© The Institution of Engineering and Technology
In this contribution, the authors investigate the single-user-bound performance of a direct-sequence code-division multiple-access (DS-CDMA) system, where one source mobile terminal (MT) communicates with its base-station (BS) with the assistance of multiple relays. The authors assume that the communications channels experience both propagation pathloss and fast fading, and that the channels from the source MT to the BS and relays as well as that from the relays to the BS may experience different fast fading modelled correspondingly by Nakagami-m distributions. In the study, they assume both the single-user combining using maximal ratio combining and the multiuser combining, which are derived based on the maximum signal-to-interference-plus-noise ratio criterion. The bit-error-rate (BER) performance of the DS-CDMA is investigated associated with considering the locations of the relays as well as the power-allocation among the source MT and relays. From the study and simulation results, it can be shown that the achievable BER performance of the DS-CDMA depends on the locations of the relays and also on the power-allocation among the source MT and relays. When the relays of a source MT are chosen from a different area, the power-allocation should also be adjusted correspondingly in order to achieve the minimum BER. Furthermore, when optimum power-allocation is assumed, the BER performance of the DS-CDMA can be significantly improved, when increasing the number of relays assisting the source MT.
References
-
-
1)
-
A. Sendonaris ,
E. Erkip ,
B. Aazhang
.
User cooperation diversity. Two Parts.
IEEE Trans. Commun.
,
1927 -
1948
-
2)
-
J. Boyer ,
D.D. Falconer ,
H. Yanikomeroglu
.
Multihop diversity in wireless relaying channels.
IEEE Trans. Commun.
,
10 ,
1820 -
1830
-
3)
-
M.O. Hasna ,
M.S. Alouini
.
Harmonic mean and end-to-end performance of transmission systems with relays.
IEEE Trans. Commun.
,
1 ,
130 -
135
-
4)
-
L.L. Yang
.
MIMO assisted space-code-division multiple-access: linear detectors and performance over multipath fading channels.
IEEE J. Sel. Areas Commun.
,
1 ,
121 -
131
-
5)
-
R. Compton
.
(1988)
Adaptive antennas: concepts and performance.
-
6)
-
P.A. Anghel ,
M. Kaveh
.
Exact symbol error probability of a cooperative network in a Rayleigh-fading environment.
IEEE Trans. Wirel. Commun.
,
5 ,
1416 -
1421
-
7)
-
M.O. Hasna ,
M-S. Alouini
.
End-to-end performance of transmission systems with relays over Rayleigh-fading channels.
IEEE Trans. Wirel. Commun.
,
1126 -
1131
-
8)
-
J.N. Laneman ,
D.N.C. Tse ,
G.W. Wornell
.
Cooperative diversity in wireless networks: efficient protocols and outage behavior.
IEEE Trans. Inf. Theory
,
12 ,
3062 -
3080
-
9)
-
V. Tarokh ,
H. Jafarkhani ,
A.R. Calderbank
.
Space-time block coding for wireless communications: Performance results.
IEEE J. Sel. Areas Commun.
,
3 ,
451 -
460
-
10)
-
N. Nakagami ,
W.G. Hoffman
.
(1960)
The , Statistical Methods in Radio Wave Propagation.
-
11)
-
S. Verdu
.
(1998)
Multiuser Detection.
-
12)
-
L.-L. Yang ,
L. Hanzo
.
Performance of generalized multicarrier DS-CDMA over Nakagami-m fading channels.
IEEE Trans. Commun.
,
956 -
966
-
13)
-
J.G. Proakis
.
(1995)
Digital communications.
-
14)
-
Y. Cao ,
B. Vojcic
.
MMSE multiuser detection for cooperative diversity CDMA systems.
IEEE Commun. Soc.
,
42 -
47
-
15)
-
Nabar, R.U., Bölcskei, H.: `Space-time signal design for fading relay channels', Proc. IEEE Globecom, December 2003, 4, p. 1952–1956.
-
16)
-
A. Bletsas ,
A. Khisti ,
D.P. Reed ,
A. Lippman
.
A simple cooperative diversity method based on network path selection.
IEEE J. Sel. Areas Commun.
,
3 ,
659 -
672
-
17)
-
H.L. Van Trees
.
(2002)
Optimum array processing.
-
18)
-
A. Goldsmith ,
S. Jafar ,
N. Jindal ,
S. Vishwanath
.
Capacity limits of MIMO channels.
IEEE J. Sel. Areas Commun.
,
5 ,
684 -
702
-
19)
-
L. Venturino ,
X. Wang ,
M. Lops
.
Multiuser detection for cooperative networks and performance analysis.
IEEE Trans. Signal Process.
,
9 ,
3315 -
3329
-
20)
-
T.S. Rappaport
.
(1996)
Wireless Communications: Principles and Practice.
-
21)
-
Sendonaris, A., Erkip, E., Aazhang, B.: `Increasing uplink capacity via user cooperation diversity', Proc. IEEE Int. Symp. Information Theory, August 1998, Cambridge, MA, p. 56.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-com_20070321
Related content
content/journals/10.1049/iet-com_20070321
pub_keyword,iet_inspecKeyword,pub_concept
6
6