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.

Properties of a TDMA pico cellular office communication system

Abstract: The properties of a TDMA/TDD (time-division multiple-access/time-division duplex) pico cellular cordless telephone system using decentralized dynamic channel allocation and handover are presented. The system has 16 time-division time-duplex channels (slots) per carrier, each occupying 2 MHz. The TDMA frame is 16-ms long, and each slot has bits for synchronization, signaling and data. The data speed is suited for 32-kb/s speech codecs. Procedures have been developed for efficient and quick dynamic channel allocation and handover, using the fact that one single radio can simultaneously monitor or communicate on all 16 channels. Simulations for a specific six-storeyed building indicate that 16 channels can provide wireless communication for up to 30% of the telephones, and 32 channels for up to 100% of the telephones. Tests show that no time dispersion equalizers are needed, and that antenna diversity is effective against fading dips and time dispersion. >

ARROW: An Efficient Traffic Scheduling Algorithm for IEEE 802.11e HCCA

Abstract: In this paper we present a novel traffic scheduling algorithm for IEEE 802.11e, referred to as ARROW (adaptive resource reservation over WLANs), which aims at providing improved performance for the support of multimedia traffic. The novel characteristic of this algorithm, compared to previous proposals, is that it performs channel allocations based on the actual traffic buffered in the various mobile stations, i.e., on the exact transmission requirements. This feature renders ARROW ideal for variable bit rate traffic. However, an enhancement is also presented that improves ARROW performance under constant bit rate traffic. The ARROW algorithm and its enhancement are discussed and evaluated against two other schedulers found in the open technical literature, namely the simple scheduler and SETT-EDD. Results from a detailed simulation model verify that ARROW provides much better channel utilization and considerably improved performance, in terms of mean delay and packet loss

Opportunistic Spectrum Access in Cognitive Radio Networks: A Queueing Analytic Model and Admission Controller Design

Abstract: Cognitive radio (CR) technology is an innovative radio design philosophy in order to increase the spectrum utilization by exploiting the unused spectrum in dynamically changing environments. Specifically, the CR technology will allow a group of potential users (referred to as secondary users) to access available spectrum resources unused by primary users (PUs) for whom the band has been licensed. The spectrum available for secondary users (SUs) depends on PUs' activity in the licensed spectrum. In this paper, we develop a queuing analytic framework to study important performance measures experienced by SUs in a CR network. We study queuing delay and buffer statistics of SUs' packets by modeling PUs' activity as a two state Markov chain and SUs' channel quality variation as a finite state Markov chain (FSMC). In order to allocate available channels among the SUs, an opportunistic channel allocation scheme is considered. The proposed framework facilitates to design an admission controller for SUs' network in order to maintain a given quality service (QoS) requirement which is specified in the form of statistical delay guarantee.

Opportunistic Spectrum Access for Energy-Constrained Cognitive Radios

Abstract: We consider a scenario in which a secondary user makes opportunistic use of a channel allocated to a primary network. The primary network operates in a time-slotted manner and switches between idle and active states according to a stationary Markovian process. At the beginning of each time slot, the secondary user can choose to stay idle or to carry out spectrum sensing to check if the primary network is idle or active. If the primary network is detected as idle, the secondary user can carry out data transmission. Spectrum sensing consumes energy and introduces false alarms and mis-detections. Given the delay cost associated with staying idle, the energy cost associated with spectrum sensing and data transmission, and the throughput gain associated with successful transmissions, the objective is to find an optimal sequence of idle/sensing actions, together with the optimal spectrum sensing durations, to maximize the expected net reward for the secondary user. We formulate this problem as a partially observable Markov decision process (POMDP) and obtain optimal control policies. Heuristic control policies that can be obtained at low complexity are also proposed.

Channel Allocation and Routing in Hybrid Multichannel Multiradio Wireless Mesh Networks

Abstract: Many efforts have been devoted to maximizing network throughput in a multichannel multiradio wireless mesh network Most current solutions are based on either purely static or purely dynamic channel allocation approaches In this paper, we propose a hybrid multichannel multiradio wireless mesh networking architecture, where each mesh node has both static and dynamic interfaces We first present an Adaptive Dynamic Channel Allocation protocol (ADCA), which considers optimization for both throughput and delay in the channel assignment In addition, we also propose an Interference and Congestion Aware Routing protocol (ICAR) in the hybrid network with both static and dynamic links, which balances the channel usage in the network Our simulation results show that compared to previous works, ADCA reduces the packet delay considerably without degrading the network throughput The hybrid architecture shows much better adaptivity to changing traffic than purely static architecture without dramatic increase in overhead, and achieves lower delay than existing approaches for hybrid networks