.wimax.com/education/wimax/wi max_overview http://www.wimax.com/education/wimax/wi max_overview The 802.16 WirelessMAN MAC: Its Done, but What Is It? (2001-11-12)
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