Adaptive Rate Control Scheme Research Articles

Adaptive Rate and Energy Harvesting Interval Control Based on Reinforcement Learning for SWIPT

In this letter, we propose a new adaptive rate and energy harvesting interval control scheme to maximize the throughout subject to the average energy constraint in the multiple-input single-output simultaneous wireless information and power transfer system. We consider the realistic scenario of time-varying fading channel. In order to maximize the throughput and simultaneously to maintain the average energy required at the receiver, we first formulate a problem of jointly optimizing the rate and energy harvesting interval based on a Markov decision process (MDP) by using a regularization parameter. However, this MDP problem is difficult to directly solve because the channel transition probabilities (i.e., the model or the environment) are challenging to estimate in the practical systems. Thus, we propose an adaptive rate and energy harvesting interval control algorithm based on the model-free reinforcement learning technique. Numerical results demonstrate that the proposed scheme significantly outperforms the conventional scheme.

Energy-Efficient Adaptive Rate Control for Streaming Media Transmission Over Cognitive Radio

In future mobile computing systems, cognitive radio (CR) emerges as a promising solution for alleviating spectrum shortage and satisfying the high bandwidth demand of multimedia streaming, while it presents tough challenges in provisioning user experience-perceived quality of service (QoS) and conserving transmission energy. In this paper, an adaptive rate control (ARC) scheme with the aid of the receive buffer is presented for energy-efficient transmission of streaming media over CR with QoS guarantee. The QoS metric, either display smoothness or transmission delay, is quantified by the state of the receive buffer. Cross-layer information is utilized to form a closed-loop feedback optimal control. A novel analytical model called event-driven discrete-time Markov control process is introduced to formulate the QoS-guaranteed energy-efficient ARC problem. Based on potential theory, a policy iteration algorithm that combines potentials estimation and stochastic approximation is proposed for finding the optimal policy online. By exploiting the system dynamics, this algorithm does not depend on any prior knowledge of channel availability or fading statistics, and it can converge to the global optimum with a low computational cost and reasonable speed. Simulation results demonstrate the effectiveness of the proposed method.

Adaptive sampling rate control for networked systems based on statistical characteristics of packet disordering

This paper investigates an adaptive sampling rate control scheme for networked control systems (NCSs) subject to packet disordering. The main objectives of the proposed scheme are (a) to avoid heavy packet disordering existing in communication networks and (b) to stabilize NCSs with packet disordering, transmission delay and packet loss. First, a novel sampling rate control algorithm based on statistical characteristics of disordering entropy is proposed; secondly, an augmented closed-loop NCS that consists of a plant, a sampler and a state-feedback controller is transformed into an uncertain and stochastic system, which facilitates the controller design. Then, a sufficient condition for stochastic stability in terms of Linear Matrix Inequalities (LMIs) is given. Moreover, an adaptive tracking controller is designed such that the sampling period tracks a desired sampling period, which represents a significant contribution. Finally, experimental results are given to illustrate the effectiveness and advantages of the proposed scheme.

Design and Evaluation of a Framework for Cooperative and Adaptive QoS Control of DSRC Network for Road Safety Applications

Dedicated short-range communications (DSRC) are a promising vehicle communication technique for collaborative road safety applications (CSA). However, road safety applications require highly reliable and timely wireless communications, which present big challenges to DSRC based vehicle networks on effective and robust quality of services (QoS) provisioning due to the random channel access method applied in the DSRC technique. In this paper we examine the QoS control problem for CSA in the DSRC based vehicle networks and presented an overview of the research work towards the QoS control problem. After an analysis of the system application requirements and the DSRC vehicle network features, we propose a framework for cooperative and adaptive QoS control, which is believed to be a key for the success of DSRC on supporting effective collaborative road safety applications. A core design in the proposed QoS control framework is that network feedback and cross-layer design are employed to collaboratively achieve targeted QoS. A design example of cooperative and adaptive rate control scheme is implemented and evaluated, with objective of illustrating the key ideas in the framework. Simulation results demonstrate the effectiveness of proposed rate control schemes in providing highly available and reliable channel for emergency safety messages.

무선 네트워크에서 스트리밍 서비스의 품질향상을 위한 Cross-layer 기반 적응적 전송률 조절 기법

무선 네트워크에서 TFRC (TCP-Friendly Rate Control)는 불안정한 채널 특성으로 인해 발생하는 손실을 모두 혼잡 손실로 인지할 뿐만 아니라, 링크 계층에서의 재전송 기법과 채널 경쟁 오버헤드로 인해 증가된 RTT(Round Trip Time)를 적용할 경우 전송 성능이 저하된다. 본 논문에서는 무선 네트워크 환경에서 스트리밍 서비스의 품질 향상을 위한 Cross-layer 기반의 적응적 전송률 조절 기법을 제안한다. 제안하는 기법은 TFRC의 전송률 향상을 위해 새로운 RTT 측정 및 패킷 손실 구별 기법을 적용하였다. 실험을 통해 제안한 기법을 적용한 TFRC의 전송 성능이 향상됨을 확인하였다. TFRC(TCP-Friendly Rate Control) has a performance degradation in wireless networks because it performs congestion control by judging all the losses occurred in wireless networks as a congestion indicator. It is also degraded by the increased Round Trip Time(RTT) due to packet retransmission and contention overhead in the link layer. In this paper, we propose an adaptive rate control scheme based on cross-layer to improve the quality of streaming services in the wireless networks. It provides new RTT estimation and loss discrimination methods to improve transmission rate of TFRC. The simulation results show that the proposed scheme can improve the performance of TFRC.

ADAPTIVE RATE CONTROL BASED ON LOSS PROBABILITY ESTIMATION CONSIDERING A CASCADE BASED MULTIFRACTAL MODEL FOR THE NETWORK TRAFFIC

In this paper, we propose an expression for estimating the byte loss probability in a single server link taking into account the multifractal properties of network traffic. Using the proposed loss probability estimation approach, we present an adaptive transmission rate control scheme for network communication servers. The proposed algorithm includes a search algorithm in order to find the rate that attains the required loss probability in a network communication link. Finally, we compare the proposed multifractal based adaptive rate allocation to a monofractal based dynamic allocation scheme present in the literature.

Adaptive Rate Control Scheme for Streaming-based Content Sharing Service

This paper presents an adaptive rate control scheme for streaming-based content sharing service. This scheme delivers multimedia contents from a user device to another device or seamlessly redirects streaming service across heterogeneous user devices. In the proposed scheme, a streaming server adjusts video quality level according to the network and client status. Our scheme is different from other rate control schemes, because the video quality at the server is decided not only based on the available bandwidth, but also based on the device characteristics and bandwidth requirement at the access network. We also propose a bandwidth estimation method to achieve more equitable bandwidth allocations among streaming flows competing for the same narrow link with different Round Trip Times (RTTs). Through the simulation, we prove that our scheme improves the network stability and the quality of streaming service by appropriately adjusting the quality of the video stream. The simulation results also demonstrate the ability of the proposed scheme in ensuring RTT-fairness while remaining throughput efficient.

Integrated scheduling of production and delivery with time windows

This paper deals with an integrated scheduling problem in which orders have been processed by a distribution centre and then delivered to retailers within time windows. We propose a nonlinear mathematical model to minimise the time required to complete producing the product, delivering it to retailers and returning to the distribution centre. The optimal schedule and vehicle routes can be determined simultaneously in the model. In addition, two kinds of genetic-algorithm-based heuristics are designed to solve the large-scale problems. The conventional genetic algorithm provides the search with a high transition probability in the beginning of the search and with a low probability toward the end of the search. The adaptive genetic algorithm provides an adaptive operation rate control scheme that changes rate based on the fitness of the parents. The experimental results have shown that the solution quality of these two algorithms is not significant but that the adaptive genetic algorithm can save more time in finding the best parameter values of the genetic algorithm.

A Mobile-aware Adaptive Rate Control Scheme for Improving the User Perceived QoS of Multimedia Streaming Services in Wireless Broadband Networks

Recently, due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services such as the mobile IPTV. In such a wireless broadband network, transmitting a continuous stream of multimedia data is difficult to achieve due to mobile stations (MSs) movement. Providing Quality of Service (QoS) for multimedia video streaming applications requires the server and/or client to be network-aware and adaptive. Therefore, in order to deploy a mobile IPTV service in wireless broadband networks, offering users efficient wireless resource utilization and seamlessly offering user perceived QoS are important issues. In this paper, we propose a new adaptive streaming scheme, called MARC (Mobile-aware Adaptive Rate Control), which adjusts the quality of bit-stream and transmission rate of video streaming based on the wireless channel status and network status. The proposed scheme can control the rate of multimedia streaming to be suitable for the wireless channel status by using awareness information of the wireless channel quality and the mobile station location. The proposed scheme can provide a seamless multimedia playback service in wireless broadband networks in addition to improving the QoS of multimedia streaming services. The proposed MARC scheme alleviates the discontinuity of multimedia playback and allocates a suitable client buffer to the wireless broadband network. The simulation results demonstrate the effectiveness of our proposed scheme.

A design for an EXIT chart based scheduling and rate control for multi-user MIMO systems

This paper proposes a scheduling and adaptive rate control scheme for multi-user multiple-input multiple-output (MIMO) systems in the uplink, designed to improve system throughput in single-carrier broadband wireless systems exploiting a frequency domain soft canceller with minimum mean square error (FD-SC/MMSE) turbo equalizer. Aiming at the reduction of computational burden involved in the scheduling and adaptive rate control while maintaining high throughput efficiency, scheduling including a stream selection is first conducted in the base station (BS) based on the expected signal to noise power ratio (SNR) under an assumption that the turbo receiver is converged. The BS then conducts a coding rate optimization for each scheduled stream to maximize the throughput efficiency. A main contribution is to reveal a mechanism that the convergence property is controlled to maximize the throughput efficiency by a prediction of the iterative behavior based on extrinsic information transfer (EXIT) trajectory which is predicted from channel transfer functions and a window control proposed in this paper. Computer simulation confirms that the achievable average system throughput can be significantly improved by the proposed scheme.

Adaptive rate control algorithm for low power video coding systems

With the recent development of third-generation communication technologies, low power video coding system (such as PDA, Handphone or system on chip) has found wide applications such as live video using a PDA and sharing it among friends, etc. However, video coding in a low power system has two major hurdles to overcome: (1) In a low power system, video coding needs to meet the rigorous constraints of the available memory and computational capacity; (2) In a low power system, the computational power allocated to video coding may vary drastically (in bursts). In this paper, a new adaptive rate control algorithm is proposed for low power video coding system. This adaptive rate control scheme takes into account the time constraint of a low power system, and its bit allocation depends not only on the available data bits, but more importantly, on the available coding time. Experimental results show that, compared to the existing rate control scheme, the new algorithm can always achieve the maximum frame rate, maximize the utilization of the available bandwidth and computing power, increase the average PSNR, and improve the subjective perceptual quality of the reconstructed video.

New rate control scheme BSased on adaptive ratelimit for 1xEV-DO reverse link traffic channels

cdma2000 UEV-130 standard has a distributed rate control scheme on a reverse link. In this paper, we propose an adaptive rate control scheme based on the control of Rate Limit, which is a maximum possible data rate in the reverse link. From numerical and simulation results, it is shown that our proposed scheme achieves significant capacity gain in reverse link compared to 1xEV-D0 rate control scheme.

A unified architecture for real-time video-coding systems

This paper presents a unified architecture for a live video over the Internet with emphasis on solving some challenging problems such as network bandwidth adaptation for rate and congestion, loss packet recovery, joint source and channel coding, and packetization. In our architecture, a time-varying bit rate for the source coding and time-varying ratios for the channel coding are simultaneously computed by a new congestion-control protocol. An adaptive rate-control scheme is then proposed to calculate quantization parameters and to determine the number of skipping frames corresponding to the bit rate. An adaptive unequal error-control scheme is also provided to protect the bitstream. Furthermore, a simple and MPEG-4 standard compatible algorithm is designed to packetize generated bitstream at the SyncLayer by using the existing resynchronization marker approach. With the proposed architecture, the coding efficiency and the robustness of the whole system are improved greatly.

Adaptive source rate control for real-time wireless video transmission

Hybrid ARQ schemes can yield much better throughput and reliability than static FEC schemes for the transmission of data over time-varying wireless channels. However these schemes result in extra delay. They adapt to the varying channel conditions by retransmitting erroneous packets, this causes variable effective data rates for current PCS networks because the channel bandwidth is constant. Hybrid ARQ schemes are currently being proposed as the error control schemes for real-time video transmission. An important issue is how to ensure low delay while taking advantage of the high throughput and reliability that these schemes provide for. In this paper we propose an adaptive source rate control (ASRC) scheme which can work together with the hybrid ARQ error control schemes to achieve efficient transmission of real-time video with low delay and high reliability. The ASRC scheme adjusts the source rate based on the channel conditions, the transport buffer occupancy and the delay constraints. It achieves good video quality by dynamically changing both the number of the forced update (intracoded) macroblocks and the quantization scale used in a frame. The number of the forced update macroblocks used in a frame is first adjusted according to the allocated source rate. This reduces the fluctuation of the quantization scale with the change in the channel conditions during encoding so that the uniformity of the video quality is improved. The simulation results show that the proposed ASRC scheme performs very well for both slow fading and fast fading channels.

Adaptive rate control scheme for very low bit rate video coding

In video coding systems, an effective rate control method is one of the most important issues for a good video quality. This paper presents an adaptive rate control scheme based on buffer fullness, quantization, and buffer utilization for very low bit rate communication lines, such as 16 kbit/s, 32 kbit/s, and so on. The strategy is implemented by the H.263, which is a video coding algorithm for narrow band telecommunication channels up to 64 kbit/s recommended by the ITU-T SG15, to show the effectiveness. The simulation result shows that the suggested rate control scheme has better SNR performance and buffer utilization of the source coder than those of linear and non-linear buffer control strategies.