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EELE 5490, Fall, 2009 Wireless Communications Ali S. Afana Department of Electrical Engineering Class 2 Oct. 2nd, 2009 Outline 2.5G cellular networks 3G cellular networks WMAX: LMDS WLAN WPAN – Bluetooth – UWB Ad Hoc Networks Sensor Networks [2] 2.5G HSCSD: high speed circuit switched data: multiple time slots, realtime 57.6 kbps GPRS: general packet radio service: non-realtime, 171.2 kbps EDGE: Enhanced Data Rates for GSM Evolution Multiple modulation and coding schemes (MCS) New hardware 384kbps IS-95B: multiple code Medium data rate (MDR) Up to 8 codes, 64kbps Easy to update [3] WCDMA-UMTS 8k-2.048 Mbps per user, future 8Mbps Spectrum 5MHz, so complete change for hardware and software Each channel, 100-350 voice call Chip rate: 16Megachips per second 6 times spectrum efficiency than GSM 2010-2015 to finish updating, slow [4] IMT-2000 GSM world: http://www.gsmworld.com UMTS world: http://www.umtsworld.com 3GPP [5] CDMA2000 1.25MHz, seamless for CDMAone, IS95B, CDMA2000 Higher data rate Seamlessly and less expensive update [6] TD-SCDMA China, 8 millions per month Time Division Synchronous CDMA GSM based infrastructure 1.6 MHz, 384 kbps Smart antenna, several time better spectrum efficiency than GSM TDD Cheap to update [7] Wireless Local Loop Last mile technology Ramp to highway [8] Local Multipoint Distribution Service [9] LMDS IEEE 802.16 WIMAX HIPERACESS Line of sight [10] WMAN Structure [11] Rain Attenuation [12] Rain Attenuation [13] 802.11 2.4G-2.4835G, 5.725-5.825G 802.11a/g, OFDM, 802.11b: CDMA [14] Channel 11, 5.5, 2, 1Mbps [15] Channelization scheme channels [16] 802.11 ISO OSI 7-layer model Application Presentation Session 802.11a/g: 54, 48, 36, 24, 18, 6Mbps 802.11e -MAC Enhancements-Security/QoS 802.11f- Inter-Access Point Protocol 802.11h- Spectrum Managed 5Ghz 802.11i- Enhanced Security (TKIP and 802.1x) IEEE 802 standards Transport Network Logical Link Control Data Link Medium Access (MAC) Physical Physical (PHY) [17] Wireless hotpot planner Wireless valley [18] Design Procedure [19] Future WIFI [20] Signal to Noise Ratio at home [21] Personal Area Networks 802.15 – Master-slave piconets – Capable of connecting a mix of multiple piconets into “scatternet” – Service discovery protocol allows invisible interaction of various “trusted” devices – Less susceptible to interference [22] Bluetooth Wireless LAN technology (10 meters) or PAN 2.4GHz band with 1Mbps speed Spread spectrum frequency-hopping “always on” user-transparent cable-replacement Combination of packet-switching & circuit-switching (good for data & voice) 3 voice channels - 64Kbps each Low power, low cost Transparently connects “office” devices – Laptop, Desktop, PDA, Phone, printer Bridging capability: network-pda-phone [23] Ultra Wide Band High speed at short range – 480 Mb/s at ~3m. Does not penetrate walls Wireless USB IP over UWB [24] Summary Trend – 802.11 - 802.15 - cellular wireless technologies all competing for customers – 802.11 WLANs offer “hotspots” at nominal cost (sometimes “free”) – Cellular services used worldwide – 802.15 Bluetooth offers bridging options for WLAN and cellular services Alliances, Partnerships, Coalitions,… – AT&T, Intel, IBM (and investors) form “Cometa”, a company to provide wireless hot spots across the country – Motorola, Proxim and Avaya form partnership to provide seamless roaming between WiFi and cellular networks – HP and Transat Technologies collaborating on project to link 2G/3G to WiFi “hotspots” [25] Wireless Technologies WAN (Wide Area Network) MAN (Metropolitan Area Network) LAN (Local Area Network) PAN PAN (Personal Area Network) LAN MAN WAN GSM, CDMA, Satellite Standards Bluetooth 802.15.3 802.11 802.11 802.16 802.20 Speed < 1 Mbps 11 to 54 Mbps 10-100+ Mbps 10 Kbps–2 Mbps Range Short Medium Medium-Long Long Peer-to-Peer Device-to-Device Enterprise Networks Last Mile Access Mobile Data Devices Applications [26] Ad Hoc Network Mobile Ad Hoc Networks (MANETs) – An autonomous collection of mobile users that communicate over relatively bandwidth constrained wireless links. – Since the nodes are mobile, the network topology may change rapidly and unpredictably over time. – The network is decentralized, where all network activity including discovering the topology and delivering messages must be executed by the nodes themselves, MANETs need efficient distributed algorithms to determine network organization, link scheduling, and routing. – The set of applications for MANETs is diverse, ranging from small, static networks that are constrained by power sources, to large-scale, mobile, highly dynamic networks – In a military environment, preservation of security, latency, reliability, intentional jamming, and recovery from failure are significant concerns [27] MANET Examples Ad hoc mode of WIFI Military [28] Wireless Sensor Network Consists of a number of sensors spread across a geographical area. Each sensor has wireless communication capability and some level of intelligence for signal processing and networking of the data. – Military sensor networks to detect and gain as much information as possible about enemy movements, explosions, and other phenomena of interest. – Sensor networks to detect and characterize Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE) attacks and material. – Sensor networks to detect and monitor environmental changes in plains, forests, oceans, etc. – Wireless traffic sensor networks to monitor vehicle traffic on highways or in congested parts of a city. – Wireless surveillance sensor networks for providing security in shopping malls, parking garages, and other facilities. – Wireless parking lot sensor networks to determine which spots are occupied and which are free. [29] Wireless Sensor Networks Classification: whether or not the nodes are individually addressable and whether the data in the network is aggregated. Goals and Tasks – – – – Determine the value of some parameter at a given location: In an environmental network, one might one to know the temperature, atmospheric pressure, amount of sunlight, and the relative humidity at a number of locations. This example shows that a given sensor node may be connected to different types of sensors, each with a different sampling rate and range of allowed values. Detect the occurrence of events of interest and estimate parameters of the detected event or events: In the traffic sensor network, one would like to detect a vehicle moving through an intersection and estimate the speed and direction of the vehicle. Classify a detected object: Is a vehicle in a traffic sensor network a car, a mini-van, a light truck, a bus, etc. Track an object: In a military sensor network, track an enemy tank as it moves through the geographic area covered by the network. [30] WSN Requirement Large number of (mostly stationary) sensors: Aside from the deployment of sensors on the ocean surface or the use of mobile, unmanned, robotic sensors in military operations, most nodes in a smart sensor network are stationary. Networks of 10,000 or even 100,000 nodes are envisioned, so scalability is a major issue. Low energy use: Since in many applications the sensor nodes will be placed in a remote area, service of a node may not be possible. In this case, the lifetime of a node may be determined by the battery life, thereby requiring the minimization of energy expenditure. Network self-organization: Given the large number of nodes and their potential placement in hostile locations, it is essential that the network be able to self-organize; manual configuration is not feasible. Moreover, nodes may fail (either from lack of energy or from physical destruction), and new nodes may join the network. Therefore, the network must be able to periodically reconfigure itself so that it can continue to function. Individual nodes may become disconnected from the rest of the network, but a high degree of connectivity must be maintained. Collaborative signal processing: Yet another factor that distinguishes these networks from MANETs is that the end goal is detection/estimation of some events of interest, and not just communications. To improve the detection/estimation performance, it is often quite useful to fuse data from multiple sensors. This data fusion requires the transmission of data and control messages, and so it may put constraints on the network architecture. Querying ability: A user may want to query an individual node or a group of nodes for information collected in the region. Depending on the amount of data fusion performed, it may not be feasible to transmit a large amount of the data across the network. Instead, various local sink nodes will collect the data from a given area and create summary messages. A query may be directed to the sink node nearest to the desired location. [31] Wireless Sensor Networks [32] Homework Read Chapter 2 [33] Questions? [34]