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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.
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TL;DR: The proposed framework for a wireless health monitoring system using wireless networks such as ZigBee has the ability to detect signals wirelessly within a body sensor network (BSN), low-power and reliable data transmission through ZigBee network nodes, secure transmission of medical data over BSN, and efficient channel allocation for medical data transmission over wireless networks.
Abstract: We present a framework for a wireless health monitoring system using wireless networks such as ZigBee. Vital signals are collected and processed using a 3-tiered architecture. The first stage is the mobile device carried on the body that runs a number of wired and wireless probes. This device is also designed to perform some basic processing such as the heart rate and fatal failure detection. At the second stage, further processing is performed by a local server using the raw data transmitted by the mobile device continuously. The raw data is also stored at this server. The processed data as well as the analysis results are then transmitted to the service provider center for diagnostic reviews as well as storage. The main advantages of the proposed framework are (1) the ability to detect signals wirelessly within a body sensor network (BSN), (2) low-power and reliable data transmission through ZigBee network nodes, (3) secure transmission of medical data over BSN, (4) efficient channel allocation for medical data transmission over wireless networks, and (5) optimized analysis of data using an adaptive architecture that maximizes the utility of processing and computational capacity at each platform.
78 citations
TL;DR: The cognitive radio functionality of this standard is provided by the dynamic channel management using channel sensing, channel classification, and maintenance of channel information, which effectively protects the incumbent users and dynamically manages the channel allocation in IEEE 802.22 WRAN systems.
Abstract: Channel management policy is one of the key functions of any cognitive radio system. The channel management decision in a cognitive radio system depends on various factors such as government regulations, limitations of transmission power between communicating devices, availability of geo-location information, and the quality of various available channels. The main purpose of channel management in a cognitive radio system is to protect the incumbent users (licensed users). The first international standard based on cognitive radio technology is IEEE 802.22, Wireless Regional Area Networks, which aims at providing broadband access in rural areas by effectively utilizing the unused TV channels. This standard aims at describing both PHY and MAC layer functionalities in an infrastructure- based broadband wireless access network for communication between consumer premises equipment using a base station. This article presents the cognitive radio functionality of this standard in detail. The cognitive functionality is provided by the dynamic channel management using channel sensing, channel classification, and maintenance of channel information. Using these techniques, this standard effectively protects the incumbent users and dynamically manages the channel allocation in IEEE 802.22 WRAN systems.
78 citations
TL;DR: This paper investigates the power- and outage-limited performance of hybrid ARQ and quantized CSI schemes under short- and long-term power constraints, and analytical and numerical results demonstrate the equivalency or the superiority of these approaches in different circumstances.
Abstract: Recently, substantial attention has been paid to increase the achievable rates of wireless networks using different kinds of limited channel quality information feedback. Hybrid automatic repeat request (ARQ) and quantized channel state information (CSI) feedback are two well-known approaches applied by experts to provide the limited channel quality information at the transmitter. Considering quasi-static fading channels, this paper aims to provide some comparisons between the performance of these methods from different points of view. The paper first investigates the power- and outage-limited performance of hybrid ARQ and quantized CSI schemes under short- and long-term power constraints. Then, 1) the feedback signaling load, 2) robustness and 3) the complexity of these schemes are compared under short-term transmission power constraint. Both INcremental Redundancy (INR) and Repetition Time Diversity (RTD) approaches are considered for hybrid ARQ feedback. Finally, approximate low-complexity solutions are presented for power allocation in the INR ARQ-based scheme under long-term transmission power constraint. Analytical and numerical results demonstrate the equivalency or the superiority of these approaches in different circumstances.
77 citations
29 Nov 2004
TL;DR: The CDF-based scheduling (CS) algorithm is employed for the subcarrier allocation, taking advantage of its distinctive feature of analyzability and multiuser diversity to present a new algorithm called proportional-fair power allocation (PFPA).
Abstract: In this paper we investigate adaptive resource allocation schemes in multiuser OFDM systems for fair share of resources and efficient operation. We employ the CDF-based scheduling (CS) algorithm for the subcarrier allocation, taking advantage of its distinctive feature of analyzability and multiuser diversity. Noting that conventional power allocation schemes do not exhibit efficient and fair operations in heterogeneous user channel environments, we present a new algorithm called proportional-fair power allocation (PFPA). This algorithm is designed to allocate transmission power in such a way that the resulting relative throughput-increment is identical for all subcarriers. The PFPA algorithm is shown to be equivalent to the power allocation of the asymptotically optimal algorithm which exhibits the largest achievable region in the asymptotic case. Numerical results reveal that the combined CS-PFPA algorithm improves the overall system capacity in terms of time-average throughput and provides efficient estimation of user performance. Further, the CS-PFPA algorithm can meet each user's requirements using a minimum amount of resources, so it renders an efficient and fair means for resource allocation in multiuser OFDM systems.
77 citations
TL;DR: An iterative algorithm is developed to efficiently obtain the optimal solution of the weighted sum rate problem for the C-MAC, and it is shown that the proposed algorithm, although developed for single channel transmission, can be extended to the case of multiple channel transmission.
Abstract: Cognitive radio is an emerging technology that shows great promise to dramatically improve the efficiency of spectrum utilization. This paper considers a cognitive radio model, in which the secondary network is allowed to use the radio spectrum concurrently with primary users (PUs) provided that interference from the secondary users (SUs) to the PUs is constrained by certain thresholds. The weighted sum rate maximization problem is studied under interference power constraints and individual transmit power constraints, for a cognitive multiple access channel (C-MAC), in which each SU having a single transmit antenna communicates with the base station having multiple receive antennas. An iterative algorithm is developed to efficiently obtain the optimal solution of the weighted sum rate problem for the C-MAC. It is further shown that the proposed algorithm, although developed for single channel transmission, can be extended to the case of multiple channel transmission. Corroborating numerical examples illustrate the convergence behavior of the algorithm and present comparisons with other existing alternative algorithms.
77 citations