TY - GEN
T1 - Capacity of Gaussian channels with duty cycle and power constraints
AU - Zhang, Lei
AU - Guo, Dongning
PY - 2011/10/26
Y1 - 2011/10/26
N2 - In many wireless communication systems, radios are subject to duty cycle constraint, that is, a radio only actively transmits signals over a fraction of the time. For example, it is desirable to have a small duty cycle in some low power systems; a half-duplex radio cannot keep transmitting if it wishes to receive useful signals; and a cognitive radio needs to listen and detect primary users frequently. This work studies the capacity of scalar discrete-time Gaussian channels subject to duty cycle constraint as well as average transmit power constraint. The duty cycle constraint can be regarded as a requirement on the minimum fraction of nontransmission or zero symbols in each codeword. A unique discrete input distribution is shown to achieve the channel capacity. In many situations, numerical results demonstrate that using the optimal input can improve the capacity by a large margin compared to using Gaussian signaling over a deterministic transmission schedule, which is capacity-achieving in the absence of the duty cycle constraint. This is in part because the positions of the nontransmission symbol in a codeword can convey information. The results suggest that, under the duty cycle constraint, departing from the usual paradigm of intermittent packet transmissions may yield substantial gain.
AB - In many wireless communication systems, radios are subject to duty cycle constraint, that is, a radio only actively transmits signals over a fraction of the time. For example, it is desirable to have a small duty cycle in some low power systems; a half-duplex radio cannot keep transmitting if it wishes to receive useful signals; and a cognitive radio needs to listen and detect primary users frequently. This work studies the capacity of scalar discrete-time Gaussian channels subject to duty cycle constraint as well as average transmit power constraint. The duty cycle constraint can be regarded as a requirement on the minimum fraction of nontransmission or zero symbols in each codeword. A unique discrete input distribution is shown to achieve the channel capacity. In many situations, numerical results demonstrate that using the optimal input can improve the capacity by a large margin compared to using Gaussian signaling over a deterministic transmission schedule, which is capacity-achieving in the absence of the duty cycle constraint. This is in part because the positions of the nontransmission symbol in a codeword can convey information. The results suggest that, under the duty cycle constraint, departing from the usual paradigm of intermittent packet transmissions may yield substantial gain.
UR - http://www.scopus.com/inward/record.url?scp=80054826088&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80054826088&partnerID=8YFLogxK
U2 - 10.1109/ISIT.2011.6034180
DO - 10.1109/ISIT.2011.6034180
M3 - Conference contribution
AN - SCOPUS:80054826088
SN - 9781457705953
T3 - IEEE International Symposium on Information Theory - Proceedings
SP - 513
EP - 517
BT - 2011 IEEE International Symposium on Information Theory Proceedings, ISIT 2011
T2 - 2011 IEEE International Symposium on Information Theory Proceedings, ISIT 2011
Y2 - 31 July 2011 through 5 August 2011
ER -