Uplink grant‐free pattern division multiple access transmission scheme by exploiting poly complementary sequence

2021 ◽  
Author(s):  
Shufeng Li ◽  
Baoxin Su ◽  
Yao Sun ◽  
Sanshan Sun ◽  
Libiao Jin
Keyword(s):  
Multiple Access ◽  
Transmission Scheme ◽  
Complementary Sequence

A Method of Constructing Quaternary Periodic Complementary Sequence Sets for Suppression of Multiple Access Interference in CDMA Communication Systems

2014 ◽  
Vol 543-547 ◽  
pp. 2323-2328
Author(s):  
Fan Xin Zeng ◽  
Zhen Yu Zhang ◽  
Lin Jie Qian
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Multiple Access ◽  
Binary Sequence ◽  
Multiple Access Interference ◽  
New Method ◽  
Complementary Sequence ◽  
The One ◽  
Spreading Sequences

For suppressing multiple access interference (MAI) in a CDMA communication system, complementary sequence sets are employed as spreading sequences in such system. In this paper, we present a method for constructing a family of quaternary periodic complementary sequence sets, which arises from the conversion of the existing binary periodic complementary sequence sets with odd period of sub-sequences. The period of sub-sequences in the proposed sequence sets is twice as long as the one of the binary sequence sets employed, which is a drawback in the proposed method. Finally, some examples are given in order to illuminate the validity of the new method.

scholarly journals Non-Orthogonal Multiple Access in Multiuser MIMO Configurations via Code Reuse and Principal Component Analysis

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1330
Author(s):  
Panagiotis K. Gkonis ◽  
Panagiotis T. Trakadas ◽  
Lambros E. Sarakis
Keyword(s):  
Principal Component Analysis ◽  
Interference Cancellation ◽  
Correlation Matrix ◽  
Multiple Access ◽  
Multiple Input Multiple Output ◽  
Principal Component ◽  
Component Analysis ◽  
Inner Product ◽  
Transmission Scheme ◽  
Code Reuse

The goal of the study presented in this paper is to evaluate the performance of a proposed transmission scheme in multiuser multiple-input multiple-output (MIMO) configurations, via code reuse. Hence, non-orthogonal multiple access (NOMA) is performed. To this end, a correlation matrix of the received data is constructed at the transmitter, with feedback as only the primary eigenvector of the equivalent channel matrix, which is derived after principal component analysis (PCA) at the receiver. Afterwards, users experiencing improved channel quality (i.e., diagonal terms of the correlation matrix) along with reduced multiple access interference (i.e., the inner product of transmission vectors) are the potential candidates for their assigned code to be reused. As the results indicate, considering various MIMO configurations, the proposed approach can achieve almost 33% code assignment gain (CAG), when successive interference cancellation (SIC) is employed in mobile receivers. However, even in the absence of SIC, CAG is still maintained with a tolerable average bit error rate (BER) degradation.

scholarly journals Rate-Splitting Multiple Access in Cache-Aided Cloud-Radio Access Networks

2021 ◽  
Vol 2 ◽  
Author(s):  
Robert-Jeron Reifert ◽  
Alaa Alameer Ahmad ◽  
Yijie Mao ◽  
Aydin Sezgin ◽  
Bruno Clerckx
Keyword(s):  
Multiple Access ◽  
Access Networks ◽  
Mixed Integer ◽  
Transmission Scheme ◽  
Common Part ◽  
Multicast Transmission ◽  
Cloud Radio Access Networks ◽  
Radio Access Networks ◽  
Radio Access ◽  
Rate Splitting

Rate-splitting multiple access (RSMA) has been recognized as a promising physical layer strategy for 6G. Motivated by the ever-increasing popularity of cache-enabled content delivery in wireless communications, this paper proposes an innovative multigroup multicast transmission scheme based on RSMA for cache-aided cloud-radio access networks (C-RAN). Our proposed scheme not only exploits the properties of content-centric communications and local caching at the base stations (BSs) but also incorporates RSMA to better manage interference in multigroup multicast transmission with statistical channel state information (CSI) known at the central processor (CP) and the BSs. At the RSMA-enabled cloud CP, the message of each multicast group is split into a private and a common part with the former private part being decoded by all users in the respective group and the latter common part being decoded by multiple users from other multicast groups. Common message decoding is done for the purpose of mitigating the interference. In this work, we jointly optimize the clustering of BSs and the precoding with the aim of maximizing the minimum rate among all multicast groups to guarantee fairness serving all groups. The problem is a mixed-integer nonlinear stochastic program (MINLSP), which is solved by a practical algorithm we propose including a heuristic clustering algorithm for assigning a set of BSs to serve each user followed by an efficient iterative algorithm that combines the sample average approximation (SAA) and weighted minimum mean square error (WMMSE) to solve the stochastic non-convex subproblem of precoder design. Numerical results show the explicit max-min rate gain of our proposed transmission scheme compared to the state-of-the-art trivial interference processing methods. Therefore, we conclude that RSMA is a promising technique for cache-aided C-RAN.

scholarly journals Improving Physical Layer Security of Cooperative NOMA System with Wireless-Powered Full-Duplex Relaying

Information ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 279
Author(s):  
Yuan Ren ◽  
Yixuan Tan ◽  
Meruyert Makhanbet ◽  
Xuewei Zhang
Keyword(s):  
Physical Layer Security ◽  
Multiple Access ◽  
Physical Layer ◽  
Cooperative Transmission ◽  
Full Duplex ◽  
Artificial Noise ◽  
Transmission Scheme ◽  
Self Energy ◽  
Wireless Energy Harvesting ◽  
Secure Transmission

Non-orthogonal multiple access (NOMA) and wireless energy harvesting are two promising technologies for improving spectral efficiency and energy efficiency, respectively. In this paper, we study the physical layer security of a wireless-powered full-duplex (FD) relay-aided cooperative NOMA system. In particular, the source is wiretapped by an eavesdropper, and the FD relay assists the transmission from the source to a near user and a far user with self-energy recycling. To enhance the security performance of the system, we propose an artificial noise (AN)-aided cooperative transmission scheme, in which the relay emits a jamming signal to confuse the eavesdropper while receiving the signal from the source. For the proposed scheme, the ergodic secrecy sum rate (ESSR) is derived to characterize the secrecy performance and a lower bound of ESSR is obtained. Finally, numerical results verify the accuracy of the theoretical analysis of the proposed AN-aided secure transmission scheme. The superiority of the proposed scheme is also demonstrated since this scheme can achieve better secrecy performance, compared to the conventional cooperative NOMA scheme.

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