3.7 3g cellular systems the 3g landscape, table 3.5 참조 , p. 139 3.7.1 umts/wcdma versus...

Supporting Wireless Technologies

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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-generat

ion (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 ITU IMT-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 telecommunications standards 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.


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3.7.2 UMTS/WCDMA W-CDMA (Wideband Code Division Multiple Access) is a type of 3G

cellular 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 2G GSM 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 definition video 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


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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 networksSmart 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.


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3.8 2G Mobile Wireless Services3.8.1 WAP and iMode Wireless application protocol (WAP) is an open-application layer protocol for mob

ile 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.


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3.8.2 Short Message Service

MT Short Message Scenario (IS—41)


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3.9 Wireless Technologies Landscape Wireless technology landscape.


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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


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3.10.5 IEEE 802.11 Family


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3.11 Bluetooth Architecture and Protocols


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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 b

andwidths of ~ 500 MHz. Will not interfere with other wireless technologies such as Wi-Fi, WiMAX,

and cellular


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3.13 Radio Frequency Identification

3.13.1 RFID System

An RFID System


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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

Feature Description

Frequency band 10-66 GHz, 2-11 GHz

Range Up to 40 km

Multiplexing/modulation

OFDM, adaptive modulation

Channel data rate 75 Mbps for both uplink and downlink

Antenna Directional antenna, point-to-multipoint

Multiple access Demand-assignment multiple access-time-division multiple access (DAMA-TDMA)


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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 , MIMO 는 IEEE 802.11n 와 함께 사용되는 것이 일반적이지만 다른 802.11 기술과 함께 사용할 수도 있다 . MIMO 는 데이터 송수신에 여러 개의 공간 채널을 사용하므로 종종 공간 다이버시티라고 한다 .

Adaptive modulation Error correction techniques Power control Security


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WiMax 다이어그램


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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 3 만 5800km 의 궤도상에 있는 정지 위성이지만 , 군사 위성이나 아마추어 위성 , 위성 휴대 통신 (GMPCS) 용 위성 등과 같이 1,000km 내외의 저궤도 또는 1 만 km 정도의 중궤도를 선회하는 통신 위성도 있다 .

지구와 위성 간의 장거리를 전파가 왕복하기 때문에 정지 위성의 경우에 약 0.25 초 간의 전송 지연 시간이 발생하거나 지상의 무선 통신 시스템과의 간섭이 일어나는 등의 단점도 있다 .


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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


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3.16.4 ZigBee ZigBee is a low-cost, low-power, wireless mesh networking standard. The low co

st 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.


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3.17 Standardization in the Wireless World

3.17.2 IEEE Standards

3.7 3g cellular systems the 3g landscape, table 3.5 참조 , p. 139 3.7.1 umts/wcdma versus...

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