The MIMO Wireless Switch: Relaying can increase the multiplexing gain

Ghozlan, Hassan; Mohasseb, Yahya; Gamal, Hesham El; Kramer, Gerhard

doi:10.1109/isit.2009.5205876

Cited by 25 publications

(16 citation statements)

References 11 publications

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“…Similarly, when > , we let = which was defined in (19). It can be readily verified that lim →∞ Pr( ) = Pr( ), where Pr( ) is the outage probability defined for the E-DDF protocol in (20), so that for any > 0 fixed arbitrarily, we can choose a large enough such that Pr( ) ≤ Pr( )+ /2.…”

Section: Achievability Proof For E-ddfmentioning

confidence: 99%

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High performance static and dynamic cooperative communication protocols for the half duplex fading relay channel

Prasad

Varanasi

2010

IEEE Trans. Wireless Commun.

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Two novel communication protocols for the quasistatic coherent fading relay channel are proposed and analyzed under the diversity-multiplexing tradeoff framework. Both these protocols satisfy the half-duplex constraint and fall under the class of decode and forward (DF) protocols, wherein the relay node attempts to decode the source signal and if successful transmits the re-encoded signal. The first protocol is a static DF protocol where the relay waits for a fixed, channel independent duration before attempting to decode. It is shown that it achieves a tradeoff curve that uniformly improves upon those of the previously best known static half-duplex protocols, which are the NAF protocol [1] and the STC3 protocol [2]. Our second protocol is a dynamic DF protocol where the relay waits for a dynamic, channel dependent duration before attempting to decode and it is shown to achieve a tradeoff curve that uniformly improves upon the previously proposed half-duplex dynamic DF protocol of [1].

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Section: Achievability Proof For E-ddfmentioning

confidence: 99%

“…Other recent work in this field includes the DMT analysis of several protocols over communication systems with multiple antennas [14]- [16], multiple relays and/or multiple sourcedestination pairs [17]- [19], as well as the analysis of fullduplex protocols [14].…”

Section: Introductionmentioning

confidence: 99%

High performance static and dynamic cooperative communication protocols for the half duplex fading relay channel

Prasad

Varanasi

2010

IEEE Trans. Wireless Commun.

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“…Specifically, the second channel is characterized by two sources and destinations communicating through the relay without the direct links between sources and destinations [37]- [39]. We refer to it as OBR Channel (OBRC) 1 .…”

Section: Introductionmentioning

confidence: 99%

“…As explained above, the two components of an IC-OBR model are an IC (see, e.g, [32] for a summary of the state of the art on the subject) and the OBRC. Assuming a half-duplex relay, the latter is modelled in two different ways (see Fig.1): (i) IC-OBR Type-I: The OBRC is operated by assuming orthogonal transmissions (e.g., via TDMA or FDMA) over the four Gaussian links connecting sources to relay and relay to destinations; (ii) IC-OBR Type-II: The OBRC is more generally operated by orthogonalizing the Gaussian multiple access channel between the two 1 Notice that, while having been studied by itself in some previous works [37]- [39], as discussed below, the relay channel that forms the OBRC does not have an agreed upon name (e.g., [37] refers to it as "gateway" channel and [39] as "switch" channel). July 29, 2018 DRAFT sources and the relay and the broadcast channel from relay to destinations.…”

Section: Introductionmentioning

confidence: 99%

Interference Channel With an Out-of-Band Relay

Şahın

Simeone

Erkip

2011

IEEE Trans. Inform. Theory

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A Gaussian interference channel (IC) with a relay is considered. The relay is assumed to operate over an orthogonal band with respect to the underlying IC, and the overall system is referred to as IC with an out-of-band relay (IC-OBR). The system can be seen as operating over two parallel interference-limited channels: The first is a standard Gaussian IC and the second is a Gaussian relay channel characterized by two sources and destinations communicating through the relay without direct links. We refer to the second parallel channel as OBR Channel (OBRC).The main aim of this work is to identify conditions under which optimal operation, in terms of the capacity region of the IC-OBR, entails either signal relaying and/or interference forwarding by the relay, with either a separable or non-separable use of the two parallel channels, IC and OBRC. Here "separable" refers to transmission of independent information over the two constituent channels. For a basic model in which the OBRC consists of four orthogonal channels from sources to relay and from relay to destinations (IC-OBR Type-I), a condition is identified under which signal relaying and separable operation is optimal. This condition entails the presence of a relay-to-destinations capacity bottleneck on the OBRC and holds irrespective of the IC. When this condition is not satisfied, various scenarios, which depend on the IC channel gains, are identified in which interference forwarding and non-separable operation are necessary to achieve optimal performance. In these scenarios, the system exploits the "excess capacity" on the OBRC via interference forwarding to drive the IC-OBR system in specific interference regimes (strong or mixed).The analysis is then turned to a more complex IC-OBR, in which the OBRC consists of only two orthogonal channels, one from sources to relay and one from relay to destinations (IC-OBR Type-II).For this channel, some capacity resuls are derived that parallel the conclusions for IC-OBR Type-I and point to the additional analytical challenges.

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“…Interestingly, it was shown in [3] that the use of a relay can be beneficial in order to reduce the number of symbol extensions spanning multiple channel realizations needed to perform alignment in the interference network [2]. Indeed, relays can even help to increase the degrees of freedom [4], which was until then thought to be not the case. On the other hand, for This work is supported by the German Research Foundation, Deutsche Forschungsgemeinschaft (DFG), Germany, under grant SE 1697/3.…”

Section: Introductionmentioning

confidence: 99%

From non-causality to causality: degrees of freedom of the interference relay channel

Chaaban¹,

Sezgin²

2010

2010 44th Annual Conference on Information Sciences and Systems (CISS)

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The achievable degrees of freedom (DOF) in an interference relay channel are examined. We highlight some differences between two relaying strategies in two different setups. Namely, we study the DOF achieved using interference alignment and interference cancellation in a cognitive relay setup and in a half-duplex relay setup. The difference between the two setups is causality, which leads to a difference in the achievable DOF. We show that 3/2 DOF are achievable almost surely in a 3-user complex Gaussian interference relay channel with quasistatic channel coefficients and with one antenna at each node. This result holds for both the cognitive as well as for the more practical half-duplex non-cognitive relay. However, while this is achieved in the cognitive relay setup using one symbol duration, it needs two symbol extensions in the half-duplex case. On the other hand, we show that in the cognitive case, interference cancellation performs better than interference alignment, since it achieves 2 DOF almost surely. Moreover, interference cancellation achieves full, i.e, K DOF for a family of K -user interference channels with a cognitive relay. Interestingly, for the half-duplex setup the outcome is swapped. Here, interference alignment outperforms interference cancellation, since the latter achieves less than 3/2 DOF almost surely in the 3 user case.Index Terms-Degrees of freedom, asymmetric complex signaling, interference management.

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The MIMO Wireless Switch: Relaying can increase the multiplexing gain

Cited by 25 publications

References 11 publications

High performance static and dynamic cooperative communication protocols for the half duplex fading relay channel

High performance static and dynamic cooperative communication protocols for the half duplex fading relay channel

Interference Channel With an Out-of-Band Relay

From non-causality to causality: degrees of freedom of the interference relay channel

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