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We analyze the reverse link of a single wireless cell in which mobile phones simultaneously transmit to the base station using code division multiple access (CDMA). The mobiles are transmitting data which is delay intolerant, so that scheduling cannot be employed. There is a finite number of data classes, and the users transmit either data or a lower rate synchronizing signal. To overcome the near-far problem, received power control is used, which has a log-normal error. For each class there is an outage probability that the user's signal-to-noise ratio (SNR) will be met (when active and when idle). Refinements of the central limit theorem are used to determine the number of users of each class that can be supported, i.e., the capacity. The approximation can also be used to determine the minimal target powers necessary to meet the outage requirements. Comparison with simulation shows these approximations to be accurate. [ABSTRACT FROM AUTHOR]

Consider several source nodes communicating across a wireless network to a destination node with the help of several layers of relay nodes. Recent work by Avestimehr has approximated the capacity of this network up to an additive gap. The communication scheme achieving this capacity approximation is based on compress-and-forward, resulting in noise accumulation as the messages traverse the network. As a consequence, the approximation gap increases linearly with the network depth. This paper develops a computation alignment strategy that can approach the capacity of a class of layered, time-varying wireless relay networks up to an approximation gap that is independent of the network depth. This strategy is based on the compute-and-forward framework, which enables relays to decode deterministic functions of the transmitted messages. Alone, compute-and-forward is insufficient to approach the capacity as it incurs a penalty for approximating the wireless channel with complex-valued coefficients by a channel with integer coefficients. Here, this penalty is circumvented by carefully matching channel realizations across time slots to create integer-valued effective channels that are well suited to compute-and-forward. Unlike prior constant gap results, the approximation gap obtained in this paper also depends closely on the fading statistics, which are assumed to be i.i.d. Rayleigh. [ABSTRACT FROM PUBLISHER]