Wideband DS-CDMA for next-generation mobile communications systems

Abstract

sion multiple access aimed at third-generation mobile communications systems is reviewed. W-CDMA is designed t o flexibly offer wideband services which cannot be provided by present cellular systems, with various data rates as high as 2 Mb/s. The important concept of W-CDMA is the introduction of intercell asynchronous operation and t h e pilot channel associated w i t h individual data channels. Intercell asynchronous operation facilitates continuous system deployment from outdoors t o indoors. Other technical features of W-CDMA include fast cell search under intercell asynchronous operation, fast transmit power control, coherent spreading code tracking, a coherent Rake receiver, orthogonal multispreading factor forward link, and variable-rate transmission w i t h blind rate detection. The introduction o f the data-channel-associated pilot channel allows W-CDMA t o support interference cancellation and adaptive antenna array techniques that can significantly increase the link capacity and coverage. This article presents radio link performance evaluated by computer simulation. Field experiment radio link performance results are also presented. ecently, mobile communications services are pen-R etrating into our society at an explosive growth rate. All of the current second-generation cellular communications systems (e.g., PDCIGSMIIS54 and IS95) have adopted digital technology. However, the major services they provide are limited to basic services, such as voice, facsimile, and low-bit-rate (far less than 64 kb/s) data. We are now approaching the 21st century, when demands for a variety of wideband services such as high-speed Internet access and videolhigh-quality image transmission, will continue to increase. The third-generation mobile communication systems, called International Mobile Telecommunications-2000 (IMT-2000) in the International Telecommunication Union (ITU) [l], must be designed to support wideband services at data rates as high as 2 Mbis, with the same quality as fixed networks. Direct sequence code-division multiple access (DS-CDMA) technology [a] is attractive for wireless access because of its numerous advantages over time-division multiple access (TDMA) and frequency-division multiple access (FDMA), including soft handoff (or site diversity), exploitation of multipath fading through Rake combining, and direct capacity increase by the use of cell sectorization. However, the current IS-95 is based on narrowband DS-CDMA technology optimized for basic services. To realize true IMT-2000 systems, a new wideband wireless access technology incorporating as many recent technology developments as possible is necessary. The most promising candidate, wideband DS-CDMA (W-CDMA), is being developed throughout the world [3, 41. In January 1998, the European Telecommunications Standards Institute (ETSI) decided to adopt W-CDMA technology for frequency-division duplex (FDD) bands. In Japan, the Association of Radio Industries and Businesses (ARIB), the standardization body of the radio sector, is now developing a...

A Novel Approach for Authentication Technique in Mobile Communications

“…Third Generation mobile service is assured mainly by two systems like WCDMA and CDMA-2000 [6]- [9]. Some of the common feature between these two systems i.…”

“…Additional networks are provided in 3-G for providing packet switched data service usually higher speed than that of circuit switched data service in 2-G. This packet switched data network [1]- [2], [6]- [9] is consisting of two parts.…”

“…interface frame and an IP end point that may be an IP-enabled phone, IP based PBX or PC etc [7]- [9].…”

“…1. This 3-G network can provide circuit switched voice service, circuit switched data service like 2-G (CDMA One or GSM) [3], [5], in addition to this packet switched data and multimedia service [6]- [9]. [2], [6], [7].…”

“…Data rates reach upto 2 Mbps or more for 3-G mobile communications, opening opportunities for extensive wireless multimedia services. Enabling packet data services off the RAN (Radio Access Network) in UMTS (Universal Mobile Telecommunication System in USA) and by passing the MSC is the beginning step for separating the circuit based world of the PSTN and the packet based world of PDNs (Public Data Networks) and the Internet [6]- [9]. The European counterpart of UMTS is WCDMA (Wideband Code Division Multiple Access), generally marketed as 3GSM.…”