Title :
Single-User Performance of Uplink DS-CDMA using Relay-Assisted Diversity
Author :
Fang, Wei ; Yang, Lie-Liang ; Hanzo, Lajos
Author_Institution :
Sch. of Electron. & Comput. Sci., Southampton Univ.
Abstract :
In a wireless system with distributed mobile users, several mobile users may cooperate with each other in order to achieve the transmit diversity. In this contribution we investigate the single-user performance of an uplink direct-sequence code-division multiple-access (DS-CDMA) scheme, where one user is assisted by several other users (relays) so as to achieve the relay-assisted diversity. Specifically, the performance of the relay-assisted DS-CDMA is investigated, when communicating over generalized Nakagami-m fading channels, where signals from the transmitter to the relays and that from the relays to the base-station (BS) receiver may experience different fading. In our study two types of detection schemes are invoked. The first detection scheme is a maximal ratio combining (MRC) assisted single-user detection (SUD) scheme, which maximizes the output signal-to-noise ratio (SNR) without taking the interference among the relays into account. By contrast, the second detection scheme maximizes the output signal-to-interference-plus-noise ratio (MSINR), which is a multiuser detection (MUD) scheme that is capable of suppressing the interference among the relays. Our study and results show that, in a relay-assisted DS-CDMA without using orthogonal spreading codes, the relay-assisted diversity may only be achievable after suppressing the inter-relay interference
Keywords :
Nakagami channels; code division multiple access; codes; diversity reception; interference suppression; multiuser detection; radio links; radiofrequency interference; spread spectrum communication; base-station receiver; direct-sequence code-division multiple-access; generalized Nakagami-m fading channels; inter-relay interference suppression; maximal ratio combining; multiuser detection; orthogonal spreading codes; relay-assisted diversity; signal-to-interference-plus-noise ratio; single-user detection; single-user performance; transmit diversity; transmitter; uplink DS-CDMA; Fading; Frequency diversity; Interference; Land mobile radio; Mobile communication; Multiaccess communication; Multiuser detection; Relays; Signal to noise ratio; Transmitters;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2006 IEEE 17th International Symposium on
Conference_Location :
Helsinki
Print_ISBN :
1-4244-0329-4
Electronic_ISBN :
1-4244-0330-8
DOI :
10.1109/PIMRC.2006.254255