TY - JOUR
T1 - Suboptimality of TDMA in the low-power regime
AU - Caire, Giuseppe
AU - Tuninetti, Daniela
AU - Verdú, Sergio
N1 - Funding Information:
Manuscript received September 20, 2002; revised November 20, 2003. This work was supported in part through collaborative participation in the Communications and Networks Consortium sponsored by the U. S. Army Research Laboratory under the Collaborative Technology Alliance Program, Cooperative Agreement DAAD19-01-2-0011. G. Caire is with the Mobile Communication Department, Eurecom Institute, Sophia-Antipolis, F-6904 France (e-mail: [email protected]). D. Tuninetti is with Mobile Communication Laboratory, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland (e-mail: Daniela. [email protected]). S. Verdú is with the Department of Electrical Engineering, Princeton University, Princeton NJ 08544, USA (e-mail: [email protected]). Communicated by ˙. E. Telatar, Associate Editor for Shannon Theory. Digital Object Identifier 10.1109/TIT.2004.825003
PY - 2004/4
Y1 - 2004/4
N2 - We consider multiaccess, broadcast, and interference channels with additive Gaussian noise. Although the set of rate pairs achievable by time-division multiple access (TDMA) is not equal to the capacity region, the TDMA achievable region converges to the capacity region as the power decreases. Furthermore, TDMA achieves the optimum minimum energy per bit. Despite those features, this paper shows that the growth of TDMA-achievable rates with the energy per bit is suboptimal in the low-power regime except in special cases: multiaccess channels where the users' energy per bit are identical and broadcast channels where the receivers have identical signal-to-noise ratios. For the additive Gaussian noise interference channel, we identify a small region of interference parameters outside of which TDMA is also shown to be suboptimal. The effect of fading (known to the receiver) on the suboptimality of TDMA is also explored.
AB - We consider multiaccess, broadcast, and interference channels with additive Gaussian noise. Although the set of rate pairs achievable by time-division multiple access (TDMA) is not equal to the capacity region, the TDMA achievable region converges to the capacity region as the power decreases. Furthermore, TDMA achieves the optimum minimum energy per bit. Despite those features, this paper shows that the growth of TDMA-achievable rates with the energy per bit is suboptimal in the low-power regime except in special cases: multiaccess channels where the users' energy per bit are identical and broadcast channels where the receivers have identical signal-to-noise ratios. For the additive Gaussian noise interference channel, we identify a small region of interference parameters outside of which TDMA is also shown to be suboptimal. The effect of fading (known to the receiver) on the suboptimality of TDMA is also explored.
KW - Broadcast channels
KW - Channel capacity
KW - Code-division multiple access (CDMA)
KW - Interference channels
KW - Low-power communication
KW - Multiple-access channels
KW - Time-division multiple access (TDMA)
KW - Wideband regime
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U2 - 10.1109/TIT.2004.825003
DO - 10.1109/TIT.2004.825003
M3 - Article
AN - SCOPUS:1942454282
SN - 0018-9448
VL - 50
SP - 608
EP - 620
JO - IEEE Transactions on Information Theory
JF - IEEE Transactions on Information Theory
IS - 4
ER -