Intercell interference severely degrades the performance of cell-edge users in cellular networks. To effectively manage the intercell interference, a heuristic scheme that jointly considers user scheduling and power control is proposed for multicell orthogonal frequency division multiple-access (OFDMA) networks with BS cooperation and limited backhaul capacity. First, a greedy user scheduling is proposed, taking both channel gain and the cost of directional cooperation into consideration. This scheme schedules the cell-edge users of all cells in the same subchannels. Second, under the guiding of user scheduling, the interference among cell-edge users of different cells can be preferentially cancelled with zero-forcing precoding. Third, a two-step power control is conducted to further improve cell-edge users performance. In the first step, with the strong duality of the nonconvex optimization subproblem, we obtain the minimum power consumption that guaranteeing the cellcenter users' rate requirement. In the second step, the residual power of per cell can be utilized to maximize cell-edge users performance. Then, with the fixed user scheduling, the iteration among interference cancelation and power control can be conducted until the backhaul capacity constraints are satisfied. Performance analysis proves the convergence of the proposed algorithm, and shows the effectiveness of the user scheduling. Simulation results show that, the proposed algorithm achieves a significant improvement of sum-rate for cell-edge users with negligible rate degradation for cell-center users.

Joint user scheduling and power control for cell-edge performance improvement in backhaul-constrained network MIMO

Information technology has considerable potential for affecting instructional methods in higher education, but its successful application depends on an understanding of underlying learning principles.

Information technology and instruction

Telecommunications in Canada-A century of symbiotic development

Telidon graphics and applications

TELIDON is a videotex development of the Canadian Department of Communications that differs radically in display presentation format from the earlier European developments. The name videotex is used internationally to represent a class of home and business information services which disseminate information from information suppliers into the home or office. In general, a television receiver, suitably modified or augmented, can serve as the consumer's terminal equipment. The system essentially makes use of the set as a still-picture display medium where the consumer has control over what is displayed. By utilizing the common-carrier telephone line or other interactive network, or broadcast system, users of the service are able to retrieve information stored in computer controlled databases and have it displayed.

H. Bown

Papers

TELIDON - A review