We introduce finite-precision encoding and decoding methods for energy-based direct arithmetic coding (AC), a newly coined technique that enables fixed-to-fixed invertible distribution matching (DM) in probabilistic amplitude shaping (PAS) systems and approaching the sphere shaping gain. Moreover, we introduce novel methods for determining calibration guarantees to account for computational precision loss due to the finite-precision nature of encoding and decoding, and present methods of finite-precision approximation for estimating key energy-based quantities. As we shall present, our methods enable efficient implementations with a negligible degradation due to the finite-precision computations, thus readily establishing a pragmatic approach to energy-efficient communication from a practical standpoint.

In Long Term Evolution (LTE) and New Radio (NR) systems, Reed-Muller (RM) code-based block codes have been employed to encode Uplink Control Information (UCI) with very small payload sizes. However, there is room for further improvement in the performance of these block codes. In this paper, we propose a unified block code design based on Golay code for UCI, considering codeword lengths of 20, 24, and 32 bits, which are potentially relevant for 6G systems. The block codes with a codeword length of 20 bits are initially constructed by shortening the extended Golay code (24,12) and subsequently adding parity check bits. These parity check bits are obtained through a nested exhaustive search, aiming to maximize the minimum Hamming distance and achieve the best weight distribution. We carefully select candidate generator matrices with the fewest low weights. Subsequently, we construct block codes with codeword lengths of 24 bits and 32 bits by extending the 20-bit block codes. Our proposed Golay-based block codes outperform RM-based block codes in LTE and NR systems in terms of both performance and complexity. Notably, for the case of a 24-bit codeword length, the proposed Golay-based block codes exhibit approximately 0.5 dB better performance than RM-based block codes for the majority of payload sizes.

We consider probabilistic amplitude shaping (PAS) of quadrature amplitude modulation (QAM) constellations. Our investigation stems from a consideration of practically achieving optimal shaping gain with very low complexity. In this paper we introduce two new energy-based arithmetic coding (AC) methods, respectively termed direct AC method and constellation selection AC method. Our methods allow for performing fixed-to-fixed and invertible distribution matching (DM) for PAS and are capable of approaching the sphere shaping gain, thereby offering a featured solution to energy-efficient transmission.

We consider approximation of N(n, E) and Nc(n, E), the number of sequences of ASK symbols of length n with energy equal to E and at most equal to E, respectively. These quantities are often encountered in the context of constellation shaping, such as in shell mapping. We provide implementation techniques for our approximation methods. Numerical evaluation shows that approximations based on the techniques are extremely tight even at lengths as short as 16. Our presented approximation formulas for such quantities, theoretically justified, in conjunction with the implementation techniques, establish a new directional and theoretical foundation that can be applied to applications such as probabilistic shaping.

From the perspective of the inhibition of privacy computing theory, taking user satisfaction as risk perception, this paper discusses how the readability of financial APP privacy policies inhibits user satisfaction, thus affecting enterprise performance. Firstly, this paper measures the readability of privacy policies by constructing a professional vocabulary and an improved Fog Index formula. Secondly, this paper collects 615 APP privacy policies and corresponding enterprise data and empirically analyzes the impact of the readability of financial APP privacy policies on enterprise performance. This paper enriches research in the field of financial technology and empirically finds that the readability of financial technology APP privacy policies has a negative impact on enterprise performance, while user satisfaction has a positive impact on enterprise performance. In practice, this paper provides a reference for financial technology enterprises to improve the readability of APP privacy policies to improve user satisfaction and enterprise performance.

In this paper, we consider multiple‐input multiple‐output (MIMO) multi‐tone code division multiple access (MT‐CDMA) uplink transmission over multipath fading channels. The zero‐forcing vertical Bell Laboratories layered space‐time architecture (ZF V‐BLAST) algorithm and maximum ratio combining scheme are applied at the receiver. The average bit error rate (BER) expression is derived provided that the number of receive antennas is not less than that of transmit antennas. The BER expression is verified by simulations. Numerical results show that the numbers of transmit and receive antennas have significant effects on the BER performance of the considered system. Spatial and path diversity show different capabilities to improve the BER performance. The MIMO MT‐CDMA system based on the ZF V‐BLAST algorithm is capable of achieving a better BER performance and a higher capacity than the conventional MT‐CDMA system. Copyright © 2011 John Wiley & Sons, Ltd.

In this paper, linear preceding is introduced into MIMO-CPSC system to enhance channel estimation. Thanks to the preceding, the input symbols have well-defined statistical correlations. This property is then used for blind channel estimation. By modifying and eigen-decomposing the statistical auto-correlation matrix of the frequency domain received signals, the channels are estimated subject to a matrix (with size K x K, where K is the number of transmitters) ambiguity. Several linear precodings are presented. The precodings do not change the power of a precoded block. Also, there are fast algorithms to implement the precodings and decodings. Simulations show that the method is effective and robust.

Singlecarriercyclicprefix(SCCP) modulation has been adopted as one of the physical layer air-interfaces for IEEE802.I6 standards due to its less stringent requirement onpeak-to-averagepowerratio(PAPR) than multicarrier modulation. As a single carrier transmission, however, the received SCCP blocks suffer from inter-symbol interference (ISI). Theblockiterativegeneralizeddecisionfeedbackequalizer(BI-GDFE) is an effective interference cancellation scheme which generally shows performance improvement over linear equalizers. However, in order to achieve a significant gain, the channel must contain rich multipath components, and this may not necessarily be true in many systems. In this paper, we propose to applycyclicdelaydiversity(CDD) to a SCCP system so that the possible performance improvement by using a BI-GDFE detector can be enhanced. The asymptotic performance of the proposed system is analyzed using random matrix results. We propose a scheme to determine the optimal delay parameter for CDD. Computer simulations have shown that by incorporating CDD into the transmitter and using a BI-GDFE receiver, the BER performance of the system can approach the MFB within several iterations for high SNR region.

In this letter, we propose a low complexity algorithm for extended turbo product codes by considering both the encoding and decoding aspects. For the encoding part, a new encoding scheme is presented for which the operations of looking up and fetching error patterns are no longer necessary, and thus the lookup table can be omitted. For the decoder, a new algorithm is proposed to extract the extrinsic information and reduce the redundancy. This new algorithm can reduce decoding complexity greatly and enhance the performance of the decoder. Simulation results are presented to show the effectiveness of the proposed scheme.

We address the issue of delay selection for cyclic delay diversity (CDD) for single carrier cyclic prefix (SC-CP) transmissions over correlated clustered channel and detected using the BI-GDFE. Due to the correlation among the transmit antennas, beamforming is used to generate uncorrelated virtual channels for the application of CDD using the generalized transmit MMSE method. As the BI-GDFE can exploit the frequency diversity present, judicious selection of the cyclic shifts would improve the performance of system. Delay selection is performed by finding the delays which minimizes the variance of the even order channel statistics, and using these delays will yield the best performance. Computer simulations are presented to show the effectiveness of the delay selection scheme for the considered system.

We present a downlink single carrier cyclic prefix transmission method which employs directional beamforming and artificial delay for channels with dominant cluster paths. The proposed technology robustly manages the overall delay of the transmission channel for performance gain. For channels with delays larger than the cyclic prefix, the proposed method shortens the delay for IBI-free transmission. When the cyclic prefix duration exceeds that of the channel duration, the proposed technique can lengthen the effective channel delay to possibly improve the system's performance. Computer simulations are presented to verify the efficacy of the proposed transmission technology.

In this paper, we present a soft decoding algorithm for the concatenated code as defined in the IEEE 802.16 OFDM specification. The concatenation is between a Reed-Solomon and convolutional code. We propose a low complexity soft output Viterbi algorithm for convolutional codes and Chase II decoding algorithm for Reed-Solomon codes. The simulation results of the six modes of concatenated codes found in the IEEE 802.16 technical specification are presented.

This paper addresses the problem of signal detection for a single carrier cyclic prefix (SC-CP) system. As a single carrier transmission, the received SC-CP blocks suffer from intersymbol interference (ISI). Although it is possible to deploy linear equalizers to mitigate the ISI, their performance is usually far away from the matched filter bound (MFB). The block iterative generalized decision feedback equalizer (BI-GDFE) is an effective interference cancellation scheme which generally shows performance improvements over linear equalizers. However, in order to achieve a significant gain, the channel must contain rich multipath components, and this may not necessarily be true in many systems. By applying cyclic delay diversity (CDD) to a SC-CP system, the frequency diversity of the system can be improved, and thus, the possible performance improvement by using a BI-GDFE detector is also enhanced. Computer simulations have shown that by incorporating CDD into the transmitter and using a BI-GDFE receiver, the BER performance of the system can approach the MFB within several iterations for high SNR region.

In this paper, we study the design and decoding schemes for shortened turbo product codes adopted in IEEE 802.16 standard. To design a good structure for shortened turbo product code, we compute the undetected error probability of the component codes and select the optimal generator polynomials in terms of their undetected error probability. For the decoding algorithm, we present an efficient Chase decoding algorithm for shortened turbo product codes in which the reliability factor used in Pyndiah's scheme is not needed. Thus the decoding complexity is reduced greatly by avoiding the normalization operation of the whole codeword at each iteration. Simulation results are presented to verify the performance of the proposed algorithm

In this paper, we consider the performance enhancement of signal detection for single carrier-cyclic prefix (SC-CP) transmissions over correlated multiple inputs single outputs (MISO) channels. The block-iterative generalized decision feedback equalizer (BI-GDFE) receiver is used to combat the effect of intersymbol interference (ISI). While BI-GDFE outperforms linear equalizers, the improvement could be limited if the channel does not contain a high degree of frequency-selectivity. On the other hand, direct application of cyclic delay diversity (CDD) to a highly correlated MISO channel generally cannot increase the frequency diversity significantly. In this paper, we propose combining eigen-beamforming and CDD for frequency diversity enhancement, with which the performance of the BI-GDFE is also greatly improved. Computer simulations show that the proposed system not only offers diversity improvement but also beamforming gain. It is also observed that the BER performance of the proposed system can approach its matched filter bound (MFB)

Based on orthogonal designs, space-time (ST) block codes that enable full diversity as well as a simple maximum likelihood (ML) decoding algorithm at the decoder can be constructed for more than two transmit antennas. For real constellations (such as PAM), ST block codes with transmission rate 1 can be designed from the real Hurwitz-Radon families for any number of transmit antennas. However, for complex constellations (such as M-PSK or M-PAM), ST block codes for more than two transmit antennas can only be constructed with rates less than 1. Previous attempts have been concentrated on complex orthogonal designs that provide ST block codes with full diversity and high transmission rates. In this paper, we present two rate 2/3 complex ST block codes from orthogonal designs for five and six transmit antennas, respectively.

A joint receiving scheme of RAKE combining and soft-output Viterbi equalization for low spreading factor wideband DS-CDMA systems is proposed in this paper. The equalization technique based on soft-output Viterbi algorithm (SOVA) is applied to symbol sequences after RAKE combining to effectively eliminate the multi-path interference (MPl) and inter-symbol interference (ISI) during transmission of high rate data in wideband DS-CDMA systems, which provides significant improvement over conventional RAKE receiver.

For continuous pilot CDMA system, the moving average filter is a conventional scheme for channel estimation, which can suppress the noise. To reduce the noise further, a novel channel estimation scheme that fits the output sequence of the moving average filter with least square approach is presented in this paper. The proposed scheme improves the accuracy of channel estimation and the BER performance of the coherent RAKE receiver, which is demonstrated by analysis and simulations.