Capacity estimates for mixed-rate traffic on the integrated wireless access network

The integrated wireless access network provides for simultaneous transmission of speech, data, and video signals on a shared spectrum basis. All services employ the same chip rate and rate differences manifest themselves in variations on the resulting processing gain and/or transmitted power. The capacity of the system to carry stream traffic is estimated as a function of system bandwidth, source data rate and path loss exponent. Both stream and packet traffic capacities are of interest, however, the focus is on the stream traffic, both low rate and high rate sources, some constant rate and some variable rate. The bandwidth efficiency, defined as the number of simultaneous calls per cell or sector per MHz of bandwidth, is found to increase due to improved multiplexing gains as well as due to better averaging of the multiuser interference. On the downlink there is an additional source of multiplexing due to the addition of the powers transmitted to different portables, subject to a maximum total transmitted power constraint. The results suggest that aggregating contiguous blocks of available spectrum increases the capacity, bandwidth efficiency and peak service rate at the cost of the added complexity of transmission at higher chip rates.