Zhipeng Pan

Bio: Zhipeng Pan is an academic researcher from National University of Defense Technology. The author has contributed to research in topics: Telecommunications link & Encryption. The author has an hindex of 5, co-authored 12 publications receiving 85 citations. Previous affiliations of Zhipeng Pan include University of Defence.

Uplink Spatial Modulation SCMA System

Abstract: Multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA) are two effective techniques supporting high spectral efficiency and massive connectivity, respectively. Although the combination of these two techniques, namely MIMO-SCMA, can further improve the spectral efficiency, it deteriorates the error performance and greatly increases the computational costs. In this letter, in order to enhance the error performance and reduce the receiver complexity of the uplink MIMO-SCMA system, we propose a new scheme named spatial modulation sparse code multiple access (SM-SCMA). At the receiver, a low complexity joint message passing algorithm based on the principle of the maximum a posterior probability and the simplified factor graph is proposed. Simulation results show that the SM-SCMA can achieve a better bit-error-rate performance while significantly reducing the receiver complexity compared with the conventional MIMO-SCMA.

Design and Optimization of Joint Iterative Detection and Decoding Receiver for Uplink Polar Coded SCMA System

Abstract: SCMA and polar coding are possible candidates for 5G systems In this paper, we firstly propose the joint iterative detection and decoding (JIDD) receiver for the uplink polar coded sparse code multiple access (PC-SCMA) system Then, the EXIT chart is used to investigate the performance of the JIDD receiver Additionally, we optimize the system design and polar code construction based on the EXIT chart analysis The proposed receiver integrates the factor graph of SCMA detector and polar soft-output decoder into a joint factor graph, which enables the exchange of messages between SCMA detector and polar decoder iteratively Simulation results demonstrate that the JIDD receiver has better BER performance and lower complexity than the separate scheme Specifically, when polar code length $N=256$ and code rate $R = 1/2$ , JIDD outperforms the separate scheme 48 and 6 dB over AWGN channel and Rayleigh fading channel, respectively It also shows that, under 150% system loading, the JIDD receiver only has 03 dB performance loss compared to the single user uplink PC-SCMA over AWGN channel and 06 dB performance loss over Rayleigh fading channel

Multi-Dimensional Space-Time Block Coding Aided Downlink MIMO-SCMA

Abstract: Multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA) are two key techniques supporting high spectral efficiency and massive connectivity. In this paper, we consider the downlink MIMO communication scenario where SCMA is used for multiuser access. We aim to improve the performance of the traditional single-input single-output SCMA (SISO-SCMA) by exploiting the transmit diversity of multiple antennas at the transmitter. Specifically, we propose a multi-dimensional space-time block code (MSTBC) aided downlink MIMO-SCMA and derive the design criteria of MSTBC that can achieve full diversity while keep the symbol rate same as the traditional SISO-SCMA system. In particular, the MSTBC-2 for two transmit antennas and the MSTBC-4 for four transmit antennas are designed by extending the Alamouti code and quasi-orthogonal STBC into multi-dimension. Due to the orthogonality/quasi-orthogonality of the two MSTBCs, a linear decoder is available at the receiver, which keeps the complexity of the proposed MSTBC aided MIMO-SCMA almost the same as the conventional SISO-SCMA. Furthermore, the performance of the proposed schemes is evaluated based on both Monte Carlo simulations and analytical results. Simulation results show that the proposed MSTBC aided MIMO-SCMA can significantly outperform the conventional SISO-SCMA, STBC-MIMO-OFDM, and multiplexing MIMO-SCMA schemes.

Physical Layer Encryption Algorithm Based on Polar Codes and Chaotic Sequences

Abstract: Researches on 5th generation mobile communication networks (5G) are emerging to meet the demands of rapidly developing communications applications. The reliability and security of data have become key factors of its development, and thus 5G has put forward higher requirements for new coding and encryption technologies. In this paper, a physical layer encryption algorithm based on polarization codes and chaotic sequences is proposed to improve the reliability and confidentiality of transmission. In our scheme, chaotic sequences are allocated in the frozen bits of polar codes. Therefore, error correction and encryption can be performed simultaneously. Since the frozen bits are unknown to the eavesdroppers, it is difficult for them to decode the transmitted bits without the knowledge of the chaotic sequences. To further improve the security, we propose to generate the chaotic sequences by using the channel state information. Besides, the chain effects of delayed feedback are applied to increase the decrypted complexity of the eavesdroppers in this paper. Theoretic analysis and simulation results both show that the proposed algorithms can achieve high security without any error rate performance loss.

Parameter Identification of Reed-Solomon Codes Based on Probability Statistics and Galois Field Fourier Transform

Abstract: The parameter identification of channel codes plays a significant role in the fields of adaptive modulation and coding (AMC) as well as non-cooperative communications. In this paper, an algorithm based on probability statistics and Galois field Fourier transform (PS-GFFT) is proposed to identify the parameters of the Reed–Solomon (RS) codes. A threshold obtained by the probability statistics is used to skip wrong parameters within a candidate set, while GFFT is applied to reduce the error identification probability. Meanwhile, the upper bound on correct recognition rate of RS codes has been derived and proved, which quantifies the influence of the received codewords’ length, the bit-error-rate of codewords, and the number of bits per symbol on the accuracy of parameters estimation. To the best of our knowledge, the upper bound, which is of great significance in evaluating the performance of recognition algorithms, is provided in this paper for the first time. The numerous simulation results illustrate that the proposed algorithm has better recognition performance than the existing RS codes recognition algorithms. Specifically, the correct recognition probability of the RS codes whose length is no more than 255 can be over 90% when the bit error rate of codewords is below 3 * 10−3, while the conventional algorithms have the best correct recognition probability of 10%. Furthermore, it is observed that the correct recognition rate of our proposed algorithm is close to the derived upper bound, especially for long code length, which further verifies the superiority of our proposed algorithm.

Non-Orthogonal Multiple Access (NOMA) for cellular future radio access

Abstract: Radio access technologies for cellular mobile communications are typically characterized by multiple access schemes, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and OFDMA. In the 4th generation (4G) mobile communication systems such as Long-Term Evolution (LTE) (Au et al., Uplink contention based SCMA for 5G radio access. Globecom Workshops (GC Wkshps), 2014. doi:10.1109/GLOCOMW.2014.7063547) and LTE-Advanced (Baracca et al., IEEE Trans. Commun., 2011. doi:10.1109/TCOMM.2011.121410.090252; Barry et al., Digital Communication, Kluwer, Dordrecht, 2004), standardized by the 3rd Generation Partnership Project (3GPP), orthogonal multiple access based on OFDMA or single carrier (SC)-FDMA is adopted. Orthogonal multiple access was a reasonable choice for achieving good system-level throughput performance with simple single-user detection. However, considering the trend in 5G, achieving significant gains in capacity and system throughput performance is a high priority requirement in view of the recent exponential increase in the volume of mobile traffic. In addition the proposed system should be able to support enhanced delay-sensitive high-volume services such as video streaming and cloud computing. Another high-level target of 5G is reduced cost, higher energy efficiency and robustness against emergencies.

Multidimensional Constellations for Uplink SCMA Systems—A Comparative Study

Abstract: Sparse code multiple access (SCMA) is a class of non-orthogonal multiple access (NOMA) that is proposed to support uplink machine-type communication services. In an SCMA system, designing multidimensional constellation plays an important role in the performance of the system. Since the behavior of multidimensional constellations highly depends on the type of the channel, it is crucial to employ a constellation that is suitable for a certain application. In this paper, we first highlight and review the key performance indicators (KPIs) of multidimensional constellations that should be considered in their design process for various channel scenarios. We then provide a survey on the known multidimensional constellations in the context of SCMA systems with their design criteria. The performance of some of those constellations are evaluated for uncoded, high-rate, and low-rate LTE turbo-coded SCMA systems under different channel conditions through extensive simulations. All turbo-coded comparisons are performed for bit-interleaved coded modulation, with a concatenated detection and decoding scheme. Simulation results confirm that multidimensional constellations that satisfy KPIs of a certain channel scenario outperform others. Moreover, the bit error rate performance of uncoded systems, and the performance of the coded systems are coupled to their bit-labeling. The performance of the systems also remarkably depends on the behavior of the multiuser detector at different signal-to-noise ratio regions.

Design and Optimization of Joint Iterative Detection and Decoding Receiver for Uplink Polar Coded SCMA System

Abstract: SCMA and polar coding are possible candidates for 5G systems In this paper, we firstly propose the joint iterative detection and decoding (JIDD) receiver for the uplink polar coded sparse code multiple access (PC-SCMA) system Then, the EXIT chart is used to investigate the performance of the JIDD receiver Additionally, we optimize the system design and polar code construction based on the EXIT chart analysis The proposed receiver integrates the factor graph of SCMA detector and polar soft-output decoder into a joint factor graph, which enables the exchange of messages between SCMA detector and polar decoder iteratively Simulation results demonstrate that the JIDD receiver has better BER performance and lower complexity than the separate scheme Specifically, when polar code length $N=256$ and code rate $R = 1/2$ , JIDD outperforms the separate scheme 48 and 6 dB over AWGN channel and Rayleigh fading channel, respectively It also shows that, under 150% system loading, the JIDD receiver only has 03 dB performance loss compared to the single user uplink PC-SCMA over AWGN channel and 06 dB performance loss over Rayleigh fading channel

Multi-Dimensional Space-Time Block Coding Aided Downlink MIMO-SCMA

Abstract: Multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA) are two key techniques supporting high spectral efficiency and massive connectivity. In this paper, we consider the downlink MIMO communication scenario where SCMA is used for multiuser access. We aim to improve the performance of the traditional single-input single-output SCMA (SISO-SCMA) by exploiting the transmit diversity of multiple antennas at the transmitter. Specifically, we propose a multi-dimensional space-time block code (MSTBC) aided downlink MIMO-SCMA and derive the design criteria of MSTBC that can achieve full diversity while keep the symbol rate same as the traditional SISO-SCMA system. In particular, the MSTBC-2 for two transmit antennas and the MSTBC-4 for four transmit antennas are designed by extending the Alamouti code and quasi-orthogonal STBC into multi-dimension. Due to the orthogonality/quasi-orthogonality of the two MSTBCs, a linear decoder is available at the receiver, which keeps the complexity of the proposed MSTBC aided MIMO-SCMA almost the same as the conventional SISO-SCMA. Furthermore, the performance of the proposed schemes is evaluated based on both Monte Carlo simulations and analytical results. Simulation results show that the proposed MSTBC aided MIMO-SCMA can significantly outperform the conventional SISO-SCMA, STBC-MIMO-OFDM, and multiplexing MIMO-SCMA schemes.