Bit Rate Increase Research Articles

An efficient early-termination mode decision algorithm for H.264

We present a novel early-termination motion estimation scheme specifically designed for the H.264 standard. Our method takes advantage of correlation between the rate-distortion cost of the 16times16 pixel motion search and the cost of the potential best choice for the block size in order to terminate the motion search before all possible options have been checked. A pixel decimation method yields additional reduction in computational complexity. The method is suitable for supplementing various existing fast motion estimation algorithms. When supplementing the EPZS method [1] presently used in H.264, our method achieves total computational savings of 55% for almost the same picture quality, and a slight increase in bitrate.

Pre-, Post and Hybrid Dispersion Mapping Techniques for CSRZ Optical Networks with Nonlinearities

In this paper, different dispersion mapping techniques like pre-compensated, post-compensated or hybrid-compensation are compared in the presence of fiber nonlinearities in 10 and 40 Gbps carrier-suppressed return to zero (CSRZ) systems. It is observed that the hybrid-compensation is the best in dispersion mapping technique, which reduces the bit error rate (BER) produced due to the fiber nonlinearities to the more extent than that of pre- and post-compensations. By using the hybrid-compensation, the repeater length is increased almost up to double than that of pre- and post-compensations. It is also observed that with increase in the input bit rate and input power, the BER for hybrid is better as compared to other mapping techniques.

Two-bit transform based block motion estimation using second derivatives

Binary motion estimation algorithms reduce the computational complexity of motion estimation, but, sometimes generate an inaccurate motion vector. This paper proposes a novel two-bit representation, called twobit transform-second derivatives (2BT-SD) which improves the efficiency of image binarization and the accuracy of motion estimation by making use of the positive and negative second derivatives independently in the derivation of the second bit plane. The second derivatives are also used to detect flat or background regions, avoiding expensive motion vector search operations for macroblocks in these areas, and deriving the motion vectors by prediction from neighboring blocks. In applying the proposed 2BT-SD in the H.264/AVC standard, a further reduction of motion estimation complexity with a minor accuracy reduction is achieved by using 2BT-SD representation for secondary motion estimation while using the full resolution representation for the primary motion estimation. A hardware cost analysis shows that about 209 K gates of hardware logics and 2.7 K bytes of memory are reduced by 2BT-SD for motion estimation of 1280times720 size videos when compared with the full resolution motion estimation. Experiments show that the proposed 2BT-SD achieves better motion estimation accuracy than other binary motion estimations and provides faster processing time in flat or background regions with an acceptable bit-rate increase.

Adaptive Global Elimination Algorithm for Low Power Motion Estimation

Motion estimation typically consumes 50% to 70% of total power in video encode application. Optimizing the power consumption of motion estimation process is of great importance to low power video applications. Power dissipation increases with computational complexity. Reduction in motion estimation complexity is usually associated with increase in bit rate and a loss of quality. We explore a set of algorithms that reduce the complexity of motion estimation by adaptively changing the matching complexity based on macro-block features yet have only a modest cost in terms of bit rate increase and quality loss. The adaptive techniques are applied to the global elimination algorithm, which is a well known motion estimation algorithm. The global elimination algorithm uses fixed partition sizes and shapes irrespective of the nature of the macro-block. We show that by adapting the partition sizes and shapes according to the macro-block features such as variance and Hadamard coefficients, the computational complexity of global elimination algorithm can be significantly reduced with only a small increase in bit rate. We also propose a novel center-biased search order that uses early termination method designed to work with the global elimination algorithm. The adaptive match and center-biased search together result in around 57% reduction in computational complexity and 50% reduction in power dissipation compared to the original global elimination algorithm.

A joint encoder–decoder framework for supporting energy efficient audio decoding

In comparison with the relatively slow progress of battery technology, semiconductor memory has improved much more rapidly, making storage a less critical limiting factor in designing low power embedded systems such as PDAs. To exploit such technology trends, we present a novel framework, a joint encoder–decoder framework (JEDF), which allows the decoder to tradeoff energy and memory consumption without sacrificing playback quality. We employ sum-of-powers-of-two (SOPOT) technique, an approximate signal processing (ASP) technique, in an MPEG AAC decoder to reduce the computational workload. The SOPOT introduces additional ASP noise (in the decoder) on top of the quantization noise introduced in the process of lossy compression (in the encoder). The sum of these two kinds of noise may become audible when it exceeds the masking threshold. We tackle this problem from a new perspective: the proposed JEDF allows the ASP and quantization noises to be shaped jointly to match the masking threshold. In the case that the perceptual room between the masking threshold and the quantization noise is insufficient for the ASP noise, the JEDF can reduce the quantization noise level which results in an increase in bitrate. To implement the proposed scheme, we have developed two new techniques: (1) SOPOT truncation noise shaping; (2) truncation noise allocation based on a perceptual model. Experimental results show the effectiveness of our approach.

Compression Independent Reversible Encryption for Privacy in Video Surveillance

One of the main concerns of the wide use of video surveillance is the loss of individual privacy. Individuals who are not suspects need not be identified on camera recordings. Mechanisms that protect the identity while ensuring legitimate security needs are necessary. Selectively encrypting regions that reveal identity (e.g., faces or vehicle tags) are necessary to preserve individuals' right to privacy while recognizing the legitimate needs for video surveillance. The video used in surveillance applications usually needs to be transcoded or recoded for distribution and archival. Transcoding a traditionally encrypted video is not possible without decrypting the video first. This paper presents a compression algorithm independent solution that provides privacy in video surveillance applications. The proposed approach uses permutation-based encryption in the pixel domain to hide identity revealing features. The permutation-based encryption tolerates lossy compression and transcoding and allows decryption of the transcoded video at a later time. The use of permutation-based encryption makes the proposed solution independent of the compression algorithms used and robust to transcoding. The cost of providing this privacy is an increase in bitrate that depends on the percentage of blocks encrypted.

Fast Inter Mode Decision Based on RD Costs and Frequencies of Modes

The new video coding standard H.264/AVC achieves higher coding efficiency than previous standards. However, the efficiency arises at the cost of significant complexity. In this paper, an efficient intermode decision algorithm is proposed to cut down the complexity of an exhaustively full mode decision algorithm in the reference software. Statistical variables including RD (Rate Distortion) costs and frequencies of various modes, correlation of modes between current MB (Macroblock), and their spatial and temporal neighbor MBs are utilized to achieve fast mode decision in the algorithm. The proposed algorithm is composed of three primary steps: The characteristics information of video content, RD cost, and frequency of each mode, are obtained by statistics to assist the decision of the best coding mode for the MB. Because the accuracy of the statistical results will affect the succedent mode decision process, FMD (Full Mode Decision) algorithm are used to get the statistical values from several training frames. In addition, considering the above statistical variables change with video content's changes, they are updated at regular intervals. The best coding modes of current MBs and their neighbor MBs (both spatial and temporal) are highly correlated, so the coding mode of these neighbor MBs are used as an indication to that of current MBs. The difference of RD costs between MB mode (16×16, 16×8 and 8×16) and non-MB modes is used to decide the possible modes class for current MB. Furthermore, the possible modes are prioritized based on their occurring probabilities such that the highest probable mode will be tried first. During this process, the computed RD cost is checked against a content adaptive RD cost threshold to decide if the mode decision process should be terminated before trying the remaining modes in the class. In this way many unlikely coding modes are skipped, and the computational time is significantly reduced. Experimental results show that the proposed algorithm performs well on both the low motion sequences and the high motion sequences due to utilizing the sequence-dependent statistical variables as adaptive threshold to decide the best coding modes. On average, the algorithm reduces the total encoding time by 66.3% while image quality (PSNR) degradation is only 0.154dB with bitrate increase about 0.21%.

Intra-Skip in Inter-Frame Coding of H.264/AVC

In inter-frame coding of H.264/AVC standard, not only seven inter-partition modes but also intra-modes are taken into account for seeking the best coding mode so as to maintain higher encoding efficiency by sacrificing the speed of H.264/AVC encoder. Aiming at intra-skip, this paper proposes a novel mathematical model for intra-skip in inter-frame coding to alleviate the complexity of the process; the model provides remarkable performance increment by cutting down encoding time while accompanying very minor bitrate increase. The critical advantage of this proposed scheme most emphasized on is that it can optimize H.264 encoder in conjunction with any proposed fast inter- and intra-methods which are focusing on inter-partition mode decision, motion search algorithms, and fast intra-algorithms.

A Study on Intrabody Communication for Personal Healthcare Monitoring System

In this paper we propose the use of intrabody communication (IBC) for a personal health monitoring system employing inexpensive, lightweight, miniature sensor platforms. Body area networks (BANs) with physiological sensors could improve current healthcare services and at the same time significantly reduce costs to public health systems. We are primarily looking to reduce the transmission power consumption of the wireless communication links by using very low power IBC to connect the BAN sensors, a change that has also been shown to increase the durability of the sensors. There has been no specific study carried out to date on the optimal modulation scheme for such IBC. For this reason, we investigated the transmission characteristics of the human body as a conductor of signal up to 2.4 GHz by considering different transmitter power consumption and data transmission rates. We believe that an optimal modulation scheme for IBC would allow an increase of the data transmission bit rate in our personal health monitoring system model. Therefore, we evaluated the performance of two different modulation schemes, QPSK and BPSK. Our experiment is conducted with point-to-point communication between an electrocardiogram sensor located in the chest region and a central hub located on the left wrist.

Digital Video Watermarking in P-Frames With Controlled Video Bit-Rate Increase

Most video watermarking algorithms embed the watermark in I-frames, but refrain from embedding in P- and B-frames, which are highly compressed by motion compensation. However, P-frames appear more frequently in the compressed video and their watermarking capacity should be exploited, despite the fact that embedding the watermark in P-frames can increase the video bit rate significantly. This paper gives a detailed overview of a common approach for embedding the watermark in I-frames. This common approach is adopted to use P-frames for video watermarking. We show that by limiting the watermark to nonzero-quantized AC residuals in P-frames, the video bit-rate increase can be held to reasonable values. Since the nonzero-quantized AC residuals in P-frames correspond to nonflat areas that are in motion, temporal and texture masking are exploited at the same time. We also propose embedding the watermark in nonzero quantized AC residuals with spatial masking capacity in I-frames. Since the locations of the nonzero-quantized AC residuals is lost after decoding, we develop a watermark detection algorithm that does not depend on this knowledge. Our video watermark detection algorithm has controllable performance. We demonstrate the robustness of our proposed algorithm to several different attacks.

Joint partial crosstalk cancellation and modified iterative water-filling algorithm for upstream VDSL systems

Full crosstalk cancellation (FCC) techniques have been proposed to mitigate the effect of crosstalk in upstream xDSL systems. However, these are too complex for application in typical VDSL binders. Partial crosstalk cancellation (PCC) technique limits the cancellation to cross-talkers that cause severe interference to the other lines. It can be simplified to line selection, tone selection and joint line-tone selection (JLTS) techniques. In addition, much more online complexity reduction can be obtained by joint using multi-user power control and PCC algorithms. However, the joint solution suffers from very high start-up complexity that makes it impractical. In this paper first, we propose a new modified JLTS algorithm with significantly lower start-up complexity than the optimal JLTS algorithm and approximately with similar performance. Secondly, we use modified iterative water-filling (IWF) algorithm as a multi-user power control technique joined with one of existing PCC schemes while considering dynamic online complexity constraint for each user. This leads to an efficient very low start-up and online complexity joint algorithm that can achieve near the capacity rates. The bit-rate increase of the proposed joint algorithm is demonstrated by some simulation results and compared with the current proposed joint algorithms and independent solution that use flat PSDs.

Edge Block Detection and Motion Vector Information Based Fast VBSME Algorithm

Compared with previous standards, H.264/AVC adopts variable block size motion estimation (VBSME) and multiple reference frames (MRF) to improve the video quality. Full search motion estimation algorithm (FS), which calculates every search candidate in the search window for 7 block type with multiple reference frames, consumes massive computation power. Mathematical analysis reveals that the aliasing problem of subsampling algorithm comes from high frequency signal components. Moreover, high frequency signal components are also the main issues that make MRF algorithm essential. As we know, a picture being rich of texture must contain lots of high frequency signals. So based on these mathematical investigations, two fast VBSME algorithms are proposed in this paper, namely edge block detection based subsampling method and motion vector based MRF early termination algorithm. Experiments show that strong correlation exists among the motion vectors of those blocks belonging to the same macroblock. Through exploiting this feature, a dynamically adjustment of the search ranges of integer motion estimation is proposed in this paper. Combing our proposed algorithms with UMHS almost saves 96–98% Integer Motion Estimation (IME) time compared to the exhaustive search algorithm. The induced coding quality loss is less than 0.8% bitrate increase or 0.04 dB PSNR decline on average.

Analysis of Packet Loss for Compressed Video: Effect of Burst Losses and Correlation Between Error Frames

Video communication is often afflicted by various forms of losses, such as packet loss over the Internet. This paper examines the question of whether the packet loss pattern, and in particular, the burst length, is important for accurately estimating the expected mean-squared error distortion resulting from packet loss of compressed video. We focus on the challenging case of low-bit-rate video where each P-frame typically fits within a single packet. Specifically, we: 1) verify that the loss pattern does have a significant effect on the resulting distortion; 2) explain why a loss pattern, for example a burst loss, generally produces a larger distortion than an equal number of isolated losses; and 3) propose a model that accurately estimates the expected distortion by explicitly accounting for the loss pattern, inter-frame error propagation, and the correlation between error frames. The accuracy of the proposed model is validated with H.264/AVC coded video and previous frame concealment, where for most sequences the total distortion is predicted to within plusmn0.3 dB for burst loss of length two packets, as compared to prior models which underestimate the distortion by about 1.5 dB. Furthermore, as the burst length increases, our prediction is within plusmn0.7 dB, while prior models degrade and underestimate the distortion by over 3 dB. The proposed model works well for video-telephony-type of sequences with low to medium motion. We also present a simple illustrative example, of how knowledge of the effect of burst loss can be used to adapt the schedule of video streaming to provide improved performance for a burst loss channel, without requiring an increase in bit rate.

H.264/AVC 표준에서 역트리 구조를 이용하여 고속으로 화면내 모드를 결정하는 방법

The H.264/AVC standard achieves higher coding efficiency than previous video coding standards with the rate-distortion optimization (RDO) technique which selects the best coding mode and reference frame for each macroblock. As a result, the complexity of the encoder have been significantly increased. In this paper, a fast intra-mode decision algorithm is proposed to reduce the computational load of intra-mode search, which is based on the inverse tree-structure edge prediction algorithm. First, we obtained the dominant edge for each block from local edge information, then the RDO process is only performed by the mode which corresponds to dominant edge direction. Then, for the (or ) block stage, the dominant edge is calculated from its four (or ) blocks` dominant edges without additional calculation and the RDO process is also performed by the mode which is related to dominant edge direction. Experimental results show that proposed scheme can significantly improve the speed of the intra prediction with a negligible loss in the peak signal to noise ratio (PSNR) and a little increase of bits.

H.264|MPEG-4 AVC 비디오 부호화에서 움직임 벡터 정보와 16~16 및 4X4 화면 내 예측 최종 모드간 통계적 연관성을 이용한 화면 간 프레임에서의 4X4 화면 내 예측 고속화 방법

H.264|MPEG-4 AVC는 ITU-T와 ISO/IEC 공동으로 결성된 JVT (Joint Video Team)에 의해서 정의된 가장 최신의 영상 압축 표준이다. H.264|MPE6-4 AVC는 효율적 부호화를 위하여 여러 방법이 제안되었는데, 화면 간 프레임(P-frame)에서의 화면 내 예측(Intra Prediction)의 경우 매크로블록마다 후보 모드 결정 및 율-왜곡 비용 계산에 따른 부호화 시간의 급격한 증가를 초래하여 고속화 방법의 필요성이 대두되고 있다 본 논문에서는 <TEX>$16{\times}16$</TEX>과 <TEX>$4{\times}4$</TEX> 화면 내 예측 부호화 결과를 바탕으로, 두 예측 결과의 통계적 상관관계를 규정한 후, 이를 활용한 <TEX>$4{\times}4$</TEX> 화면 내 예측의 후보 모드 수를 감소시키는 방법을 제안한다. 구체적으로는 화면 간 예측(Inter Prediction) 단계에서 결정된 움직임 벡터 정보를 이용하여 현재 매크로블록의 화면 내 예측이 필요한지를 미리 판정한 후, 매 화면 내 프레임(I-frame)의 <TEX>$16{\times}16$</TEX> 화면 내 예측의 최종 후보 모드에 따른 <TEX>$4{\times}4$</TEX> 화면 내 예측의 최종 결정 모드들의 발생분포를 누적 확률 순으로 배열하여 특정 누적 확률에 도달하기까지 만의 후보 모드들만을 예측에 포함하는 참조 테이블을 부호화 과정 중에 생성한 후 동일 GOP 내에 위치하는 모든 화면 간 프레임의 화면 내 예측 시 활용하게 된다. 제안하는 방법은 H.264|MPEG-4 AVC의 참조 소프트웨어인 JM11.0을 사용하여 실험하였으며, 총 부호화 시간을 최대 51.24% 감소시킬 수 있었으며 PSNR 감소와 비트율 증가는 무시할 정도의 작은 변화만 있었다. H.264| MPEG-4 AVC is a new video codingstandard defined by JVT (Joint Video Team) which consists of ITU-T and ISO/IEC. Many techniques are adopted fur the compression efficiency: Especially, an intra prediction in an inter frame is one example but it leads to excessive amount of encoding time due to the decision of a candidate mode and a RDcost calculation. For this reason, a fast determination of the best intra prediction mode is the main issue for saving the encoding time. In this paper, by using the result of statistical relation between intra <TEX>$16{\times}16$</TEX> and <TEX>$4{\times}4$</TEX> intra predictions, the number of candidate modes for <TEX>$4{\times}4$</TEX> intra prediction is reduced. Firstly, utilizing motion vector obtained after inter prediction, prediction of a block mode for each macroblock is made. If an intra prediction is needed, the correlation table between <TEX>$16{\times}16$</TEX> and <TEX>$4{\times}4$</TEX> intra predicted modes is created using the probability during each I frame-coding process. Secondly, using this result, the candidate modes for a <TEX>$4{\times}4$</TEX> intra prediction that reaches a predefined specific probability value are only considered in the same GOP For the experiments, JM11.0, the reference software of H.264|MPEG-4 AVC is used and the experimental results show that the encoding time could be reduced by 51.24% in maximum with negligible amounts of PSNR drop and bitrate increase.

Fast intra-prediction with near pixel correlation approach for H.264/AVC system

A fast intra-prediction algorithm to determine the coding mode for 4×4 blocks is presented. The near pixel-correlation integration approach is proposed to compute the parameter for each mode along the predictive direction. The parameters that can be easily estimated with the simple computation are useful to represent the feature of block mode. On the basis of the fast algorithm, only three to four candidate modes are selected from nine reference blocks to find the best coding mode with a minimum rate–distortion (RD) cost for H.264 system coding. The complexity of intra-prediction can be reduced ∼60% compared with the exhaustive search and the processing time of full H.264 coding can be reduced ∼45% while maintaining the same video quality, but the bit-rate increases ∼2%. When compared with the recent competing algorithms, the proposed algorithm can achieve better coding efficiency with faster speed, higher quality, lower bit-rate and lower matching error in the experimental results.

영상 내용 특성과 주위 블록 모드 상관성을 이용한 H.264|AVC 화면 간 프레임에서의 화면 내 예측 부호화 결정 방법과 화면 내 예측 고속화 방법

H.264|AVC 영상 압축부호화 국제 표준은 영상의 효율적인 압축을 위하여 화면 내 프레임뿐만 아니라 화면 간 프레임에서도 다양한 블록 크기로 화면 내 예측을 수행할 수 있도록 설계되어 있다. 그러나 이는 영상 부호화 처리 시간의 급격한 증가를 초래하여 부호화기의 실시간 응용에 걸림돌이 될 수 있다. 본 논문에서는 먼저 화면 내 예측 부호화 수행 여부에 대한 조기 결정 방법과 화면 내 예측 부호화 수행 시 부호화하고자 하는 블록의 영상 내용 특성과 QP값의 변화에 따른 부호화 대상 주변 블록 모드 정보를 이용하여 만들어진 조건부 확률을 이용하여 화면 내 예측 부호화를 고속화하는 방법을 제안한다 제안된 방법은 기본적으로 화면 간 프레임 부호화에 있어서 화면 내 예측 수행 여부에 대한 조건을 결정하고, 화면 내 예측이 사용될 경우 부호화하고자 하는 블록의 내용 특성과 부호화된 주변 블록의 결정 모드를 고려하여 화면 내 예측을 고속화하는 것이다. 본 논문의 실험은 H.264|AVC의 참조 소프트웨어인 JM 11.0을 사용하여 검증하였으며, 제안된 방법을 사용하였을 경우 무시할 수 있을 정도의 PSNR 감소와 비트율 증가를 가져 왔으며, 전체 부호화 시간은 최대 41.63%가 단축되는 효과를 얻을 수 있었다. The H.264|AVC standard incorporates an intra prediction tool into inter frame coding. However, this leads to excessive amount of increase in encoding time, thus resulting in the difficulty in real-time implementation of software encoders. In this paper, we first propose an early decision on intra prediction coding and a fast intra prediction method using the characteristics of block contents and the context of neighboring block modes for the intra prediction in the inter frame coding of H.264/AVC. Basically, the proposed methods determine a skip condition on whether the <TEX>$4{\times}4$</TEX> intra prediction is to be used in the inter frame coding by considering the content characteristics of each block to be encoded and the context of its neighboring blocks. The performance of our proposed methods is compared with the Joint Model reference software version 11.0 of H.264|AVC. The experimental results show that our proposed methods allow for 41.63% reduction in the total encoding time with negligible amounts of PSNR drops and bitrate increases, compared to the original Joint Model reference software version 11.0.

공간 향상 계층에서 효율적인 화면 내 예측 모드 선택 방법

In this parer, we propose an efficient intra prediction mode decision scheme in Scalable Video Coding(SVC) which is an emerging video coding standard as an extension of H.264/MPEG-4 AVC(Advanced Video Coding). The proposed method in base on the characteristic of macroblock smoothness follows the statistical analysis of intra prediction mode in an enhancement layer and it decides a candidate intra prediction mode. We also propose an early termination scheme for Intra_BL mode decision where the RD cost value of Intra_BL is utilized. Simulation results show that the proposed method reduces 54.67% of the computation complexity of intra prediction coding, while the degradation in video quality is negligible; for low QP values, the average PSNR loss is very negligible, equivalently the bit rate increases by 0.011%. For high QP values, the average PSNR loss is less than 0.01dB, which equals to 0.249% increase in bitrate.

Modeling the Longitudinal Temperature Evolution of a Chirped Fiber Bragg Grating Submitted to Temperature Gradients

The chromatic dispersion of optical fiber is a limiting factor in the increase of optical communications transmission bitrates. Chirped Fiber Bragg Gratings submitted to temperature gradients can provide tuneable dispersion compensation, being the tuneability achieved by an appropriate control of the applied temperature gradient. In this work we propose a numerical model that describes heat transfer mechanisms along the fiber grating and its surroundings to obtain a temperature distribution along the fiber grating longitudinal axis. This model, which enables the subsequent modeling of the grating dispersion, demonstrated that the temperature distribution in a steady state is linear. The subsequent modeling of the fiber grating chromatic dispersion agreed with experimental results.

회전 위상을 파일롯과 데이터 심볼에 덧붙인 첨두대 평균 전력비 저감 기법

이 논문은 직교 주파수 다중 전송 통신 방식의 첨두대 평균 전력비를 줄이기 위하여 대역폭과 전력의 효율성을 고려하여 파일롯과 데이터 심볼에 회전 위상을 중첩한 기법에 대한 연구 논문이다. 즉 파일롯 심볼에 위상 회전 벡터를 부가하여 파일롯 심볼 사이의 데이터 심볼의 위상 회전 벡터를 파일롯 심볼의 위상 회전 벡터와 동일하게 하여 전송하는 기법이다. 이러한 방식에 따라 송신기는 부분 분할 전송 기법에 의한 첨두대 평균 전력비를 줄일 수 있고 수신기에서 위상 회전 벡터를 파일롯 심볼의 채널 추정에 의하여 원래의 데이터 심볼을 복원할 수 있다. 따라서 송신기에서는 별도의 부반송파를 첨두대 평균 전력비의 저감하는 용도로 사용하지 않음으로써 효율적인 대역폭의 운용이 가능하고 수신기에서 위상 회전 벡터에 대한 부가적인 전송에 따른 오류에 의한 비트 오율의 급격한 증가를 방지할 수 있다. 다시 말해서 대역폭과 전력 및 통신 성능을 모두 개선할 수 있는 방법이라 할 수 있다. This paper researches on the scheme superimposing the rotation phases over the pilot and data symbols in order to reduce the peak-to-average power ratio(PAPR) of the orthogonal frequency division multiplexing(OFDM) communication. The bandwidth and power efficiency are the main consideration. The phases of rotation vector are added to those of both pilot symbols and data symbols interlaying between any two pilot symbols in an OFDM block. Owing to this scheme the transmitter reduces the PAPR using the partial transmit sequences(PTS) and the receiver restores the data symbol utilizing the channel estimation of pilot symbols. Therefore, the bandwidth efficiency is accomplished by not using the further subcarriers for the reduction of PAPR and the enormous increase of bit error rate according to the receiving error of the side information, i.e. the phases of rotation vector, is prevented. In other words, both bandwidth-and power-efficiency and quality of communication performance can be improved.