Multi-channel Multi-interface Wireless Mesh Networks Research Articles

Performance Analysis of Large Multi-Interface Wireless Mesh Networks with Multi-Different Bandwidth Channel

In this paper, we study the asymptotic throughput capacity of a static multi-channel multi-interface infrastructure wireless mesh network (InfWMN) wherein each infrastructure node has m interfaces and c channels of unequal bandwidth are available. First, an upper bound on the InfWMN per-user capacity is established. Then, the feasible lower bound is derived by construction. We prove that both lower and upper bounds are tight. We limit our analysis for more practical case of $\mathrm{m} \le \mathrm{c}$ . However, for the asymptotic upper bound, our analysis can be used for the general case in which there is no constraint on m and c. Our study shows that in such a network with Nc randomly distributed mesh clients, Nr regularly placed mesh routers, and Ng gateways, the asymptotic per-client throughput capacity has different bounds, which depend on the ratio between the total available bandwidth for the network and the sum of m first greatest data rates of c available channels, i.e., $\sum \limits_{\mathrm{j} = 1}^\mathrm{C} \mathrm{w}_\mathrm{j} / \sum \limits_{\mathrm{j} = 1}^\mathrm{m} \mathrm{w}_\mathrm{j}$ . The results of this paper are more general compared to the existing published researches. In addition, in the case that $\mathrm{w}_\mathrm{i} = \mathrm{W}/\mathrm{c} \forall \mathrm{i},\mathrm{}1 \le \mathrm{i} \le \mathrm{c}$ , our results reduce to the previously reported studies. This implies that our study is comprehensive compared to the formerly published researches.

A new quality of service aware multi-channel multi-interface link layer protocol for wireless mesh networks

A new link layer protocol, quality of service hybrid multi channel protocol (QoS---HMCP), that takes into account the need for QoS support in multi-channel multi-interface wireless mesh networks (MCMI---WMNs) is proposed in this paper. QoS---HMCP protocol retains most properties of enhanced distributed channel access (EDCA) mechanism, defined by the 802.11 standard, as well as the basic mechanisms of HMCP protocol. To achieve good network performances with QoS---HMCP protocol in MCMI network, it was necessary to precisely define the channel coordination and procedure for the medium competition of EDCA functions (EDCAFs) after the expiration of interval of time within which a particular EDCAF has the right to initiate data exchange sequences onto the wireless medium--transmission opportunity. Taking into consideration the previously defined conditions, four versions of QoS---HMCP protocol are proposed in this paper. These versions were compared with each other and with basic HMCP with regard to the throughput of user data and delay through the network. The four versions of the QoS---HMCP protocol, multi channel routing (MCR) protocol and chosen metric were implemented in Glomosim simulator. The results have shown that implementation of QoS---HMCP protocol in MCMI---WMN resulted in a very small delay for voice and video traffic, while low-priority traffic categories (best effort and background) were still able to access the media.

IEEE 802.11s 무선 메쉬 네트워크에서 종단간 대역폭 예약을 위한 멀티 인터페이스 멀티 채널 R-HWMP 라우팅 프로토콜

무선 메쉬 네트워크는 인프라 없이 무선 멀티홉으로 네트워크를 구성해야 하는 환경에서 매우 각광받고 있는 기술로서 현재 IEEE 802.11s 메쉬 네트워크 표준이 제정되었다. 이 표준과 기존 IEEE 802.11과의 큰 차이점 중의 하나는 메쉬 표준에서 QoS를 지원하기 위한 MAC 인 MCCA 가 추가된 것이다. MCCA 는 이웃 노드와의 대역폭 예약을 제공하고 이를 통해 대역폭 보장의 QoS를 만족할 수 있다. 그러나 MCCA 는 종단간 대역폭을 보장할 수 없는 단점이 있고, 또한 표준에서는 메쉬 노드가 멀티 인터페이스, 멀티 채널을 지원하는 경우 대역폭 예약 프로토콜과 무선 채널의 예약 방법 등이 규정되어 있지 않다. 이에 본 논문에서는 싱글 인터페이스에서의 종단간 대역폭 예약을 수행하는 예약 기반의 HWMP 프로토콜(R-HWMP)을 멀티인터페이스, 멀티 채널로 확장한 MIMC R-HWMP를 제안하고, 시뮬레이션을 통하여 멀티 인터페이스를 지원하는 무선 메쉬네트워크에서 종단간 대역폭의 보장과 인터페이스 확장에 따른 가용 대역폭의 증가를 보였다.

Joint power and multiple access control for wireless mesh network with Rose projection method.

This paper investigates the utility maximization problem for the downlink of the multi-interface multichannel wireless mesh network with orthogonal frequency division multiple access. A cross-layer joint power and multiple access control algorithm are proposed. Rosen projection matrix is combined with Solodov projection techniques to build a three-memory gradient Rosen projection method, which is applied to solve this optimization problem. The convergence analysis is given and simulations show that the proposed solution achieves significant throughput compared with existing approaches.

Novel power-based routing metrics for multi-channel multi-interface wireless mesh networks

In this paper the problem of selecting optimal paths in a MCMI (Multi-Channel Multi-Interface) WMN (Wireless Mesh Network) is considered. The WMNs are characterized by high dynamic range of the received signal level, especially in the indoor environment. To improve the existing routing metrics and track fast changes that occur in the link state, a corresponding parameter based on the received signal level was assigned to each link. By combining this parameter and known metrics, ETX (Expected Transmission Count), WCETT (Weighted Cumulative ETT) and MIC (Metric of Interference and Channel-switching), three new metrics were formed. All metrics were incorporated in MCR (Multi Channel Routing) protocol and an appropriate propagation model was used for simulations in a real, indoor environment. Proposed metrics, original metrics, MCR protocol, and indoor propagation model were implemented in Glomosim simulator. New metrics were compared against known metrics and also among each other in terms of throughput of user data and average end-to-end delay of the network. The results have shown that proposed metrics significantly outperform original metrics. With this approach, better network performance can be achieved without any additional hardware and with minimal software changes.

Using Orthogonal Channels for Supporting Multicast Service in Multi-channel Wireless Mesh Networks

Unlike wired networks, the capacity of a wireless network is interference limited due to the broadcast nature of wireless medium. Some multicast wireless network protocols do not consider channel assignment issue, that they cause interference at transmission nodes, hence do not use full capacity of the network. Interference can be reduced and throughput improved with the use of multichannel features. Therefore, this paper used orthogonal channels for sending and receiving nodes in the network. We propose EWM (Efficient Wireless Multicast) method that is distributed scheme for constructing multicast tree in multi-channel multi-interface wireless mesh networks (MIMC-WMN) which selects relay nodes and in distributed form assign orthogonal radio channels to them. To more decrease of interference in adding a branch to the tree, the route with minimum end-to-end delay from the source to the multicast receiver will be chosen. Thus, the tree is suitable for multimedia applicants. We also employ the broadcast nature of the wireless media to reduce the number of relay nodes. The proposed algorithm is compared with MCM algorithm in NS2.

Disjoint Path Routing for Multi-Channel Multi-Interface Wireless Mesh Network

Disjoint Path Routing for Multi-Channel Multi-Interface Wireless Mesh Network

Design and implementation of multicasting for multi-channel multi-interface wireless mesh networks

Multicasting is a useful communication method in wireless mesh networks (WMNs). Many applications in WMNs require efficient and reliable multicast communications, i.e., high delivery ratio with low overhead among a group of recipients. In spite of its significance, little work has been done on providing such multicast service in multi-channel WMNs. Traditional multicast protocols for wireless and multi-hop networks tend to assume that all nodes, each of which is equipped with a single interface, collaborate on the same channel. This single-channel assumption is not always true, as WMNs often provide nodes with multiple interfaces to enhance performance. In multi-channel and multi-interface (MCMI) WMNs, the same multicast data must be sent multiple times by a sender node if its neighboring nodes operate on different channels. In this paper, we try to tackle the challenging issue of how to design a multicast protocol more suitable for MCMI WMNs. Our multicast protocol builds multicast paths while inviting multicast members, and tries to allocate the same channel to neighboring members in a bottom-up manner. By unifying fixed channels of one-hop multicast neighbors, the proposed algorithm can improve the performance such as reducing multicast data transmission overhead and delay, while managing a successful delivery ratio. In order to prove such expectation on the performance, we have implemented and evaluated the proposed solution on the real testbed having the maximum 24 nodes, each of which is equipped with two IEEE 802.11a Atheros WLAN cards.

Maximizing Multicast Call Acceptance Rate in Multi-Channel Multi-Interface Wireless Mesh Networks

In this paper, we consider the problem of constructing bandwidth-guaranteed multicast tree in multi-channel multi-interface wireless mesh networks. We focus on the scenario of dynamic multicast call arrival, where each call has a specific bandwidth requirement. A call is accepted if a multicast tree with sufficient bandwidth on each link can be constructed. Intuitively, if the carried load on both the most-heavily loaded channel and the most-heavily loaded node is minimized, the traffic load in the network will be balanced. If the network load is balanced, more room will be available for accommodating future calls. This would maximize the call acceptance rate in the network. With the above notion of load balancing in mind, an Integer Linear Programming (ILP) formulation is formulated for constructing bandwidth-guaranteed tree. We show that the above problem is NP-hard, and an efficient heuristic algorithm called Largest Coverage Shortest-Path First (LC-SPF) is devised. Simulation results show that LC-SPF yields comparable call acceptance rate as the ILP formulation, but with much shorter running time.

Reducing Multicast Redundancy and Latency in Multi-Interface Multi-Channel Wireless Mesh Networks

In wireless mesh networks, each node can be equipped with multiple network interface cards tuned to different channels. In this paper, we study the problem of collision-free multicast in multi-interface multi-channel wireless mesh networks. The concept of interface redundancy is proposed as a new criterion for the multicast/broadcast redundancy in wireless mesh networks, and we prove that building a multicast/broadcast tree with the minimum interface redundancy is NP-hard. We also prove that the minimum-latency multicasting problem in multi-channel wireless mesh networks is NP-hard. We present two heuristic-based algorithms which jointly reduce the interface redundancy and the multicast latency. Since broadcast can be considered as a special case of multicast, an approximate algorithm for low-redundancy broadcast tree construction is also proposed, which has a constant approximation ratio. Finally, the simulation results prove the effectiveness of our approach.

Interface assignment and bandwidth allocation for multi-channel wireless mesh networks

With the ability of simultaneous transmissions, multi-channel multi-interface wireless mesh networks (WMNs) have emerged with great potential in the improvement of network throughput and fairness. However, most proposed channel assignment algorithms for WMNs made an assumption that the network interface cards (NICs) are evenly assigned to the mesh routers. In this paper, we investigate the problems of NIC assignment and bandwidth allocation to minimize the infrastructure cost, and meanwhile guarantee the application requirements. We argue evenly assigning NICs to all routers is neither a necessary condition nor an effective solution, since not only the interference but also the traffic flows are important factors that will affect the parallel use of the bandwidth. One of the principal challenges addressing these problems is their interactive impact on the optimization of network throughput. By analyzing all kinds of constraints for traffic, NIC and performance, we formally define a problem space that addresses the relationships between different assignment and allocation problems. Furthermore, we demonstrate that a hard NIC assignment and bandwidth allocation problem can be decomposed and formulated into a well-defined single or multiple-phase problem. In addition to the linear programming (LP) solutions, we propose novel efficient heuristics for on-line decisions for the situation whenever the network architecture changes and needs recompute the system performance in real-time. We show through extensive simulations that the heuristic algorithms can achieve close to optimal solution and outperform the equal NIC assignment method with even a smaller number of NICs.

A MAC Protocol for Multi-Channel Multi-Interface Wireless Mesh Network Using Hybrid Channel Assignment Scheme

In recent years, Wireless Mesh Network (WMN) which uses a multi-hop configuration to extend the reach of the last-mile access to Internet has come into public notice. WMN improves network performance by the use of multiple orthogonal (non-overlapping) channels and multiple wireless interfaces. However, the Medium Access Control (MAC) protocol in IEEE 802.11 standard was designed and suited for only one channel and one interface. In this paper, we present a new MAC protocol which is specially designed for multi-channel and multi-interface WMNs. The proposed MAC protocol employs a hybrid channel assignment strategy to solve the rendezvous problem and a waiting time scheme for updating network allocation vectors (NAVs) to solve the multichannel hidden terminal problem. Simulation results show that the proposed protocol can achieve a better utilization of both interfaces and channels.