Channel allocation schemes

About: Channel allocation schemes is a research topic. Over the lifetime, 10656 publications have been published within this topic receiving 182117 citations.

Interference measurement mechanism for frequency reuse in cellular ofdma systems

Abstract: Under adaptive frequency reuse technique, mobile stations in a cellular orthogonal frequency division multiple access (OFDMA) system are served by different radio resource regions with appropriate frequency reuse patterns to mitigate inter-cell interference and improve system capacity. In a first novel aspect, the mobile stations measure interference statistics and obtain interference measurement results. The mobile stations report the obtained interference measurement results to serving base stations. The serving base stations determine adaptive frequency reuse patterns based on the received interference measurement result. In a second novel aspect, a radio resource control element receives the interference measurement results, determines frequency reuse patterns and configures radio resource allocation based on the received interference measurement results. In a third novel aspect, the base stations obtain the interference measurement results and schedule the mobile stations to be served with appropriate radio resource regions.

Distributed dynamic fault-tolerant channel allocation for cellular networks

Abstract: Efficient allocation of communication channels is critical for the performance of cellular systems. The centralized channel allocation algorithms proposed in literature are neither robust nor scalable. Several of these algorithms are unable to dynamically adjust to spatial and temporal fluctuations in channel demand (load). We present a distributed dynamic channel allocation (DCA) algorithm in which heavily loaded regions acquire a large number of communication channels, while their lightly loaded neighbors get assigned fewer channels. As the spatial distribution of channel demand changes with time, the spatial distribution of allocated channels adjusts accordingly. The algorithm described in this paper requires minimal involvement of the mobile nodes, thus conserving their limited energy supply. The algorithm is proved to be deadlock free, starvation free, and fair. It prevents cochannel interference and can tolerate the failure of mobile as well as static nodes without any significant degradation in service. Simulation experiments demonstrate that the performance of the proposed distributed dynamic algorithm is comparable to, and for some metrics, better than that of efficient centralized dynamic algorithms where the central switch has complete and latest information about channel availability. The major advantages of the proposed algorithm over its dynamic centralized counterparts are its scalability, flexibility, and low computation and communication overheads.

Channel assignment problem in cellular systems: a new model and a tabu search algorithm

Abstract: The channel assignment in cellular systems has the task of planning the reuse of available frequencies in a spectrum efficient way. A classical approach to frequency assignment problems, when applied to the frequency planning of cellular networks, does not enable this task to be performed in an efficient way, since it does not consider the cumulative effect of interferers. We propose a new model for the channel assignment problem in narrow-band cellular networks, which accounts for the cumulative effect of interferers. In this model, the service area is partitioned into regions and the propagation characteristics are assigned by means of the levels received in each region by the considered base stations (BSs). The objective is to maximize the sum of traffic loads offered by regions in which the ratio between the received power and the sum of powers received from interfering transmissions is above a threshold value. We also present an algorithm, based on tabu search (TS) techniques, to solve this problem. This algorithm has been tested on some instances obtained by using a simple radio channel model and on a real world instance.

Method and apparatus for transmitting channel quality information in an orthogonal frequency division multiplexing communication system

Abstract: A method and apparatus for efficiently transmitting channel quality information in an OFDM communication system using dynamic channel allocation and adaptive modulation, and determining parameters required for time-division channel quality information transmission in an asynchronous CDMA communication system are provided. In the OFDM communication system in which a plurality of subcarriers are allocated to a plurality of UEs, the subcarriers are divided into a plurality of subcarrier groups each having at least one subcarrier. Each of the UEs determines and transmits the channel quality information of each of the subcarrier groups according to predetermined transmission parameters at transmission time points that do not overlap with those of other UEs. A Node B dynamically allocates the subcarriers to the UEs and their corresponding modulation schemes according to the channel quality information.

Virtual path bandwidth allocation in multi-user networks

Abstract: Considers a multi-user network that is shared by noncooperative users. Each user sets up virtual paths that optimize its own, selfish, performance measure. This measure accounts for both the guaranteed call level quality of service, as well as for the cost incurred for reserving the resource. The interaction between the user strategies is formalized as a game. The authors show that this game has a unique Nash equilibrium, and that it possesses a certain fairness property. They investigate the dynamics of this game, and prove convergence to the Nash equilibrium of both a Gauss-Seidel scheme and a Jacobi scheme. They extend their study to various general network topologies.