Sheng-Yang Huang

Design of low peak-to-average power ratio transceiver with enhanced link quality for coded single-carrier frequency division multiple access system

A new low peak-to-average power ratio (PAPR) transceiver is proposed for the coded single-carrier frequency division multiple access (SC-FDMA) system over frequency selective fading channels. By exploiting the constant envelope of the Chu-sequence in both frequency and time domains, the parallel spreading scheme and M-ary cyclic shift mapping technique can support the coded SC-FDMA system with a low PAPR for transmission at a high data rate. Interleaved time and frequency domain orthogonal modulation can increase the frequency diversity gain through the frequency domain equaliser and the time domain despreader. Moreover, the maximum likelihood rule is designed to detect the M-ary mapping data, which can provide M-ary gain to improve system performance. Simulation results reveal that the proposed high-rate coded SC-FDMA system can provide a lower PAPR and a better bit error rate (BER) performance than the conventional interleaved SC-FDMA system.

Doubly weighted DFT-based feedback codebook design for orthogonal space-time block codes

A doubly weighted DFT-based feedback codebook design for systems using linear precoding scheme and orthogonal space-time block codes (OSTBCs) is proposed. The proposed codebook design employs a two-stage phase-amplitude weighting of the DFT codewords, which can be better to match the channel state information (CSI) than that using phase-weighting only [1]. With the same amount of feedback bits, say 10 bits (1024 possible codewords), our codebook design can not only save a lot of codeword searching operations (80 vs 1024), but also achieve a precoding performance more close to the optimal scheme with full CSI feedback. The simulation results demonstrate that the proposed scheme is superior to the existing codebook design schemes in terms of both BER performance and computational complexity.

Precoding Design with Joint Dynamic Channel Assignment and Band Selection Techniques for Downlink CoMP OFDMA Systems

Multi cell transmission can prevent the multi-cell interference by localizing the signals at different sub-band for the downlink (DL) localized orthogonal frequency division multiple access (OFDMA) systems. However, the synchronized errors, such as carrier frequency offset (CFO), will induce the challenging problems of interference due to the non-orthogonality between the subcarriers and cells. In this paper, we propose the novel precoding design with joint dynamic channel assignment and band selection techniques for DL coordinated multipoint (CoMP) OFDMA systems with CFO effect. Further, a two-stage pre-processing technique is proposed to eliminate the above interference problems and reduce the computational complexity of the cell-edge users for DL CoMP OFDMA systems. Moreover, the central unit can assign the resource dynamically to enhance the link quality. Therefore, the dynamic channel on/off assignment techniques and the dynamic band selection techniques are proposed to enhance the bit error rate (BER) performance. Simulation results confirm that the proposed precoding transceiver provides excellent BER and lower computational complexity of the cell-edge communication than the conventional block diagonalization technique.

Precoding design with joint dynamic channel assignment and band selection techniques for downlink CoMP OFDMA systems

The interference mitigation techniques are proposed to acquire better performance and reduce the receiver computational complexity for downlink (DL) coordinated multipoint (CoMP) orthogonal frequency division multiple access (OFDMA) systems. It is designed in accordance with the following procedures. First, the block diagonalization (BD) pre-processing technique is designed to cancel multicell interference (MCI). Next, the upper-triangular dirty paper coding (UDPC) is proposed to pre-cancel the inter-carrier interference due to carrier frequency offset effect. Then, one-tap frequency-domain equalizer is utilized to detect signal at receiver. Finally, to combat deep fading problem, the dynamic channel on/off assignment techniques via the maximum capacity algorithm (MCA) or minimum BER algorithm (MBA) and dynamic band selection are proposed to enhance the bit error rate (BER) performance. Simulation results confirm that the proposed precoding transceiver can provide excellent BER for the DL-CoMP OFDMA system over carrier frequency offset and multipath fading channel environment.

Low PAPR Precoding Design with Dynamic Channel Assignment for SCBT System

The single carrier block transmission (SCBT) system has become one of most popular modulation system due to its low peak to average power ratio (PAPR). In this paper, the precoding systems at the transmitter side are proposed to retain low PAPR, acquire better performance, and reduce the computation complexity at receiver side. It is designed in accordance with the following procedure. First, the upper-triangular dirty paper coding (UDPC) is proposed to pre-cancel the multiple streams interference and post one-tap time-domain equalizer for SCBT system. Next, to overcome the high PAPR problem for UDPC precoding system, Tomlinson-Harashima precoding (THP) is introduced to maintain low PAPR performance. Finally, because the UDPC-THP system will be degraded by the deep fading channel, the dynamic channel on/off assignment via the water filling algorithm is proposed to enhance bit error rate (BER) performance. Simulation results show that the proposed precoding transceiver can provide excellent BER and low PAPR performances for SCBT system over multipath fading channel.

A low-complexity precoding transceiver design for double STBC system

A precoding design for double space-time block coding (STBC) system is investigated in this paper, i.e., the joint processing of STBC and dirty paper coding (DPC) techniques. These techniques are used for avoiding dual spatial streams interference and improving the transmitter diversity. The DPC system is interference free on multi-user or multi-antenna. The STBC transceiver can provide the transmit diversity. Due to the benefits about the STBC and DPC system, we propose a new scheme called STBC-DPC system. The transceiver design involves the following procedures. First, the ordering QR decomposition of channel matrix and the maximum likelihood (ML) one-dimensional searching algorithm are proposed to acquire a reliable performance. Next, the channel on/off assignment using water filling algorithm is proposed to overcome the deep fading channel problem. Finally, the STBC-DPC system with the modulus operation to limit the transmit signal level, i.e., Tomlinson-Harashima precoding (THP) scheme, is proposed to retain low peak-to-average power ratio (PAPR) performance. Simulation results confirm that the proposed STBC-DPC/THP with water filling ML algorithm can provide the low PAPR and excellent bit error rate (BER) performances.

Partial PIC-MRC Receiver Design for Single Carrier Block Transmission System over Multipath Fading Channels

Single carrier block transmission (SCBT) system has become one of the most popular modulation systems due to its low peak-to-average power ratio (PAPR), and it is gradually considered to be used for uplink wireless communication systems. In this paper, a low complexity partial parallel interference cancellation (PIC) with maximum ratio combining (MRC) technology is proposed to use for receiver to combat the intersymbol interference (ISI) problem over multipath fading channel. With the aid of MRC scheme, the proposed partial PIC technique can effectively perform the interference cancellation and acquire the benefit of time diversity gain. Finally, the proposed system can be extended to use for multiple antenna systems to provide excellent performance. Simulation results reveal that the proposed low complexity partial PIC-MRC SIMO system can provide robust performance and outperform the conventional PIC and the iterative frequency domain decision feedback equalizer (FD-DFE) systems over multipath fading channel environment.