Asymmetric degrees of freedom of the full-duplex MIMO 3-way channel

Elmahdy, Adel M.; El-Keyi, Amr; Mohasseb, Yahya; ElBatt, Tamer; Nafie, Mohammed; Seddik, Karim G.

doi:10.1109/itw.2016.7606878

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…In this subsection we present a non-adaptive transmission scheme based on ZF, IA and EC that provides an inner bound on sum-DoF and DoF region of 3WCs. Previous works [18], [19], [21], [47] developed similar ZF/IA-based schemes only to the limited extent necessary to analyze the sum-DoF of various 3WCs. We take EC as additional technique to mitigate intermittency and develop the resulting ZF/IA/ECbased scheme in full generality, i.e., for arbitrary numbers of antennas and flexible allocation of DoFs to the available transmission techniques ZF, IA and EC.…”

Section: A a Non-adaptive Scheme Based On Zf Ia And Ecmentioning

confidence: 99%

“…To this end, several bounds are reported in the literature, among them cut-set outer bounds [49] on pairs of DoFs (involving two messages either intended for or originating at a certain node), and tighter genie-aided outer bounds on triplets of DoFs (involving two messages either intended for or originating at a certain node, and one message exchanged between the remaining two nodes). The latter bounding technique is due to [18], [19] and was later taken up in [21], [47].…”

Section: B Conversesmentioning

confidence: 99%

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Degrees-of-Freedom of the MIMO Three-Way Channel With Node-Intermittency

Neu

Chaaban

Sezgin

et al. 2019

IEEE Trans. Inform. Theory

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The characterization of fundamental performance bounds of many-to-many communication systems in which participating nodes are active in an intermittent way is one of the major challenges in communication theory. In order to address this issue, we introduce the multiple-input multiple-output (MIMO) three-way channel (3WC) with an intermittent node and study its degrees-of-freedom (DoF) region and sum-DoF. We devise a non-adaptive encoding scheme based on zero-forcing, interference alignment and erasure coding, and show its DoF region (and thus sum-DoF) optimality for non-intermittent 3WCs and its sum-DoF optimality for (node-)intermittent 3WCs. However, we show by example that in general some DoF tuples in the intermittent 3WC can only be achieved by adaptive schemes, such as decodeforward relaying. This shows that non-adaptive encoding is sufficient for the non-intermittent 3WC and for the sum-DoF of intermittent 3WCs, but adaptive encoding is necessary for the DoF region of intermittent 3WCs. Our work contributes to a better understanding of the fundamental limits of multi-way communication systems with intermittency and the impact of adaptation therein.

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Section: A a Non-adaptive Scheme Based On Zf Ia And Ecmentioning

confidence: 99%

Section: B Conversesmentioning

confidence: 99%

Degrees-of-Freedom of the MIMO Three-Way Channel With Node-Intermittency

Neu

Chaaban

Sezgin

et al. 2019

IEEE Trans. Inform. Theory

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“…III achieves the DoF region of the nonintermittent 3WC (τ = 1) given by D a,1 = D [in] r,1 . Proof: The proof is based on upper bounds in [9], [21], and is omitted for lack of space. Therefore, from a DoF-region point-of-view, adaptation is not necessary in the nonintermittent case.…”

Section: B Dof Regionmentioning

confidence: 99%

“…[in] r,1 . Proof: The proof is based on upper bounds in [9], [21], and is omitted for lack of space.…”

Section: B Dof Regionmentioning

confidence: 99%

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On the degrees-of-freedom of the MIMO three-way channel with intermittent connectivity

Chaaban

Sezgin

Alouini

2017

2017 IEEE International Symposium on Information Theory (ISIT)

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The degrees-of-freedom (DoF) of the multi-antenna three-way channel (3WC) with an intermittent node is studied. Special attention is given to the impact of adaptation. A nonadaptive transmission scheme based on interference alignment, zero-forcing, and erasure-channel treatment is proposed, and its corresponding DoF region is derived. Then, it is shown that this scheme achieves the sum-DoF of the intermittent channel, in addition to the DoF region of the nonintermittent one. Thus, adaptation is not necessary from those perspectives. To the contrary, it is shown that adaptation is necessary for achieving the DoF region of the intermittent case. This is shown by deriving an outer bound for the intermittent channel with nonadaptive encoding, and giving a counterexample of an adaptive scheme which achieves DoF tuples outside this bound. This highlights the importance of cooperation in this intermittent network. I. INTRODUCTIONMulti-way, full-duplex, and device-to-device (D2D) communications are important techniques that are expected to gain more prominence in future communication systems. Multiway communication refers to communication between multiple nodes each acting as a source, a destination, and possibly a relay. Full-duplex operation is defined as when these three functionalities take place over the same time/frequency resources, and D2D communication refers to direct communication between users without or with limited base-station intervention. Those techniques attracted and continue to attract research attention [1]- [5].Consider a setup where three nodes (D2D users e.g.) communicate with each other in a multi-way fashion. This setup can be modeled as a three-way channel (3WC), an extension of Shannon's two-way channel [6] which has been studied in [7]- [9]. Therein, it is assumed that the nodes are always connected. This assumption is not always valid in practice since a node might have intermittent connectivity, e.g. due to shadowing, or if a D2D node causes strong interference to a cellular user, in which case it is not permitted to use its band [10].The impact of intermittency on the performance of various networks was studied in [11]-[14] for instance. In this paper, we study the impact of intermittency on the multiple-input multiple-output (MIMO) 3WC. We consider a full-duplex MIMO 3WC with full message-exchange, where each node has an independent message to each of the other two nodes. The permanent nodes have only causal knowledge of the A. Chaaban and M.-S. Alouini are with the Division of Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) at King Abdullah

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Degrees of Freedom of the Full-Duplex Asymmetric MIMO 3-Way Channel with Unicast and Broadcast Messages

Elmahdy

El-Keyi

Mohasseb

et al. 2017

IEEE Trans. Commun.

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In this paper, we characterize the asymmetric total degrees of freedom (DoF) of a multiple-input multiple-output (MIMO) 3-way channel. Each node has a separate-antenna fullduplex MIMO transceiver with a different number of antennas, where each antenna can be configured for either signal transmission or reception. We study this system under two message configurations; the first configuration is when each node has two unicast messages to be delivered to the two other nodes, while the second configuration is when each node has two unicast messages as well as one broadcast message to be delivered to the two other nodes. For each configuration, we first derive upper bounds on the total DoF of the system. Cut-set bounds in conjunction with genie-aided bounds are derived to characterize the achievable total DoF. Afterwards, we analytically derive the optimal number of transmit and receive antennas at each node to maximize the total DoF of the system, subject to the total number of antennas at each node. Finally, the achievable schemes for each configuration are constructed. The proposed schemes are mainly based on zeroforcing and null-space transmit beamforming.

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Asymmetric degrees of freedom of the full-duplex MIMO 3-way channel

Cited by 5 publications

References 7 publications

Degrees-of-Freedom of the MIMO Three-Way Channel With Node-Intermittency

Degrees-of-Freedom of the MIMO Three-Way Channel With Node-Intermittency

On the degrees-of-freedom of the MIMO three-way channel with intermittent connectivity

Degrees of Freedom of the Full-Duplex Asymmetric MIMO 3-Way Channel with Unicast and Broadcast Messages

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