Multicell CDMA network design

Abstract

Abstract-Traditional design rules for cellular networks are not directly applicable to code division multiple access (CDMA) networks where intercell interference is not mitigated by cell placement and careful frequency planning. For transmission quality requirements, a minimum signal-to-interference ratio (SIR) must be achieved. The base-station location, its pilot-signal power (which determines the size of the cell), and the transmission power of the mobiles all affect the received SIR. In addition, because of the need for power control in CDMA networks, large cells can cause a lot of interference to adjacent small cells, posing another constraint to design. In order to maximize the network capacity associated with a design, we develop a methodology to calculate the sensitivity of capacity to base-station location, pilot-signal power, and transmission power of each mobile. To alleviate the problem caused by different cell sizes, we introduce the power compensation factor, by which the nominal power of the mobiles in every cell is adjusted. We then use the calculated sensitivities in an iterative algorithm to determine the optimal locations of the base stations, pilot-signal powers, and power compensation factors in order to maximize capacity. We show examples of how networks using these design techniques provide higher capacity than those designed using traditional techniques.

Throughput optimization in multi-cell CDMA networks

“…For more details on the choice of these parameters refer to [12]. Per user inter-cell interference factors are evaluated numerically by dividing the whole area into small grids of size 150 m by 150 m (for more detail see [6]). The blocking probability threshold, η, is set to 0.02.…”

“…Assuming a total of M cells with n i calls in cell i, the number of calls in every cell must satisfy [6] …”

Optimal CDMA Network Design with Uplink and Downlink Rate Guarantees

“…The optimization problem for network design is formally posed as follows: (10) subject to the UL and the DL QoS constraints given by (8) and (9) and the constraints on the variables given by (1)- (6). Note that the terms being summed together in (10) have different units; the weighting terms λ u , λ d , and λ r have the appropriate units to ensure conformability and can be selected based on the relative importance of the UL power, DL power and profit.…”

“…Note that the terms being summed together in (10) have different units; the weighting terms λ u , λ d , and λ r have the appropriate units to ensure conformability and can be selected based on the relative importance of the UL power, DL power and profit. If λ u = λ d = 0, then (10) is equivalent to maximizing the profit.…”

UMTS Capacity and Throughput Maximization for Different Spreading Factors

“…This study assumes that both large scale path loss and shadow fading are compensated by the perfect power control mechanism. Let I ji,g be the average inter-cell interference that all users n j,g using services g with activity factor v g and received signal S g at BS j impose on BS i. Modifying the average inter-cell interference given by [7], it becomes…”