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24
Aligned interference neutralization and the degrees of freedom of the 2×2×2 interference channel with . . .
, 2010
"... Previous work showed that the 2×2×2 interference channel, i.e., the multihop interference network formed by concatenation of two 2user interference channels, achieves the mincut outer bound value of 2 DoF. This work studies the 2×2×2 interference channel with one additional assumption that two re ..."
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Cited by 53 (15 self)
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Previous work showed that the 2×2×2 interference channel, i.e., the multihop interference network formed by concatenation of two 2user interference channels, achieves the mincut outer bound value of 2 DoF. This work studies the 2×2×2 interference channel with one additional assumption that two relays interfere with each other. It is shown that even in the presence of the interfering links between two relays, the mincut outer bound of 2 DoF can still be achieved for almost all values of channel coefficients, for both fixed or timevarying channel coefficients. The achievable scheme relies on the idea of aligned interference neutralization as well as exploiting memory at source and relay nodes.
Interference Channels with Source Cooperation
, 2009
"... Interference is a fundamental feature of the wireless channel. Cooperation among the radios has been shown to manage interference in a multiple unicast wireless network in a near optimal scaling law sense [4]. In this paper, we study the two user Gaussian interference channel where the source nodes ..."
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Cited by 42 (3 self)
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Interference is a fundamental feature of the wireless channel. Cooperation among the radios has been shown to manage interference in a multiple unicast wireless network in a near optimal scaling law sense [4]. In this paper, we study the two user Gaussian interference channel where the source nodes can both talk and listen. Focusing on the fullduplex mode of operation, we characterize the sum capacity up to 18 bits. Novel inner and outer bounds are derived in arriving at our main result. 1
Approximate Capacity of a Class of Gaussian InterferenceRelay Networks
"... Abstract—In this paper, we study a Gaussian relayinterference network, in which relay (helper) nodes are to facilitate competing information flows between different sourcedestination pairs. We focus on twostage relayinterference networks where there are weak cross links, causing the networks to ..."
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Cited by 13 (2 self)
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Abstract—In this paper, we study a Gaussian relayinterference network, in which relay (helper) nodes are to facilitate competing information flows between different sourcedestination pairs. We focus on twostage relayinterference networks where there are weak cross links, causing the networks to behave like a chain of Gaussian channels. Our main result is an approximate characterization of the capacity region for such and networks. We propose a new interference management scheme, termed interference neutralization, which is implemented using structured lattice codes. This scheme allows for overtheair interference removal, without the transmitters having complete access the interfering signals. This scheme in conjunction a new network decomposition technique provides the approximate characterization. Our analysis of these Gaussian networks is based on insights gained from an exact characterization of the corresponding linear deterministic model. Index Terms—Deterministic model, Gaussian wireless network, interference neutralization, lattice codes, relayinterference network,
Capacity of a class of multisource relay networks
 in Information Theory and Applications Workshop
, 2009
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Symmetric Capacity of the Gaussian Interference Channel With an OutofBand Relay to Within 1.15 Bits
, 2010
"... Abstract—This paper studies the Gaussian interference channel (IC) with a relay, which transmits and receives in a band that is orthogonal to the IC. The channel associated with the relay is thus an outofband relay channel (OBRC). The focus is on a symmetric channel model, in order to assess the f ..."
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Cited by 7 (2 self)
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Abstract—This paper studies the Gaussian interference channel (IC) with a relay, which transmits and receives in a band that is orthogonal to the IC. The channel associated with the relay is thus an outofband relay channel (OBRC). The focus is on a symmetric channel model, in order to assess the fundamental impact of the OBRC on the signal interaction of the IC, in the simplest possible setting. First, the linear deterministic model is investigated and the sum capacity of this channel is established for all possible channel parameters. In particular, it is observed that the impact of OBRC, as its links get stronger, is similar to that of output feedback for the IC. The insights obtained from the deterministic model are then used todesignachievableschemes for the Gaussian model. The interference links are classified as extremely strong, very strong, strong, moderate, weak, and very weak. For strong and moderate interference, separate encoding is near optimal. For very strong and extremely strong interference, the interference links provide side information to the destinations, which can help the transmission through the OBRC. For weak or very weak interference, an extension of the Han–Kobayashi scheme for the IC is utilized, where the messages are split into common and private. To achieve higher rates, it is beneficial to further split the common message into two parts, and the OBRC plays an important role in decoding the common message. It is shown that our strategy achieves the symmetric capacity to within 1.14625 bits per channel use with duplexing factor 0.5, and 1.27125 bits per channel use for arbitrary duplexing factors, for all channel parameters. An important observation from the constant gap result is that strong interference can be beneficial with the presence of an OBR. Index Terms—Approximate capacity, deterministic model, interference relay channel (IFRC), nested lattice codes, outofband relay (OBR). I.
On the Sum Secure Degrees of Freedom of TwoUnicast Layered Wireless Networks
"... Abstract—In this paper, we study the sum secure degrees of freedom (d.o.f.) of twounicast layered wireless networks. Without a secrecy constraint, the sum d.o.f. of this class of networks was studied by [1] and shown to take only one of three possible values: 1, 3/2 and 2, for all network configura ..."
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Cited by 7 (4 self)
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Abstract—In this paper, we study the sum secure degrees of freedom (d.o.f.) of twounicast layered wireless networks. Without a secrecy constraint, the sum d.o.f. of this class of networks was studied by [1] and shown to take only one of three possible values: 1, 3/2 and 2, for all network configurations. We consider the setting where the message of each sourcedestination pair must be kept informationtheoretically secure from the unintended receiver. We show that the sum secure d.o.f. can take 0, 1, 3/2, 2 and at most countably many other positive values, which we enumerate. s1 u1 u2 u3 t1 t2 s2 w1 w2 w3
Capacity of deterministic Zchain relayInterference network, EPFL Technical Report, Available at http://infoscience.epfl.ch ��� Authorized licensed use limited to
 EPFL LAUSANNE. Downloaded on November 20, 2009 at 11:54 from IEEE Xplore. Restrictions apply
"... Abstract The wireless multipleunicast problem is considered over a layered network, where the rates of transmission are limited by the relaying and interference effect. The deterministic model introduced in [3] is used to capture the broadcasting and multiple access effects. The capacity region of ..."
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Cited by 4 (2 self)
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Abstract The wireless multipleunicast problem is considered over a layered network, where the rates of transmission are limited by the relaying and interference effect. The deterministic model introduced in [3] is used to capture the broadcasting and multiple access effects. The capacity region of the Zchain relayinterference network is fully characterized. In order to solve the problem, we introduce a new achievability scheme based on interference neutralization and a new analysis technique to bound the number of noninterfering (pure) signals. I.
Reciprocity in Linear Deterministic Networks under Linear Coding
, 907
"... Abstract—The linear deterministic model has been used recently to get a first order understanding of many wireless communication network problems [1][3][4][8]. In many of these cases, it has been pointed out that the capacity regions of the network and its reciprocal (where the communication links a ..."
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Cited by 3 (2 self)
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Abstract—The linear deterministic model has been used recently to get a first order understanding of many wireless communication network problems [1][3][4][8]. In many of these cases, it has been pointed out that the capacity regions of the network and its reciprocal (where the communication links are reversed and the roles of the sources and the destinations are swapped) are the same. In this paper, we consider a linear deterministic communication network with multiple unicast information flows. For this model and under the restriction to the class of linear coding, we show that the rate regions for a network and its reciprocal are the same. This can be viewed as a generalization of the linear reversibility of wireline networks, already known in the network coding literature [10]. I.
Sum Capacity of Multisource Linear Finitefield Relay Networks With Fading
, 905
"... Abstract — We study a fading linear finitefield relay network having multiple sourcedestination pairs. Because of the interference created by different unicast sessions, the problem of finding its capacity region is in general difficult. We observe that, since channels are timevarying, relays can ..."
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Cited by 2 (2 self)
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Abstract — We study a fading linear finitefield relay network having multiple sourcedestination pairs. Because of the interference created by different unicast sessions, the problem of finding its capacity region is in general difficult. We observe that, since channels are timevarying, relays can deliver their received signals by waiting for appropriate channel realizations such that the destinations can decode their messages without interference. We propose a block Markov encoding and relaying scheme that exploits such channel variations. By deriving a general cutset upper bound and an achievable rate region, we characterize the sum capacity for some classes of channel distributions and network topologies. For example, when the channels are uniformly distributed, the sum capacity is given by the minimum average rank of the channel matrices constructed by all cuts that separate the entire sources and destinations. We also describe other cases where the capacity is characterized. I.