Dynamic Channel Assignment Method Research Articles

A dynamic channel assignment method for multichannel multiradio wireless mesh networks

The popularity of wireless communication accelerates research on new technologies that are required to satisfy users' needs. Wireless mesh networks (WMNs), which are additional access technologies instead of being a renewed one, have an important place among next-generation wireless networks. In particular, the capability of working without any infrastructure is the most outstanding advantage of WMNs. There are many studies aimed at WMNs, particularly channel assignment and routing methods for multichannel multiradio structures that provide higher data capacity. Interference, which has a direct effect on the quality of communication, is still a challenge to be addressed. In this study, multichannel multiradio WMNs and various channel assignment schemes are analyzed. Directional mesh (DMesh) architecture, which uses directional antennas to form a multichannel structure, is analyzed in terms of channel assignment procedure. A new interference-aware channel assignment scheme that aims to eliminate DMesh's disadvantages is proposed and performances of both schemes are compared. Several results of experimental analysis prove that the proposed channel assignment scheme improves the performance of DMesh

A QoS Aware Learning Automata Based Channel Assignment Method in Cognitive Network

With the rapid growth of wireless services and technologies, and as a result, increasing demand for the spectrum, cognitive network (CN) has been proposed as a promising solution for accomplishing the problem of spectrum scarcity. Channel assignment (CA) problem in CN is NP-complete and hence, in terms of scalability it should be solved through heuristic or meta-heuristic approaches. The main goal of dynamic CA in CN environment is to improve the QoS provisioning for SUs as well as protecting the Primary Users (PUs) from interference. To achieve this goal, a Secondary User may have to change its transmission channel several times during the established communication. Channel switching is a costly task due to the time overhead and interruptions that imposes on the given communication. To overcome these problems, two learning based dynamic CA methods are introduced; In the first method, by proposing a channel allocation scheme based on learning automata a trade-off between different QoS parameters will be made. In the second method, it is trying to decrease the overhead and interruptions because of switching channels of the first algorithm. Simulation results demonstrate the superiority of the proposed method in terms of delay, data delivery ratio, throughput, and data loss rate in comparison with other representative methods.

A Petri-Net-Based Automated Distributed Dynamic Channel Assignment for Cellular Network

In this paper, we propose a Petri-net (PN)-based automated distributed dynamic channel assignment (DDCA) method for the cellular network. We view DDCA as a discrete event system (DES) and propose a PN to model the automated DDCA. The spontaneous handshaking mechanism in the proposed PN can resolve the hard constraint of the cellular network so that no two cells within the channel reuse distance can use the same channel. Instead of the commonly adopted packing and resonance conditions for channel assignment and reassignment, we propose available channel-based channel-selection and channel-reassignment schemes. We rigorously prove the adequacy of the proposed PN and the satisfaction of hard constraint. We also test the proposed PN-based automated DDCA method using numerous test cases. The test results show that our method outperforms the comparing methods in terms of blocking probability.

A distributed dynamic channel assignment method with packet‐data transmission during the silent periods of circuit‐switched‐voice communications for cellular systems

AbstractChannel efficiency can be improved by transmission that integrates voice and the data. When this idea is applied to multicellular systems, channels must be assigned so that the intercellular interference power is minimized. Furthermore, channels must be provided with priority for voice calls, since real‐time transmission is required. As a system that considers these requirements, this paper investigates a method of reducing intercellular interference in a circuit‐switching system with channel segregation in which data are transmitted with priority, using the silent period of voice calls. It is shown by computer simulation that the proposed method can improve performance characteristics such as the interference rate, blocking rate, forced termination rate, and hand‐off rate. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(10): 93–101, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10148

Dynamic guard channel assignment for bidirectional call-overflow scheme in Hierarchical Cellular System

In this paper, a Hierarchical Cellular System (HCS) supporting two classes of users with high and low velocity is considered. Based on the analytical model of the bidirectional call-overflow scheme, a new dynamic guard channel assignment method is proposed. In this method, the number of guard channels in both macrocells and microcells varies in realtime according to the different call traffic load in the HCS, and as a result, the lowest dissatisfaction grade of users is achieved.

A dynamic channel assignment method for TDMA/FDMA packet transmission cellular system

AbstractIn the packet transmission cellular system using TDMA/FDMA with a small number of carrier frequencies, the assignment of the carrier frequency to the cell, as well as the assignment of the slot, are crucial issues regarding efficient use of the frequency resources. In the micro‐cellular system, it is difficult to assign the frequency beforehand, and a procedure is desired for each base station whereby the channel is assigned dynamically by an autonomous and distributed process. In the method proposed herein, the channel is assigned dynamically in each base station by an autonomous and distributed process, not only for the time‐division channel, but also for the frequency‐division channel. It is shown by a computer simulation that the proposed system can efficiently utilize the channels on both the time and the frequency axis. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(6): 25–32, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10046

A distributed dynamic channel assignment method for a mixture of narrowband and broadband traffic in a cellular system

This paper proposes an autonomous distributed dynamic channel assignment method, considering a mixture of narrowband and broadband traffic processing in a multicarrier TDMA mobile communication system. As the first step, narrowband and broadband calls are considered, and the system in which the calls share the carrier [carrier-sharing (CS) method], and the system in which the calls use separate carriers [carrier partitioning (CP) method], are compared. For each method, a mathematical model is proposed for the blocking probability analysis in the dynamic channel assignment, based on the steady-state probability. Using the models, the range for which the CS method exhibits a better performance than the CP method is specified. A problem in the dynamic channel assignment in the CS method is that the transmission quality of the broadband call may be degraded by interference from a narrowband call. In order to overcome such a problem, a method is proposed where the suppression of the leftovers of nonavailable channels for assignment, the multicarrier modulation using frequency hopping, the reallocation connection of calls, the variable-rate transmission connection, and the retry-type hand-off are combined. It is verified by computer simulation that the proposed method exhibits a performance which is better than that of the conventional method. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(11): 85–94, 2000

Self-organized reuse partitioning: A distributed dynamic channel assignment method in cellular systems

Self-organized reuse partitioning: A distributed dynamic channel assignment method in cellular systems

Clique packing and dynamic channel assignment in cellular mobile communication systems

AbstractThis paper discusses the communication traffic characteristics of Dynamic Channel Assignment (DCA) in cellular mobile communication systems. In general, it is difficult theoretically to analyze the communication traffic characteristics of DCA. This paper proposes an approximate method called clique packing, for analyzing the blocking probability performance of an idealized DCA. For calculating the blocking probability of clique packing, an approximate formula is derived which is based on the Erlang B formula and is in a simple form. It is shown that the numerical results of the approximate method agree with computer simulation results.An approximate analytical method for calculation of the blocking rate of practical DCA methods such as the first‐available method also is proposed. To calculate the blocking rate of the practical DCA methods, the simple formula for clique packing is used after modeling the practical DCA methods as clique packing. It is shown that the modeling is appropriate. This modeling enables the blocking rate of the practical DCA methods to be calculated by using the approximate formula for clique packing.

A pilot-based dynamic channel assignment scheme for wireless access TDMA/FDMA systems

We propose a control architecture for implementing a dynamic channel assignment (DCA) algorithm which optimizes two-way channel quality in a TDMA portable radio system. Computer simulations are used to evaluate the performance of this DCA method. A common control frequency, which is frame-synchronized among base stations, provides (1) beacons for portables to locate base stations and obtain DCA information, (2) broadcast channels for system and alerting information, and (3) pilot signals to permit portables to evaluate downlink interference. This allows low-complexity radio ports and portables to mutually select channels to avoid interference and avoid creating excessive interference. Results from computer simulations demonstrate the good spectrum efficiency of this method and its potential for handling nonuniform traffic demand. This work is targeted toward understanding the implications to local exchange networks of wireless system alternatives that could provide access to those networks.