[show abstract][hide abstract] ABSTRACT: Recent years have seen significant growth in the use of IP based multimedia and streaming applications over wireless network links, which are characterized by low (or shared) capacity, appreciable delay and variable (sometimes high BER). This has motivated the development of innovative design techniques and protocols to increase the amount of bandwidth per user, improving perceived quality and using the available energy efficiently. This paper presents experimental quantitative and qualitative performance metrics using H.264 and ROHC for a multicast video streaming. The simulation results show that the proposed Cross-Layer ROHC compression outperforms IP/UDP/RTP and ROHC U-Mode strategies by offering the highest video quality and reducing both, the bandwidth usage and the average delay to start video reproduction.
Vehicular Technology Conference, 2008. VTC Spring 2008. IEEE; 06/2008
[show abstract][hide abstract] ABSTRACT: The enormous growth in the use of the IP-based multimedia and other applications has increased the need to use the available communication technologies including satellite and radio links efficiently. These wireless links generally induce high bit error rates and long delays. Moreover, the deployment of IP protocols over these links leads to significant header overhead. IP tunneling mechanisms, widely used in the network security, IPv4-to-IPv6 transition, and mobile networks also have long delay characteristics. This paper studies the behavior of one of the most commonly used Robust Header Compression (ROHC) mechanism over such long delay links and tunnels. We show the impact of long delay, high bit error rate, and packet reordering on ROHC performance. Some of the experiments have been conducted over L2TP tunnel between France and Korea. The results show that ROHC compression can be used over long delay links to reduce header overheads with certain limitations. The results presented in this paper will provide the basis for further designing header compression schemes specifically suited for links and tunnels with long delays.
Vehicular Technology Conference, 2008. VTC Spring 2008. IEEE; 06/2008
[show abstract][hide abstract] ABSTRACT: The deployment of interactive services such as instant messaging, Internet telephone calls, videoconferencing and other multimedia connections has increased the use of bandwidth. The session initiation protocol (SIP) used for these applications is text-based with long signaling messages. Using SIP in wireless networks will result in significant transmission delays because of the large message size and relatively low data rates across the radio interface. SigComp (SIP signaling compression mechanism) provides a solution to this problem by offering a robust, efficient and loss-less compression of SIP messages. SigComp requires UDVM (universal decompressor virtual machine), which provides decompression functionality and is one of the most essential parts of SigComp. UDVM gives an edge to SigComp over other compression architectures by providing a flexible choice of compression algorithms. UDVM allows the applications to choose any appropriate compression algorithm of their choice. Besides signaling overhead, there is protocol header overhead due to the use of IP protocols by multimedia applications. The robust header compression (ROHC) scheme has been developed to reduce the header overhead over wireless links. This paper discusses the collective usage and deployment of SigComp and ROHC schemes in wireless networks to reduce the signaling and the protocol header overhead, respectively. We performed experiment chat sessions on our SIP platform to analyze the overhead due to long SIP messages. We present results for the performance of SigComp compression used to compress SIP messages for different compression algorithms.
[show abstract][hide abstract] ABSTRACT: The IP tunneling mechanisms have important applications in network solutions and are widely used in numerous contexts such as security (VPN), IPv4 to IPv6 transition, and mobility support (MobileIP and NEMO). However, these tunneling mechanisms induce a large overhead resulting from adding several protocol headers in each packet. Moreover, this header overhead could be found on wireless links which have scarce resources by nature. Header compression methods are often used on connection oriented communication (e.g., UMTS networks) to reduce overhead on the wireless part. In this paper we describe our work toward a novel tunneling header compression protocol, TuCP (tunneling compression protocol), that could be used over IP tunneling mechanisms. It can compress headers of various tunneling protocols such as UDP, PPP, L2TP, GRE etc. TuCP provides a solution for the reordering problem (in tunneling) and thus it extends the usage of header compression mechanisms such as ROHC from point to point links to the IP tunnels passing over the Internet. We present the design and a preliminary implementation of TuCP. Further, we give an evaluation of header overhead reduction and compression efficiency achieved by the protocol.
[show abstract][hide abstract] ABSTRACT: The use of ROHC (robust header compression) for multimedia applications as VoIP over 3G radio links has shown a good performance in reducing the overhead of RTP encapsulation. Some efforts have been made to use ROHC over IEEE 802 links, but the solution needs to be optimized. The use of ROHC out of its operating assumptions adds some additional problems. These problems occur when the padding is used within small packets. This paper introduces an optimized solution to send ROHC packets over IEEE 802 links
Wireless and Mobile Computing, Networking and Communications, 2006. (WiMob'2006). IEEE International Conference on; 07/2006
[show abstract][hide abstract] ABSTRACT: The header compression mechanisms have been defined to work on a peer-to-peer noisy links, nevertheless the interest to integrate these schemes in multicast diffusion is increasing because this option will offer bandwidth savings. In this paper, ROHC unidirectional mode is used as a current possibility to make header compression to multicast packets. In a multicast distribution service users join the group at any time. Thus, the use of ROHC header compression will create a waiting time to start receiving the application information because all the header information is sent in a periodical time. A context recovery process (CRP) is proposed to improve ROHC multicast performance. This CRP reduces the waiting time to receive the context and may decrease the probability of context damage in a noisy link. The waiting time to receive the context is a new indicator to be considered in addition to ROHC performance indicators, when studying ROHC multicast performance. Our solution is evaluated by simulation means
Personal, Indoor and Mobile Radio Communications, 2005. PIMRC 2005. IEEE 16th International Symposium on; 10/2005
[show abstract][hide abstract] ABSTRACT: The use of ROHC (robust header compression) over low bandwidth and noisy links saves bandwidth and reduces packet loss by decreasing the probability of header corruption. Nevertheless, the packets can still be dropped if errors occur in payload. To counter this problem, the applications can use error resilient coders and in addition can use UDP-Lite protocol which allows applications to have partially damaged payload rather than discarded. Multimedia applications will benefit from the use of both ROHC and UDP-Lite. Both mechanisms reduce the number of packets dropped and improve the quality of multimedia flows. In this paper we compare and study the proposed strategies for using UDP-Lite with ROHC. Our results show significant improvements in the performance of multimedia flows
Information, Communications and Signal Processing, 2005 Fifth International Conference on; 01/2005
[show abstract][hide abstract] ABSTRACT: The use of IPv6 in the third generation of cellular networks leads to weak performance of the network systems because the IPv6 header size sent in each packet represents more than twice the payload normally used in video or audio applications. The IETF ROHC (robust header compression) working group has defined a new header compression mechanism to reduce the transmission time and increment the use of the bandwidth in networks with scarce resources. The present version of ROHC considers a static configuration of the ROHC implementation parameters and at the same time does not negotiate some of the link parameters. This paper proposes a dynamic configuration for UMTS radio networks through negotiation. Dynamic configuration enables ROHC to improve its efficiency and robustness based on radio link parameters.
Communications, 2004 IEEE International Conference on; 07/2004
[show abstract][hide abstract] ABSTRACT: The use of interactive services in a low bandwidth link leads to a weak performance because of the large size of encapsulations. The performance could be increased using a header compression algorithm. The IETF ROHC working group has defined a new header compression algorithm used in low bandwidth links with high-level errors. This paper gives a description of the proposed infrastructure for ROHC and the differences between the profile 1 and profile 2 based profiles that are used. The results are based on our IPv6 ROHC implementation.
Computer Science, 2003. ENC 2003. Proceedings of the Fourth Mexican International Conference on; 10/2003
[show abstract][hide abstract] ABSTRACT: ROHC Bormann C., et al. (2001) is the new standard for header compression proposed by the IETF (Internet engineering task force) to compress different protocol headers. ROHC needs to be configured to afford the changes in the characteristics of the UMTS radio link and to enable a better compression of the IPv6 flows. In this document we will introduce the characteristics and the behavior of ROHC. Also we study the compression parameters that are recommended as implementation dependent in the ROHC specification and we show how to configure them. This study can help to improve the efficiency and robustness of ROHC when it is used in scarce resources links, such as UMTS.
Personal, Indoor and Mobile Radio Communications, 2003. PIMRC 2003. 14th IEEE Proceedings on; 10/2003