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.

HERA: An Optimal Relay Assignment Scheme for Cooperative Networks

Abstract: Exploiting the nature of broadcast and the relaying capability of wireless devices, cooperative communication is becoming a promising technology to increase the channel capacity in wireless networks. In cooperative communication, the scheme for assigning relay nodes to users plays a critical role in the resulting channel capacity. A significant challenge is how to make the scheme robust to selfish and cheating behavior of users while guaranteeing the social optimal system capacity. In this paper, we design an integrated optimal marriage scheme called HERA for cooperative networks. To avoid system performance degradation due to the selfish relay selections by the source nodes, we propose a payment mechanism for charging the source nodes to induce them to converge to the optimal assignment. To prevent relay nodes from manipulating the marriage by reporting transmission power untruthfully, we propose a payment mechanism to pay them for providing relaying service. We also show that HERA is budget-balanced, meaning that the payment collected from source nodes is no smaller than the payment paid to relay nodes.

Joint Beamforming and User Maximization Techniques for Cognitive Radio Networks Based on Branch and Bound Method

Abstract: We consider a network of cognitive users (also referred to as secondary users (SUs)) coexisting and sharing the spectrum with primary users (PUs) in an underlay cognitive radio network (CRN). Specifically, we consider a CRN wherein the number of SUs requesting channel access exceeds the number of available frequency bands and spatial modes. In such a setting, we propose a joint fast optimal resource allocation and beamforming algorithm to accommodate maximum possible number of SUs while satisfying quality of service (QoS) requirement for each admitted SU, transmit power limitation at the secondary network basestation (SNBS) and interference constraints imposed by the PUs. Recognizing that the original user maximization problem is a nondeterministic polynomial-time hard (NP), we use a mixed-integer programming framework to formulate the joint user maximization and beamforming problem. Subsequently, an optimal algorithm based on branch and bound (BnB) method has been proposed. In addition, we propose a suboptimal algorithm based on BnB method to reduce the complexity of the proposed algorithm. Specifically, the suboptimal algorithm has been developed based on the first feasible solution it achieves in the fast optimal BnB method. Simulation results have been provided to compare the performance of the optimal and suboptimal algorithms.

Dynamic channel management and signalling method and apparatus

Abstract: There is provided a dynamic and adaptable method and apparatus to support two-way multi-media communication services on a multiple access communication system, which comprises a central controller, a shared transmission media and a plurality of remote terminals dispersed throughout the network. The central controller comprises switch and control apparatus and a pool of transmitters and receivers. The communication channels between the central controller and remote terminals are arranged for signalling data and traffic bearer channels in the forward and reverse directions. The number of signalling data channels is adjusted to satisfy the traffic requirements and for redundancy purposes. The forward and reverse signalling data channels are coupled in different mappings to support terminal grouping. Multiple access of the remote terminals for the upstream traffic are mitigated by separating remote terminals in groups via the channel allocation and the terminal assignment process. Communication between the central controller and the remote terminals follows a multiple access scheme controlled by the central controller via polling procedure on each of the forward signalling data channels independently. In case of collision, the central controller engages the remote terminals in a selective polling process to resolve the contention. The overlapping polling method of the controlled access scheme increases the utilization of the signalling channel and reduces the time required to gain access to the shared transmission media. By dynamically adjusting the load on signalling data channels, the signalling process is greatly improved for efficiency and redundancy against anomalies with the added benefit of improved flexibility and extensibility. The system is especially useful in a two-way CATV network.

Cooperative channel allocation and scheduling in multi-interface wireless mesh networks

Abstract: Cooperative channel allocation and scheduling are key issues in wireless mesh networks with multiple interfaces and multiple channels. In this paper, we propose a load balance link layer protocol (LBLP) aiming to cooperatively manage the interfaces and channels to improve network throughput. In LBLP, an interface can work in a sending or receiving mode. For the receiving interfaces, the channel assignment is proposed considering the number, position and status of the interfaces, and a task allocation algorithm based on the Huffman tree is developed to minimize the mutual interference. A dynamic link scheduling algorithm is designed for the sending interfaces, making the tradeoff between the end-to-end delay and the interface utilization. A portion of the interfaces can adjust their modes for load balancing according to the link status and the interface load. Simulation results show that the proposed LBLP can work with the existing routing protocols to improve the network throughput substantially and balance the load even when the switching delay is large.

FRACTEL: a fresh perspective on (rural) mesh networks

Abstract: The use of commodity 802.11 hardware to provide network connectivity to rural regions is an appealing proposition. In this paper, we consider such networks, with a combination of long-distance and short-distance links. In such a setting, we offer a fresh perspective on a variety of technical issues in multi-hop mesh networks. To support QoS for voice, video-based real-time applications, the use of a TDMA-based MAC is appropriate. In this context, we argue that existing approaches to TDMA scheduling and channel allocation are either inapplicable, or are too general and hence complicated. We apply extensive domain knowledge in designing a solution applicable in our context. We also suggest appropriate implementation strategies for the TDMA MAC, capable of scaling to large networks. In all of the above topics, we articulate open technical issues wherever applicable.