Outline. IEEE and Background: Wireless Landscape. What is WiMAX? WiMAX Overview. Background: Wireless Technologies

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1 Outline IEEE and An overview An insight into IEEE WiMAX An introduction to Bluetooth 10/6/ Background: Wireless Landscape Background: Wireless Technologies Low Cost & Complexity High-Speed Connectivity & Hierarchy of Networks Personal Area Network Local Area Networks (e.g ) Fixed Broadband Wireless (e.g ) Cellular Mobile Networks (e.g. GPRS,3G) Satellite High Cost Global Area Network & Complexity Increasing Coverage Area 10/6/ Standards Speed Range PAN Bluetooth, UWB < 1Mbps Short WAN (Wide Area Network) MAN (Metropolitan Area Network) LAN (Local Area Network) PAN (Personal Area Network) LAN HiperLAN2 11 to 54 Mbps Medium MAN MMDS, LMDS 11 to 100+ Mbps Medium-Long WAN GSM, GPRS, CDMA, 2.5-3G, to 384Kbps Long Peer-to to-peer T1 replacement, last PDAs, Mobile Phones, Applications 10/6/2008 Enterprise networks Device-to to-device mile access cellular access 4 What is WiMAX? WiMAX Overview WiMAX (Worldwide Interoperability for Microwave Access) BWA (Broadband Wireless Access) Solution Standard (IEEE is the standard) for constructing Wireless Metropolitan Area Networks (WMANs) Can go places where no wired infrastructure can reach Backhauling Wi-Fi hotspots & cellular networks Offers new and exciting opportunities to established and newly emerging companies Incorporate cable (wired technology) standard Comply with European BWA standard 10/6/ Complement the existing last mile wired networks (i.e. xdsl, cable modem) Fast deployment, cost saving High speed data, voice and video services Fixed BWA, Mobile BWA 10/6/

2 Comparing Technologies Potential Services Bandwidth Range (LOS) Range (NLOS) Mobility Frequency/ Spectrum Licensing Standardization Availability WiFi Mbps shared 100 meters 30 meters Portable 2.4 GHz for b/g 5.2 GHz for a Unlicensed a, b and g standardized In market today WiMAX Share up to 70 Mbps km 2-5 km ( 07) Fixed (Mobile - 16e) 2-11 GHz for a GHz for Both , a and REVd standardized, other under development Products 2H UMTS Mobile-FI 3G Up to 1.5 Mbps each 384 Kbps 2 Mbps Coverage is overlaid 3 8 km on wireless infrastructure Full mobility Full mobility <3.5 GHz Licensed in development Standards coming Product late 06 Existing wireless spectrum Licensed Part of GSM standard CW in 6+ cities Intel, Fujitsu, Alcatel, Cisco, Motorola, GSM Wireless Backers Industry-wide Siemens, BT, AT&T, Qualcom and Industry Qwest, McCaw Flarion 10/6/ VoIP Video Data/Internet WLAN Security QoS WiFi Limited, QoS concerns Yes, in home Yes Yes, small scale WEP & i e WiMAX Limited, QoS concerns Possible, QoS concerns Yes Yes, large scale Developing WEP b in development Mobile-FI Limited, QoS concerns None (today) None (today) 10/6/ No Yes No UMTS 3G Yes Possible, via HSDPA Yes No WEP None (today) Benefits of WiMAX Speed Faster than broadband service Wireless Not having to lay cables reduces cost Easier to extend to suburban and rural areas An Insight into IEEE Broad coverage Much wider coverage than WiFi hotspots 10/6/ IEEE Evolution Fixed BWA at 10-66hz Line of sight Fixed BWA at 2-11hz None line of sight Revision of Combine previous standards Mobile BWA based on (802.16a) Roaming with vehicular speed 10/6/ IEEE Specifications a use the licensed and license-exempt frequencies from 2 to 11Ghz Support Mesh-Network b Increase spectrum to 5 and 6GHz Provide QoS (for realtime voice and video service) c Represents a 10 to 66GHz system profile d Improvement and fixes for a e Addresses on Mobile Enable high-speed signal handoffs necessary for communications with users moving 10/6/ at vehicular speeds 2

3 IEEE Basics IEEE Operation Completed a/REVd a: Jan REVd: Q e Approved on Dec.7, 2005 WiMAX consists of two parts Spectrum < 11 GHz < 11 GHz Channel Conditions Non line of sight Non line of sight Bit Rate Up to 75 Mbps at 20MHz Up to 75 Mbps at 20MHz Modulation Mobility Channel Bandwidths OFDM 256 sub-carriers QPSK, 16QAM, 64QAM Fixed Selectable channel bandwidths between 1.25 and 20 MHz OFDMA OFDM Pedestrian mobility High-speed mobility Same as d with subchannelization A WiMAX tower, similar in concept to a cell-phone tower - A single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles A WiMAX Receiver The receiver and antenna could be a small box or PCMCIA card, or they could be built into a laptop the way WiFi access is today 10/6/ /6/ How WiMax Works WiMax can provide 2 forms of wireless services: - Non-LOS, Wi-Fi sort of service, where a small antenna on a computer connects to the tower. Uses lower frequency range (2 to 11 GHz). - LOS, where a fixed antenna points straight at the WiMax tower from a rooftop or pole. The LOS connection is stronger and more stable, so it is able to send a lot of data with fewer errors. Uses higher frequencies, with ranges reaching a possible 66 GHz. Through stronger LOS antennas, WiMax transmitting stations would send data to WiMax enabled computers or routers set up within 30 (3,600 square miles of coverage) mile radius. 10/6/ WiMax Spectrum Broad Operating Range WiMax Forum is focusing on 3 spectrum bands for global deployment: Unlicensed 5 GHz: Includes bands between 5.25 and 5.85 GHz. In the upper 5 GHz band ( GHz) many countries allow higher power output (4 Watts) that makes it attractive for WiMax applications. Licensed 3.5 GHz: Bands between 3.4 and 3.6 GHz have been allocated for BWA in majority of countries. Licensed 2.5 GHz: The bands between 2.5 and 2.6 GHz have been allocated in the US, Mexico, Brazil and in some SEA countries. In US this spectrum is licensed for MDS and ITFS. 10/6/ Benefits of Licensed and License-Exempt Solutions Licensed Solution Better QoS Better NLOS reception at lower frequencies Higher barriers for entrance License-Exempt Solution Fast Rollout Lower Costs More worldwide options Technical Similarities and Differences Between Licensed and License-Exempt Bands Both solutions are based on IEEE standard, which uses OFDM in the physical (PHY) layer. OFDM provides benefits such as increased SNR of subscriber stations and improved resiliency to multi-path interference. For creating bi-directional channels for uplink and downlink, licensed solutions use FDD while license exempt solutions use TDD. 10/6/ /6/

4 Time Division Duplexing (TDD) Time Division Duplexing (TDD) Description Advantages Disadvantage s Usage A duplexing technique used in licenseexempt solutions, which uses a single channel for uplink and downlink. Enhanced flexibility, easier to pair with smart antenna technologies, asymmetrical. Cannot transmit and receive at the same time. Bursty, asymmetrical data applications, environments with varying traffic patterns, where RF efficiency is more important than cost. 10/6/ In case of TDD both uplink and downlink transmissions share the same frequency but are separated on time A TDD frame has a fixed duration and also consists of one uplink and one downlink frame TDD framing is Adaptive 10/6/ Description Advantages Frequency Division Duplexing (FDD) A duplexing technique used in licensed solutions that uses a pair of spectrum channels, one for the uplink and another for the downlink. Proven technology for voice, designed for symmetrical traffic, does not require guard time. Frequency Division Duplexing (FDD) In case of FDD both uplink and downlink channels are on separate frequencies The capability of downlink to be transmitted in bursts simultaneously supports two different modulation types Full Duplex SS's (which can transmit and receive simultaneously Half Duplex SS's (which cannot) Disadvantage s Usage Cannot be deployed where spectrum is unpaired, spectrum is usually licensed, higher cost associated with spectrum purchase. Environments with predictable traffic patterns, where equipment costs are more important than RF efficiency. 10/6/ /6/ Architecture P2MP Architecture P2MP (Point to Multi point) Wireless MAN BS connected to Public Networks BS serves Subscriber Stations (SS) Provides SS with first mile access to Public Networks Base Station Non Line-of-Sight Point to Multi-Point d Line-of-Sight Backhaul Mesh Architecture Optional architecture for WiMAX Telco Core Network or Private (Fiber) Network 10/6/ /6/2008 INTERNET 24 BACKBONE 4

5 Mesh Architecture Reference Model Supports multiple services (e.g. IP, voice over IP, video) simultaneously, with different QoS priorities Covers MAC layer and PHY layer 10/6/ /6/ MAC Layer MAC Addressing Wireless MAN: Point-to-Multipoint and optional mesh topology Connection-oriented Connection ID (CID) SS has 48-bit MAC address BS has 48-bit base station ID Not a MAC address MAC layer is further subdivided into three layers Convergence sub-layer (CS) Common part sub-layer (CPS) Privacy sub-layer Connection ID (CID) 16 bit Used in MAC PDU Connection Oriented Service 10/6/ /6/ MAC PDU Each MAC packet consists of the three components, A MAC header, which contains frame control information. A variable length frame body, which contains information specific to the frame type. A frame check sequence (FCS), which contains an IEEE 32-bit cyclic redundancy code (CRC). MAC PDU LEN lsb (8) msb Generic MAC Header (6 bytes) Generic MAC Header Format (Header Type (HT) = 0) LEN H E rs C EKS rs Type (6 bits) msb T C v I (2) v (3) CID msb (8) payload (optional) BW Req. Header Format (Header Type (HT) =1) BW Req. msb (8) CRC (optional) CID lsb (8) HCS (8) CID lsb (8) HCS (8) 10/6/ H E T C Type (6 bits) BWS Req. lsb (8) CID msb (8) lsb MAC PDU Types Data MAC PDUs HT = 0 Payloads are MAC SDUs/segments, i.e., data from upper layer (CS PDUs) Transmitted on data connections Management MAC PDUs HT = 0 Payloads are MAC management messages or IP packets encapsulated in MAC CS PDUs Transmitted on management connections BW Req. MAC PDUs HT = 1; and no payload, i.e., just a Header 10/6/

6 MAC PDU Transmission MAC CS Sub-layer MAC PDU s are transmitted on PHY bursts The PHY burst can contain multiple FEC blocks Interoperability requires convergence sub-layer to be service specific Concatenation Multiple MAC PDU's can be concatenated into a single transmission in either uplink or downlink direction Fragmentation Each MAC SDU can be divided into one or more MAC PDU's Packing Packs multiple MAC SDU's into a single MAC PDU Separate CS layers for upper layer (ATM & packet) protocols CS Layer: Receives data from higher layers Classifies data as ATM cell or packet Forwards frames to CPS layer 10/6/ /6/ MAC CPS Sub-layer Performs typical MAC functions such as addressing Each SS assigned 48-bit MAC address Connection Identifiers used as primary address after initialization MAC policy determined by direction of transmission Uplink is DAMA-TDM Downlink is TDM Data encapsulated in a common format facilitating interoperability Fragment or pack frames as needed Changes transparent to receiver 10/6/ MAC Privacy Sub-layer Provides secure communication Data encrypted with cipher clock chaining mode of DES Prevents theft of service SSs authenticated by BS using key management protocol 10/6/ How It Works Network Entry Scanning Scan for BS downlink channel Synchronize with BS Specifies channel parameters Ranging Set PHY parameters correctly Establish the primary management channel (for negotiation, authentication, and key management) Registration Result in establishment of secondary management connection (for transfer of standard based management messages such as DHCP, TFTP ) Establishment of transport connection 10/6/ /6/

7 Scalability QoS Range Coverage IEEE Features WiMAX vs. Wi-Fi IEEE vs. IEEE (1/4) Scalability Channel bandwidth for 20MHz is fixed MAC designed to support 10 s of users Channel b/w is flexible from 1.5 MHz to 20 MHz. Frequency re-use. Channel bandwidths can be chosen by operator (e.g. for sectorization) MAC designed to support thousands of users. 10/6/ /6/ IEEE vs. IEEE (2/4) Quality Of Service (QoS) No QoS support today (802.11e working to standardize ) Contention-based MAC (CSMA/CA) => no guaranteed QoS QoS designed in for voice/video Grant-request MAC Supports differentiated service levels. e.g. T1 for business customers; best effort for residential. Centrally-enforced QoS 10/6/ IEEE vs. IEEE (3/4) Range Optimized for users within a 100 meter radius Add access points or high gain antenna for greater coverage Designed to handle indoor multi-path delay spread of 0.8μ seconds Optimized for typical cell size of 7-10km Up to 50 Km range No hidden node problem Designed to tolerate greater multi-path delay spread (signal reflections) up to 10.0μ seconds 10/6/ IEEE vs. IEEE (4/4) Introduction to Bluetooth Coverage Optimized for indoor performance No mesh topology support within ratified standards Optimized for outdoor NLOS performance (trees, buildings, users spread out over distance) Standard supports mesh network topology Standard supports advanced antenna techniques 10/6/ /6/

8 Bluetooth named after a Danish Viking and King, Harald Blåtand it is a cable-replacement technology: new technology using short-range radio links, intended to replace the cable(s) connecting portable and/or fixed electronic devices conceived initially by Ericsson in 1994, set to commercially come out in bulk around 2002 a standard for a small, cheap radio chip to be plugged into computers, printers, mobile phones, etc The Bluetooth Special Interest Group (SIG) was founded by Ericsson,IBM,Intel,Nokia and Toshiba in February 1998, to develop an open specification for short-range wireless connectivity 10/6/ Bluetooth Bluetooth radio modules operate in the unlicensed ISM band centered at at 2.45GHz. RF channels:2402+k MHZ, k= Bluetooth devices within 10m of each other can share up to 720kbps of capacity Projected cost for a Bluetooth chip is ~$5. Plus its low power consumption, means you could literally place one anywhere. Can operate on both circuit and packet switching modes, providing both synchronous and asynchronous data services It is intended to support an open-ended list of applications, including data, audio, graphics and even video. 10/6/ Bluetooth Bluetooth must be able to: Recognize any other Bluetooth device in radio range Permit easy connection of these devices Be aware of the device types Support service discovery Support connectivity aware applications Examples of Bluetooth uses: Briefcase access while the PC is still in the briefcase; when PC receives an , you are notified thru the mobile phone. Use the mobile phone to browse the . Cordless desktop: connect your desktop/laptop cordlessly to printers, scanner, keyboard, mouse, etc. 10/6/ IEEE In 1999, IEEE established a working group for wireless personal area networks (WPAN) Contains multiple subgroups IEEE Standardizes the lower layers of the Bluetooth (together with the Bluetooth consortium) Bluetooth also specifies higher layers IEEE Focuses on the coexistence of WPAN and WLAN Proposes the adaptive frequency hopping (used since version 1.2) that requires a WPAN device check for the occupied channels and exclude them from their hopping list IEEE For high-rate at low-power low cost IEEE Low-rate low-power consumption WPAN enabling multi-year battery life 10/6/2008 Zigbee consortium tries to standardize the higher layers of Bluetooth is a PAN Technology Personal Area Network (PAN) Offers fast and reliable transmission for both voice and data Can support either one asynchronous data channel with up to three simultaneous synchronous speech channels or one channel that transfers asynchronous data and synchronous speech simultaneously Support both packet-switching and circuitswitching 10/6/ /6/

9 Bluetooth is a standard that will Eliminate wires and cables between both stationary and mobile devices Facilitate both data and voice communications Offer the possibility of ad hoc networks and deliver synchronicity between personal devices Characteristics of Bluetooth Technology 2M is expected for Bluetooth 2 79 frequencies, each channel is used for 625 microseconds 10/6/ /6/ Bluetooth Topology Bluetooth-enabled devices can automatically locate each other Topology is established on a temporary and random basis Up to eight Bluetooth devices may be networked together in a master-slave relationship to form a piconet One is master, which controls and setup the network All devices operate on the same channel and follow the same frequency hopping sequence The slave of one piconet can be the Two or more piconet interconnected to form a scatternet Only one master for each picon A device can t be masters for two piconets master of another piconet 10/6/ A Typical Bluetooth Network 10/6/ Piconet Master sends its globally unique 48-bit id and clock Hopping pattern is determined by the 48-bit device ID Phase is determined by the master s clock Why at most 7 slaves? Active member address is 3-bit Parked and standby nodes Parked devices can not actively participate in the piconet but are known to the network and can be reactivated within some milliseconds 8-bit for parked nodes No id for standby nodes Standby nodes do not participate in the piconet 10/6/ ScatterNet FH-CDMA to separate piconets within a scatternet More piconets within a scatternet degrades performance Possible collision because hopping patterns are not coordinated A device participating in more than one piconet At any instant of time, a device can participate only in one piconet If the device participates as a slave, it just synchronize with the master s hop sequence The master of a piconet can join another piconet as a slave; in this case, all communication within in the former piconet will be suspended When leaving a piconet, a slave notifies the master about its absence for certain amount of time Communication between different piconets takes place by devices jumping back and forth between these nets 10/6/

10 Frequency Selection FH is used for interference mitigation and media access; TDD is used for separation of the transmission directions In 3-slot or 5-slot packets, why frequency does not change? Why some frequencies are skipped? f k f k+1 f k+2 f k+3 f k+4 f k+5 f k+6 M S M S M S M Physical Links Synchronous Connection Oriented (SCO) : allocates a fixed bw between a point-to-point connection involving the master and one slave. The master reserves slots periodically. It primarily supports time-bounded information like voice. SCO packets do not include a CRC and are never retransmitted. The master can support up to 3 simultaneous SCO links f k f k+3 f k+4 f k+5 f k+6 M (3-slot packet) S M S M f k f k+1 f k+6 M S (5-slot packet) M 10/6/ Asynchronous connectionless (ACL) : a point-to-multipoint link between the master and all slaves in the piconet. Packet-switch style of connection No bw reservation possible Delivery may be guaranteed thru error detection and retransmission Only single ACL link can exist 10/6/ Physical Links Synchronous connection-oriented link (SCO) Reserve two consecutive slots at fixed intervals Asynchronous connectionless Link (ACL) Polling scheme master polls each slave Error recovery ACK a packet in the slot following the packet Negative ACK or timeout signals a retransmission 10/6/ Benefits Cable Replacement Replace the cables for peripheral devices, USB 1.1 and 2.0, printers, etc Ease of file sharing Panel discussion, conference, etc. Wireless synchronization Synchronize personal information contained in the address books and date books between different devices such as PDAs, cell phones, etc. Bridging of networks Cell phone connects to the network through dial-up connection while connecting to a laptop with Bluetooth. 10/6/