Abstract
Space-time spreading (STS) is an appealing open-loop transmit diversity scheme, which has recently been included into the cdma2000 standard. It has been shown that the performance of the STS scheme is highly sensitive to fading coefficient estimation errors, particularly when the channel is highly time dispersive. In practical systems, channel estimation is normally performed after the multipath components are resolved, which suggests that improving multipath detection reduces such estimation errors. Motivated by this, we address, in this paper, the problem of multipath detection in STS-based code division multiple access (CDMA) systems. We first extend the conventional energy-based multipath detection scheme (EMDS) to cope with the spatial channel structure. We derive approximate expressions for the probability of detection and probability of false alarm. It is shown that the errors produced by the conventional scheme in detecting the potential multipath components severely impact the performance of the receiver. To improve upon the EMDS, we introduce and analyze an improved multipath detection scheme (IMDS) based on the estimation of the interference power in the individual resolved multipath components. The efficacy of the proposed scheme stems from the fact that the interference in each potential path is estimated and subtracted before that path is detected. We also present a simple and realizable version of the proposed IMDS detection scheme. Our results show that the proposed scheme not only improves the bit-error-rate performance significantly but also utilizes the pilot power much more efficiently.
| Original language | English |
|---|---|
| Pages (from-to) | 146-156 |
| Number of pages | 11 |
| Journal | IEEE Transactions on Vehicular Technology |
| Volume | 57 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 2008 |
| Externally published | Yes |
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Keywords
- CDMA systems
- Code division multiple access (CDMA) systems
- Multipath detection
- Space & time spreading (STS)
- Space-time spreading
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering
Cite this
A multipath detection scheme for CDMA systems with space-time spreading. / Abou-Khousa, Mohamed; Ghrayeb, Ali; El-Tarhuni, Mohamed.
In: IEEE Transactions on Vehicular Technology, Vol. 57, No. 1, 01.2008, p. 146-156.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A multipath detection scheme for CDMA systems with space-time spreading
AU - Abou-Khousa, Mohamed
AU - Ghrayeb, Ali
AU - El-Tarhuni, Mohamed
PY - 2008/1
Y1 - 2008/1
N2 - Space-time spreading (STS) is an appealing open-loop transmit diversity scheme, which has recently been included into the cdma2000 standard. It has been shown that the performance of the STS scheme is highly sensitive to fading coefficient estimation errors, particularly when the channel is highly time dispersive. In practical systems, channel estimation is normally performed after the multipath components are resolved, which suggests that improving multipath detection reduces such estimation errors. Motivated by this, we address, in this paper, the problem of multipath detection in STS-based code division multiple access (CDMA) systems. We first extend the conventional energy-based multipath detection scheme (EMDS) to cope with the spatial channel structure. We derive approximate expressions for the probability of detection and probability of false alarm. It is shown that the errors produced by the conventional scheme in detecting the potential multipath components severely impact the performance of the receiver. To improve upon the EMDS, we introduce and analyze an improved multipath detection scheme (IMDS) based on the estimation of the interference power in the individual resolved multipath components. The efficacy of the proposed scheme stems from the fact that the interference in each potential path is estimated and subtracted before that path is detected. We also present a simple and realizable version of the proposed IMDS detection scheme. Our results show that the proposed scheme not only improves the bit-error-rate performance significantly but also utilizes the pilot power much more efficiently.
AB - Space-time spreading (STS) is an appealing open-loop transmit diversity scheme, which has recently been included into the cdma2000 standard. It has been shown that the performance of the STS scheme is highly sensitive to fading coefficient estimation errors, particularly when the channel is highly time dispersive. In practical systems, channel estimation is normally performed after the multipath components are resolved, which suggests that improving multipath detection reduces such estimation errors. Motivated by this, we address, in this paper, the problem of multipath detection in STS-based code division multiple access (CDMA) systems. We first extend the conventional energy-based multipath detection scheme (EMDS) to cope with the spatial channel structure. We derive approximate expressions for the probability of detection and probability of false alarm. It is shown that the errors produced by the conventional scheme in detecting the potential multipath components severely impact the performance of the receiver. To improve upon the EMDS, we introduce and analyze an improved multipath detection scheme (IMDS) based on the estimation of the interference power in the individual resolved multipath components. The efficacy of the proposed scheme stems from the fact that the interference in each potential path is estimated and subtracted before that path is detected. We also present a simple and realizable version of the proposed IMDS detection scheme. Our results show that the proposed scheme not only improves the bit-error-rate performance significantly but also utilizes the pilot power much more efficiently.
KW - CDMA systems
KW - Code division multiple access (CDMA) systems
KW - Multipath detection
KW - Space & time spreading (STS)
KW - Space-time spreading
UR - http://www.scopus.com/inward/record.url?scp=39549118438&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=39549118438&partnerID=8YFLogxK
U2 - 10.1109/TVT.2007.905327
DO - 10.1109/TVT.2007.905327
M3 - Article
VL - 57
SP - 146
EP - 156
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
SN - 0018-9545
IS - 1
ER -