Adaptive variable bit-rate speech coder for wireless applications

In wireless communication, speech is an essential service for which low rate speech coding is a key technique. Reducing the transmission bandwith and achieving higher speech quality are primary concerns in developing new speech coding algorithms. This report develops a joint channel and source controlled adaptive variable bit-rate algorithm to achieve a high speech quality and maintain an efficient spectrum.

Adaptive variable bit-rate speech coder for wireless applications

In wireless communication, speech is an essential service for which low rate speech coding is a key technique. Reducing the transmission bandwith and achieving higher speech quality are primary concerns in developing new speech coding algorithms. This report develops a joint channel and source controlled adaptive variable bit-rate algorithm to achieve a high speech quality and maintain an efficient spectrum.

Preventing the Video Leakages from The Traffic Streaming

Video streaming takes up an increasing proportion of network traffic nowadays. Dynamic Adaptive Streaming over HTTP (DASH) becomes the defacto standard of video streaming and it is adopted by YouTube, Netflix, etc.Despite of the popularity, network traffic during video streaming shows identifiable pattern which brings threat to user privacy.In this paper, to proposea video identification method using network traffic while streaming. Though there is bitrate adaptation in DASH streaming, we observe that the video bit rate trend remains relatively stable because of the widely used Variable Bit-Rate(VBR) encoding. Accordingly, we design a robust video feature extraction method for eavesdropped video streaming traffic. Meanwhile, we design a VBR based video fingerprinting method for candidate video set which can be built using downloaded video files. Finally, to propose an efficient partial matching method for computing similarities between video fingerprints and streaming traces to derive video identities. To evaluate our attack method in different scenarios for various video content, segment lengths and quality levels. The experimental results show that the identification accuracy can reach up to 90%using only three minute continuous network traffic eavesdropping.

Introduction to inmarsat broadband global area network for mobile backbone networks

In this paper is introduced the Inmarsat Global Area Network (GAN) as backbone to mobile networks. At the end of 2005 Inmarsat launched its BGAN service as the first high speed wireless data solutions with voice available on a global basis. The service is accessed through a portable, broadband satellite transceiver with antenna easy to carry as a laptop. The BGAN network consists constellation of Geostationary Earth Orbit (GEO) I-4 and I-5 satellites with an optimized ground network, which interconnects variety of terrestrial infrastructures at local BGAN users. This system employs bandwidth efficient modulation and coding techniques, capable of supporting variable bit-rate services and QoS depending on the needs of the application. The BGAN system is satellite component of 3G IMT-2000, specially the Universal Mobile Telecommunications Service (UMTS) standards. It will provide a near-global coverage overlay for the terrestrial networks, giving users service availability beyond the reach of terrestrial IMT-2000 networks. A range of supported terminals, personal devices, portable and mobile units linked with onboard entertainment, communications systems to remote base stations for civilian and military applications and SCADA or M2M are discussed.