Title :
On the transport capacity of Gaussian multiple access and broadcast channels
Author :
Gupta, G.A. ; Toumpis, S. ; Sayir, J. ; Muller, R.R.
Author_Institution :
Dept. of Mathematics, Indian Inst. of Technol., New Delhi, India
Abstract :
We study the transport capacity of a Gaussian multiple access channel, which consists of a set of transmitters and a single receiver. The transport capacity is defined as the sum, over all transmitters, of the product of the transmission rate with a reward r(x), which is a function of the distance x between the transmitter and the receiver, and quantifies the usefulness of the transmitting information over a distance x. Assuming that the sum of the transmitter powers is upper bounded, we present in closed form the optimal power allocation among the transmitters, that maximizes the transport capacity. We then present simple expressions for the optimal power allocation and induced transport capacity, as the number of transmitters approaches infinity. We also study the transport capacity of a Gaussian broadcast channel, which consists of a single transmitter and multiple receivers. Here, the transport capacity is defined as the sum, over all receivers, of the product of the transmission rate with a reward r(x). We determine in closed form the maximum possible transport capacity and the distribution of the available transmitter power among the receivers that achieve it. Although this result has already been reported in the literature, our derivation is shorter, and leads to simpler expressions. Our results can be used to gain intuition and develop good design principles in a variety of settings. For example, they apply to the uplink and downlink channel of cellular networks, and also to sensor networks which consist of multiple sensors that communicate with a single central station.
Keywords :
Gaussian channels; broadcast channels; cellular radio; channel allocation; channel capacity; multi-access systems; radio links; radio receivers; radio transmitters; Gaussian broadcast channel; Gaussian multiple access; Gaussian multiple access channel; cellular network; cellular radio; downlink channel; power allocation; radio receiver; radio transmitter; sensor network; transport capacity; uplink and downlink channel; Bandwidth; Broadcast technology; Broadcasting; Downlink; H infinity control; Land mobile radio cellular systems; Mathematics; Spread spectrum communication; Transmitters; Wireless networks;
Conference_Titel :
Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, 2005. WIOPT 2005. Third International Symposium on
Print_ISBN :
0-7695-2267-X
DOI :
10.1109/WIOPT.2005.35