Downlink Transmission of Broadband OFCDM Systems—Part I: Hybrid Detection

Zhou, Yiqing; Wang, Jiangzhou; Sawahashi, Mamoru

doi:10.1109/tcomm.2005.844962

Cited by 193 publications

(81 citation statements)

References 12 publications

(15 reference statements)

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“…In addition, this scheme can be easily applied to orthogonal frequency division multiple access (OFDMA) networks [18,19], or orthogonal frequency and code division multiplexing (OFCDM) systems [20]. In the future, we plan to incorporate the user mobility model to study its effect on the performance of the proposed scheme and evaluate the energy consumption with the prominent related schemes.…”

Section: Resultsmentioning

confidence: 99%

Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

Zheng

Xie

et al. 2012

International Journal of Distributed Sensor Networks

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A large-scale deployment of femtocell BSs (FBSs) causes substantial energy consumption. This paper proposes a hybrid BScooperative power management (HBCPM) scheme with self-organized sleep mode in virtual cell-based femto networks. Firstly, HBCPM builds a leader-member virtual cell framework, in which only one FBS is a FBS leader (FL) and others are FBS members (FMs). Then, the FL acts as an autonomous entity and is responsible for detecting active calls in the virtual cell coverage, while the FMs without active connections can entirely shut down pilot transmissions and the related processing all the time. So it is suited for self-organizing networks (SONs). Based on the proposed scheme, the state transition model is established by the semi-Markov stochastic process, and the analytic formulas of average cumulative delay and interference time as well as the energy consumption are derived. Meanwhile, three prominent-related schemes are also studied by the proposed model. With the practical long-term evolution (LTE) system parameters and three-dimensional femtocell network model, the numerical simulation and theoretical analysis match pretty well, and the tradeoff between the energy consumption and average cumulative delay is also manifested. Moreover, simulation results show that the proposed algorithm outperforms other three schemes in terms of average cumulative interference time and the energy consumption.

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Section: Resultsmentioning

confidence: 99%

Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

Zheng

Xie

et al. 2012

International Journal of Distributed Sensor Networks

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“…describes the performance of non cooperative OFCDMA system, combined CDD cooperative OFCDMA system (CC cooperative OFCDMA system), allocated code cooperative OFCDMA system (AC cooperative OFCDMA system), cooperative OFDMA system, and 2 × 1 OFCDMA system. AC cooperative OFCDM system is studied in [1]. This system allocates different code channels to each user.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…The structure of the OFCDM symbol frequency and code division multiplexing (OFCDM) is proposed to satisfy these conditions at downlink through diversity gain and the advantages of OFDM [1,2] In the OFCDM, diversity gain can be achieved by frequency domain despreading owing to subcarriers which experienced the different fading [1][2][3][4][5]. To help understanding OF-CDM, Fig.…”

mentioning

confidence: 99%

“…An OFCDM symbol combines OFDM and 2-D spreading codes, which are frequency domain and time domain as Fig.1. However OFCDM has been mostly studied for downlink system [1][2][3][4][5][6]. For these reason, in this paper, we extend OFCDM to orthogonal frequency and code division multiple access (OFCDMA) for efficiently embodying uplink system, and supporting multiple users as OFDMA [6].…”

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confidence: 99%

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Cooperative Relaying Scheme for Orthogonal Frequency and Code Division Multiple Access Uplink System

Baik

Song

2012

Wireless Pers Commun

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Orthogonal frequency and code division multiplexing (OFCDM) which can be extended orthogonal frequency and code division multiple access (OFCDMA) has a good performance, because it can mitigate multi path interference while maintaining high data rate. Furthermore, cooperative OFCDM relaying system provides these advantages, and this system can effectively use the limited resource with respect to data rate and each terminal's energy efficiency. Therefore we proposed cooperative OFCDMA relaying uplink system because of the user's requirement of the high data rate at uplink. However, a throughput performance decreases when this system employs many relays in case of each relay allocated code channel to separate each relay's signal. Therefore, in this paper, we present that the proposed system combines cyclic delay diversity due to complement throughput performance problem. DF (Decode-and-Forward) is assumed in this paper. It is considered that the users which want to send data to BS only decode the data from other users. In addition to that, we propose the adaptive cooperative communication for the OFCDMA uplink system. The proposed adaptive system can easily select the cooperative relay.

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“…Following the E-A optimization, in this contribution we investigate the spectral-efficiency of the TDD-based two-hop network in conjunction with the MC-CDMA [6,7]. Specifically, the spectral-efficiency of the two-hop MC-CDMA systems is investigated, when assuming that the relays are in cooperation or they do not cooperate with each other.…”

Section: Introductionmentioning

confidence: 99%

Spectral-Efficiency of TDD Multiuser Two-Hop MC-CDMA Systems Employing Egocentric-Altruistic Relay Optimization

Liu

Yang

2010

2010 IEEE 71st Vehicular Technology Conference

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Abstract-In this contribution we investigate the spectral-efficiency of a two-hop cooperative network using multicarrier code-division multipleaccess (MC-CDMA) transmission scheme. The two-hop network constitutes K source users transmitting signals to K destinations with the aid of N relays. Our focus is on the relay optimization, when assuming that the N relays cooperate or do not cooperate with each other. Specifically, in this contribution the egocentric-altruistic (E-A) optimization is introduced, which constitutes an E-optimization motivating to suppress the multiuser interference (MUI) of the source-relay channels and an A-optimization aiming to pre-mitigate the potential MUI of the relay-destination channels. Both the minimum mean-square error (MMSE) and zero-forcing (ZF) optimization criteria are considered. Furthermore, the spectral-efficiency performance of the two-hop MC-CDMA systems using the proposed E-A relay optimization is investigated by simulations, when assuming communications over frequency-selective fading channels. I. INTRODUCTIONIn order to increase the link quality, reliability, and data rate of wireless networks, future wireless communication systems are required to be developed for cooperation rather than merely for coexistence [1]. In order to accomplish such cooperation, relay nodes may be deployed to assist the communications between sources and destinations, making the signal processing at sources and destinations simple in addition to the other advantages. Specifically, in a two-hop network operated in time-division duplex (TDD) principles, the main signal processing may be implemented at the relays so that the complexity of source and destination devices is as low as possible.In TDD-based networks, owing to the reciprocal characteristics of the bidirectional communication channels, it is usually convenient for relays to attain the channel state information (CSI) required for carrying out some signal processing. Assuming that the CSI of both the source-relay and relay-destination channels is known to the relays, then, signal detection and transmission at the relays can be represented by one joint optimization problem, which is referred to as the joint detection/transmission relay optimization. This joint relay optimization problem may be solved in the principles of, such as, MMSE [2][3][4] or ZF [5]. However, this joint detection/transmission relay optimization problem is usually hard to solve. Therefore, in this contribution we propose and investigate a relatively simple relay optimization scheme, which is developed based on the concepts of egocentric (E)-optimization and altruistic (A)-optimization [8,9], referred to as the E-A optimization or E-A relay optimization for convenience. As our forthcoming discourse shown, the E-A relay optimization is constituted by an E-optimization resulting in a multiuser detector (MUD) and an A-optimization leading to a multiuser transmitter (MUT). The MUD motivates to suppress the MUI from the source-relay channels and the MUT aims to pre-mitiga...

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Downlink Transmission of Broadband OFCDM Systems—Part I: Hybrid Detection

Cited by 193 publications

References 12 publications

Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

Cooperative Relaying Scheme for Orthogonal Frequency and Code Division Multiple Access Uplink System

Spectral-Efficiency of TDD Multiuser Two-Hop MC-CDMA Systems Employing Egocentric-Altruistic Relay Optimization

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