Wireless Broadcast Advantage Research Articles

MRCSC: A cross-layer algorithm for joint Multicast Routing, Channel selection, Scheduling, and Call admission control in multi-cell multi-channel multi-radio cognitive radio wireless networks

This paper addresses the problem of joint multicast routing, channel selection, scheduling, and call admission control in multi-cell multi-channel multi-radio cognitive radio wireless mesh networks. The applied model relies on the QoS sessions, where each one is expressed with a bandwidth requirement. We propose a cross-layer algorithm named “Multicast Routing, Channel selection, Scheduling, and Call admission control (MRCSC)”. The proposed scheme, considering wireless broadcast advantage, channel/radio diversity, and spatial reuse, uses both intra- and inter-cell relaying to create multicast trees with a specific bandwidth. MRCSC considers both inter-flow and intra-flow interferences. It adopts an efficient collision-free mechanism to greedily schedule different multicast transmission in the network. As an advantage, considering the multi-radio technology, MRCSC allows the nodes to simultaneously send/receive data on different available non-overlapping channels. Numerical results of our comprehensive simulations confirm the efficiency of the MRCSC algorithm in terms of the number of transmissions, stability, and multicast period.

SoftHM: A Software-Based Hierarchical Modulation Design for Wireless System

Hierarchical Modulation (HM) is quite efficient for multimedia broadcast in wireless networks. It exploits the wireless broadcast advantage and allows a transmission to reach different users with various qualities. However, existing HM related schemes are based on specially designed hardware, leading to extra hardware and deployment cost in practice. As a remedy for this, we design and implement a software-based HM scheme, named as SoftHM. By carefully tuning the Physical Layer input of a packet (a sequence of “0” or “1” bits, known as PHY payload), a transmitter simply broadcasts the packet with a single rate (e.g., 54Mbps, the highest rate in 802.11g WLAN), while diverse receivers can decode and extract different amount of information (with different reception rate, e.g., 12Mbps or 54Mbps) from it based on their link qualities. Reverse engineering techniques are adopted so that SoftHM works in a plug-in mode, offering it high potentials for wireless systems without any changes in existing modulation and coding modules. We implement SoftHM based on Universal Software Radio Peripheral (USRP) B210 and Commercial of the Shelf (COTS) Wi-Fi devices. Both rigorous analysis on its performance and comprehensive implementation-based experiments show that compared with the traditional time-sharing approach, to support low-quality users with the same bandwidth, high-quality users in SoftHM achieve 111.1% to 616.7% higher throughput. Likewise, to serve high-quality users with the same bandwidth, low quality users in softHM achieve 176.9% to 390.9% higher throughput.

Online multicast tree construction with bandwidth and delay constraints in multi-channel multi-radio wireless mesh networks

This paper deals with online QoS multicast tree construction problem, which is essential to support multimedia services, in multi-channel multi-radio wireless mesh networks. The proposed algorithm satisfies both delay and bandwidth requirements of each arrived session. It breaks down the original problem into two phases of satisfying delay and bandwidth constraints. The first phase devotes to preserving delay constraint of the arrived session, in which a number of delay-bounded paths are determined between each receiver and the source node. In the proposed scheme, to diminish the utilized bandwidth, the overlapping of the regarding paths of the receivers is maximized as much as possible. We propose a mathematical model to satisfy bandwidth requirement in the second phase, which constructs the tree over the selected paths. The data transmission rate on the tree is set to the requested rate by the session, to satisfy its bandwidth requirement. The proposed model has a global view over the network and constructs the most appropriate trees. It also exploits wireless broadcast advantage property to enhance the performance. Through extensive simulations, the effectiveness of the proposed algorithm is verified. In particular, it improves the acceptance rate by 60% compared to previous schemes.

EEHRT: Energy Efficient Technique for Handling Redundant Traffic in Zone-Based Routing for Wireless Sensor Networks

This paper presents an energy-efficient technique to handle redundant traffic (EEHRT) in the zone-based routing for wireless sensor networks. In this technique, multihop routing is performed based on the remaining energy of the nodes. Afterwards, it performs position-based routing without the need for the nodes to know their respective position. The main objective of this paper is to handle the redundant packets generated in zone-based routing using short beacon messages. Nodes of lower zones route the data of the higher zone to base station (BS) with a minimum number of hops and utilize only those nodes on the path which are energy efficient and located closer to BS. Moreover, the source node is acknowledged by the relaying node using a wireless broadcast advantage (WBA) without sending any special ACK packet to the sender, which reduces the control overhead in the routing process. The EEHRT technique improves the routing against RARZ by ensuring only one copy of the packet is propagated at each hop along the routing path to BS. Simulation results show that EEHRT achieved 28% improvement in energy efficiency, 10% and 25% improvements in data throughput against total and distinct packet reception at BS respectively, 35% increase in overall network lifetime, and 100% reduction in redundant packets generation and propagation in the network against RARZ routing.

Exploiting Wireless Broadcast Advantage for Energy Efficient Packet Overhearing in WiFi

The energy efficiency of WiFi interfaces has become a significant concern for battery-powered mobile stations. In WiFi networks, a station's backoff procedure is interrupted by other stations’ channel activities to receive and decode useless packets that are not intended for it, which consumes a non-negligible amount of its energy. To reduce the energy consumption induced by such packet overhearing, we propose a novel transmission scheme, data symbol silence (DSS), which inserts silent data symbols into the front part of a data packet at the physical layer to encode information. By exploiting the wireless broadcast advantage, the embedded information is received by neighboring stations. Data symbol level energy detection is used to extract the embedded information without receiving and decoding the whole data packet. Thus, unintended receivers can quickly stop useless packet receiving and processing. The signal-to-noise ratio (SNR) gap in current WiFi networks is utilized to ensure the inserted silent data symbols do not affect the correct decoding of the original data packet. We analyze the minimum SNR required for effective DSS and implement DSS to validate its feasibility. Compared with the 802.11 standards, our studies show that DSS significantly improves the energy efficiency of WiFi interfaces.

Online network coding-based multicast routing in multichannel multiradio wireless mesh networks

In this paper, we consider the problem of online multicast routing in multichannel multiradio wireless mesh networks (WMNs). We propose an efficient online algorithm, namely zone-based multicast routing (ZBMR), which exploits network coding and wireless broadcast advantage. In the proposed algorithm, to investigate the acceptance of an arrived session in polynomial time, the WMN is divided into some zones. The derived zones are processed sequentially, where the zone processing is defined as connecting the receivers in a given zone to the session. The main challenge in this scheme is to enable data transmission to the receivers in each zone. If a zone does not contain the source node, it should obtain data from the previously processed neighboring zones. The problem is that the data transmission fails if there is no receiver on the common border between the considered zone and its processed neighboring zones. Our solution to tackle this challenge is to add some virtual receivers to the borders of the zones. The extensive simulations show that ZBMR increases the acceptance rate by 50% in comparison to the previous approaches.

Interference optimization for multicast and broadcast traffics in multi-radio multi-channel WMNs equipped with directional antennas

This paper addresses the interference optimization problem for multicast/broadcast traffics in multi-radio multi-channel wireless mesh networks equipped with directional antennas. Since a directional antenna radiates the major of transmission power to the main-lobe, it can reduce the interference. However, this may increase the number of transmissions. The adaptive directional antenna is an effective tool in controlling the above-mentioned trade-off. The main goal of this paper is to linearly model the multicast/broadcast interference in the presence of directional antennas. In this regard, the authors provide a Mixed Integer Linear Programming (MILP) formulation named “Minimum Interference and Transmission Tree with Directional Antenna (MITT-DA)” to jointly select the best multicast/broadcast routing tree, antenna beam, and transmission channel. The proposed MITT-DA is a comprehensive model which supports both directional and omni-directional antennas. It not only considers wireless broadcast advantage, but also optimizes both inter-flow and intra-flow interferences. Numerical results demonstrate the efficiency of the proposed MILP scheme in terms of the interference and the number of transmissions.

A Load-Balanced Multicast Routing Algorithm Using Diversity Rate in CWMNs

Cognitive wireless mesh networks (CWMNs) were developed to improve the utilization ratio of licensed spectrum. Since the spectrum opportunities for users vary over time and location, enhancing the spectrum effectiveness is a goal and also a challenge for CWMNs. Multimedia applications have recently generated much interest in CWMNs supporting quality-of-service (QoS) communications. Multicast routing and spectrum allocation is an important challenge in CWMNs. In this paper, we study to design an effective multicast routing algorithm based on diversity rate with respect to load balancing and the number of transmissions for CWMNs. In this paper, a load balancing wireless links weight computing function and computing algorithm based on diversity rate (DRLB) are proposed, and a load balancing channel and rate allocating algorithm based on diversity rate (DR2CS) is proposed. On this basis, a load balancing joint multicast routing, channel and rate allocation algorithm based on diversity rate with QoS constraints for CWMNs (LMR2D) is proposed. Balancing the load of node and channel, and minimizing the number of transmissions of multicast tree are the objectives of LMR2D. Firstly, LMR2D computes the weight of wireless links using DRLB and Dijkstra for constructing the load balancing multicast tree step by step. Secondly, LMR2D uses DR2CS to allocate channel and rate of channel to links which is based on the wireless broadcast advantage. Simulation results show that LMR2D can achieve the expected goal. It can not only balance the load of node and channel, but also need lower number of transmissions for multicast tree.

Cooperation forwarding data gathering strategy of wireless sensor networks

Limited energy and easy invalidation are the characteristics of WSNs (Wireless Sensor Networks). To prolong the lifetime of WSNs for building monitoring, an algorithm named CFDGSBRWB is proposed, which is a Cooperation Forwarding Data Gathering Strategy Based on Random Walk Backup in Wireless Sensor Networks. The algorithm consists of data backup based on random walk and cooperation forwarding data gathering by WBA (Wireless Broadcast Advantage). Simulation results show that CFDGSBRWB can reduce packet lost ratio and enhance fault-tolerance significantly under the condition of the insignificant increase of communication traffic, and is suitable for large-scale wireless sensor networks.

Low-interference multicast routing in multi-radio multi-channel wireless mesh networks using adaptive directional antennas

This paper deals with the problem of multicast routing in Multi-Radio Multi-Channel Wireless Mesh Networks (MRMC-WMNs) equipped with directional antennas. We jointly consider the wireless broadcast advantage, the directional antenna technology, and the interference-aware path selection metric to improve the network performance. Although using directional antennas reduces the interference, it increases the number of transmissions. The adaptive directional antenna is an effective approach to control this trade-off. In this regard, we propose four cross-layer algorithms named “Directional Transmission aware Multicast Tree (DTMT)”, “Directional Interference-aware Multicast Tree (DIMT)”, “Steerable Beam Multicast routing (SBM)”, and “Interference-aware Steerable Beam Multicast routing (ISBM)”. As an advantage, these algorithms jointly address the problems of multicast tree construction, transmission channel selection, and transmission beam specification. DTMT and DIMT are implemented on three types of graphs called “Random Oriented Graph (ROG)”, “Adaptive Oriented Graph (AOG)”, and “Adaptive beam Graph (ABG)”. AOG and ABG try to find the best sector by steering the directional antennas. Differently, in SBM and ISBM, the beam-width and orientation of each antenna are adaptively characterized during the procedure of the tree construction. Numerical results demonstrate that the proposed algorithms effectively outperform other existing algorithms in terms of the interference and the number of transmissions.

A novel approach for multicast call acceptance in multi-channel multi-radio wireless mesh networks

Multicasting is an efficient data transmission approach for group communication applications in multi-channel multi-radio wireless mesh networks. In this paper we have studied the problem of accepting on-line multicast requests, which is quite important for supporting multimedia applications. Our proposed algorithm investigates the acceptance of an arrived call in two phases. In the first phase, a loop-free mesh backbone is constructed. In this mesh, the set of possible parents of each node is limited to the neighbors that are one hop closer to the source node. The neighbors with the same distance from the source node are also acceptable under the circumstance that two neighboring nodes cannot be the possible parents of each other. Next, a sub-optimal mathematical model has been proposed for tree construction over the obtained mesh. The derived multicast trees utilize the minimum amount of bandwidth; are load-balanced; and exploit wireless broadcast advantage. The results show that the proposed algorithm improves the rate of multicast call acceptance by 40% on average compared to previous algorithms in a short running time.

Joint multicast routing and channel assignment for multi-radio multi-channel wireless mesh networks with hybrid traffic

In this paper, joint multicast routing and channel assignment problem in wireless mesh networks (WMNs) with hybrid traffic is investigated. Previous works design routing and channel assignment schemes for WMNs with single multicast session, however, resource usage is optimized for only one multicast session in this case and overall network load balance is left out of consideration. This may result in high congestion in some links, while others are underutilized. In this paper, multicast routing and channel assignment problem is solved from traffic management perspective by introducing load balance. Programming formulation is formulated to obtain the optimal results which can be used as benchmark to evaluate other schemes. Multicast weighted conflict graph is designed to model partially overlapped channels (POCs) interference in hybrid traffic scene. It regards links originating from the same node as one transmission to fully exploit wireless broadcast advantage; it uses link weight to measure interference degree and gives full consideration to interference characteristics of POCs. A heuristic multicast routing and channel assignment scheme based on multicast weighted conflict graph is designed to solve the joint problem, and simulation results show that the heuristic scheme can reduce network interference and improve WMNs service capability while dramatically reducing computational complexity.

An optimization framework for multicasting in MCMR wireless mesh network with partially overlapping channels

This paper focuses on the problem of maximizing throughput in multicast routing in Multi-Channel, Multi-Radio (MCMR) wireless mesh network. We propose an optimization framework based on binary integer programming that minimizes interference in multicast communication. Our Multicasting with multiple Gateways and Partially Overlapped Channels (MG-POC) framework utilizes a rational node selection to construct multicast tree that increases network performance. MG-POC is efficient as it (1) constructs the paths between source and receivers with minimal number of data forwarding nodes; (2) employs multiple gateways to substantially reduce interference and usage of resources; (3) benefits from wireless broadcast advantage and partially overlapped channels in channel assignment; (4) solves channel assignment and tree construction problems simultaneously. A weakly decoupled approach is also presented which finds a nearly optimal solution for large network problems in a reasonably short amount of time. Our schemes are proved to offer a connected and loop-free tree; and their performance are well compared to that of several existing methods on different simulation scenarios. The results of our simulations also demonstrate that incorporating multi-gateway and partially overlapping channels has a significant impact on minimizing network interference which, in turn, dramatically enhances network throughput.

A Throughput-oriented Reliable Multicast in Multi-rate Wireless Networks

As low transmission delays can meet the requirements of many applications, high-throughput is the request of various others. Therefore, with consideration of the multi-user diversity (MUD) and the wireless broadcast advantage (WBA) features, we deal with the problem of maximising the multicast throughput. Hence, we introduce two new rate-aware multicast metrics: EMTH and XMTH. EMTH helps to choose the transmission rates that estimate the best multicast throughput expected. XMTH can reach extreme throughput values if the high computational needs are satisfied. Both metrics carry out a rate adaptation process and take into consideration the link reliabilities. They can be used to choose multi-rate multicast schemes and to decide reliable multicast paths. Results show that the proposed metrics give the best system performance in terms of throughput. They confirm that, using EMTH and XMTH, it is possible to trade-off a very good throughput improvement for an insignificant delay increase.

Minimizing Expected Transmissions Multicast in Wireless Multihop Networks

We address the multicast problem in a wireless multihop network in the presence of errors. Finding the multicast schedule that minimizes the expected number of transmissions, while accounting for both the wireless broadcast advantage (WBA) and the wireless unreliable transmission (WUT) characteristics, has not been solved optimally before. We formally define the problem and propose an initial algorithm of non-polynomial complexity to obtain the optimal solution. The algorithm starts by transforming the wireless network topology into an auxiliary expanded graph that captures the WBA property, and assigning appropriate weights to the links so as to capture the WUT property. The proposed transformation is interesting on its own merit, since it permits us to consider only point-to-point transmissions (as in wireline networks) in the expanded graph, instead of the point-to-multipoint transmissions present in the original wireless network, and can also be useful in other optimization problems some of which we briefly describe. By solving the minimum Steiner tree problem on the expanded graph we obtain the optimal multicast solution for the initial graph. Since the optimal algorithm is of non-polynomial complexity, we also propose a number of heuristic algorithms. In particular, we first present a truncated graph transformation and then describe two heuristic algorithms for obtaining the multicast schedule. Simulation results show that the proposed heuristics have performance close to that of the optimal algorithm, at least for the instances for which we were able to track optimal solutions, while outperforming other heuristic multicast algorithms.

High-Throughput Reliable Multicast in Multi-Hop Wireless Mesh Networks

This paper presents a cross-layer approach for enabling high-throughput reliable multicast in multi-hop wireless mesh networks. The building block of our approach is a multicast routing metric, called the expected multicast transmission count (EMTX). EMTX is designed to capture the combined effects of MAC-layer retransmission-based reliability, wireless broadcast advantage, and link quality awareness. The EMTX of single-hop transmission of a multicast packet from a sender is the expected number of multicast transmissions (including retransmissions) required for its next-hop recipients to receive the packet successfully. We formulate the EMTX-based multicast problem with the objective of minimizing the sum of EMTX over all forwarding nodes in the multicast tree, aiming to reduce network bandwidth consumption while ensure high end-to-end packet delivery ratio for the multicast traffic. We provide rigorous mathematical formulations and methods to find near-optimal solutions of the problem computationally efficiently. We present centralized and distributed algorithms, and demonstrate their effectiveness in tackling the EMTX-based multicast problem with a combination of theoretical and numerical results. Simulation experiments show that, in comparison with two baseline approaches, EMTX-based multicast routing reduces the number of hop-by-hop transmissions per packet by up to 40 percent and yet improves the multicast throughput by up to 24 percent.

Efficient multicast tree construction in wireless mesh networks

Multicast routing algorithms designed for wireline networks are not suitable for wireless environments since they cannot efficiently exploit the inherent characteristics of wireless networks such as the broadcast advantage. There are many routing protocols trying to use these advantages to decrease the number of required transmissions or increase the reception probability of data (e.g., opportunisticrouting). Reducing the number of transmissions in a multicast tree directly decreases the bandwidth consumption and interference and increases the overall throughput of the network. In this paper, we introduce a distributed multicast routing protocol for wireless mesh networks called NCast which take into account the data delivery delay and path length when constructing the tree. Furthermore, it effectively uses wireless broadcast advantage to decrease the number of forwarding nodes dynamically when a new receiver joins the tree. Our simulation results show that NCast improves network throughput, data delivery ratio and data delivery delay in comparison with on demand multicast routing protocol. It is also comparable with multichannel multicast even though it does not use channeling technique which eliminates the interference inherently.

Video Multicast With Joint Resource Allocation and Adaptive Modulation and Coding in 4G Networks

Although wireless broadband technologies have evolved significantly over the past decade, they are still insufficient to support the fast-growing mobile traffic, especially due to the increasing popularity of mobile video applications. Wireless multicast, aiming to exploit the wireless broadcast advantage, is a viable approach to bridge the gap between the limited wireless capacity and the ever-increasing mobile video traffic demand. In this paper, we propose MuVi, a Multicast Video delivery scheme through joint optimal resource allocation and adaptive modulation and coding scheme in OFDMA-based 4G cellular networks. MuVi differentiates video frames based on their importance in reconstructing the video and incorporates an efficient radio resource allocation algorithm to optimize the overall video quality across all users in the multicast group. MuVi is a lightweight solution with most of the implementation in the gateway, slight modification in the base station, and no modification at the clients. We implement MuVi on a WiMAX testbed and compare its performance to a Naive wireless multicast scheme that employs the most robust Modulation and Coding Scheme (MCS), and an Adaptive scheme that employs the highest MCS supportable by all clients. Experimental results show that MuVi improves the average video peak signal-to-noise ratio (PSNR) by up to 13 and 7 dB compared to the Naive and the Adaptive schemes, respectively. MuVi does not require modification to the video encoding scheme or the air interface. Thus, it allows speedy deployment in existing systems.

Minimum Cost Bandwidth Guaranteed Multicast Routing in Multi-channel Multi-radio Wireless Mesh Networks

Multicast communication is an important service in wireless mesh networks (WMNs). It covers a broad range of applications, including data distribution, video conferencing, and distance learning. In this paper, we discuss the issue of bandwidth guaranteed multicast routing in multi-channel multi-radio WMNs. The problem of our concern is to construct a tree per multicast session such that the cost of the system, which is defined as the amount of total consumed bandwidth, is minimized. In order to solve the problem efficiently, we design Bandwidth Guaranteed Minimum Cost Tree construction (BGMCT) algorithm. Our algorithm yields cost-effective solutions as it exploits the wireless broadcast advantage (WBA) property of the wireless medium. In the proposed algorithm, we have developed two strategies for constructing minimum cost trees. Firstly, the number of the relay nodes in each tree is minimized. Secondly, the amount of overlapping between the shortest paths which connect different destinations of each session to its source node, is taken into account. The simulation results demonstrate that our algorithm outperforms existing solutions. Moreover, BGMCT provides near to optimal outcomes in a reasonable time.

A Load-Balanced Multicast Routing Algorithm in Cognitive Wireless Mesh Networks

A load balanced wireless links weights computing function and computing algorithm(LBWC) are proposed.On this basis,a load balanced joint multicast routing and spectrum allocation algorithm with QoS constraints in cognitive wireless mesh networks(LMRS2A) is proposed.Balancing the load of network and minimizing the number of transmission of multicast tree are the objective of LMRS2A under the QoS constraints.First,LMRS2A computes the weights of wireless links using LBWC for constructing the load balanced multicast tree.Second,LMRS2A uses the algorithm WBA2S with QoS constraints allocating channel to links which is based on the Wireless Broadcast Advantage(WBA).Simulation results show that LMRS2A algorithm can achieve expectation goal.It can not only avoid the congestion of node,but also need lower number of transmission of multicast tree.