An adaptive control for video transmission over bluetooth

This paper is concerned with an intelligent application of Moving Picture Expert Group (MPEG) video transmission in a Bluetooth link. MPEG Variable Bit Rate (VBR) video is data hungry and results in excessive data loss and time delay over wireless networks. In a Bluetooth channel transmission rate is unpredictable as result of interferences by channel noises or other close by wireless devices. Therefore, it is difficult to transmit MPEG VBR video in Bluetooth without data loss and/or time delay. A buffer entitled ‘traffic regulating buffer’ is introduced before the Bluetooth protocol stack to prevent excessive overflow of MPEG video data over the network. Two novel neural fuzzy schemes are presented in this paper to monitor the traffic regulating buffer input and output rates, in order to ensure the video stream conforms to the traffic conditions of Bluetooth. The computer simulation results demonstrate that the two supervised neural fuzzy schemes reduce standard deviation and data loss, when compared with a traditional MPEG VBR video transmission over Bluetooth.KeywordsVideo TransmissionInternal Model ControlGeneral Packet Radio ServiceAdaptive Neural Fuzzy Inference SystemMove Picture Expert GroupThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The error and delay performance of variable bit rate (VBR) video transmission over non-ideal channels is examined using equalization schemes. The temporal correlation features of the fading signal and the source video are modeled using finite state Markov chains. The source and training signals are multiplexed using a time slotted multiple access scheme. For slow-fading channels, the characteristic time-scale of the fade durations, the step-size parameter of the LMS equalizer training algorithm, and the number of training sequences allocated per time slot are found to jointly influence error performance. Simulation results show that the proposed channel access scheme can lead to an order of magnitude decrease in the bit error ratio if the combination of training overhead and step-size parameter are chosen judiciously with respect to the fading time-scale. In addition, the multiplexing efficiency of VBR encoded video is shown to be useful for limiting the channel access delays when the training overhead is increased.

The transmission of variable-bit rate (VBR) video over ATM is a challenge because it combines the requirement for on-time data delivery with a bursty traffic characteristic. We focus on the role of ATM endsystems in the transmission of VBR video and examine how traffic shaping in the sender reduces the burstiness of the video stream and therefore the network resource requirements, both for video encoded in real-time and stored video. Shapers based on multiple leaky buckets are popular because they are particularly simple to implement. We present basic results on their buffer requirements and provide new, tighter bounds for their output traffic, enabling efficient resource allocation as well as a significant reduction in the number of leaky buckets required. We extend the basic shaping mechanism to provide efficient shaping for stored video. Finally we compare empirically the performance of multiple leaky bucket shaping with an optimal algorithm for MPEG-1 encoded video and find under realistic conditions near-optimal performance with very few leaky buckets.

The ATM transport concept of B-ISDN allows for an efficient and flexible use of network resources for variable bit rate services with high transmission rates. One major traffic source which will make use of this capability will be video and multimedia applications. The changes in the cell rate of such sources are caused by the compression of the digitized video frames. The MPEG (ISO Moving Picture Expert Group) coding scheme is expected to be the major compression algorithm for the first ATM video applications. Thus there is a need to find source traffic descriptors of MPEG video sources which can be used efficiently for connection admission control and usage parameter control for these sources. Besides the peak cell rate, the sustainable cell rate might be used for these purposes. Both the ITU-T and the ATM Forum propose the Generic Cell Rate Algorithm (GCRA) for policing these two cell rates. In this paper we develop a novel model for the cell stream of an MPEG video coder output and present a cell loss analysis for a GCRA monitoring its sustainable cell rate. A variety of ATM link capacities and sustainable cell rate parameters are studied to show the accuracy of the analysis and to test the appropriateness of the sustainable cell rate as traffic descriptor of MPEG video sources.

In this paper, we describe MPEGTool, an X window-based tool that can be used to generate a motion picture expert group (MPEG) encoded bit stream for video sequences and to study the statistical properties of the encoded data. The tool was designed to study the characteristics of variable bit rate video sources for transmission over asynchronous transfer mode (ATM) based broadband integrated services digital network (B-ISDN). The tool, which has a window-based graphic user interface, allows a user to specify several of the MPEG parameters such as the intraframe-to-interframe ratio and the quantizer scale. The tool also includes a statistical package that allows the user to plot graphs of various statistics including bit distributions, ATM cell distributions, time se ries, autocorrelation functions and cell interarrival times.

Rate Control is an important component in a video encoder for date storage or real-time visual communication. In this paper, we will discuss the rate control in MPEG encoder for real-time video communication over Variable Bit Rate (VBR) channel. In interactive video communication, the video transmission is subject to both channel rate constraints and end-to-end delay constraints. Our goal in this paper is to modify the rate control in MPEG-2 encoder and satisfy the rate constraints, and study how to improve the video quality in the scenario of VBR transmission. Here, we employ Leaky- Bucket to describe the traffic parameters and monitor the encoder's output. Depending on the Rate-distortion models developed by us, we present a rate control algorithm to achieve almost uniform distortion both within a frame and between frames in a scene. With adaptive rate-distortion models and additional function of scene detecting, our method can robustly deal with scenes of different statistical characteristics. Comparing to MPEG2 TM5, in real time video communication, we could keep the constant buffer delay while maintain the decoded image quality stable. Furthermore, the bit allocation in our algorithm is more reasonable and controllable. Therefore, our method realized the advantages that advanced by VBR video communication, such as small end-to-end delay, consistent image quality and high channel efficiency.

In the past few years, video streaming over cellular networks has become increasingly popular due to which managing end-user Quality of Experience (QoE) has become a crucial problem. We consider the problem of variable bit rate (VBR) video streaming over heterogeneous cellular networks (HetNets). We address this problem as a joint assignment and scheduling problem and design QoE-aware greedy algorithms to solve it. The greedy assignment algorithm links users to femtocells for downloading the videos from, and the greedy scheduling algorithm fairly allocates time slots to the users assigned to a specific femtocell. Our experiments on real-world 4G LTE wireless connectivity and VBR video traces show the superior performance of our algorithm.

This paper is to introduce an application of Artificial Intelligence (AI) to Moving Picture Expert Group-4 (MPEG-4) video compression over IEEE.802.15.1 wireless communication in order to improve quality of picture. 2.4GHz Industrial, Scientific and Medical (ISM) frequency band is used for the IEEE 802.15.1 standard. Due to other wireless frequency devices sharing the same carrier, IEEE 802.15.1 can be affected by noise and interference. The noise and interference create difficulties to determine an accurate real-time transmission rate. MPEG-4 codec is an “object-oriented” compression system and demands a high bandwidth. It is therefore difficult to avoid excessive delay, image quality degradation or data loss during MPEG-4 video transmission over IEEE 802.15.1 standard. Two buffers have been implemented at the input of the IEEE 802.15.1 device and at the output respectively. These buffers are controlled by a rule based fuzzy logic controller at the input and a neural fuzzy controller at the output. These rules manipulate and supervise the flow of video over the IEEE 802.15.1 standard. The computer simulation results illustrate the comparison between a non-AI video transmission over IEEE 802.15.1 and the proposed design, confirming that the applications of intelligent technique improve the image quality and reduce the data loss.

In this paper, a practical dynamic resource allocation scheme for real-time variable bit rate (VBR) video transmission is investigated. This scheme uses time-domain adaptive linear prediction, instead of the conventional size prediction of I-, P- and B- frames, to forecast future bandwidth requirement in time. Media delivery index (MDI) is used here as QoS measurement and complementary reference for adjustment. Besides, considering that the practical multi-user application may arouse adjustment collision, an adjustment priorities classified strategy based on the user-level classifications is put forward. Last, a test-bed based on the proposed scheme is constructed and the experimental results show that the bandwidth effective utilization has increased by 20%-60% compared to a fixed service rate with QoS guaranteed and no collisions.

The Internet Engineering Task Force (IETF) has defined the integrated services model for supporting real-time services. Guaranteed service is one of these services with firm delay and bandwidth guarantees. Before setting up a guaranteed service flow, traffic parameters of the source have to be specified in terms of token bucket traffic descriptors. The source must conform to these descriptors by shaping its traffic. In this paper, we study the effects of a token bucket traffic shaper at the source on the transmission characteristics of Motion Picture Experts Group (MPEG) video streams over the guaranteed service. For different types of MPEG video sequences, the effects of the shaper parameters on the transmission performance are studied. We develop an analytical model of the traffic shaper, and also carry out numerical simulation of the transmission performance to verify the analytical model. Our study also provides a technique to analyze stored MPEG video sequences to determine the token bucket traffic descriptors that have to be specified during flow set up.

Variable Bit Rate (VBR) video traffic modeling is one of the most important challenges in setting up the communication networks. It is applicable to the efficient designing and using of the networks. There are some solutions to the problem of VBR Video traffic modeling. These solutions are divided in to two categories: statistical modeling and deterministic modeling. In this paper, we propose a new deterministic model based on the nonlinear mapping characteristic of fuzzy systems, implemented using a Generalized Regression Neural Network (GRNN). This model is tested with prediction of next 5, 10 and 20 frames of I, P and B frames of the desired movie, using 100 current frames. The model generated data is examined by the matching of autocorrelation function and histogram. This model can regenerate the ACF and histogram of video traces, in order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> in error.

Performance evaluation of transmission schemes for real-time traffic in a high-speed timed-token MAC network

In this paper, we study the optimal streaming of variable bit-rate (VBR) videos over random VBR channels. We define the main performance metric of a streaming system as the probability of un-interrupted video presentation, or jitter-free probability. Previous literature has described solutions to estimate the jitter-free probability by assuming either independence in the encoded data process or simplistic channel models. In this work, we present an novel analytical framework, which requires only the maximum channel bit rate and some statistical information of an arbitrary VBR channel, to bound the probability of jitter-free playback under the constraint of initial playback delay and receiver buffer size. Both the infinite and finite buffer cases are considered. This technique is then applied to investigate streaming over a wireless system modelled by an extended Gilbert channel with ARQ transmission control. Experimental results with MPEG-4 VBR encoded videos show that the proposed analysis provides close bounds to the actual system performance. Finally, we show that the proposed analysis provides a theoretical foundation to quantify the tradeoff between initial playback delay, receiver buffer size, and the jitter free probability for a general class of VBR video streaming over random VBR channels.

It has been shown that Variable Bit Rate (VBR) video exhibits long-range dependence characteristics. Several models have been proposed to synthesize traces whose autocorrelation match that of the video traffic traces. Given the relationship between self-similarity and long- range dependence, we investigate the application of discrete-time linear scale invariant systems provided by Zhao and Rao to modeling VBR video traffic. This formulation, called a DLSI system, was derived using a continuous dilation operator in discrete-time as a direct analog of the continuous-time linear scale-invariant system formulation of Wornell and differs from other approaches such as wavelet based construction. While simulations had shown that DLSI systems were capable of generating self- similar data such as those found in network traffic, questions regarding their long-range behavior remained. Answers to these questions are dealt in this paper. We present an alternative modeling technique to model VBR video traffic using DLSI system. The proposed model has a fractional pole-zero structure and provides a good model for long-range dependent and self-similar time series. The behavioral pattern of the fractional pole-zero filter for a range of the Hurst parameter is also shown. The time-domain characteristics of the filter are analyzed using power series approximations. Comparison of output autocorrelation function (ACF) to those of the video trace ACF is made. We conclude that some samples of video data are indeed better modeled by the LSI models than the conventional models such as Markovian and Long-range dependent models.

Streaming videos over wireless networks suffers from low video quality due to network ability limitations. The quality of the channel and the characteristics of source play the major role in transmitting video stream over mobile environments. On failure of wireless video transmission, retransmission method was employed to improve the reliability of wireless link. However, retransmission of video leads to significant impact on energy consumption and bounded average waiting time is also increased. The longer waiting time on retransmission results in buffer starvation. Therefore, it is desirable to reduce the variable bit rate of transmitted video signal and increase the stability level when buffer starvation is occurs. In order to overcome such limitation, a technique named Response based Stabilization Analysis (RSA) using Distributed Optimality Bit Rate Allocation (RSA-DOBRA) is proposed in this paper. Initially, video stream is segregated into frames of different classes (i.e., size). Each frame is transmitted based on the variable bit rate response using Optimal Quantization process. Secondly, Linear Lyapunov Functions is employed with RSA to prove the stability of different bit rates on wireless video streaming. The application of Linear Lyapunov Function maintains the stability level of bit rate on different class of frame transmission on wireless link. Finally, Distributed Optimality Bit Rate Allocation uses the time slicing procedure to reduce the bounded average waiting time. RSA performs the time slicing based on multiplexed wireless video transmission on variable bit rate to avoid buffer starvation. RSA at the final stage reduces the energy consumption by improving the reliability of wireless link. Experiment is conducted on factors such as buffered starvation rate, waiting time on video frame transmission, and energy consumption rate.