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38
Embracing wireless interference: Analog network coding
- in ACM SIGCOMM
, 2007
"... Traditionally, interference is considered harmful. Wireless networks strive to avoid scheduling multiple transmissions at the same time in order to prevent interference. This paper adopts the opposite approach; it encourages strategically picked senders to interfere. Instead of forwarding packets, r ..."
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Cited by 358 (10 self)
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Traditionally, interference is considered harmful. Wireless networks strive to avoid scheduling multiple transmissions at the same time in order to prevent interference. This paper adopts the opposite approach; it encourages strategically picked senders to interfere. Instead of forwarding packets, routers forward the interfering signals. The destination leverages network-level information to cancel the interference and recover the signal destined to it. The result is analog network coding because it mixes signals not bits. So, what if wireless routers forward signals instead of packets? Theoretically, such an approach doubles the capacity of the canonical relay network. Surprisingly, it is also practical. We implement our design using software radios and show that it achieves significantly higher throughput than both traditional wireless routing and prior work on wireless network coding. 1.
Reliable physical layer network coding
- PROCEEDINGS OF THE IEEE
, 2011
"... When two or more users in a wireless network transmit simultaneously, their electromagnetic signals are linearly superimposed on the channel. As a result, a receiver that is interested in one of these signals sees the others as unwanted interference. This property of the wireless medium is typicall ..."
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Cited by 54 (5 self)
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When two or more users in a wireless network transmit simultaneously, their electromagnetic signals are linearly superimposed on the channel. As a result, a receiver that is interested in one of these signals sees the others as unwanted interference. This property of the wireless medium is typically viewed as a hindrance to reliable communication over a network. However, using a recently developed coding strategy, interference can in fact be harnessed for network coding. In a wired network, (linear) network coding refers to each intermediate node taking its received packets, computing a linear combination over a finite field, and forwarding the outcome towards the destinations. Then, given an appropriate set of linear combinations, a destination can solve for its desired packets. For certain topologies, this strategy can attain significantly higher throughputs over routing-based strategies. Reliable physical layer network coding takes this idea one step further: using judiciously chosen linear error-correcting codes, intermediate nodes in a wireless network can directly recover linear combinations of the packets from the observed noisy superpositions of transmitted signals. Starting with some simple examples, this survey explores the core ideas behind this new technique and the possibilities it offers for communication over interference-limited wireless networks.
Network coding for two-way relay channels using lattices,” in Telecommunications review vol
- Korea Advanced Institute of Science and Technology. Downloaded on May 21,2010 at 14:26:43 UTC from IEEE Xplore. Restrictions apply
"... Abstract—In this paper, we propose a network coding using a lattice for the two-way relay channel with two nodes communi-cating bidirectionally through a relay, which we call modulo-and-forward (MF). Our scheme extends the network coding in the binary channel to the Gaussian channel case, where XOR ..."
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Cited by 32 (0 self)
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Abstract—In this paper, we propose a network coding using a lattice for the two-way relay channel with two nodes communi-cating bidirectionally through a relay, which we call modulo-and-forward (MF). Our scheme extends the network coding in the binary channel to the Gaussian channel case, where XOR in the binary case is replaced by modΛ for the Gaussian case, where Λ is a high-dimensional lattice whose shaping gain is close to optimal. If the relay node re-transmits the received signal after the mod Λ operation, we can reduce the complexity compared to decode-and-forward (DF) and can get a better power efficiency compared to amplify-and-forward (AF). When the transmission powers of two nodes are different, we use superposition coding and partial decoding at the relay node. Finally, we plot and compare the sum rates of three different schemes, i.e., AF, DF, and MF. We show that by applying the proposed scheme, we can get better performance than AF and DF schemes under some conditions. I.
Multiuser two-way relaying: detection and interference management strategies
- IEEE TRANS. WIRELESS COMMUN
, 2009
"... We consider a multiuser two-way relay network where multiple pairs of users communicate with their preassigned partners, using a common intermediate relay node, in a two-phase communication scenario employing Code Division Multiple Access (CDMA). By taking advantage of the bidirectional communicati ..."
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Cited by 26 (2 self)
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We consider a multiuser two-way relay network where multiple pairs of users communicate with their preassigned partners, using a common intermediate relay node, in a two-phase communication scenario employing Code Division Multiple Access (CDMA). By taking advantage of the bidirectional communication structure, we first propose that each pair of partners share a common spreading signature and design a jointly demodulate-and-XOR forward (JD-XOR-F) relaying scheme, where all users transmit to the relay simultaneously followed by the relay broadcasting an estimate of the XORed symbol for each user pair. We derive the decision rules and the corresponding bit error rates (BERs) at the relay and at the users ’ receivers. We then investigate the joint power control and receiver optimization problem for each phase for this multiuser two-way relay network with JD-XOR-F relaying. We solve each optimization problem by constructing the iterative power control and receiver updates that converge to the corresponding unique optimum. Simulation results are presented to demonstrate the performance of the proposed multiuser two-way JD-XOR-F relaying scheme in conjunction with the joint power control and receiver optimization algorithms. Specifically, we observe significant power savings and user capacity improvement with the proposed communication scheme as compared to the designs with a “one-way” communication perspective.
Network coding for two-way relaying: rate region, sum rate and opportunistic scheduling
- in the Proc. of IEEE International Conf. on Comm. (ICC
, 2008
"... Abstract—Network coding for two-way relaying in a three-node network is considered. The achievable rate regions under both traditional four-slot multi-hopping (FSMH) and network coding (MAC-XOR) are characterized, showing a combination between the two is needed for a larger region. This is accomplis ..."
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Cited by 25 (1 self)
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Abstract—Network coding for two-way relaying in a three-node network is considered. The achievable rate regions under both traditional four-slot multi-hopping (FSMH) and network coding (MAC-XOR) are characterized, showing a combination between the two is needed for a larger region. This is accomplished by an opportunistic network coding scheduling which requires minimal information. Queuing analysis shows that for any pair of random Poisson arrivals with rates within the convex hull of FSMH and MAC-XOR regions is stabilizable. Next we consider how traffic pattern, described by the rate ratio between uplink and downlink, influences the sum rate. It is analyzed and compared with that of FSMH. It is shown that network coding achieves the maximum gain when traffic is symmetric, while it could be worse than FSMH when the traffic is very asymmetric. How multiple antennas influence the performance of network coding is also discussed. Finally, simulations based on Erceg fading model under a WiMAX setting are presented, which shows that the network coding gain (vs FSMH) improves further under MIMO. I.
On the Design of Practical Asynchronous Physical Layer Network Coding
- IEEE 10th Workshop on Signal Processing Advances in Wireless Communications, SPAWC '09
, 2009
"... Decode-and-forward physical layer network coding is one of the most high-performing ideas for wireless network coding. However, all the present schemes work under rather ideal assumptions, such as synchronous reception of the colliding signals. This paper proposes a simple and practical system which ..."
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Cited by 12 (1 self)
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Decode-and-forward physical layer network coding is one of the most high-performing ideas for wireless network coding. However, all the present schemes work under rather ideal assumptions, such as synchronous reception of the colliding signals. This paper proposes a simple and practical system which removes many of the assump-tions made in the past and also designs a soft-output demodulator for this type of network coding. 1.
MAC-layer and PHY-layer Network Coding for Two-way Relaying: Achievable Regions and Opportunistic Scheduling
"... Abstract — We consider two-way relay channel with three nodes: two source nodes and one relay in the middle. We characterize the end-to-end rate regions achieved by MAClayer network coding (MAC-XOR) and PHY-layer network coding (PHY-XOR). Noticing that MAC-XOR does not always achieve better performa ..."
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Cited by 9 (1 self)
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Abstract — We consider two-way relay channel with three nodes: two source nodes and one relay in the middle. We characterize the end-to-end rate regions achieved by MAClayer network coding (MAC-XOR) and PHY-layer network coding (PHY-XOR). Noticing that MAC-XOR does not always achieve better performance than pure multi-hopping, we show a simple opportunistic scheduling to achieve the combined region. A similar opportunistic scheduling is also presented for PHY-XOR operation. It is shown that the system is stabilized for any Poisson arrivals with rate pair within their respective Shannon rate regions. Moreover, we also present simulation results based on practical cellular system models for both SISO and MIMO cases. I.
Interference Management for Multiuser Two-Way Relaying
, 2008
"... We consider a multiuser two-way relay network where multiple pairs of users communicate with their pre-assigned partners, using a common intermediate relay node, in a two-phase communication scenario. In this system, a pair of partners transmit to the relay sharing a common spreading signature in t ..."
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Cited by 9 (1 self)
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We consider a multiuser two-way relay network where multiple pairs of users communicate with their pre-assigned partners, using a common intermediate relay node, in a two-phase communication scenario. In this system, a pair of partners transmit to the relay sharing a common spreading signature in the first phase, and the relay broadcasts an estimate of the XORed symbol for each user pair in the second phase employing the relaying scheme termed jointly demodulate-and-XOR forward (JD-XOR-F) in [1]. We investigate the joint power control and receiver optimization problem for this multiuser two-way relay system with JD-XOR-F relaying. We show that the total power optimization problem decouples into two subproblems, one for each phase. We construct the distributed power control and receiver updates in each phase which converge to the corresponding unique optimum. Simulation results are presented to demonstrate the significant power savings of the multiuser two-way relay system with the proposed iterative power control and receiver optimization algorithms, as compared to the designs with a “one-way ” communication perspective.
