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A Channel Allocation Algorithm for Hot-Spot Cells in Wireless Networks  [cached]
Rana Ejaz Ahmed
Journal of Advances in Information Technology , 2010, DOI: 10.4304/jait.1.3.136-140
Abstract: Recent growth in mobile telephone traffic in wireless cellular networks, along with the limited number of channels available, presents a challenge for the efficient reuse of channels. Channel allocation problem becomes more complicated if one or more cells in the network become “hot-spots” for some period of time, i.e., the bandwidth resources currently available in those cells are not sufficient to sustain the needs of current users in the cells. This paper presents a new hybrid channel allocation algorithm in which the base station sends a multi-level “hotspot” notification to the central pool located at Mobile Switching Station (MSC) on each channel request that cannot be satisfied locally at the base station. This notification will request more than one channel be assigned to the requesting cell, proportional to the current hot-spot level of the cell. When a call using such a “borrowed” channel terminates, the cell may retain the channel depending upon its current hot-spot level. The simulation study of the protocol indicates that the protocol has low overhead, and it behaves similar to the Fixed Channel Allocation (FCA) scheme at high traffic and to the Dynamic Channel Allocation (DCA) scheme at low traffic loads. The proposed algorithm also offers low-overhead in terms of the number of control messages exchanged between a base station and the MSC on channel acquisition and release phases.
Channel Allocation in Wireless Networks with Directional Antennas  [PDF]
Hong-Ning Dai,Kam-Wing Ng,Min-You Wu
Journal of Sensor and Actuator Networks , 2013, DOI: 10.3390/jsan2020213
Abstract: In this paper, we study the channel allocation in multi-channel wireless ad hoc networks with directional antennas. In particular, we investigate the problem: given a set of wireless nodes equipped with directional antennas, how many channels are needed to ensure collision-free communications? We derive the upper bounds on the number of channels, which heavily depend on the node density and the interference ratio ( i.e., the ratio of the interference range to the transmission range). We construct several scenarios to examine the tightness of the derived bounds. We also take the side-lobes and back-lobes as well as the signal path loss into our analysis. Our results can be used to estimate the number of channels required for a practical wireless network (e.g., wireless sensor network) with directional antennas.
A Distributed Channel Allocation Algorithm for Multi-channel Wireless Networks  [PDF]
Xutao Yu,Xiaoxiang Shi,Jingyu Hua
Information Technology Journal , 2013,
Abstract: Multi-channel can increase the network throughput but require new algorithm to allocate channels. This study proposed a new distributed channel allocation algorithm which utilizes multi-channel to improve network performances, such as network throughput, end to end delay. The algorithm is based on contention graph and adopts contention factor to evaluate conflicts in a channel. In a local contention graph, the link with maximal degree is assigned to channel with minimal contention factor. Simulation results show that the proposed algorithm improves the network throughput and end to end delay. Especially, with the increase of network load, the improvement increases significantly.
A Survey of Channel Allocation Algorithms for Wireless Local Loops  [PDF]
Xihui Zhang,Yingping Huang,John Crabtree,Xiang Li
Information Technology Journal , 2011,
Abstract: A Wireless Local Loop (WLL) uses radio signals to connect customer premise equipment to a local exchange on the public switched telephone network. Compared to wireline local loops, WLLs are easier to deploy and less costly to maintain. As such, WLLs have the potential to help telephony providers overcome the “last mile” problem in delivering telephony services. One of the most important considerations in deploying WLLs is to determine the best channel allocation algorithm. Numerous channel allocation algorithms exist, including no repacking, always repacking and repacking on demand. This study provides an overview of channel allocation algorithms for WLLs, using a decision-tree approach. It also reviews related studies and recommends several future research directions. The algorithm overview and research review can help Information Systems (IS) and Computer Science (CS) researchers as well as practitioners gain a solid understanding of these channel allocation algorithms. The recommended research directions can serve to guide interested IS and CS researchers in future research.
Efficient Channel Allocation and Congestion Control Technique for Wireless Adhoc Networks  [PDF]
J.Aruna Deepika,K.Manikandan
International Journal of Engineering Sciences & Research Technology , 2013,
Abstract: Internet is widely used in the fast growing world. So the wired and wireless networks are mainly used in an active area and there are many limitations in the wireless mesh network. The Congestion Control in the Network field is by means of Scheduling packets from different traffic flows for processing at a specific node is done. In Wireless Adhoc Network, a channel assignment has to balance the connectivity and aggregate bandwidth. In order to increase the maintaince, we use channel assignment algorithm. This algorithm is used to assign the channels to the network interfaces from the given expected load on each virtual link. In the existing work , there is no combined solution of multi-channel assignment with routing and congestion control. In this paper, we propose an efficient multi channel allocation and congestion control technique for wireless mesh networks. The frequency channels are assigned according to the congestion measure which indicates the congestion status at each link. Depending on the selected congestion measure i.e. queuing delay, packet loss probability and differential backlog and various design objectives can be achieved. Our proposed algorithm is simple to implement as it requires each node to perform a local search. Unlike most of the previous channel assignment schemes, our proposed algorithm assigns not only the non-overlapped frequency channels but also the partially-overlapped channels. This technique uses traffic aware metic to provide quality of service and it comprises requirements on all the aspects of connection such as service response time, loss, signal-to-noise ratio, cross-talk, echo, interrupts, frequency response, loudness levels and so on. To overcome this problem, we use proposed technique which can improve throughput and channel utilization to very high extent because it provides solution for multi-channel assignment and congestion control. And also assigns the channels so that congestion is avoided and co-channel interference levels with same channel are reduced. In this paper, we evaluate high throughput and channel utilization along with reduced latency which can be implemented in the Adhoc Network. Thus the efficient channel allocation with congestion control technique for Wireless Mesh Network can be done using NS-2 Simulation tool for attaining high throughput and reduced latency. Thus the paper proposes an efficient channel allocation for Congestion Control in Adhoc Network.
Efficient Load-Aware Channel Allocation in Wireless Access Networks  [PDF]
George Athanasiou,Ioannis Broustis,Leandros Tassiulas
Journal of Computer Networks and Communications , 2011, DOI: 10.1155/2011/972051
Abstract: Dense deployments of hybrid WLANs result in high levels of interference and low end-user throughput. Many frequency allocation mechanisms for WLANs have been proposed by a large body of previous studies. However, none of these mechanisms considers the load that is carried by APs in terms of channel conditions, number of affiliated users as well as communication-load, in conjunction. In this paper, we propose LAC, a load-aware channel allocation scheme for WLANs, which considers all the above performance determinant factors. LAC incorporates an airtime cost metric into its channel scanning process, in order to capture the effects of these factors and select the channel that will provide approximately maximum long-term throughput. We evaluate LAC through extensive OPNET simulations, for many different traffic scenarios. Our simulations demonstrate that LAC outperforms other frequency allocation policies for WLANs in terms of total network throughput by up to 135%. 1. Introduction The growing demand for high-throughput wireless Internet connectivity has enabled the deployment of thousands of WLANs in urban areas, during the last decade. This, however, has resulted in increased amounts of interference and contention among cochannel access points (APs) [1]. As a consequence, the end-users (affiliated clients with those APs) end up enjoying very low throughputs in the long term. Towards addressing this problem, various performance enhancement mechanisms have been proposed, a set of which considers the efficient allocation of frequency bandwidth (i.e., the available channels) to the APs and their clients (i.e., the AP cells) [2–6]. However, each of these frequency allocation studies considers only a subset of the parameters that affect the performance of the network. (a)Number of associated clients. The number of the clients that are distributed in a network affects the communication interference that is present in the network. In other words, the higher the number of the clients associated with an AP, the higher the interference effect in the neighboring cells. (b)Channel conditions. The channel conditions reflect the projected interference (SINR) and thereby the achievable transmission rates for a specific channel. (c)Communication load. The communication load (amount of traffic that the APs must forward to the associated clients or to the network) affects the achievable throughput. The use of channels that are more capable to serve the load in the cells is expected to improve the network throughput. There are no studies that embrace all these parameters
Optimized RMSE Power Allocation for Wireless Image transmission Using binary DPSK over Rayleigh Fading Channel
International Journal of Electronics and Computer Science Engineering , 2012,
Abstract: Optimized root mean square error plays an important role in the analysis of wireless transmission. In this paper, an optimized power allocation method is considered for transmission of images over Rayleigh fading channel using differential phase shift keying. Rayleigh fading channel plays an important role in PSK transmission. Optimized power allocation method shows better performance than fixed power allocation method in terms of Bit error rate and Peak signal to noise ratio, which indicates the quality of the image..
A maximum-independent-set-based channel allocation algorithmfor multi-channel wireless networks  [PDF]
Yu Xutao, Shi Xiaoxiang, Zeng Shaoxiang
- , 2015, DOI: 10.3969/j.issn.1003-7985.2015.01.003
Abstract: A channel allocation algorithm based on the maximum independent set is proposed to decrease network conflict and improve network performance. First, a channel allocation model is formulated and a series of the maximum independent sets(MISs)are obtained from a contention graph by the proposed approximation algorithm with low complexity.Then, a weighted contention graph is obtained using the number of contention vertices between two MISs as a weighted value. Links are allocated to channels by the weighted contention graph to minimize conflicts between independent sets. Finally, after channel allocation, each node allocates network interface cards(NICs)to links that are allocated channels according to the queue lengths of NICs. Simulations are conducted to evaluate the proposed algorithm. The results show that the proposed algorithm significantly improves the network throughput and decreases the end to end delay.
Minimization of Call Blocking Probability by Using an Adaptive Heterogeneous Channel Allocation Scheme for Next Generation Wireless Handoff Systems
Debabrata Sarddar,Arnab Raha,Shubhajeet Chatterjee,Ramesh Jana
International Journal of Computer Science Issues , 2011,
Abstract: Nowadays IEEE 802.11 based wireless local area networks (WLAN) have been widely deployed for business and personal applications. The main issue regarding wireless network technology is handoff or hand over management. The minimization of handoff failure due to call blocking is an important issue of research. For the last few years plenty of researches had been done to reduce the handoff failure. Here we also propose a method to minimize the handoff failure by using an adaptive heterogeneous channel allocation scheme.
Quantization and Bit Allocation for Channel State Feedback for Relay-Assisted Wireless Networks  [PDF]
Ehsan Karamad,Behrouz Khoshnevis,Raviraj Adve
Mathematics , 2011,
Abstract: This paper investigates quantization of channel state information (CSI) and bit allocation across wireless links in a multi-source, single-relay cooperative cellular network. Our goal is to minimize the loss in performance, measured as the achievable sum rate, due to limited-rate quantization of CSI. We develop both a channel quantization scheme and allocation of limited feedback bits to the various wireless links. We assume that the quantized CSI is reported to a central node responsible for optimal resource allocation. We first derive tight lower and upper bounds on the difference in rates between the perfect CSI and quantized CSI scenarios. These bounds are then used to derive an effective quantizer for arbitrary channel distributions. Next, we use these bounds to optimize the allocation of bits across the links subject to a budget on total available quantization bits. In particular, we show that the optimal bit allocation algorithm allocates more bits to those links in the network that contribute the most to the sum-rate. Finally, the paper investigates the choice of the central node; we show that this choice plays a significant role in CSI bits required to achieve a target performance level.
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