Topic
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: A cooperative reconnaissance and spectrum access scheme for task-driven heterogeneous coalition-based UAV networks by jointly optimizing task layer and resource layer and a joint bandwidth allocation and coalition formation (JBACF) algorithm to achieve stable coalition partition.
Abstract: Coalition structure is an efficient networking architecture for task implementation in unmanned aerial vehicle (UAV) networks. However, both the formation of coalition and the spectrum resource for intra-coalition communication affect the reconnaissance performance. In this paper, we investigate a cooperative reconnaissance and spectrum access (CRSA) scheme for task-driven heterogeneous coalition-based UAV networks by jointly optimizing task layer and resource layer. Specifically, coalition formation game (CFG) is formulated to jointly optimize task selection and bandwidth allocation. In addition to the traditional Pareto order and selfish order, coalition expected altruistic order maximizing coalitions’ utility is proposed. The CFG under the proposed order is proved to be an exact potential game (EPG). Then the existence of stable coalition partition is guaranteed with the help of Nash equilibrium (NE). We propose a joint bandwidth allocation and coalition formation (JBACF) algorithm to achieve stable coalition partition wherein an efficient gradient projection (GP) based method is applied to solve bandwidth allocation. The effectiveness of the proposed scheme and algorithms are demonstrated through in-depth numerical simulations. The results show that our proposed CRSA scheme is superior to non-joint optimization scheme. Also, the proposed order is superior to traditional Pareto order and selfish order.
51 citations
TL;DR: It is found that with HFD, careful assignment in which adjacent cells use different frequency channels does not improve the overall network capacity, and a simple scheme with overlaid cellular WiFi networks in which each cell uses all frequencies yields near-optimal performance.
Abstract: This paper investigates the hidden-node phenomenon (HN) in IEEE 802.11 wireless networks. HN occurs when nodes outside the carrier-sensing range of each other are nevertheless close enough to interfere with each other. As a result, the carrier-sensing mechanism may fail to prevent packet collisions. HN can cause many performance problems, including throughput degradation, unfair throughput distribution among flows, and throughput instability. The contributions of this paper are threefold. 1) This is a first attempt to identify a set of conditions - which we called hidden-node-free design (HFD) - that completely remove HN in 802.11 wireless networks. 2) We derive variations of HFD for large-scale cellular WiFi networks consisting of many wireless LAN cells. These HFDs are not only HN-free, but they also reduce exposed nodes at the same time so that the network capacity is improved. 3) We investigate the problem of frequency-channel assignment to adjacent cells. We find that with HFD, careful assignment in which adjacent cells use different frequency channels does not improve the overall network capacity (in unit of bits per second per frequency channel). Indeed, given frequency channels, a simple scheme with overlaid cellular WiFi networks in which each cell uses all frequencies yields near-optimal performance.
51 citations
TL;DR: This article introduces a coordinate descent algorithm that decomposes the UEs’ energy consumption minimization problem into several subproblems which can be efficiently solved and demonstrates the advantages of the proposed algorithm in terms of the reduced total energy consumption of UEs.
Abstract: Unmanned aerial vehicles (UAVs) are expected to be deployed as aerial base stations (BSs) in future wireless networks to provide extensive coverage and additional computational capabilities for user equipments (UEs). In this article, we study mobile-edge computing (MEC) in air–ground integrated wireless networks, including ground computational access points (GCAPs), UAVs, and UEs, where UAVs and GCAPs cooperatively provide computing resources for UEs. Our goal is to minimize the total energy consumption of UEs by jointly optimizing users’ association, uplink power control, channel allocation, computation capacity allocation, and UAV 3-D placement, subject to the constraints on deterministic binary offloading, UEs’ latency requirements, computation capacity, UAV power consumption, and available bandwidth. Due to the nonconvexity of the primary problem and the coupling of variables, we introduce a coordinate descent algorithm that decomposes the UEs’ energy consumption minimization problem into several subproblems which can be efficiently solved. The simulation results demonstrate the advantages of the proposed algorithm in terms of the reduced total energy consumption of UEs.
51 citations
TL;DR: The preemptive borrowing scheme is observed to perform better than the nonpreemptive scheme at the cost of increased handoff for nonreal-time service calls, and the impact of the long-term dependence of data traffic on system performance is discussed.
Abstract: In this paper, we propose and analyze two different handoff schemes in integrated wireless mobile networks. The channels in each cell are divided into two parts and pre-allocated for real-time and nonreal-time services. To increase the channel utilization while keeping the quality of service (QoS) of each type for traffic, one type of service is allowed to borrow channels from the other under certain constraints. Depending on whether or not nonreal-time service calls can be interrupted, we have two channel borrowing schemes: nonpreemptive and preemptive. We use a system model defined by a multidimensional Markov chain and compute the performance in terms of blocking probability of originating calls, forced termination probability of real-time service calls, and average transmission delay of nonreal-time service calls. The simulation results are observed to match closely with the analytical model. The preemptive borrowing scheme is observed to perform better than the nonpreemptive scheme at the cost of increased handoff for nonreal-time service calls. The impact of the long-term dependence of data traffic on system performance is also discussed.
51 citations
27 Oct 1997
TL;DR: A new broadcasting method is presented, which can reduce the user's waiting time much greater than previous schemes, and needs much less bandwidth and, thus, greatly saves the bandwidth requirements.
Abstract: Using multiple channels to broadcast a popular video can reduce the viewer's waiting time. With the same bandwidth allocation as conventional broadcasting schemes, pyramid broadcasting schemes can provide users with shorter waiting time. This paper presents a new broadcasting method, which can reduce the user's waiting time much greater than previous schemes. With the same waiting requirement for a popular movie, the new algorithm needs much less bandwidth and, thus, greatly saves the bandwidth requirements. At the client end, the buffer requirement is in between previous pyramid schemes. However, using the new scheme, if a set-top box has no buffer, its user can still have the movie with longer waiting time, but previous pyramid schemes cannot provide continuous video service without buffer.
51 citations