Experimental QOS-based comparison of olsr and B.A.T.M.A.N. mesh routing algorithms for multimedia home networks

Abstract

Wireless Mesh Networks (WMNs) allow communication of two nodes via a multi-hop route, without the need for an infrastructure such as base stations. Routing has been a fundamental issue for this type of communication networks. In this thesis, we compare two well-known routing algorithms for WMNs, namely OLSR and B.A.T.M.A.N., in their achieved QoS for video streaming, on a real life WMN test-bed. Our test-bed consists of seven mesh access points (MAPs) placed on several rooms spread on two floors of Ozyegin University Engineering Building. We installed B.A.T.M.A.N.-Adv, a layer two implementation of B.A.T.M.A.N. routing algorithm, and OLSRd, a layer three implementation of OLSR routing algorithm, on the MAPs. We used a laptop as a video server and another laptop placed on the other corner of the building as a client. A test video is streamed from the server to the client using the said routing algorithms several times and the sample means and standard deviations of the PSNR values between compressed and received videos as well as between uncompressed and received videos are calculated. In the calculation of the PSNR values, we developed a novel method to overcome the problem of mismatched frames in the case of dropped frames. The experiments are repeated for varying levels of video compression rates, cross-traffic levels on the network, and by changing settings of the RTS/CTS handshaking mechanism. The PSNR values are reported and compared between the two routing algorithms for these different cases, and their effects are discussed.