High Capacity Networks

High-capacity solutions are about building high-capacity networks in the most economical way, and therefore, GSM radio network capacity solutions are becoming increasingly important. Radio network capacity solutions can be divided into three categories: cell capacity, network capacity, and channel capacity. The author discusses various solutions for improving radio network capacity in each of these areas. He also describes different implementations and recommends three general steps for introducing solutions in the network.

cells and on making the most of cell capacity by distributing traffic as efficiently as possible; and • channel capacity solutions—these solutions center on ways of using the available throughput of the channels in the air in a more efficient manner, for example halfrate voice channels and GPRS.

Cell capacity
The one factor that has the greatest influence on cell capacity is frequency reuse. Cell capacity is thus determined by different methods and functions to enhance frequency reuse. Two common methods are • multiple reuse pattern (MRP); and • fractional load planning (FLP). The multiple reuse pattern, which is based on baseband frequency hopping, yields the best results for networks composed mainly of filter combiners. The primary transceiver carries the broadcast control channel (BCCH) and must therefore have a relatively loose reuse pattern (explanation: a handset must listen to the information broadcast on the BCCH before it can make calls in a cell). But thanks to the frequency hopping gain, all remaining transceivers in the network can have a successively tighter reuse pattern. Compared to a non-hopping network, the MRP solution can more than double cell capacity. The drawbacks of MRP are that it requires • considerable spectrum (greater than 7 MHz); and • at least three transceivers per cell for good performance. Fractional load planning is based on synthesized frequency hopping, which requires the use of hybrid combiners. In...