Adaptive cell sectorization for CDMA systems

Abstract

Abstract-Given the user distribution in a cell, we investigate the two problems of how to appropriately sectorize the cell such that we minimize the total received power and the total transmit power of all the users, while giving each user acceptable quality of service in both cases. For the received power optimization problem, we show that the optimum arrangement equalizes the number of users in each sector. The transmit power optimization is formulated as a graph partitioning problem that is polynomially solvable. We provide an algorithm that finds the best sectorization assignment as well as the optimal transmit powers for all the users. The computational complexity of the algorithm is polynomial in the number of users and sectors. For both the received power optimization and the transmit power optimization, under nonuniform traffic conditions, we show that the optimum arrangement can be quite different from uniform cell sectorization (equal width sectors). We also formulate and solve the transmit power optimization and cell sectorization problem in a multicell scenario that would improve the capacity of a hot spot in the network. We observe that, with adaptive sectorization, where the sector boundaries are determined in response to users' locations, received and transmit power savings are achieved, and the number of users served by the system (system capacity) is increased compared to uniform sectorization of the cell.

Adaptive Load Balancing of Cellular CDMA Systems Considering Non-uniform Traffic Distributions

“…Considering linear distribution, as in highway, power control may not be appropriate approach in the scenario. For non-uniform traffic distribution, sectorization is an effective way to maximize the network capacity [2] [3]. The goal of dynamic sectorization is similar to load balancing in previous studies [4] [5].…”

“…The proposed scheme is called "adaptive load balancing" to optimally assigning FS with respect to traffic loads, the interferences between cells/sectors can be mitigated by bandwidth segmentation. (1), (2), (3), (4), (5), (1,2), (2,3), (3,4), (4,5), (1,2,3), (2,3,4), (3,4,5), (1,2,3,4), (2,3,4,5), ( …”

“…Performance analysis is based on the average of 100 tests. 1,2 Detailed algorithms are omitted due to the length limitation of the paper. A complete version of the paper is available upon request.…”

“…Sectorization utilizes the spatial domain to introduce orthogonalization [2][3] to the system. Since only a subset of the users is received at each antenna, the interference that each user incurs is less compared to a single antenna system.…”

An Efficient Adaptive Cell Sectoring Technique for Non-Uniform Traffic in DS-CDMA Systems

“…In [13], the paper presents an optimized cell sectorization scheme to maximize the system capacity, in which the optimal sectoring (OS) problem was transformed into the shortest path problem and then solved by the well-known Dijkstra's algorithm. In our scheme, we adopt the similar formulation, and use a dynamic programming technique to solve the OS problem.…”