Pattern smoothing compressed video transmission

A fuzzy bit allocation method, applicable to many rate control algorithms targeted for variable rate video applications, is proposed in this paper. In low-delay video communication applications, a constant short-term average bit rate is required. However, in variable bit rate applications, such as streaming and broadcast applications, a constant long-term average bit rate is sufficient and a higher short-term variation in bit rate is acceptable. A variable bit rate video can provide better visual quality and coding efficiency in comparison with a constant bit rate video. The proposed fuzzy bit allocation algorithm is employed for encoding special P frames. To take advantage of variable bit rate video, the proposed method is implemented independently of the rate control algorithm. Two fuzzy systems are used to determine the location and the quantization parameter of special P frames. The proposed method is implemented on a JM H.264/AVC video encoder. Experimental results show that it can improve the quality of compressed video while having a low degree of computational complexity.

Fuzzy logic control has been employed to improve the rate control mechanism for a MPEG2 video encoder. The data rate of compressed video is controlled by video encoders for either variable bit rate (VBR) or constant bit rate (CBR) applications. In VBR video transmission, it is considered to be more efficient to regulate the video rate by the video coder than by network management in order to avoid network congestion and maintain stable video quality. This rationale can also be applied to CBR transmission. Two fuzzy-logic-based rate control techniques are proposed which maintain the buffer occupancy within a specified range. In the proposed technique for VBR applications, a video quality measure is taken as the crucial control parameter. In CBR rate control, the video data rate or the buffer occupancy is also considered as a fuzzy logic variable. The proposed techniques are designed to control either data rate or video quality, depending on the mode of transmission, i.e. CBR or VBR for the MPEG2 encoder. The performance is compared to a typical VBR MPEG video coder with fixed quantiser step sizes for VBR and also to the CBR video coder with MPEG2 TM5 at typical channel rates. Simulation results are presented with peak signal-to-noise ratio, data rate variation and buffer occupancy as the performance measures.

Compressed digital video can be transported on ATM networks using either a constant bit rate (CBR) or a variable bit rate (VBR) network transport service. The use of VBR transport is generally considered to offer some potentially attractive advantages over more traditional CBR transport. These potential advantages include the expectation of improved reconstructed video quality, shorter end—to—end delays and improved statistical multiplexing performance. Unfortunately, most evaluations of the relative end—to—end performance of VBR versus CBR transport of digital video fail to adequately take into account the effects of lost cells in transporting multiple VBR streams which compete for limited network resources. These effects can be avoided with CBR transport using appropriate call admission control (CAC) procedures. Furthermore, these relative performance evaluations are generally not provided under comparable levels of network resource utilizations. Indeed, no methodology presendy exists for fairly assessing the relative end—to—end performance of CBR and VBR encoded video at the same level of resource utilization. In this paper, we develop and illustrate a methodology for comparing the relative performance, in terms of the corresponding end—to—end distortion, of CBR and VBR encoded digital video transport for fixed network resources and at identical multiplexing levels. The approach is an extension of a previously developed joint source—channel coding approach for VBR digital video transport on ATM networks. Our objective in this paper is to provide a common comparison framework for CBR and VBR video streams.

최근에는 UHD(Ultra High Definition) 방송과 같은 단일 채널 전송용량을 초과하는 새로운 대용량 방송 서비스들이 소개되고 있다. 이러한 대용량 방송 콘텐츠를 전송하기 위해 주로 통신 채널을 통한 데이터 전송에 사용되던 채널 결합 기술들을 적용한 솔루션들이 검토되고 있다. HFC(Hybrid Fiber Coaxial) 망에서는 양방향 데이터 전송서비스를 제공하기 위해서 적용하고 있는 DOCSIS 3.0(Data Over Cable Service Interface Specification 3.0) 규격이 상/하향 채널 결합 기술을 지원하고 있다. 주로 하향 채널을 이용한 단방향 전송 특성을 갖는 방송서비스에 이러한 채널 결합 기술을 적용하기 위해서는 DOCSIS 3.0 규격과는 다른 전송 방식에 관한 연구가 필요하다. 또한, 방송을 위해 다수의 전송 채널을 점유하는 대용량 방송 콘텐츠의 특성 상 기존과 같은 CBR(Constant Bit Rate) 전송보다는 전송 대역 효율 측면에서 유리한 VBR(Variable Bit Rate) 전송에 관한 연구필요성도 제기되고 있다. 이와 더불어 전송 지연 및 지터에 민감한 방송서비스의 특성 상 채널 결합을 위한 채널 할당 및 전송 스케줄링에 관한 연구도 필요하다. 본 논문에서는 HFC 망에서 UHD(Ultra High Definition) 방송콘텐츠와 같은 대용량 방송콘텐츠를 전송하기 위해서 채널 결합 기반의 VBR 방송콘텐츠 전송 방식을 제안하고, OPNET 기반의 전송 시뮬레이터를 개발하여 제안한 전송 방식의 성능을 평가한다. 이를 위해, HFC 망에서 대용량 방송콘텐츠를 전송하기 위한 다양한 시나리오를 정의하고, 전송 시뮬레이터를 이용하여 각 시나리오별 전송 성능을 평가한다. 개발된 시뮬레이터를 통해서 HFC 망에서 효율적으로 대용량 방송서비스를 제공하기 위해 VBR 콘텐츠 전송 및 채널 결합 기술의 필요성을 검토하고 전송 시나리오 별 전송 성능을 평가한다. 이를 통해 개발된 시뮬레이터는 향후 효율적인 대용량 방송콘텐츠 전송 기술 및 시스템 개발에 활용될 수 있을 것으로 기대된다. Massive broadcasting contents such as UHD(Ultra High Definition) TV which requires multi-channel capacity for transmission has been introduced in recent years. A transmission scheme with channel bonding has been considered for transmission of massive broadcasting contents. In HFC(Hybrid Fiber Coaxial) networks, DOCSIS 3.0(Data Over Cable Service Interface Specification 3.0) has already applied channel bonding schemes for up/downstream of data service. A method unlike DOCSIS 3.0 is required to introduce a channel bonding scheme in the broadcasting service having unidirectional transmission with a downstream. Since a massive broadcasting content requires several channels for transmission, VBR(Variable Bit Rate) transmission has been emerging for the bandwidth efficiency. In addition, research on channel allocation and resource scheduling is required to guarantee QoS(Quality of Service) for the broadcasting service based on VBR. In this paper, we propose a transmission method for mass broadcasting service in HFC network and show the UHD transmission simulator developed to evaluate the performance. In order to evaluate the performance, we define various scenarios. Using the simulator, we assess the possibility of channel bonding and VBR transmission for UHD broadcasting system to provide mass broadcasting service efficiently. The developed simulator is expected to contribute to the efficient transmission system development of mass broadcasting service.

An efficient cell scheduling algorithm is proposed for multiplexing traffic sources with variable bit rate requirement in an ATM multiplexer. Three types of traffic sources an assumed in the multiplexer, namely the constant bit rate (CBR), variable bit rate (VBR), and best-effort traffic. For VBR and CBR sources, a statistical bandwidth requirement should be claimed before they are multiplexed in the ATM outgoing link. The proposed algorithm dynamically schedules the traffic and preserves the claimed throughput in the outgoing link for each CBR or VBR source. When there is no cell arrival at the VBR or CBR sources, the proposed algorithm assigns the bandwidth to the best-effort sources. The performance of the proposed algorithm is evaluated via simulation. The result shows that the proposed method has better performance over other static multiplexing schemes such as the weighted round-robin method.

This paper considers the problem of power management and throughput maximization for energy neutral operation when using an energy harvesting sensor (EHS) to send data over a wireless link. The EHS is assumed to be able to harvest energy at a constant rate, and use a fixed part of the energy harvested in a slot for measuring the channel state. The rest of the energy harvested is available for transmission, however, it can be stored in an inefficient battery if it is not fully utilized. The key constraint that the EHS needs to satisfy is energy neutrality, i.e., the expected energy drawn from the battery should equal the expected energy deposited into the battery. In this scenario, two popular models for data transmission are contrasted: the constant bit rate (CBR) model and the variable bit rate (VBR) model. In the CBR model, it is assumed that the EHS are designed to transmit data at a constant rate (using a fixed modulation and coding scheme) but are power-controlled. In the VBR model, the EHS selects both the transmit power and the data rate of transmission in each slot based on the channel instantiation. A framework under which the system designer can optimize several parameters of the EHS that determine the average data rate performance when the channel is Rayleigh fading is developed. Using this framework, the two transmission schemes are contrasted. It is shown that, with the right choice of parameter settings, the CBR scheme can perform nearly as well as the VBR scheme at significantly lower complextiy. The usefulness and validity of the framework developed is illustrated through simulations for specific examples.

A joint rate control algorithm for variable bit rate(VBR) MPEG-compressed digital video on point-to-point permanent virtual circuit (PVC) ATM links is proposed.The algorithm controls the encoding mode of a numberof video encoders that operate either on VBR or constantbit rate (CBR) mode. The algorithm selects the encodingmode based on the buffer occupancy of a multiplexer co-located with the encoders that interfaces them to the PVClink. VBR encoding is the predominant encoding mode usedduring congestion-free periods. CBR mode is used only during congested periods. When CBR is selected, new bit ratesare jointly assigned to the encoders based on their relativeencoding complexities. The bit rate assigned to the encodersare enforced by a CBR rate control local to each encoder.The performance of the joint rate control algorithm is evaluated through simulation of a packet multiplexer, where anumber of connections are multiplexed onto a fixed-capacity channel. The performance is compared to that of multiplexing conventional CBR and open-loop VBR from the videoquality and bandwidth efficiency points of view. Simulation results show that the proposed algorithm improves performance over multiplexed conventional CBR or open-loop VBR MPEG video, without significantly increasing implementation complexity. The application of the algorithm, tovideo-on-demand over ATM is discussed.

The constant and rapid expansion of the Internet at such a high rate has caused its traffic to double every four to six months. A large portion of this traffic is known to be multimedia and real time traffic, which has strict requirements in term of bandwidth, delay, jitter, and loss rate. Recent studies showed that constant bit rate (CBR) and variable bit rate (VBR) traffic can reduce both the transmission and storage costs for real time traffic. Other studies showed that optical burst switching (OBS) appears to be a promising switching technique for building the next-generation Internet infrastructure. In this paper, the compatibility between the requirements of CBR and VBR traffic and the services provided by the OBS networks are investigated. Initial finding shows that there is a need for quality of service (QoS) mechanisms to guarantee the CBR and VBR traffic characteristics and contract over OBS networks. This paper also discusses the issue of providing QoS over OBS network. The result of the study shows that the current QoS over OBS is insufficient for meeting the CBR and VBR traffic requirements if carried over the OBS networks. Nevertheless, it can be a motivation for further research.

Scalability refers to the ability to modify the resolution and/or bit rate associated with an already compressed data source in order to satisfy requirements which could not be foreseen at the time of compression. A number of researchers have already demonstrated the feasibility of efficient scalable image and video compression. The principle focus of this paper is to describe data structures for highly scalable compressed video, which are able to support simple, generic scaling approaches for both constant bit rate and constant distortion scaling criteria. Interactive video material presents particular challenges when the data stream is to be scaled to maintain an approximately constant level of distortion, rather than just a constant bit rate. Special attention is paid, therefore, to the development of generic, robust scaling algorithms for such applications. The data structures and scaling methodologies developed are particularly appealing for the distribution of highly scalable compressed video over heterogeneous media, because they simultaneously support both variable bit rate (VBR) and constant bit rate (CBR) services with a wide range of available service qualities, using only simple, generic mechanisms for scaling. The performance of the proposed scaling methodologies is experimentally investigated using a highly scalable video compression algorithm, which is able to achieve comparable compression performance to that of the inherently nonscalable MPEG-1 compression standard.

In this paper, two combined power and rate control (CPRC) algorithms, without-priority CPRC and priority-based CPRC, are proposed for the uplink of a cellular system integrated constant bit rate (CBR) voice and variable bit rate (VBR) data transmission. The CBR users and the VBR users are treated equally when assigning power and rate by the without-priority CPRC algorithm; while the CBR users are given higher priority by the priority-based CPRC algorithm. Simulation results demonstrate that the proposed algorithms can provide better performance than SPC (selective power control) algorithm proposed by S.-L.Kim. Comparing with the without-priority CPRC, the priority-based CPRC can provide lower outage probability for CBR users and less transmission power at the cost of throughput of VBR users under heavy system load.

In this paper, we extend our previous dynamic reservation integrated services multiple access (DRISMA) protocol for the integration of constant bit rate (CBR), variable bit rate (VBR) and unspecified bit rate (UBR) traffic over wireless ATM networks. DRISMA provides CBR services by pre-assigning slots in a frame and VBR services by reserving slots on a bandwidth-on-demand basis. By using a request-mini-slot method, it also ensures that UBR traffic only utilizes the residual bandwidth of the CBR and VBR traffic. However, our previous DRISMA protocol provides isochronous services only. In this paper, we propose a novel credit-based scheme for supporting bursty VBR traffic more effectively. This paper describes the operation of the credit-based scheme and presents some simulation results to illustrate its performance.

Sparse code multiple access (SCMA) is one of the competitive non-orthogonal multiple access (NOMA) techniques for the next generation communication systems. In this paper, we put forward a simple and efficient design method named divided extended mother codebook (DEMC) to construct SCMA codebooks based on golden angle modulation (GAM) constellation points. First, we generate a vector defined by the GAM. Second, we design the extended mother codebook (<inline-formula> <tex-math notation="LaTeX">$\mathbf {EMC}$ </tex-math></inline-formula>) by introducing the power and phase dependent constraints of symbols in multi-dimension codewords. The power constraints can ensure the power of each codeword is the same which leads to the optimal peak to average power ratio (PAPR) especially for the uplink channel. Third, we divide the <inline-formula> <tex-math notation="LaTeX">$\mathbf {EMC}$ </tex-math></inline-formula> into several mother codebooks (<inline-formula> <tex-math notation="LaTeX">$\mathbf {MC}\text{s}$ </tex-math></inline-formula>) to generate the constant bit rate (CBR) or variable bit rate (VBR) SCMA codebooks. The structure of the VBR SCMA codebooks is compatible with that of CBR. The VBR codebooks and CBR codebooks use the same factor graph, therefore, the users employed the VBR codebooks can also utilize the efficient message passing algorithm (MPA) for multi-user detection. Simulations reveal that the bit error rate (BER) performance of the proposed CBR DEMC-SCMA codebooks is outstanding with low complexity. The VBR DEMC-SCMA codebooks can flexibly satisfy the different service requirements, and the BER performance of the VBR DEMC-SCMA codebooks is close to each other though their modulation orders are various. This feature shows that the users can apply for a high order codebook to get a faster information transfer rate without increasing transmission power and bandwidth.

MPEG-2, the international standard of the ISO/IEC, is a key technology for video coding and is widely used in digital television etc. Its most frequently used coding rate control is the constant bit rate (CBR) mode. CBR's bandwidth requirement is relatively low, but it needs further improvement in terms of the coding efficiency. On the other hand, the variable bit rate (VBR) mode may be able to enhance the picture quality in situations that are rich in bandwidth or in storage media such as DVD. We have already developed a one-chip MPEG-2 video encoder LSI (SuperENC) to cope with the broader range of digital image communication applications. This paper discusses a new one-pass VBR coding control algorithm based on mathematical relations among coding parameters such as quantization parameter, bit rate and decoded image distortion. Our aim is to solve the problems of conventional techniques and verify the algorithm's effectiveness through hardware implementation. A one-pass VBR control function was implemented in the chip's firmware. Not being a very complex algorithm, it is robust with respect to abrupt scene changes. The SNR gain in a TM-5-based CBR mode was 1.5 to 1.8 dB, and the bit rate reduction under the same subjective quality was 10-30 %.

In the future high speed networks, e.g., Broadband ISDN and Gigabit networks, we can expect three major types of traffic; namely, the variable bit rate data traffic, the variable bit rate video traffic, and the constant bit rate service traffic. The three types have different traffic characteristics and quality of service requirements. The variable bit rate data traffic is extremely bursty, and the connection between the source and the destination operates at its peak bandwidth, or is quiescent. The variable bit rate video traffic is not as bursty as the variable bit rate data traffic, but is more delay-sensitive, as the temporal relationship of the information is significant. The constant bit rate service traffic has a constant cell stream, and is sensitive to delay and delay variation, as the data need to be delivered timely. Its sensitivity to cell loss will depend on the application of the service.

A mixed bit rate (MBR) video coding method is presented for asynchronous transfer mode (ATM) networks which has communication compatibility between constant bit rate (CBR) video codecs and variable bit rate (VBR) codecs. In MBR video coding, essential information is encoded at a CBR by using a conventional CBR coding method such as H.261 and enhancement information is encoded at a VBR to attain constant image quality. To realize the MBR coding of video, the conventional embedded pulse code modulation (PCM) quantization is extended by applying the requantization method only to the least significant bit (LSB) of the quantizer output. In the EX-EMB PCM method, the most significant part and least significant part (MSP/LSP) separation of embedded PCM and an additional threshold for the requantizer are dynamically determined to attain a desired distortion. The MBR codec with EX-EMB PCM was evaluated by computer simulations. The simulation results showed that the proposed method was effective not only for improving video quality but also it prevented the degradations of image quality at the scene change by increasing the bit rate for the VBR channel. >