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.

Topology design and bandwidth allocation in ATM nets

Abstract: The design of a P/S network embedded into a backbone facility network is discussed. The problem is formulated as a network optimization problem where a congestion measure based on the average packet delay is minimized, subject to capacity constraints posed by the underlying facility trunks. The variables in this problem are the routing on the express pipes (i.e. the channels that interconnect the P/S modes) and the allocation of bandwidth to such pipes. An efficient algorithm is presented for the solution of the above problem and it is applied to some representative examples. It is shown that for some test cases the congestion measure is substantially reduced with respect to the values obtained when the embedded topology is kept identical to the backbone topology. Dynamic reconfiguration schemes where the embedded topology is periodically adjusted to track the fluctuations in traffic requirements are discussed. >

A cellular mobile telephone system with load sharing-an enhancement of directed retry

Abstract: A load sharing facility, which enables subscribers in a mobile telephone system to look for free radio channels in more than one cell, is investigated with respect to blocking probability and channel utilization. Results show that a substantial improvement, compared to other channel allocation techniques, can be achieved. The positive effects are especially notable for an asymmetric traffic situation. The improvement is accomplished at the expense of an increased risk of cochannel interference between mobiles. >

Dynamic TDMA slot assignment in ad hoc networks

Abstract: In this paper we propose a TDMA slot assignment protocol to improve the channel utilization, which controls the excessive increase of unassigned slots by changing the frame length dynamically. Our proposed protocol assigns one of the unassigned slots to a node which joins the network. If there are no unassigned slots available, our proposed protocol generates unassigned slots by depriving one of the multiple slots assigned to a node, or enlarging frame length of nodes which can cause collision with each other. Moreover, by setting frame length as a power of 2 slots, our proposed protocol provides the collision-free packet transmission among nodes with different frame length. The simulation results show that our proposed protocol improves the channel utilization dramatically as compared with the conventional protocols.

A stackelberg game for power control and channel allocation in cognitive radio networks

Abstract: The ongoing growth in wireless communication continues to increase demand on the frequency spectrum. The current rigid frequency band allocation policy leads to a significant under-utilization of this scarce resource. However, recent policy changes by the Federal Communications Commission (FCC) and research directions suggested by the Defense Advanced Research Projects Agency (DARPA) have been focusing on wireless devices that can adaptively and intelligently adjust their transmission characteristics, which are known as cognitive radios. This paper suggests a game theoretical approach that allows master-slave cognitive radio pairs to update their transmission powers and frequencies simultaneously. This is shown to lead to an exact potential game, for which it is known that a particular update scheme converges to a Nash Equilibrium (NE). Next, a Stackelberg game model is presented for frequency bands where a licensed user has priority over opportunistic cognitive radios. We suggest a modification to the exact potential game discussed earlier that would allow a Stackelberg leader to charge a virtual price for communicating over a licensed channel. We investigate virtual price update algorithms for the leader and prove the convergence of a specific algorithm. Simulations performed in Matlab verify our convergence results and demonstrate the performance gains over alternative algorithms.

Method for planning radio cells

Abstract: The present invention relates to a method for planning radio cells. The method utilizes an exclusion matrix calculated on the basis of measured field strengths and an iterative allocating algorithm, which allows an adaptation of the cell planning to prevailing traffic demand. The method includes the following steps: the traffic demand is geographically estimated; an acceptable coverage of the traffic demand is produced with the aid of a number of cells with suitable transmitter powers and antenna arrangements; each cell is allocated a number of channels, which corresponds to the estimated traffic demand, having regard to a margin for acceptable blocking; coverage and interference measurements are carried out for the cells, which measurement results are stored in a measurement data base; an exclusion matrix is calculated on the basis of the measurement results, which matrix represents the interaction between the cells in the system; an allocating algorithm is iterated, which algorithm, by utilizing a random technique, provides different collections of channel allocations for the cells; if the channel allocation is not possible with regard to the number of channels in a given frequency band, a new attempt is made and the subsequent steps are repeated; if the number of channels was sufficiently high, a radio cell design is obtained which is acceptable from the point of view of interference and the point of view of blocking. The present invention also provides a method for constructing the exclusion matrix and a method for determining uplink interferences.