Channel Assignment For Systems Research Articles

Joint power allocation and channel assignment for device‐to‐device communication using the Hungarian model and enhanced hybrid Red Fox‐Harris Hawks Optimization

SummaryMultihop device‐to‐device (D2D) communication is a promising advancement since it allows wireless users in close proximity to communicate directly with one another without using base stations (BSs). With two nearby users, this technology intends to keep up with the accelerating development of mobile devices and the rising demands of local traffic loads. High‐data‐rate short‐range transmission is made possible by this paradigm, which also lowers network backhaul expenses while improving end‐user experience, spectral efficiency (SE) and network coverage. In order to maximize the cell's overall sum rates, this article examines the problem of selecting the optimal M‐D2D linkages and cellular users (CUs) to form spectrum‐sharing partners while taking quality of service (QoS) and energy efficiency (EE) needs into consideration. This study examines the use of a channel assignment system and a power allocation technique to manage interference in D2D communication scenarios involving many hops (more than one hop). The suggested channel assignment approach is based on the Hungarian method, but the power allocation system is based on the time‐efficient enhanced Harris hawks optimization (HHO) and red fox (RF) algorithms. A genetic algorithm (GA)‐based methodology and various baseline approaches are used to compare the effectiveness of the suggested system. Because it combines exploitation and exploration using a memory‐based local search methodology and a perturbation mechanism, the suggested approach outperforms the GA in simulations. The results clearly demonstrate that the suggested method increases EE by up to 13% by producing the appropriate channel and power assignment for CUs and M‐D2D users.

生体情報モニタ・医用テレメータの無線データ伝送周波数の新規割り当て方法 : データ伝送周波数の変更なくして病棟間移動を可能にする割り当て

生体情報モニタ・医用テレメータの無線データ伝送周波数の新規割り当て方法 : データ伝送周波数の変更なくして病棟間移動を可能にする割り当て

LACAV: an energy-efficient channel assignment mechanism for vehicular ad hoc networks

Designing an efficient channel assignment system for Vehicular Ad hoc Networks (VANETs), which conserves energy, is a challenging task, primarily because of the high degrees of mobility of nodes in these networks. As the high mobility of nodes in vehicular networks leads to frequent handoffs, channel assignment in VANETs becomes a tedious task. In this paper, we propose a channel assignment mechanism using the concepts of learning automata (LA) and reusability. LA is used to optimize the performance of the proposed system by selecting suitable number of reserved channels for the handoff calls and reusability allows the channel to be reused by the different base stations (BSs) based on the reuse distance. The proposed system is designed to reduce the dropping probability. The proposed system is suitable for network architectures in which it is possible to arrange the BSs with different groups of channels sequentially in a particular order that helps in conserving energy. Our experiments clearly indicate that the system reduces the dropping probability and allows a continuous communication throughout the duration of the call. The performance of proposed algorithm is compared with the Vehicular Fast Handover Scheme (VFHS), and the Cooperative scheme for service channel reservation (CRaSCH) scheme in terms of handoff latency, and it is shown that the proposed algorithm performs better than VFHS and CRaSCH.

Radio channel assignment system for cellular mobile communications

AbstractTo use finite spectral resources more efficiently, the cellular mobile communications method reuses frequencies (radio channels) repeatedly. With the cellular method, channel assignment that efficiently allocates radio channels to each base station while guaranteeing fixed communication quality becomes harder as the number of base stations grows, making it difficult to achieve optimization in a short time. This paper looks at the autonomous function for learning the channel used by each base station in autonomous distributed channel assignment and proposes a new channel assignment algorithm for determining channel assignments from the results that are obtained. It also clarifies the application results in a channel assignment system that incorporates the proposed algorithm. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 59–71, 2003; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecja.1162

Performance of Channel Carrying for Handoff in a DCA Cellular Network

Channel carrying allows a mobile station to continue the use of its currently occupied channel when it hands off to a new cell. Since in a dynamic channel assignment (DCA) system, generally, any channel can be used by any cell, channel carrying can be more easily implemented than in a fixed channel assignment (FCA) system which supports channel carrying through borrowing channels or extending channel reuse distance. Therefore, this paper investigates different channel carrying strategies maybe used in the distributed timid DCA scheme with the seamless handoff policy (DCA-DT/SLH), namely, channel carrying first (CCF) and channel carrying last (CCL). This study shows that (1) CCL generally outperforms CCF; (2) in DCA-DT/SLH without channel carrying, handoff calls may suffer higher dropping probabilities than new calls if no priority is given to handoff calls while channel carrying can easily avoid such undesirable situation; and (3) channel carrying in DCA-DT/SLH is comparable and even better than the guard channel (GC) in FCA and can also slightly improve the performance of GC in DCA-DT/SLH.

Performance evaluation of LIBTA/hybrid time‐slot selection algorithm for cellular systems

AbstractThis paper studies the performance of radio assignment algorithms for portable access in cellular systems. Several channel access procedures are proposed and simulated using block oriented network simulator (BONeS) simulation of a model 36‐port system. Simulation results exhibit that load‐sharing system with LIBTA algorithm is better than directed retry system with the same algorithm by around 0.9 erlangs while better than quasi‐fixed channel assignment (QFCA) system by around 2 erlangs if the grade of service (GOS) is constrained to less than 10 per cent. Plus, a hybrid time‐slot selection procedure is proposed to enhance the system performance. It is observed that systems with hybrid time‐slot selection perform better than those with LIBTA algorithm in GOS under heavy load. It is also observed that load sharing system with hybrid time‐slot selection algorithm is better than directed retry system with the same algorithm by around 0.7 erlangs and better than QFCA system by around 2 erlangs. Copyright © 2001 John Wiley & Sons, Ltd.

An Error Recovery Technique for a Satellite Channel Assignment System with Distributed Control

A distributed control system for a set of earth stations sharing satellite communication channels is studied. The stations communicate by messages which may be corrupted by errors. A sufficient set of message types are defined to allow stations to enter and leave the system, to arbitrate for communication channels, and to recover from error situations. The errorprocesses assumed are of a transient nature, mainly existing on the interstation control channels. The signaling communication protocols are informally described in a Pascal-like language. The protocols are simulated in Simula and are found to work correctly in all cases studied.

Increasing Channel Occupancy in Large-Scale Mobile Radio Systems: Dynamic Channel REassignment

Large-scale mobile radio systems using dynamic channel REassignment switch the channels assigned to some of the calls in progress to maintain a nearly optimum separation between coverage areas simultaneously using the same channel. Dynamic channel REassignment produces a significant increase in channel occupancy. For example, in the systems studied, which have a uniform distribution of their fixed channels and were operated against a uniform spatial distribution of offered traffic, the channel occupancy was increased by \frac23 over a pure fixed channel assignment system at a blocking rate of one percent. This corresponds to a channel savings of about 40 percent for the same traffic carried at one percent blocking by the hybrid systems that were studied.

Increasing channel occupancy in large-scale mobile radio systems: Dynamic channel REassignment

Large-scale mobile radio systems using dynamic channel REassignment switch the channels assigned to some of the calls in progress to maintain a nearly optimum separation between coverage areas simultaneously using the same channel. Dynamic channel REassignment produces a significant increase in channel occupancy. For example, in the systems studied, which have a uniform distribution of their fixed channels and were operated against a uniform spatial distribution of offered traffic, the channel occupancy was increased by 2/3 over a pure fixed channel assignment system at a blocking rate of one percent. This corresponds to a channel savings of about 40 percent for the same traffic carried at one percent blocking by the hybrid systems that were studied.

Dynamic Channel Assignment in Two-Dimensional Large-Scale Mobile Radio Systems

A computer simulation of two-dimensional mobile radio systems arranged with square coverage areas on a square grid and using dynamic channel assignment techniques is described. Parameters for the simulation are: (i) 729 distinct coverage areas (27 on a side), (ii) 160 radio channels and (iii) a radio channel reuse interval of every fourth coverage area. Three different channel assignment strategies are considered and the results are compared to previous one-dimensional simulated systems and to a fixed channel assignment system. At call blocking rates below about 10 percent, the two-dimensional dynamic channel assignment systems carry more traffic and produce fewer forced call terminations at coverage cell boundaries than do fixed channel assignment systems. For example, at a blocking rate of 1 percent, the traffic carried, TC, expressed in Erlangs per channel per coverage area by the various systems are as follows: fixed channel assignment systems, TC = 0.44, one-dimensional dynamic channel assignment system, TC = 0.62, two-dimensional dynamic channel assignment system, TC = 0.63.

Effects of some nonuniform spatial demand profiles on mobile radio system performance

The design of future mobile radio systems will be based upon an estimated user demand. Systems probably will be engineered to serve the business day spatial distribution of call attempts, which for the purpose of this study was assumed to be uniform. There will be day-to-day fluctuations about this long-term average, the magnitudes of which are only to be conjectured at this time. This paper compares the performance of computer simulated mobile radio systems operating with several demand profiles. The profiles were selected to give an indication of the effects on system performance of either uncompensated changes in average traffic or normal fluctuations which occur in the randomly offered traffic even when the long-term average value does not change. The dynamic channel assignment systems increased the traffic capacity at low blocking levels even over a perfectly designed fixed channel assignment system. In addition, it was found that the dynamic channel assignment systems were relatively insensitive to the periodic spatial demand distributions studied by this computer simulation. Even though new call attempts were made to fluctuate markedly between adjacent base stations within a reuse interval, the blocking rate of each base station remained constant. It appears that the blocking rate within a reuse interval depends (in the dynamic channel assignment systems) mainly on the average demand within that interval and not very strongly upon the distribution of that demand. In the fixed channel assignment system, uncompensated fluctuations in the spatial demand distribution away from the design value always degrade system performance.

Dynamic Channel Assignment in High-Capacity Mobile Communications Systems

Computer simulations of high-capacity mobile radio systems using different channel assignment philosophies are described. These simulations initiate call attempts and move vehicles about randomly according to prescribed statistical distributions. Base stations and radio channels are assigned to serve mobiles and system operating statistics are accumulated. Relationships between systems parameters obtained from the simulation are presented. Performance of a dynamic channel assignment system (DYNSYS) which has all channels available at all base stations is compared with performance of a fixed-channel assignment system (FIXSYS) which reserves channel subsets for use at specific base stations. For uniform spatial distributions of call attempts and 40-channel systems with reuse intervals of four base station radio coverage areas, the DYNSYS outperforms the FIXSYS at blocking rates up to 13 percent. For example, at a 3 percent blocking rate the DYNSYS provides 20 percent more calls “on” in the system.