[Parejiya, 4(2): February, 2015] ISSN: 2277-9655 Scientific Journal Impact Factor: 3.449 (ISRA), Impact Factor: 2.114 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [346] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY TRANSFORMING NETWORK CODING WITH TCP FOR BROADCASTING STREAMING DATA IN MULTI-HOP WIRELESS LAN Ashish Parejiya * , Dr. Vinod Desai * PhD Scholer(CSS), Mewar University, Chittorgarh, INDIA Computer Science Departments, Govt. Science College, Navsari, INDIA ABSTRACT This paper focuses on using Network Coding (NC) with TCP for multi-hop wireless networks to provide fault- tolerant and timely delivery of streaming data. The paper shows that there is an inherent latency in video playback when TCP with random linear NC is employed. With the objective of reducing latency and jitter at the receiver, the paper proposes a Variable Bucket size based Network Coding (VBNC) technique that modifies the TCP congestion control to adapt to the arriving traffic and dynamic network conditions. Simulation results demonstrate that on an average the proposed algorithm reduces observed latency at playback by 80% and jitter by more than 50% over standard TCP. More importantly, a significant reduction in the initial start-up delay is observed which enhances the performance of streaming services. Keywords: Bucket size, congestion control, finite field, intra-session network coding, latency, random linear network coding, ns-3, round trip time, streaming media, video aware network coding INTRODUCTION Network coding has found many applications [1] in wireless networks, since the idea was first developed by Ahlswede, et. al [2]. Recent research has shown that due to the throughput-enhancing and error- resilient capabilities of NC in wireless networks, delay-optimized and quality media streaming delivery is achievable [3], [4], [5], and [6]. However, reliable streaming media delivery still faces challenges of low bandwidth availability, channel variations and congestion in the network [7], [8]. In order to achieve reliability, most of the streaming traffic use TCP as a transport protocol [9] which is designed to handle network congestion and varying bandwidth for wired networks [10]. On the other hand, TCP adds inherent delays in wireless networks mainly due to undesirable retransmissions [11], [12]. Seminal work on combining TCP with NC, demonstrated enhancement in the throughput by avoiding undesirable packet retransmissions both using bidirectional flows of traffic [13] and modified TCP ACKs [14]. Recent work on coded TCP [6] presented a new congestion control technique for NC that entirely replaces the current TCP stack but provides significant benefits in throughput and data completion times. However, this technique requires a complete overhaul of the current TCP stack which makes it difficult to implement on already existing networks. Fig. 1. System model depicting the video source and receiǀer’s netǁork stack; the arroǁs indicate the direction of packet flow along the stack The main contribution of this paper is the modification to the existing TCP’s packet -sending mechanism by using a variable coding block size (bucket size) NC technique. This technique is bounded by the amount of traffic available to send, transmission opportunity available from the TCP ACK feedback and the total round-trip-time obtained after receiving the TCP ACK. This paper will demonstrate using simulations that the proposed approach reduces average latency and jitter significantly, while also providing low latency at the start of a video in wireless networks. The paper is organized as follows: Section II describes our system model and assumptions. Section III presents our analysis, implementation details and results observed