A comparative study of wireless mesh and ad- hoc network : A Cross layer design approach Yashpal Rohilla M.Tech(C.S) Department of computer scince & application M.D. university, Rohtak-124001, haryana,india yashrohillartk@yahoo.co.in Preeti Gulia Department of computer scince & application M.D. university, Rohtak-124001, haryana,india Preetigulia81@gmail.com Abstract : Due to Wi-Fi marketing 802.11 becomes a universal solution for wireless connectivity. A wireless network is that in which the performance of a network depends on the layering structure of protocol. A wireless network is many types like Ad-hoc, cellular and mesh network. A mesh is used to optimize performance in better way as compare to traditional approach . A network can be optimized using different –2 ways. Physical and mac layer are used for implementation. Physical layer consist of communication channel like TDMA, CDMA, OFDM, MIMO-OFDM etc each layer is designed independently and contain full transparency. A comparative study shows the best way of current technology in wireless network. Many algorithm are designed for QoS (Quality of services) in the wireless network. In this paper we compare ad-hoc and mesh network to show the pros & cons and their functionality on the basis of cross layer design approach. Keywords- ad-hoc, mesh, QoS, cross layer, ofdm, Wi-Fi. INTRODUCTION In mesh network, radio within each node enables it to support multiple functions such as user access, backhaul services and scanning. Its reduction of radio size, cost and power has enabled the mesh node to be more modular. A mesh network consists of different-2 network protocol to get the suitable structure and performance of a network. The QoS that contain resources delivery between the nodes from source to destination with minimum delay a max throughput in a network. Traditional network structures are used in wired and wireless network Sanjay shakkottal [1] of layering. But in current generation network structure there is need of a new layering structure for a wireless network some researchers have been are suggested the Cross layer design for wireless network and at some places, this approach is used for better resource utilization in a network. Some channels used the OFDM techniques in wireless network for increasing the performance and spectrum utilization. An OFDM technique is that in which narrow band / multi -career or multiple subcarrier are used. Some approaches in wireless mesh network consist of different -2 routing algorithm and joint channel allocation, like other network (multihop, Ad-hoc network). According to some researchers cross layer design is implemented using theoretical and practical aspects. In practical implementation of physical and other layers are used, different-2 simulation software like: MATLAB, NS2, OPNET etc there software help in simulation of the entire network and performance optimization of channel. On the other hand these are helping in designing of Ad-hoc, mesh and different-2 network structure. RELATED WORK There are a number of approaches where wireless network and cross layer architecture is specified Ian F. akyildiz [3] has said that the cross layer architecture used in wireless mesh network to get the better performance. Wireless mesh network contain mesh router and mesh client that form multi-hop wireless network. There are two approach used in mesh network (i.e. theoretical and practical framework) for protocol design. The protocols are design with full transparency and independency of layer from each other. In theoretical framework, the problem is decompose according to the function of primal or langrage dual variable. In practical approach simulation software like opnet,matlab,ns2 etc. Cross layer design can significantly improve the network performance R. Bhatia , U. C. Kozat, M. Chiang [5-7] The Cross layer design performed in two ways Yashpal Rohilla et al. / International Journal on Computer Science and Engineering (IJCSE) ISSN : 0975-3397 Vol. 4 No. 06 June 2012 1181