TY - GEN

T1 - Optimal rate and power allocation in uplink packet CDMA transmission

AU - Kim, Byoung Hoon

AU - Oh, Seong Jun

PY - 2009

Y1 - 2009

N2 - This paper revisits an optimal rate and power allocation problem to maximize throughput in uplink CDMA singlecell packet data communications. First, we show that the widelyaccepted belief that an optimally selected rate always keeps a constant value of the resulting bit energy to the interference plus noise power spectral density ratio is not true in most practical CDMA packet transmission environments, where the packet size varies in proportion to the rate. Then, we derive the rate-dependent optimal bit energy-to-interference- noise power spectral density ratio, based on which we convert the original joint optimization problem of rate and power to an equivalent but simple power allocation problem. Finally, we derive an optimal power allocation strategy by applying the convex optimization theory. Through two instructive examples, we show that the optimality of the well-known bang bang power control, that is, each user (except at most one user) should either transmit his data at the maximum allowed power level or at the minimum required power level meeting the SINR requirement in order to maximize the system throughput, may or may not be true depending on the incorporated channel coding scheme.

AB - This paper revisits an optimal rate and power allocation problem to maximize throughput in uplink CDMA singlecell packet data communications. First, we show that the widelyaccepted belief that an optimally selected rate always keeps a constant value of the resulting bit energy to the interference plus noise power spectral density ratio is not true in most practical CDMA packet transmission environments, where the packet size varies in proportion to the rate. Then, we derive the rate-dependent optimal bit energy-to-interference- noise power spectral density ratio, based on which we convert the original joint optimization problem of rate and power to an equivalent but simple power allocation problem. Finally, we derive an optimal power allocation strategy by applying the convex optimization theory. Through two instructive examples, we show that the optimality of the well-known bang bang power control, that is, each user (except at most one user) should either transmit his data at the maximum allowed power level or at the minimum required power level meeting the SINR requirement in order to maximize the system throughput, may or may not be true depending on the incorporated channel coding scheme.

UR - http://www.scopus.com/inward/record.url?scp=70349191671&partnerID=8YFLogxK

U2 - 10.1109/WCNC.2009.4917867

DO - 10.1109/WCNC.2009.4917867

M3 - Conference contribution

AN - SCOPUS:70349191671

SN - 9781424429486

T3 - IEEE Wireless Communications and Networking Conference, WCNC

BT - 2009 IEEE Wireless Communications and Networking Conference, WCNC 2009 - Proceedings

T2 - 2009 IEEE Wireless Communications and Networking Conference, WCNC 2009

Y2 - 5 April 2009 through 8 April 2009

ER -