Rake Reception with Maximal-ratio and Equal-gain Combining for Ds-cdma Systems in Nakagami Fading
نویسندگان
چکیده
We study coherent binary direct-sequence code division multiple access (DS-CDMA) systems operating over frequency-selective Nakagami fading channels. In particular a performance comparison between maximal-ratio combining (MRC) and equal-gain combining (EGC) RAKE receivers is considered. For interference limited systems, perfect MRC RAKE receivers can accommodate about 5m=(5m ? 1) more users than EGC RAKE receivers, where m is the Nakagami fading parameter. MRC has a higher rate of improvement than EGC as the number of combined paths increases. However, imperfect or inaccurate channel fading estimation leads to serious degradation in the performance of MRC receivers and in that case EGC becomes superior to MRC.
منابع مشابه
Average channel capacity for generalized-selection combining RAKE receivers
RAKE reception has been considered as an effective way to anticipate multipath signal fading in direct sequence code division multiple access (DS-CDMA) communications systems. Common diversity techniques used in conventional fingered RAKE receivers are maximal-ratio combining (MRC) and equal-gain combining (EGC). Conventional fingered RAKE receivers offer increased complexity, since the number ...
متن کاملDiversity Combining for DS CDMA Systems with Synchronization Errors
An eecient series that is used to calculate the probability of error for a BPSK modulated DS CDMA system with chip timing and carrier phase errors in a slowly fading , multipath channel is derived. The receiver is assumed to be a coherent RAKE receiver. Three types of diversity schemes are considered: selection diversity, equal gain diversity combining and maximal ratio diversity combining. The...
متن کاملJoint Closed-Loop Power Control and Base Station Assignment for DS-CDMA Receiver in Multipath Fading Channel with Adaptive Beamforming Method
In this paper, we propose smart step closed-loop power control (SSPC) algorithm and base station assignment based on minimizing the transmitter power (BSAMTP) technique in a direct sequence-code division multiple access (DS-CDMA) receiver in the presence of frequency-selective Rayleigh fading. This receiver consists of three stages. In the first stage, with conjugate gradient (CG) adaptive ...
متن کاملA Generalized Performance Study of DS-CDMA Uplink/Downlink Receivers in NakagamiWideband Fading Channel
In this paper, we consider a mobile system consisting of a single isolated circular cell with K independent users simultaneously sharing the channel using binary DS-CDMA to establish a full duplex channel with the base station. Both coherent and differential detection RAKE receivers with Maximal Ratio Combining (MRC) techniques are considered. The performance of two uplink/downlink receivers in...
متن کاملPerformance of multicode DS-CDMA using frequency domain equalisation in frequency selective fading channel
For the reception of multicode direct sequence (DS)-CDMA signals, the MMSE frequency domain equalisation is applied instead of RAKE combining. The achievable BER performance in a frequency selective Rayleigh fading channel is evaluated by computer simulation. It is shown by computer simulation that the DS-CDMA with MMSE frequency domain equalisation outperforms the DS-CDMA with RAKE combining a...
متن کامل