Effective Rate Adaptation Research Articles

Spatial and Temporal Consistency-Aware Dynamic Adaptive Streaming for 360-Degree Videos

The 360-degree video allows users to enjoy the whole scene by interactively switching viewports. However, the huge data volume of the 360-degree video limits its remote applications via network. To provide high quality of experience ( QoE ) for remote web users, this paper presents a tile-based adaptive streaming method for 360-degree videos. First, we propose a simple yet effective rate adaptation algorithm to determine the requested bitrate for downloading the current video segment by considering the balance between the buffer length and video quality. Then, we propose to use a Gaussian model to predict the field of view at the beginning of each requested video segment. To deal with the circumstance that the view angle is switched during the display of a video segment, we propose to download all the tiles in the 360-degree video with different priorities based on a Zipf model. Finally, in order to allocate bitrates for all the tiles, a two-stage optimization algorithm is proposed to preserve the quality of tiles in FoV and guarantee the spatial and temporal smoothness. Experimental results demonstrate the effectiveness and advantage of the proposed method compared with the state-of-the-art methods. That is, our method preserves both the quality and the smoothness of tiles in FoV, thus providing the best QoE for users.

Certain investigations on effective rate adaptation in cognitive radio with channel characteristics

The role of cognitive radio is finding the unused spectrum and providing effective transmission. This has been investigated with the concept of multi-user multi-channel capability in terms of protocols in this work. The problem of lack of synchronisation among user leads to ineffective transmission among secondary users. This is much worse in the case of fading channel. So two protocol one based on multi user multi channel particle swarm optimisation-based cognitive radio (MUMC-PSO-CR) were the rate adaptation has been done with particle swarm optimisation technique and other multi user multi channel tree seed algorithm cognitive radio (MUMC-TSA-CR) were rate adaptation has been done with tree seed algorithm. MUMC-TSA-CR protocol implements a simple statistical analysis for the criteria of forwarding without congestion.

Certain investigations on effective rate adaptation in cognitive radio with channel characteristics

The role of cognitive radio is finding the unused spectrum and providing effective transmission. This has been investigated with the concept of multi-user multi-channel capability in terms of protocols in this work. The problem of lack of synchronisation among user leads to ineffective transmission among secondary users. This is much worse in the case of fading channel. So two protocol one based on multi user multi channel particle swarm optimisation-based cognitive radio (MUMC-PSO-CR) were the rate adaptation has been done with particle swarm optimisation technique and other multi user multi channel tree seed algorithm cognitive radio (MUMC-TSA-CR) were rate adaptation has been done with tree seed algorithm. MUMC-TSA-CR protocol implements a simple statistical analysis for the criteria of forwarding without congestion.

IDMA-based MAC protocol for satellite networks with consideration on channel quality.

In order to overcome the shortcomings of existing medium access control (MAC) protocols based on TDMA or CDMA in satellite networks, interleave division multiple access (IDMA) technique is introduced into satellite communication networks. Therefore, a novel wide-band IDMA MAC protocol based on channel quality is proposed in this paper, consisting of a dynamic power allocation algorithm, a rate adaptation algorithm, and a call admission control (CAC) scheme. Firstly, the power allocation algorithm combining the technique of IDMA SINR-evolution and channel quality prediction is developed to guarantee high power efficiency even in terrible channel conditions. Secondly, the effective rate adaptation algorithm, based on accurate channel information per timeslot and by the means of rate degradation, can be realized. What is more, based on channel quality prediction, the CAC scheme, combining the new power allocation algorithm, rate scheduling, and buffering strategies together, is proposed for the emerging IDMA systems, which can support a variety of traffic types, and offering quality of service (QoS) requirements corresponding to different priority levels. Simulation results show that the new wide-band IDMA MAC protocol can make accurate estimation of available resource considering the effect of multiuser detection (MUD) and QoS requirements of multimedia traffic, leading to low outage probability as well as high overall system throughput.

RAM: Rate Adaptation in Mobile Environments

Channel asymmetry and high fluctuation of channel conditions are two salient characteristics of wireless channels in mobile environments. Therefore, when using IEEE 802.11 devices in mobile environments, it is critical to have an effective rate adaptation scheme that can deal with these issues. In this paper, we propose a practical rate adaptation scheme called Rate Adaptation in Mobile environments (RAM) and implement it in the MadWifi device driver. RAM uses a receiver-based approach to handle channel asymmetry and a conservative SNR prediction algorithm to deal with high channel fluctuation. More importantly, RAM allows the receiver to convey the feedback information to the transmitter in a creative manner via ACK transmission rate variation, which does not require changes to the device firmware and hence is implementable at the device driver level. In addition, RAM adopts an effective scheme to guarantee that RAM-based and legacy IEEE 802.11 devices can interoperate with each other. The effectiveness of RAM is demonstrated via in-depth experimental evaluation in indoor static and mobile environments as well as outdoor vehicular environments.

Rate adaptation with loss diagnosis on IEEE 802.11 networks

SUMMARYRate adaptation in wireless networking aims to seek the optimal data transmission rate most appropriate for current wireless channel conditions to make full use of the channel potentials. It is important in wireless networks because (1) most of them support multiple data rates, and (2) wireless channel is unstable with fast changes on which a single rate thereby may not be proper for long. Based on a comprehensive survey of the rate adaptation for IEEE 802.1 networks in literature, this work proposes a rate adaptation scheme, dubbed effective rate adaptation (ERA), for IEEE 802.11 networks. ERA takes advantage of the fragmentation technique in IEEE 802.11 standard and utilizes the lowest rate retransmission in diagnosing frame loss cause (collision or channel degradation), diffusing collision, and promptly recovering frame losses. It also adopts an adaptive rate increase threshold concept to exploit channel potentials. Different from other rate adaptation schemes, ERA effectively addresses two challenges in rate adaptation on IEEE 802.11 networks: (1) it does not require RTS/CTS for loss diagnosis purpose; the use of RTS/CTS that are optional in IEEE standard results in inefficiency on channel utilization; (2) it promptly responds to frame failure due to channel degradation, unlike others waiting till the end of a transmission window or cycle. With extensive simulation, ERA shows its unique strength in different lossy environments, especially in collision‐prone environments. Copyright © 2011 John Wiley & Sons, Ltd.