TY - CHAP
T1 - Adaptive power and rate transmission with single-and multi-user detection
AU - Zarringhalam, F
AU - Seyfe, B
AU - Shikh-Bahaei, M R
AU - Kobravi, A
AU - Charbit, G
PY - 2007
Y1 - 2007
N2 - We propose a technique for enhancing the achievable spectral efficiency of multiuser direct-sequence code-division multiple-access (DS-CDMA) channels in the presence of additive white Gaussian noise (AWGN) and multiple access interference (MAI). The proposed scheme is the joint optimization of outer loop power control and variable spreading factors (VSFs). The optimum SNR-target, the SNR that results in optimal spectral efficiency, is set in the outer loop. Accordingly, appropriate spreading factor is selected, and along with the transmit power adaptation in the inner loop, it leads to maximized spectral efficiency. Total and truncated channel inversion strategies are used in the inner loop. Analytical expressions are derived for the spectral efficiency of the joint optimization scheme for the conventional matched-filter and the multiuser decorrelating detectors. Average transmit power and instantaneous BER constraints are considered and the performance is evaluated over Nakagami-m flat fading channels. We show that our scheme achieves higher spectral efficiency than a system that uses VSF transmission but without outer loop optimal SNR-target. The gain is realized at no transmit power cost and without sacrificing the BER.
AB - We propose a technique for enhancing the achievable spectral efficiency of multiuser direct-sequence code-division multiple-access (DS-CDMA) channels in the presence of additive white Gaussian noise (AWGN) and multiple access interference (MAI). The proposed scheme is the joint optimization of outer loop power control and variable spreading factors (VSFs). The optimum SNR-target, the SNR that results in optimal spectral efficiency, is set in the outer loop. Accordingly, appropriate spreading factor is selected, and along with the transmit power adaptation in the inner loop, it leads to maximized spectral efficiency. Total and truncated channel inversion strategies are used in the inner loop. Analytical expressions are derived for the spectral efficiency of the joint optimization scheme for the conventional matched-filter and the multiuser decorrelating detectors. Average transmit power and instantaneous BER constraints are considered and the performance is evaluated over Nakagami-m flat fading channels. We show that our scheme achieves higher spectral efficiency than a system that uses VSF transmission but without outer loop optimal SNR-target. The gain is realized at no transmit power cost and without sacrificing the BER.
UR - http://www.scopus.com/inward/record.url?scp=36349010637&partnerID=8YFLogxK
U2 - 10.1109/WCNC.2007.324
DO - 10.1109/WCNC.2007.324
M3 - Conference paper
SN - 1424406587
T3 - IEEE Wireless Communications and Networking Conference
SP - 1722
EP - 1727
BT - Wireless Communications & Networking Conference, 2007, WCNC 2007. IEEE
PB - IEEE
CY - NEW YORK
T2 - IEEE Wireless Communications and Networking Conference
Y2 - 1 January 2007
ER -