Relay Broadcast Research Articles

Uplink-Downlink Duality Between Multiple-Access and Broadcast Channels With Compressing Relays

Uplink-downlink duality refers to the fact that under a sum-power constraint, the capacity regions of a Gaussian multiple-access channel and a Gaussian broadcast channel with Hermitian transposed channel matrices are identical. This paper generalizes this result to a cooperative cellular network, in which remote access-points are deployed as relays in serving the users under the coordination of a central processor (CP). In this model, the users and the relays are connected over noisy wireless links, while the relays and the CP are connected over noiseless but rate-limited fronthaul links. Based on a Lagrangian technique, this paper establishes a duality relationship between such a multiple-access relay channel and broadcast relay channel, under the assumption that the relays use compression-based strategies. Specifically, we show that under the same total transmit power constraint and individual fronthaul rate constraints, the achievable rate regions of the Gaussian multiple-access and broadcast relay channels are identical, when either independent compression or Wyner-Ziv and multivariate compression strategies are used. The key observations are that if the beamforming vectors at the relays are fixed, the sum-power minimization problems under the achievable rate and fronthaul constraints in both the uplink and the downlink can be transformed into either a linear programming or a semidefinite programming problem depending on the compression technique, and that the uplink and downlink problems are Lagrangian duals of each other. Moreover, the dual variables corresponding to the downlink rate constraints become the uplink powers; the dual variables corresponding to the downlink fronthaul constraints become the uplink quantization noises. This duality relationship enables an efficient algorithm for optimizing the downlink transmission and relaying strategies based on the uplink.

Traditional and Revised Importance-Performance Analysis of Viewer Perceptions Regarding Korea Baseball Organization Broadcasting

Given the expectations regarding continued improvement in sports relay broadcasting, research related to Korea Baseball Organization (KBO) relay broadcasting is necessary for it to align with the priorities of viewers. The present study aimed to investigate viewers’ perceptions of the importance and performance of various aspects of KBO relay broadcasting. In May 2021, purposive sampling was used to select 523 participants who had watched KBO broadcasts for more than one year. Participants completed an online survey administered via Google Forms. Frequency analysis, reliability analysis, descriptive statistical analysis, paired t-tests, importance–performance analysis, and revised importance–performance analysis were used to analyze the data. Ratings of importance were higher than those for performance for all sub-factors of KBO relay broadcasting. The IPA, based on the method developed by Martilla and James, yielded 12 factors in Quadrant I, one factor in Quadrant II, five factors in Quadrant III, and two factors in Quadrant IV. In contrast, the use of Vavra’s revised IPA method yielded eight factors in Quadrant I, two factors in Quadrant II, five factors in Quadrant III, and four factors in Quadrant IV. Based on the results derived using these two methods, we discuss the strategic and practical implications of identifying priorities via IPA for future improvements in KBO relay broadcasting.

Capacity Limits of Full-Duplex Cellular Network

This paper aims to characterize the capacity limits of a wireless cellular network with a full-duplex (FD) base-station (BS) and half-duplex user terminals, in which three independent messages are communicated: the uplink message $m_1$ from the uplink user to the BS, the downlink message $m_2$ from the BS to the downlink user, and the device-to-device (D2D) message $m_3$ from the uplink user to the downlink user. From an information theoretical perspective, the overall network can be viewed as a generalization of the FD relay broadcast channel with a side message transmitted from the relay to the destination. We begin with a simpler case that involves the uplink and downlink transmissions of $(m_1,m_2)$ only, and propose an achievable rate region based on a novel strategy that uses the BS as a FD relay to facilitate the interference cancellation at the downlink user. We also prove a new converse, which is strictly tighter than the cut-set bound, and characterize the capacity region of the scalar Gaussian FD network without a D2D message to within a constant gap. This paper further studies a general setup wherein $(m_1,m_2,m_3)$ are communicated simultaneously. To account for the D2D message, we incorporate Marton's broadcast coding into the previous scheme to obtain a larger achievable rate region than the existing ones in the literature. We also improve the cut-set bound by means of genie and show that by using one of the two simple rate-splitting schemes, the capacity region of the scalar Gaussian FD network with a D2D message can already be reached to within a constant gap. Finally, a generalization to the vector Gaussian channel case is discussed. Simulation results demonstrate the advantage of using the BS as relay in enhancing the throughput of the FD cellular network.

On the Capacity Regions of Degraded Relay Broadcast Channels with and without Feedback.

The four-node relay broadcast channel (RBC) is considered, in which a transmitter communicates with two receivers with the assistance of a relay node. We first investigate three types of physically degraded RBCs (PDRBCs) based on different degradation orders among the relay and the receivers’ observed signals. For the discrete memoryless (DM) case, only the capacity region of the second type of PDRBC is already known, while for the Gaussian case, only the capacity region of the first type of PDRBC is already known. In this paper, we step forward and make the following progress: (1) for the first type of DM-PDRBC, a new outer bound is established, which has the same rate expression as an existing inner bound, with only a slight difference on the input distributions; (2) for the second type of Gaussian PDRBC, the capacity region is established; (3) for the third type of PDRBC, the capacity regions are established both for DM and Gaussian cases. Besides, we also consider the RBC with relay feedback where the relay node can send the feedback signal to the transmitter. A new coding scheme based on a hybrid relay strategy and a layered Marton’s coding is proposed. It is shown that our scheme can strictly enlarge Behboodi and Piantanida’s rate region, which is tight for the second type of DM-PDRBC. Moreover, we show that capacity regions of the second and third types of PDRBCs are exactly the same as that without feedback, which means feedback cannot enlarge capacity regions for these types of RBCs.

Design and Analysis of Three-Way Relay Network Coding Schemes Based Differential Chaos Shift Keying Communication System

In this paper, a three-way relay network coding schemes based differential chaos shift keying (DCSK) communication system are investigated. Two schemes of physical layer network coding (PLNC) schemes are proposed to communicate between three users. In the first scheme, three users send their information’s using DCSK modulation in different time slots to the relay, then two encoded bits are extracted from the received bits. After that, the relay broadcast the two encoded bits to three users using DCSK modulation in different time slots. To improve the throughput, energy and spectral efficiency of scheme-1, a new model of PNC scheme is developed based on multiple access DCSK (MA-DCSK) and quadrature chaos shift keying (QCSK) systems. In the first phase, the users send their information’s via MA-DCSK, while in the second phase, the relay broadcast the two encoded bits using QCSK system. In both schemes, the BER analytics are derived and compared with the simulated results under AWGN and multipath Rayleigh fading channel. Furthermore, throughput, link bandwidth and energy efficiency are also derived and compared for two schemes.

문자 중계방송과 의미 연결망 분석을 이용한 KBL 선수들과 경기력 요소들과의 관계

문자 중계방송과 의미 연결망 분석을 이용한 KBL 선수들과 경기력 요소들과의 관계

Penalty Dual Decomposition Method for Nonsmooth Nonconvex Optimization—Part II: Applications

In Part I of this paper, we proposed and analyzed a novel algorithmic framework, termed penalty dual decomposition (PDD), for the minimization of a nonconvex nonsmooth objective function, subject to difficult coupling constraints. Part II of this paper is devoted to evaluation of the proposed methods in the following three timely applications, ranging from communication networks to data analytics: i) the max-min rate fair multicast beamforming problem; ii) the sum-rate maximization problem in multi-antenna relay broadcast networks; and iii) the volume-min based structured matrix factorization problem. By exploiting the structure of the aforementioned problems, we show that effective algorithms for all these problems can be devised under the PDD framework. Unlike the state-of-the-art algorithms, the PDD-based algorithms are proven to achieve convergence to stationary solutions of the aforementioned nonconvex problems. Numerical results validate the efficacy of the proposed schemes.

Routing Methodology for Secure Transmission of data in Physical Layer

The difficulties of privacy and security in WANETs have taken on a step by step more vital responsibility as those networks persist to increase their role globally. Historically, physical layer is regarded as biased function addressed below the security, and all broadly used cryptographic protocols like Rivest-Shamir–adlemen, Advanced encryption standard and Data Encryption standard are developed and applied assuming an error-free physical layer already exists . Contrasting the traditional cryptography hwhich neglects distinction among the communication channels, the current physical layer safety accomplish data protection using well designing channel code consistent with the channel capacities assuming that the authentic data can never be recovered. The standard system protection makes use of encryption and deciphering activities inside the application layer. Under any circumstances, this won't just construct the computational overhead of system. There's no actual way to avoid eavesdropper listening in and assault from the physical layer. Addressing this problem, this paper proposes a basic system model in which the cooperative relay broadcast channel with the user cooperation is introduced and the overall performance metrics based on the physical layer safety can viably enhance the system protection limit.

아프리카TV 프로야구 편파중계 방송에서 나오는 선수 등장곡이 시청자의 태도에 미치는 영향

아프리카TV 프로야구 편파중계 방송에서 나오는 선수 등장곡이 시청자의 태도에 미치는 영향

아프리카TV 프로야구 편파 중계방송 시청동기와 시청만족 관계 분석 : BJ 친밀성을 매개변인으로

프로야구는 인기가 높은 관람 스포츠로 야구장은 직장인들의 스트레스 해소와 주말 가족 나들이 장소가 되었다. 그러나 야구장을 찾아가는 시간적, 공간적 제약으로 많은 사람들은 TV로 야구 중계방송 시청을 통해 관람 요구를 충족하고 있는데, 이러한 프로야구 중계방송은 오랜 기간 지상파와 유료방송사의 핵심경쟁력 중 하나로 인식되었다. 또한 기술의 발달과 1인 방송과 새로운 플랫폼의 등장은 프로야구를 시청하는 시청 형태의 변화도 가지고 왔다. 기존 프로야구 중계방송을 TV와 인터넷에서 전문 아나운서와 해설가의 방송이 있음에도 불구하고 BJ가 진행하고 양팀 모두 공정하게 중계하는 방송이 아닌 BJ가 선호하는 팀에 편파적으로 방송하는 프로야구 편파중계방송을 시청하는 시청자의 수요가 증가하고 있다.BR 이러한 상황에서 본 연구는 아프리카TV 프로야구 편파 중계방송 시청 동기가 무엇이며, 시청동기와 시청 만족과 영향 관계에 있어 BJ의 친밀성이 어떤 매개 역할을 할 것인가를 알아보고자 한다. 이를 위해 2018년 9월 13일부터 19일까지 7일간 온라인 설문을 실시하였으며 회수된 설문지 185부 중, 불성실한 응답을 한 11부를 제외한 총 174부를 최종 결과 분석에 사용하였다. 분석 결과 첫째, 아프리카TV 프로야구 편파 중계방송 시청 동기 요인은 ‘사회교류추구’, ‘오락추구’, ‘정보추구’ 요인으로 나타났다. 둘째, 아프리카TV 프로야구 편파 중계방송 시청동기 요인이 시청만족에 미치는 영향 결과 ‘사회교류추구’, ‘오락추구’, ‘정보추구’ 요인 모두 시청만족에 정(+)의 영향력을 갖는 것으로 확인되었으며, ‘오락추구’ 요인이 변수들 중에서 가장 높은 영향력을 보였다. 셋째, 아프리카TV 프로야구 편파 중계방송 시청동기 요인이 BJ친밀성에 미치는 영향 결과 ‘사회교류추구’과 ‘정보추구’ 요인은 BJ친밀성에 정(+)의 영향력을 갖는 것으로 확인되었으나 ‘오락추구’ 요인은 유의한 영향을 보이지 않았으며, ‘정보추구’ 요인이 변수들 중에서 가장 높은 영향력을 보였다. 넷째, BJ친밀성은 아프리카TV 프로야구 편파 중계방송 시청동기 요인이 시청만족 관계에서 어떤 매개 역할을 할 것인가에 대한 분석 결과 ‘사회교류추구’ 요인과 ‘정보추구’ 요인 모두 BJ친밀성에 유의한 영향을 미치지 않은 것으로 나타나 완전매개 효과가 있는 것으로 나타났다.BR 이는 프로 야구와 같이 팀에 대한 펜의 충성도와 우호적인 친밀성이 존재 하고 있는 시청자들에게 BJ와의 친밀성은 시청만족에 영향을 주지 않는다는 것을 보여준다고 할 수 있다. 이는 추후 1인 방송 BJ들이 장르와 소재 선택에 있어 중요한 자료가 될 것이다.

An analysis of critical success factors on hosting professional golf tournaments using analytic hierarchy process - Korean experts' perspective

The success of sports tournaments can be beneficial to organisations and event venues involved because of their potential to attract viewers, tourists, sponsors as well as investors. In relation to this, the study analysed critical success factors for hosting professional golf championships in Korea using the Delphi method which was facilitated by a panel composed of experts in the golf industry, with the resulting data undergoing further analysis through SPSS 18.0 and expert choice 2000. The top priority in the 1st order criteria for success factors on hosting golf tournaments was determined to be spectator dimension, followed by promotion, competition environment and operating dimensions. In terms of the operating dimension, the top priority in the 2nd order criteria was services. For the spectator dimension, the top priority was the presence of professional golfers. The promotion dimension's top priority was relay broadcasting while the competition environment listed location.

Distributed Decode–Forward for Relay Networks

A new coding scheme for general $N$ -node relay networks is presented for unicast, multicast, and broadcast. The proposed distributed decode–forward scheme combines and generalizes Marton coding for single-hop broadcast channels and the Cover–El Gamal partial decode–forward coding scheme for three-node relay channels. The key idea of the scheme is to precode all the codewords of the entire network at the source by multicoding over multiple blocks. This encoding step allows these codewords to carry partial information of the messages implicitly without complicated rate splitting and routing. This partial information is then recovered at the relay nodes and forwarded further. For $N$ -node Gaussian unicast, multicast, and broadcast relay networks, the scheme achieves within $0.5 N$ bits from the cutset bound, and thus from the capacity (region), regardless of the network topology, channel gains, or power constraints. Roughly speaking, distributed decode–forward is dual to noisy network coding, which generalized compress–forward to unicast, multicast, and multiple access relay networks.

Research on capacity region of Gaussian degraded relay broadcast channel

Research on capacity region of Gaussian degraded relay broadcast channel

An analysis of critical success factors on hosting professional golf tournaments using analytic hierarchy process - Korean experts' perspective

The success of sports tournaments can be beneficial to organisations and event venues involved because of their potential to attract viewers, tourists, sponsors as well as investors. In relation to this, the study analysed critical success factors for hosting professional golf championships in Korea using the Delphi method which was facilitated by a panel composed of experts in the golf industry, with the resulting data undergoing further analysis through SPSS 18.0 and expert choice 2000. The top priority in the 1st order criteria for success factors on hosting golf tournaments was determined to be spectator dimension, followed by promotion, competition environment and operating dimensions. In terms of the operating dimension, the top priority in the 2nd order criteria was services. For the spectator dimension, the top priority was the presence of professional golfers. The promotion dimension's top priority was relay broadcasting while the competition environment listed location.

テレビジョン中継システム用1.2 GHz/2.3 GHz帯受信アンテナの開発

テレビジョン中継システム用1.2 GHz/2.3 GHz帯受信アンテナの開発

CRB: Cooperative Relay Broadcasting for Safety Applications in Vehicular Networks

Vehicular networks require a reliable and efficient one-hop broadcast service to disseminate delay sensitive messages for high-priority safety applications. However, frequent link breakage in the dynamic networking conditions, in the presence of high relative mobility and channel fading, poses technical challenges in satisfying the strict service requirements. Makeup transmissions can improve the performance through repetitive broadcasting of packets before detecting a transmission failure. In this paper, we introduce a node cooperation based makeup strategy for vehicular networks, referred to as cooperative relay broadcasting (CRB), such that neighboring nodes rebroadcast the packet from a source node, increasing the reliability of the broadcast service. The decision to perform CRB is taken proactively and based on the channel conditions between the relaying nodes and the target one-hop neighbors. We propose an optimization framework that provides an upper bound on the CRB performance with accurate channel information. Further, we propose a channel prediction scheme based on a two-state first-order Markov chain to select the best relaying node for CRB. We study the reliability of the broadcast service in terms of packet received rate and packet delivery rate. Through extensive simulations, we demonstrate that the proposed CRB scheme provides a more reliable broadcast service, as compared with existing approaches.

Sum-Rate Enhancement in Multiuser MIMO Decode-and-Forward Relay Broadcasting Channel With Energy Harvesting Relays

In this paper, we consider a multiuser multiple-input multiple-output (MIMO) decode-and-forward (DF) relay broadcasting channel (BC) with single source, multiple energy harvesting (EH) relays, and multiple destinations. All the nodes are equipped with multiple antennas. The EH and information decoding tasks at the relays and destinations are separated over the time, which is termed as the time switching scheme. As optimal solutions for the sum-rate maximization problems of BC channels and the MIMO interference channels are hard to obtain, the end-to-end sum rate maximization problem of a multiuser MIMO DF relay BC channel is even harder. In this paper, we propose to tackle a simplified problem, where we employ the block diagonalization (BD) procedure at the source, and we mitigate the interference between the relay-destination channels using an algorithm similar to the BD method. In order to show the relevance of our low complex proposed solution, we compare it with the minimum mean-square error (mmse) solution that was shown in the literature to be equivalent to the solution of the sum-rate maximization in the MIMO broadcasting interfering channels. We also investigate the time division multiple access (TDMA) solution, which separates all the information transmissions from the source to the relays and from the relays to the destinations over time. We provide the numerical results to show the relevance of our proposed solution, in comparison with the no co-channel interference case, the TDMA-based solution, and the mmse-based solution.

On the Gaussian Fading Broadcast Relay Channel With Causal State Feedback

We investigate a typical setup of a heterogeneous network that can be modeled as a fast Rayleigh fading broadcast relay channel with one source (macrocell Base Station), one full-duplex relay (smallcell BS), and two destinations (mobile users). It is assumed that instantaneous channel state information (CSI) is available at the receivers’ side, while only a noiseless causal state feedback from the destinations about the source-to-destination channels is available at the relay. We propose a relaying scheme based on a two-stage decode-compress-forward strategy. The essential idea is to let the relay decode the source messages and then forward to the destinations a function of both the decoded messages and the CSI feedback. By characterizing and evaluating the achievable rate region of the proposed relaying scheme, we reveal that non-negligible performance gains over conventional cooperative strategies can be obtained by exploiting CSI feedback at the relay.

Relay Broadcast Channel With Confidential Messages

In this paper, we investigate the effects of a trusted relay node on the secrecy of the broadcast channel by considering the model of relay broadcast channel with confidential messages (RBC-CM). Inner and outer bounds on the capacity-equivocation region of the RBC-CM are provided, and the capacity results are further explained via a degraded Gaussian example, which we call the degraded Gaussian relay broadcast channel with one common and one confidential messages. Numerical results show that this trusted relay node helps to enhance the security of the Gaussian broadcast channel with one common and one confidential messages.

Robust MMSE Beamforming for Multiantenna Relay Networks

In this paper, we propose a robust minimum mean square error (MMSE)-based beamforming technique for multiantenna relay broadcast channels, where a multiantenna base station transmits signal to single antenna users with the help of a multiantenna relay. The signal transmission from the base station to the single antenna users is completed in two time slots, where the relay receives the signal from the base station in the first time slot, and it then forwards the received signal to different users based on amplify and forward (AF) protocol. We propose a robust beamforming technique for a sum-power minimization problem with an imperfect channel state information (CSI) between the relay and the users. This robust scheme is developed based on the worst-case optimization framework and the Nemirovski Lemma by incorporating uncertainties in the CSI. The original optimization problem is divided into three subproblems due to joint nonconvexity in terms of beamforming vectors at the base station, the relay amplification matrix, and receiver coefficients. These subproblems are formulated into a convex optimization framework by exploiting the Nemirovski Lemma, and an iterative algorithm is developed by alternatively optimizing each of them with channel uncertainties. In addition, we provide an optimization framework to evaluate the achievable worst-case mean square error (MSE) of each user for a given set of design parameters. Simulation results are provided to validate the convergence of the proposed algorithm.