Relaying And Scheduling In Interference Limited Wireless Networks

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Relaying and Scheduling in Interference Limited Wireless Networks

Author : Chandrasekharan Raman
Publisher :
ISBN 13 :
Total Pages : 106 pages
Book Rating : 4.:/5 (667 download)

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Book Synopsis Relaying and Scheduling in Interference Limited Wireless Networks by : Chandrasekharan Raman

Download or read book Relaying and Scheduling in Interference Limited Wireless Networks written by Chandrasekharan Raman and published by . This book was released on 2010 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we address two issues related to communication in interference-limited wireless networks. In the first part of the thesis, we study benefits of deploying inexpensive half-duplex relays in interference-limited cellular system. We study two relaying schemes in a downlink system, users sharing the same frequency band. In the first collaborative relaying scheme, relays help users after they decode the message intended for the user by a collaborative power addition scheme. We evaluate power savings and rate improvement for delivering a common rate for 90% of users in the system. We then consider power control at the base stations and relays in order to manage the interference. In both cases, the ability of relays to reduce the peak base station transmit power while delivering the baseline rate or alternately to increase the user rate is computed. When power control is employed, the peak power saving is 2.6 dB and the average total power in the system can be reduced by 3 dB. We also observe a 34% improvement over the baseline in the users' common rate. In the second orthogonal relaying scheme, we study a simple scheme where the base station and relays transmit in orthogonal time slots. We find that the performance of the simple orthogonal relaying scheme comes very close to that of the collaborative power addition scheme. In the second part of the thesis, we consider a centralized spectrum server that coordinates the transmissions of a group of links sharing a common spectrum. Links employ on-off modulation with fixed transmit power when active. The rate obtained by an active link depends on the activity of all other links. With knowledge of the link gains in the network, the spectrum server schedules the on/off periods of the links so as to satisfy constraints on link fairness and efficiency. We then extend the centralized scheduling framework to multi-hop wireless networks with interfering links. A framework for cross-layer scheduling of end-to-end flows in a multi-hop wireless network with links sharing a common spectrum is presented. Given a set of known routes, the optimization framework can be used to find the flow on each route in order to maximize an objective function. The framework encompasses a variety of physical layer transmission schemes. The rates in the individual links are determined based on the transmission strategy employed. With the knowledge of the link rates in the network, the spectrum server schedules the rates on the links and flows on the sessions to maximize a utility function of the source rates. The schedules are a collection of time shared transmission modes (sets of active links).

Opportunistic Scheduling, Cooperative Relaying and Multicast in Wireless Networks

Author : Chandrashekhar Thejaswi Paataguppe Suryanarayan Bhat
Publisher :
ISBN 13 :
Total Pages : 130 pages
Book Rating : 4.:/5 (85 download)

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Book Synopsis Opportunistic Scheduling, Cooperative Relaying and Multicast in Wireless Networks by : Chandrashekhar Thejaswi Paataguppe Suryanarayan Bhat

Download or read book Opportunistic Scheduling, Cooperative Relaying and Multicast in Wireless Networks written by Chandrashekhar Thejaswi Paataguppe Suryanarayan Bhat and published by . This book was released on 2011 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation builds a clear understanding of the role of information in wireless networks, and devises adaptive strategies to optimize the overall performance. The meaning of information ranges from channel/network states to the structure of the signal itself. Under the common thread of characterizing the role of information, this dissertation investigates opportunistic scheduling, relaying and multicast in wireless networks. To assess the role of channel state information, the problem of opportunistic distributed opportunistic scheduling (DOS) with incomplete information is considered for ad-hoc networks in which many links contend for the same channel using random access. The objective is to maximize the system throughput. In practice, link state information is noisy, and may result in throughput degradation. Therefore, refining the state information by additional probing can improve the throughput, but at the cost of further probing. Capitalizing on optimal stopping theory, the optimal scheduling policy is shown to be threshold-based and is characterized by either one or two thresholds, depending on network settings. To understand the benefits of side information in cooperative relaying scenarios, a basic model is explored for two-hop transmissions of two information flows which interfere with each other. While the first hop is a classical interference channel, the second hop can be treated as an interference channel with transmitter side information. Various cooperative relaying strategies are developed to enhance the achievable rate. In another context, a simple sensor network is considered, where a sensor node acts as a relay, and aids fusion center in detecting an event. Two relaying schemes are considered: analog relaying and digital relaying. Sufficient conditions are provided for the optimality of analog relaying over digital relaying in this network. To illustrate the role of information about the signal structure in joint source-channel coding, multicast of compressible signals over lossy channels is studied. The focus is on the network outage from the perspective of signal distortion across all receivers. Based on extreme value theory, the network outage is characterized in terms of key parameters. A new method using subblock network coding is devised, which prioritizes resource allocation based on the signal information structure.

Communications in Interference Limited Networks

Author : Wolfgang Utschick
Publisher : Springer
ISBN 13 : 3319224409
Total Pages : 519 pages
Book Rating : 4.3/5 (192 download)

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Book Synopsis Communications in Interference Limited Networks by : Wolfgang Utschick

Download or read book Communications in Interference Limited Networks written by Wolfgang Utschick and published by Springer. This book was released on 2016-02-04 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

Delay-aware Scheduling in Wireless Coding Networks

Author : Solairaja Ramasamy
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (78 download)

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Book Synopsis Delay-aware Scheduling in Wireless Coding Networks by : Solairaja Ramasamy

Download or read book Delay-aware Scheduling in Wireless Coding Networks written by Solairaja Ramasamy and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless technology has become an increasingly popular way to gain network access. Wireless networks are expected to provide efficient and reliable service and support a broad range of emerging applications, such as multimedia streaming and video conferencing. However, limited wireless spectrum together with interference and fading pose signi cant challenges for network designers. The novel technique of network coding has a significant potential for improving the throughput and reliability of wireless networks by taking advantage of the broadcast nature of wireless medium. Reverse carpooling is one of the main techniques used to realize the benefits of network coding in wireless networks. With reverse carpooling, two flows are traveling in opposite directions, sharing a common path. The network coding is performed in the intermediate (relay) nodes, which saves up to 50% of transmissions. In this thesis, we focus on the scheduling at the relay nodes in wireless networks with reverse carpooling. When two packets traveling in opposite directions are available at the relay node, the relay node combines them and broadcasts the resulting packet. This event is referred to as a coding opportunity. When only one packet is available, the relay node needs to decide whether to wait for future coding opportunities, or to transmit them without coding. Though the choice of holding packets exploits the positive aspects of network coding, without a proper policy in place that controls how long the packets should wait, it will have an adverse impact on delays and thus the overall network performance. Accordingly, our goal is to find an optimal control strategy that delicately balances the tradeoff between the number of transmissions and delays incurred by the packets. We also address the fundamental question of what local information we should keep track of and use in making the decision of of whether to transmit uncoded packet or wait for the next coding opportunity. The available information consists of queue length and time stamps indicating the arrival time of packets in the queue. We could also store history of all previous states and actions. However, using all this information makes the control very complex and so we try to find if the overhead in collecting waiting times and historical information is worth it. A major contribution of this thesis is a stochastic control framework that uses state information based on what can be observed and prescribes an optimal action. For that, we formulate and solve a stochastic dynamic program with the objective of minimizing the long run average cost per unit time incurred due to transmissions and delays. Subsequently, we show that a stationary policy based on queue lengths is optimal, and the optimal policy is of threshold-type. Then, we describe a non-linear optimization procedure to obtain the optimal thresholds. Further, we substantiate our analytical ndings by performing numerical experiments under varied settings. We compare systems that use only queue length with those where more information is available, and we show that optimal control that uses only the queue length is as good as any optimal control that relies on knowing the entire history.

Relay-Aided Communication in Large Interference Limited Wireless Networks

Author : Daniel Papsdorf
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (115 download)

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Book Synopsis Relay-Aided Communication in Large Interference Limited Wireless Networks by : Daniel Papsdorf

Download or read book Relay-Aided Communication in Large Interference Limited Wireless Networks written by Daniel Papsdorf and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Scheduling in Wireless Networks

Author : Anna Pantelidou
Publisher : Now Publishers Inc
ISBN 13 : 1601984200
Total Pages : 101 pages
Book Rating : 4.6/5 (19 download)

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Book Synopsis Scheduling in Wireless Networks by : Anna Pantelidou

Download or read book Scheduling in Wireless Networks written by Anna Pantelidou and published by Now Publishers Inc. This book was released on 2011 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the problem of scheduled channel access in wireless networks with emphasis on ad hoc and sensor networks as opposed to WiFi, cellular, and infrastructure-based networks. It is intended to provide a reference point for the rich set of problems that arise in the allocation of resources in modern and future networks.

Advanced Wireless Networks

Author : Savo G. Glisic
Publisher : John Wiley & Sons
ISBN 13 : 111909688X
Total Pages : 864 pages
Book Rating : 4.1/5 (19 download)

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Book Synopsis Advanced Wireless Networks by : Savo G. Glisic

Download or read book Advanced Wireless Networks written by Savo G. Glisic and published by John Wiley & Sons. This book was released on 2016-07-22 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third edition of this popular reference covers enabling technologies for building up 5G wireless networks. Due to extensive research and complexity of the incoming solutions for the next generation of wireless networks it is anticipated that the industry will select a subset of these results and leave some advanced technologies to be implemented later,. This new edition presents a carefully chosen combination of the candidate network architectures and the required tools for their analysis. Due to the complexity of the technology, the discussion on 5G will be extensive and it will be difficult to reach consensus on the new global standard. The discussion will have to include the vendors, operators, regulators as well as the research and academic community in the field. Having a comprehensive book will help many participants to join actively the discussion and make meaningful contribution to shaping the new standard.

Relay Selection Protocol in Interference-Limited Cooperative Wireless Networks

Author : 林志峰
Publisher :
ISBN 13 :
Total Pages : 76 pages
Book Rating : 4.:/5 (83 download)

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Book Synopsis Relay Selection Protocol in Interference-Limited Cooperative Wireless Networks by : 林志峰

Download or read book Relay Selection Protocol in Interference-Limited Cooperative Wireless Networks written by 林志峰 and published by . This book was released on 2012 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Cooperative Relaying and Adaptive Scheduling for Low Mobility Wireless Access Networks

Author : Ingmar Hammerström
Publisher :
ISBN 13 : 9783832514662
Total Pages : 229 pages
Book Rating : 4.5/5 (146 download)

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Book Synopsis Cooperative Relaying and Adaptive Scheduling for Low Mobility Wireless Access Networks by : Ingmar Hammerström

Download or read book Cooperative Relaying and Adaptive Scheduling for Low Mobility Wireless Access Networks written by Ingmar Hammerström and published by . This book was released on 2006 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Scheduling in Omnidirectional Relay Wireless Networks

Author : Shuning Wang
Publisher :
ISBN 13 :
Total Pages : 57 pages
Book Rating : 4.:/5 (875 download)

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Book Synopsis Scheduling in Omnidirectional Relay Wireless Networks by : Shuning Wang

Download or read book Scheduling in Omnidirectional Relay Wireless Networks written by Shuning Wang and published by . This book was released on 2013 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The capacity of multiuser wireless network, unclear for many years, has always been a hot research topic. Many different operation schemes and coding techniques have been proposed to enlarge the achievable rate region. And omnidirectional relay scheme is one of them. This thesis mainly works on the achievable region of the all-source all-cast network with omnidirectional relay scheme. In order to better understand this problem, we first describe the half-duplex model on the one-dimensional and two-dimensional regular networks. And we present an optimal operation scheme for them to have the maximum achievable rate. For the one-dimensional general network, we proposed an achievable region that indicates valued improvement compared to the previous results. In the full-duplex model of the one-dimensional general network, the maximum achievable rate is presented with a simpler proof in comparison with the previous results. In this thesis, we also show some discussions on more general networks.

Towards Low-complexity Relay Selection and Scheduling in Wireless Networks

Author : Yahya Hussain Ezzeldin Essa
Publisher :
ISBN 13 :
Total Pages : 244 pages
Book Rating : 4.:/5 (122 download)

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Book Synopsis Towards Low-complexity Relay Selection and Scheduling in Wireless Networks by : Yahya Hussain Ezzeldin Essa

Download or read book Towards Low-complexity Relay Selection and Scheduling in Wireless Networks written by Yahya Hussain Ezzeldin Essa and published by . This book was released on 2020 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Next-generation wireless networks are expected to usher in a revolution of communication systems in terms of the network capabilities, technologies used, and serviced applications. A key aim in these networks is to expand available bandwidth and enable multi-gigabit emerging applications that range from ultra-high-definition video to autonomous vehicle platoons and Industry 4.0 low latency communication. The focus of this dissertation is to study two technologies that are envisioned to drive the physical layer in the next generation of networks - multi-hop relay selection and mmWave transmission - in terms of fundamental theoretical guarantees on performance and the efficiency of operation and scheduling. We study the problem of relay selection for routing in a wireless full-duplex relay network. We derive fundamental worst-case guarantees on the performance of routing in wireless relay networks operating in full-duplex with arbitrary topology. This extends the state of the art in terms of these fundamental guarantees which were previously only studied for the diamond network topology. These worst-case guarantees provide guidance for heuristic and optimal routing approaches in full-duplex wireless networks. Second, we study the problem of efficiently selecting a subset of relays in a diamond network operating in half-duplex and the fundamental guarantees that follow from the selection of the best relay subset. We prove fundamental guarantees on the retained capacity when a subset of N-1 relays are retained out of N relays in a diamond topology, For selecting k

Opportunistic Scheduling and Cooperative Relaying in Wireless Networks

Author : Yufeng Wang
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (851 download)

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Book Synopsis Opportunistic Scheduling and Cooperative Relaying in Wireless Networks by : Yufeng Wang

Download or read book Opportunistic Scheduling and Cooperative Relaying in Wireless Networks written by Yufeng Wang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the proposed scheduling scheme, we prove two key inequalities that capture the various tradeoffs inherent in the broad class of opportunistic relaying protocols, illustrating that no scheduling and routing algorithm can simultaneously yield lower delay and higher throughput. We then develop an adaptive rate transmission scheme with opportunistic scheduling, with the constraints of practical assumptions on channel state information (CSI) and limited feedback, which achieves an optimal system throughput scaling order. Along this work with the consideration of finite-buffer model, we propose a Buffer-Aware Adaptive (BAA) scheduler which considers both channel state and buffer conditions to make scheduling decisions, to reduce average packet delay, while maintaining the queue stability condition of the networks. The proposed algorithm is an improvement over existing algorithms with adaptability and bounded potential throughput reduction. In the third part, we extend the methods and analyses developed for wireless ad hoc networks to a practical Aeronautical Communication Networks (ACN) and present the system performance of such networks. We use our previously proposed scheduling schemes and analytical methods from the second part to investigate the issues about connectivity, throughput and delay in ACN, for both single-hop and two-hop communication models. We conclude that the two-hop model achieves greater throughput than the single-hop model for ACN. Both throughput and delay performances are characterized.

Increasing Throughput in Multiuser Two-Hop Relay Networks Using Time Scheduling and Signal Processing

Author : Fadhel Alhumaidi
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Increasing Throughput in Multiuser Two-Hop Relay Networks Using Time Scheduling and Signal Processing by : Fadhel Alhumaidi

Download or read book Increasing Throughput in Multiuser Two-Hop Relay Networks Using Time Scheduling and Signal Processing written by Fadhel Alhumaidi and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is concerned with the design of time scheduling and signal processing algorithms to mitigate interference effects in wireless networks with successive relaying where the nodes in the system are equipped with multiple antennas. These networks as a form of cooperative communications and multiple-input multiple-output (MIMO) systems have the promise of significantly higher spectral efficiency and reliability than the conventional networks. Reusing the same spectrum by simultaneous multiple transmissions in successive relaying increases spectrum efficiency however it also causes interference which if not mitigated may limit the overall wireless network performance. With these motivations, this dissertation presents three main contributions to lessen or completely cancel relay interference and improve bandwidth efficiency. First, we consider relay-assisted downlink transmissions to support increased data rates for single antenna users. In the first stage of the communication process, the base station with multiple antennas sends to different users. In the next stage, users and their assigned relays form independent networks. Relays using an amplify-and-forward (AF) scheme aid the recovery of messages by the user which solves linear system of equations developed in this dissertation. All of these subnetworks utilize the same bandwidth concurrently producing an acceptable level of multiple access interference (MAI) where the MAI is controlled using specialized frequency reuse plan. Secondly, we develop receiver-based inter-relay interference (IRI) cancellation in AF two-hop systems with successive transmissions. In networks with strong inter-relay channel gains, representing IRI with the recursive terms and exploiting opportunistic listening, in this dissertation, this interference is fully removed using limited channel state information (CSI) about channel gain matrices from both hops. Finally, to complement our second contribution, we develop transmitter precoding to cancel IRI in systems with successive relaying. When designing the scheme, we benefit from the broadcast channel characteristic of the radio channel and the knowledge at the source of all the data contributing to IRI. This dissertation advances the theory of successive relaying through its integration with time scheduling and signal processing within the framework of cooperative communications system designs. The results presented in this work are applicable to wireless networks on downlink and uplink in systems ranging from cellular to ad-hoc networks.

Distance-aware Relay Placement and Scheduling in Wireless Networks

Author : Shi Bai
Publisher :
ISBN 13 :
Total Pages : 172 pages
Book Rating : 4.:/5 (761 download)

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Book Synopsis Distance-aware Relay Placement and Scheduling in Wireless Networks by : Shi Bai

Download or read book Distance-aware Relay Placement and Scheduling in Wireless Networks written by Shi Bai and published by . This book was released on 2011 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Optimization in Wireless Networks

Author : Sutep Tongngam
Publisher :
ISBN 13 :
Total Pages : 248 pages
Book Rating : 4.:/5 (32 download)

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Book Synopsis Optimization in Wireless Networks by : Sutep Tongngam

Download or read book Optimization in Wireless Networks written by Sutep Tongngam and published by . This book was released on 2008 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Relays for Interference Mitigation in Wireless Networks

Author : Rohit Naini
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (776 download)

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Book Synopsis Relays for Interference Mitigation in Wireless Networks by : Rohit Naini

Download or read book Relays for Interference Mitigation in Wireless Networks written by Rohit Naini and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless links play an important role in the last mile network connectivity. In contrast to the strictly centralized approach of today's wireless systems, the future promises decentralization of network management. Nodes potentially engage in localized grouping and organization based on their neighborhood to carry out complex goals such as end-to-end communication. The quadratic energy dissipation of the wireless medium necessitates the presence of certain relay nodes in the network. Conventionally, the role of such relays is limited to passing messages in a chain in a point-point hopping architecture. With the decentralization, multiple nodes could potentially interfere with each other. This work proposes a technique to exploit the presence of relays in a way that mitigates interference between the network nodes. Optimal spatial locations and transmission schemes which enhance this gain are identified.

Cooperative Protocols for Relay and Interference Channels with Half-duplex Constraint

Author : Hossein Bagheri
Publisher :
ISBN 13 :
Total Pages : 99 pages
Book Rating : 4.:/5 (827 download)

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Book Synopsis Cooperative Protocols for Relay and Interference Channels with Half-duplex Constraint by : Hossein Bagheri

Download or read book Cooperative Protocols for Relay and Interference Channels with Half-duplex Constraint written by Hossein Bagheri and published by . This book was released on 2010 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enabling cooperation among nodes of a wireless network can significantly reduce the required transmit power as well as the induced intra-network interference. Due to the practical half-duplexity constraint of the cooperating nodes, they are prohibited to simultaneously transmit and receive data at the same time-frequency resource. The purpose of this dissertation is to illustrate the value of cooperation in such an environment. To understand how to cooperate efficiently, information theory is employed as a useful tool, which not only determines the fundamental limits of communication (i.e., capacity) over the considered network, but also provides insights into the design of a proper transmission scheme for that network. In this thesis, two simple but yet important types of wireless networks, namely Relay Channel, and Interference Channel are studied. In fact, these models constitute building blocks for larger networks. The first considered channel is a diamond-shaped relay channel consisting of a source, a destination, and two parallel relays. The second analyzed channel is an interference channel composed of two transmitter-receiver pairs with out-of-band transmitter cooperation, also referred to as conferencing encoders. While characterizing the capacity of these channels are difficult, a simpler and a more common approach is to find an achievable scheme for each channel that ensures a small gap from the capacity for all channel parameters. In chapter 2, the diamond relay channel is investigated in detail. Because of the half-duplex nature of the relays, each relay is either in transmit or receive mode, making four modes possible for the two-relay combination, specifically, 1) broadcast mode (both relays receive) 2,3) routing modes (one relay transmits, another receives) 4) multiple-access mode (both relays transmit). An appropriate scheduling (i.e., timing over the modes) and transmission scheme based on the decode-and-forward strategy are proposed and shown to be able to achieve either the capacity for certain channel conditions or at most 3.6 bits below the capacity for general channel conditions. Particularly, by assuming each transmitter has a constant power constraint over all modes, a parameter [Delta] is defined, which captures some important features of the channel. It is proven that for [Delta]=0 the capacity of the channel can be attained by successive relaying, i.e., using modes 2 and 3 defined above in a successive manner. This strategy may have an infinite gap from the capacity of the channel when [Delta][neq]0. To achieve rates as close as 0.71 bits to the capacity, it is shown that the cases of [Delta]>0 and [Delta]0 should be treated differently. Using new upper bounds based on the dual problem of the linear program associated with the cut-set bounds, it is proven that the successive relaying strategy needs to be enhanced by an additional broadcast mode (mode 1), or multiple access mode (mode 4), for the cases of [Delta]