The maximum k-colorable subgraph problem for chordal graphs
Information Processing Letters
New methods to color the vertices of a graph
Communications of the ACM
Some simplified NP-complete problems
STOC '74 Proceedings of the sixth annual ACM symposium on Theory of computing
Introduction to Space-Time Wireless Communications
Introduction to Space-Time Wireless Communications
Multiple antennas in cellular CDMA systems: transmission, detection, and spectral efficiency
IEEE Transactions on Wireless Communications
Downlink capacity of interference-limited MIMO systems with joint detection
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications
On the achievable throughput of a multiantenna Gaussian broadcast channel
IEEE Transactions on Information Theory
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In multiuser CDMA wireless systems where the base station is equipped with multiple antennas, the base station takes advantage from the spatial and code separability between the served users in order to enhance the performance of the system. However, this enhancement is constrained by the design of an appropriate scheduling scheme which is responsible of choosing the best users to serve. In this paper, we propose efficient scheduling algorithms for the downlink of multiantenna CDMA wireless systems using zero forcing beamforming. Our proposition maximizes the system sum rate and keeps the computational complexity low. We make use of a graph theoretical approach to represent the system as an undirected weighted graph. As a second step, we formulate the scheduling problem as the maximum weight k-colorable subgraph problem. We propose two heuristic solutions to find the users to serve in each time slot in an acceptable polynomial time. Finally we evaluate the efficiency of the proposed schemes by mean of simulations and the results show the near-optimal performance of the proposed schedulers with very low computational complexity compared to the optimal exhaustive search over all the possible users combinaisons.