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3.7 3G Cellular Systems The 3G Landscape, Table 3.5 참조 , p. 139 3.7.1 UMTS/WCDMA Versus cdma2000
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3.7 3G Cellular Systems • The 3G Landscape, Table 3.5 참조, p. 139 3.7.1 UMTS/WCDMA Versus cdma2000 • Universal Mobile Telecommunications System (UMTS) is one of the third-generation(3G) cell phone technologies, which is also being developed into a 4G technology. Currently, the most common form of UMTS uses W-CDMA as the underlying air interface. It is standardized by the 3GPP, and is the European answer to the ITUIMT-2000 requirements for 3G cellular radio systems. • A major difference of UMTS compared to GSM is the air interface forming (GeRAN). It can be connected to various backbone networks like the Internet, ISDN, GSM or to a UMTS network. GeRAN includes the three lowest layers of OSI model. The network layer (OSI 3) protocols form the Radio Resource Management protocol (RRM). They manage the bearer channels between the mobile terminals and the fixed network including the handovers. • CDMA2000 is a hybrid 2.5G / 3G technology of mobile telecommunicationsstandards that use CDMA, a multiple access scheme for digital radio, to send voice, data, and signaling data (such as a dialed telephone number) between mobile phones and cell sites. CDMA2000 is considered a 2.5G technology in 1xRTT and a 3G technology in EVDO. Supporting Wireless Technologies
3.7.2 UMTS/WCDMA • W-CDMA (Wideband Code Division Multiple Access) is a type of 3Gcellular network. W-CDMA is the higher speed transmission protocol used in the Japanese FOMA system and in the UMTS system, a third generation follow-on to the 2GGSM networks deployed worldwide. • More technically, W-CDMA is a wideband spread-spectrum mobile air interface that utilizes the direct sequence Code Division Multiple Access signaling method (or CDMA) to achieve higher speeds and support more users compared to the implementation of time division multiplexing (TDMA) used by 2G GSM networks. 3.7.3 cdma2000 • CDMA2000 3x • Higher rates per carrier (up to 4.9 Mbit/s on the downlink per carrier). Typical deployments are expected to include 3 carriers for a peak rate of 14.7 Mbit/s • Higher rates by bundling multiple channels together enhance the user experience and enables new services such as high definitionvideo streaming. • Uses statistical multiplexing across channels to further reduce latency, enhancing the experience for latency-sensitive services such as gaming, video telephony, remote console sessions and web browsing. • Increased talk-time and standby time Supporting Wireless Technologies
Hybrid frequency re-use which reduces the interference from the adjacent sectors and improves the rates that can be offered, especially to users at the edge of the cell. • Efficient support for services that have asymmetric download and upload requirements (i.e. different data rates required in each direction) such as file transfers, web browsing, and broadband multimedia content delivery. 3.7.4 4G Cellular Systems • 4G cellular systems provide even higher data rates of 20 Mbps to 100 Mbps. • Emerging technologies for 4G wireless networks • Smart antenna technologies exploit spatial separation of signals to allow an antenna to focus on desired signals as a way to reduce interference and improve system capacity. • MIMO (multiple-in, multiple-out) utilizes antenna arrays at both the transmitter end and receiver end to boost the link data rate and system capacity. • OFDM, MC-CDMA, modulation, and multiplexing technologies will improve the robustness of signal transmission and the data rate. • Software radio or software-defined radio will make it possible to reconfigure channel modulation and multiplexing on the fly. Supporting Wireless Technologies
3.8 2G Mobile Wireless Services • 3.8.1 WAP and iMode • Wireless application protocol (WAP) is an open-application layer protocol for mobile application targeting cell phones and wireless terminals. • WAP features • Wireless markup language (WML), WML script, and supporting WAP application environment. • WAP protocol stack. • WAP services. Supporting Wireless Technologies
3.8.2 Short Message Service • MT Short Message Scenario (IS—41) Supporting Wireless Technologies
3.9 Wireless Technologies Landscape • Wireless technology landscape. Supporting Wireless Technologies
3.10 802.11 Wireless LANs • Wireless LANs can be divided into two operational modes: infrastructure mode and ad hoc mode, depending on how the network is formed. • The Adv. of radio frequency wireless LANs • High bandwidth • No line-of-sight (LOS) restriction • Easy to set up and use 3.10.1 Architecture and Protocols Supporting Wireless Technologies
3.10.5 IEEE 802.11 Family Supporting Wireless Technologies
3.11 Bluetooth • Architecture and Protocols Supporting Wireless Technologies
3.12 Ultra-Wideband • Short distance high throughput wireless communications ideal for WPAN (wireless personal area network). • Utilizes a low power (-41db) signal from 3.1 to 11.6 GHz with channel bandwidths of ~ 500 MHz. • Will not interfere with other wireless technologies such as Wi-Fi, WiMAX, and cellular Supporting Wireless Technologies
3.13 Radio Frequency Identification • 3.13.1 RFID System • An RFID System Supporting Wireless Technologies
3.14 Wireless Metropolitan Area Networks • Wireless MANs can be categorized into following types: • Wireless “last mile” (fixed broadband wireless access) • Wireless data access for mobile terminals • Wireless backbones or wireless mesh 3.14.1 Wireless Broadband: IEEE 802.16 • IEEE 802.16 Summary Supporting Wireless Technologies
3.14.2 WiMax • WiMax employs a set of technologies to address these issues: • OFDM • Subchannelization • Directional antennas • Transmit and receive diversity: Multiple-Input Multiple-Output(다중 입력, 다중 출력)을 의미하는, MIMO는 IEEE 802.11n와 함께 사용되는 것이 일반적이지만 다른 802.11 기술과 함께 사용할 수도 있다. MIMO는 데이터 송수신에 여러 개의 공간 채널을 사용하므로 종종 공간 다이버시티라고 한다. • Adaptive modulation • Error correction techniques • Power control • Security Supporting Wireless Technologies
WiMax 다이어그램 Supporting Wireless Technologies
3.15 Satellite • 지구를 선회하는 궤도상에 발사된 인공위성을 중계하여 행하는 무선 통신. 인공위성에 탑재된 중계기는 지상 장거리 통신에서 중계국과 같이 지상의 무선국(지구국)에서 송신한 전파를 수신하고 증폭하여 하나 또는 복수의 지구국으로 송신한다. • 통신 위성의 특징은 (1) 하나의 위성이 중계할 수 있는 통신 구역의 광역성, (2) 전송 거리와 비용의 무관계성, (3) 지리적 장애의 극복, 통신 품질의 균일성 및 내재해성, (4) 고주파대의 전파 사용에 따른 광대역(고속) 전송의 가능성, (5) 다지점으로 동시에 정보를 분배할 수 있는 동보 통신과 다지점 간에 회선을 설정할 수 있는 다원 접속(multi-access)의 가능성, (6) 지구국을 이동시키면 어디에서나 자유로이 신속하게 회선을 설정할 수 있게 하는 이동 통신 기지국으로서의 기능 등이다. • 대부분의 통신 위성은 적도 상공 약 3만 5800km의 궤도상에 있는 정지 위성이지만, 군사 위성이나 아마추어 위성, 위성 휴대 통신(GMPCS)용 위성 등과 같이 1,000km 내외의 저궤도 또는 1만km 정도의 중궤도를 선회하는 통신 위성도 있다. • 지구와 위성 간의 장거리를 전파가 왕복하기 때문에 정지 위성의 경우에 약 0.25초 간의 전송 지연 시간이 발생하거나 지상의 무선 통신 시스템과의 간섭이 일어나는 등의 단점도 있다. Supporting Wireless Technologies
3.16 Wireless Sensor Networks 3.16.1 WSN Applications • WSN applications can be divided into three categories: monitoring space, including objects as part of the space; monitoring operations states of objects; and monitoring interactions between objects and space. 3.16.2 Wireless Sensor Node • A sensor node is make up of four components: sensing units, processing unit, transceiver unit, and power unit. • A list of sensor node characteristics • Size • Low power • Autonomous, unattended operations • Inexpensive • Adaptive to environments and themselves Supporting Wireless Technologies
3.16.4 ZigBee • ZigBee is a low-cost, low-power, wireless mesh networking standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range. Supporting Wireless Technologies
3.17 Standardization in the Wireless World 3.17.2 IEEE Standards Supporting Wireless Technologies