19 research outputs found
Pattern Division Multiple Access with Large-scale Antenna Array
In this paper, pattern division multiple access with large-scale antenna
array (LSA-PDMA) is proposed as a novel non-orthogonal multiple access (NOMA)
scheme. In the proposed scheme, pattern is designed in both beam domain and
power domain in a joint manner. At the transmitter, pattern mapping utilizes
power allocation to improve the system sum rate and beam allocation to enhance
the access connectivity and realize the integration of LSA into multiple access
spontaneously. At the receiver, hybrid detection of spatial filter (SF) and
successive interference cancellation (SIC) is employed to separate the
superposed multiple-domain signals. Furthermore, we formulate the sum rate
maximization problem to obtain the optimal pattern mapping policy, and the
optimization problem is proved to be convex through proper mathematical
manipulations. Simulation results show that the proposed LSA-PDMA scheme
achieves significant performance gain on system sum rate compared to both the
orthogonal multiple access scheme and the power-domain NOMA scheme.Comment: 6 pages, 5 figures, this paper has been accepted by IEEE VTC
2017-Sprin
A Survey of Downlink Non-orthogonal Multiple Access for 5G Wireless Communication Networks
Accepted by ZTE CommunicationsAccepted by ZTE CommunicationsAccepted by ZTE CommunicationsAccepted by ZTE CommunicationsAccepted by ZTE CommunicationsNon-orthogonal multiple access (NOMA) has been recognized as a promising multiple access technique for the next generation cellular communication networks. In this paper, we first discuss a simple NOMA model with two users served by a single-carrier simultaneously to illustrate its basic principles. Then, a more general model with multicarrier serving an arbitrary number of users on each subcarrier is also discussed. An overview of existing works on performance analysis, resource allocation, and multiple-input multiple-output NOMA are summarized and discussed. Furthermore, we discuss the key features of NOMA and its potential research challenges
Analysis and Evaluation of Pattern Division Multiple Access Scheme Jointed With 5G Waveforms
Nonorthogonal multiple access (NOMA) techniques represent a key feature for 5G systems in order to increase multiple users' systems' capacity. In particular, we propose, for study, a pattern division multiple access (PDMA) technique, which denes a pattern matrix used for mapping the users to a group of resource elements that might be shared by multiple users. The contribution of this paper is the analysis of the performances, in terms of bit error rate (BER), of 5G candidate waveforms, such as orthogonal frequency division multiplexing (OFDM), lter bank multi-carrier (FBMC), and generalized frequency division multiplexing (GFDM), in the PDMA scheme. Regarding the detection of different users' data, the successive interference cancellation algorithm is performed at the receiver side. The simulation results, consolidated by the analytic study, exhibit that OFDM and FBMC could be used in the NOMA context, while the BER related to GFDM is very high
ΠΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΡ ΠΈΡΠ΅ΡΠ°ΡΠΈΠΎΠ½Π½ΡΡ Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² ΠΎΡΠ΅Π½ΠΊΠΈ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΠΊΠ°Π½Π°Π»Π° ΡΠ²ΡΠ·ΠΈ Π² ΡΠΈΡΡΠ΅ΠΌΠ΅ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ Π΄ΠΎΡΡΡΠΏΠ° Ρ ΡΠ°Π·ΡΠ΅ΠΆΠ΅Π½Π½ΡΠΌ ΠΊΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ
Optimization of iterative algorithms for channel state estimation in a sparse coding multiple-access system (SCMA) is performed to reduce computational costs of the receiver. It is shown that when a signal-to-noise ratio (SNR) does not exceed 10 dB, one iteration of the algorithm is sufficient, and an increase in the number of iterations does not lead to an increase in spectral efficiency. Simulation demonstrates a possibility of a reasonable choice of the total number of decoder iterations and their distribution between different stages of the channel estimation. For an uncoded system, iterative re-estimation of the channel is proposed, as well as ways to reduce computational costs during its calculation. In the coded system, at a low SNR the achieved spectral efficiency values are approximately similar to those with pilot-only channel estimation. The article provides recommendations for the placement of data symbols and pilot signals in re-source blocks to increase the system spectral efficiency.ΠΡΠΎΠ²Π΅Π΄Π΅Π½Π° ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΡ ΠΈΡΠ΅ΡΠ°ΡΠΈΠΎΠ½Π½ΡΡ
Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² ΠΎΡΠ΅Π½ΠΊΠΈ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΠΊΠ°Π½Π°Π»Π° Π² ΡΠΈΡΡΠ΅ΠΌΠ΅ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ Π΄ΠΎΡΡΡΠΏΠ° Ρ ΡΠ°Π·ΡΠ΅ΠΆΠ΅Π½Π½ΡΠΌ ΠΊΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ, Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½Π½Π°Ρ Π½Π° ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΡΡ
Π·Π°ΡΡΠ°Ρ ΠΏΡΠΈΠ΅ΠΌΠ½ΠΈΠΊΠ°. Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΈ ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΈ "ΡΠΈΠ³Π½Π°Π»/ΡΡΠΌ" (ΠΠ‘Π¨), ΠΌΠ΅Π½ΡΡΠ΅ΠΌ 10 Π΄Π, Π΄ΠΎΡΡΠ°ΡΠΎΡΠ½ΠΎ ΠΎΠ΄Π½ΠΎΠΉ ΠΈΡΠ΅ΡΠ°ΡΠΈΠΈ Π°Π»Π³ΠΎΡΠΈΡΠΌΠ°, Π° ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΠΈΡΠ»Π° ΠΈΡΠ΅ΡΠ°ΡΠΈΠΉ Π½Π΅ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΡΠΎΡΡΡ ΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΠΎΠΉ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ (Π‘Π). ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΡΠΎΠ΄Π΅ΠΌΠΎΠ½ΡΡΡΠΈΡΠΎΠ²Π°Π»ΠΎ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΎΠ±ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ Π²ΡΠ±ΠΎΡΠ° ΠΎΠ±ΡΠ΅Π³ΠΎ ΡΠΈΡΠ»Π° ΠΈΡΠ΅ΡΠ°ΡΠΈΠΉ Π΄Π΅ΠΊΠΎΠ΄Π΅ΡΠ° ΠΈ ΠΈΡ
ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ°Π·Π»ΠΈΡΠ½ΡΠΌΠΈ ΡΡΠ°ΠΏΠ°ΠΌΠΈ ΠΎΡΠ΅Π½ΠΊΠΈ ΠΊΠ°Π½Π°Π»Π°. ΠΠ»Ρ Π½Π΅ΠΊΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½Π°Ρ ΠΈΡΠ΅ΡΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΠΏΠ΅ΡΠ΅ΠΎΡΠ΅Π½ΠΊΠ° ΠΊΠ°Π½Π°Π»Π°, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠΏΠΎΡΠΎΠ±Ρ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΡΡ
Π·Π°ΡΡΠ°Ρ ΠΏΡΠΈ Π΅Π΅ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΠΈ. Π ΠΊΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΠ΅ ΠΏΡΠΈ ΠΌΠ°Π»ΠΎΠΌ ΠΠ‘Π¨ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°Π΅ΠΌΡΠ΅ Π΄Π°Π½Π½ΡΠΌ Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠΌ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ Π‘Π ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈ Π½Π΅ ΠΎΡΠ»ΠΈΡΠ°ΡΡΡΡ ΠΎΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΌΠ΅ΡΠΎΠ΄Π°, Π² ΠΊΠΎΡΠΎΡΠΎΠΌ Π΄Π»Ρ ΠΎΡΠ΅Π½ΠΊΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ ΡΠΎΠ»ΡΠΊΠΎ ΠΏΠΈΠ»ΠΎΡ-ΡΠΈΠ³Π½Π°Π»Ρ. ΠΠ°Π½Ρ ΡΠ΅ΠΊΠΎΠΌΠ΅Π½Π΄Π°ΡΠΈΠΈ ΠΏΠΎ ΡΠ°Π·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΡΠΈΠΌΠ²ΠΎΠ»ΠΎΠ² Π΄Π°Π½Π½ΡΡ
ΠΈ ΠΏΠΈΠ»ΠΎΡ-ΡΠΈΠ³Π½Π°Π»ΠΎΠ² Π² Π±Π»ΠΎΠΊΠ°Ρ
ΡΠ΅ΡΡΡΡΠΎΠ², ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡΠΈΠ΅ ΡΠ²Π΅Π»ΠΈΡΠΈΡΡ Π‘Π ΡΠΈΡΡΠ΅ΠΌΡ
Multi-user visible light communications: State-of-the-art and future directions
Visible light communications (VLC) builds upon the dual use of existing lighting infrastructure for wireless data transmission. VLC has recently gained interest as cost-effective, secure, and energy-efficient wireless access technology particularly for indoor user-dense environments. While initial studies in this area are mainly limited to single-user point-to-point links, more recent efforts have focused on multi-user VLC systems in an effort to transform VLC into a scalable and fully networked wireless technology. In this paper, we provide a comprehensive overview of multi-user VLC systems discussing the recent advances on multi-user precoding, multiple access, resource allocation, and mobility management. We further provide possible directions for future research in this emerging topic.King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia ; TΓBΔ°TAKPublisher versio
NOMA Assisted Wireless Caching: Strategies and Performance Analysis
Conventional wireless caching assumes that content can be pushed to local
caching infrastructure during off-peak hours in an error-free manner; however,
this assumption is not applicable if local caches need to be frequently updated
via wireless transmission. This paper investigates a new approach to wireless
caching for the case when cache content has to be updated during on-peak hours.
Two non-orthogonal multiple access (NOMA) assisted caching strategies are
developed, namely the push-then-deliver strategy and the push-and-deliver
strategy. In the push-then-deliver strategy, the NOMA principle is applied to
push more content files to the content servers during a short time interval
reserved for content pushing in on-peak hours and to provide more connectivity
for content delivery, compared to the conventional orthogonal multiple access
(OMA) strategy. The push-and-deliver strategy is motivated by the fact that
some users' requests cannot be accommodated locally and the base station has to
serve them directly. These events during the content delivery phase are
exploited as opportunities for content pushing, which further facilitates the
frequent update of the files cached at the content servers. It is also shown
that this strategy can be straightforwardly extended to device-to-device
caching, and various analytical results are developed to illustrate the
superiority of the proposed caching strategies compared to OMA based schemes
Research on PDMA system based on complementary sequence and low complexity detection algorithm
With the intensive deployment of mobile networks and the vigorous development of new multimedia services, video has gradually become the mainstream of cultural consumption. The contradiction between the proliferation of video data services and the scarcity of spectrum resources has brought great challenges to the current network resource allocation. Non-orthogonal multiple access (NOMA) can be used to solve this problem by signal superposition and spectrum multiplexing to improve system access capability. As a new type of joint optimization design of transmitter and receiver side, PDMA has high research value. In this paper, a framework of PDMA video transmission system based on H.264 video compression coding (HVC-PDMA) is proposed. Poly complementary sequence (PCS) spread spectrum coding is performed on the transmission codebook in order to improve the transmission accuracy. Meanwhile, a low complexity serial sphere compensated Max-log MPA (SSCM-MPA) algorithm is proposed to reduce the complexity of the multi-user detection algorithm. Simulation results show that the PCS spread spectrum can improve system throughput and peak signal-to-noise ratio (PSNR) while reducing bit error rate (BER). SSCM-MPA algorithm can greatly reduce the complexity and improve the transmission efficiency