AmplifyandForward in Wireless Relay Networks Samar Agnihotri Sidharth
- Slides: 20
Amplify-and-Forward in Wireless Relay Networks Samar Agnihotri, Sidharth Jaggi, Minghua Chen Institute of Network Coding The Chinese University of Hong Kong
In the Beginning … … there was Analog network coding in the high-SNR regime - Marić, Goldsmith, Médard. Wi. NC 2010 - Layered networks - High SNR ITW 2011 2
Relay Channel s t Capacity is known only for some special cases Capacity of the general relay channel is not known ITW 2011 3
Achievability Schemes • • • Decode-and-Forward (Cover/El Gamal 1979) Compress-and-Forward (Cover/El Gamal 1979) Amplify-and-Forward (Laneman/Tse 2002) Compute-and-Forward (Nazer/Gastpar 2006) Quantize-map-and-Forward (ADT 2010) ITW 2011 4
Achievability Schemes • • • Decode-and-Forward (Cover/El Gamal 1979) Compress-and-Forward (Cover/El Gamal 1979) Amplify-and-Forward (Laneman/Tse 2002) Compute-and-Forward (Nazer/Gastpar 2006) Quantize-map-and-Forward (ADT 2010) ITW 2011 5
Amplify-and-Forward Relaying ITW 2011 6
Amplify-and-Forward Relaying • Cooperative communication • Capacity estimation • ANC ITW 2011 7
General Wireless Networks Any • Size • Topology • Received SNR s ITW 2011 t 8
Network Model -Bidirectional links -Single antenna -Full-duplex -Fixed channel gains, known throughout ITW 2011 9
Amplify-and-Forward in Wireless Networks “Intersymbol Interference Channel with Colored Gaussian Noise” s ITW 2011 t 10
Achievable Rate for AF Relay Network Lemma (Achievable rate for AF relay network): For an AF-relay network with M nodes, the rate achievable with a given amplification vector β is Proof technique: circular convolution, DFT Maximum Achievable rate: W. Hirt, J. L. Massey, Capacity of the discrete-time Gaussian channel with intersymbol interference, Trans. IT, vol IT-34, 1988. ITW 2011 11
“Shout Only If You Make Sense” R 1 1 Ps = P 1 = P 2 = 10 1 Amplify-and-Forward t s Scale-and-Forward 1 0. 1 R 2 ITW 2011 12
Approximating IAF(Ps) Computing IAF(Ps) is ``hard’’ Relay without Delay Approximation* S. Katti, I. Marić, A. Goldsmith, D. Katabi, M. Médard, Joint relaying and network coding in wireless networks, Proc. IEEE ISIT 2007, Nice, France, June 2007. ITW 2011 13
Lower Bound Computation-I βi = β, 1≤ i ≤ M No Attenuation Constant Total Relay Power Type-A Network ITW 2011 14
Lower Bound Computation-II βi = β, 1≤ i ≤ M No Attenuation Constant Total Relay Power Type-B Network ITW 2011 15
Cut-set Upper Bounds s t BC Cut MAC Cut M Relays C ≤ min(CBC , CMAC) ITW 2011 16
Asymptotic Capacity No Attenuation, Constant Total Relay Power (Type-A Network) (Type-B Network) ITW 2011 17
Conclusions A unified framework for AF relay networks Tighter lower bounds for AF relay networks AF relaying can be capacity achieving for a broader class of networks ANC in a class of general networks ITW 2011 18
Current and Future Work Half-duplex networks, multiple-antennas/node, … Distributed schemes Resource-Performance trade-off – rates beyond AF ITW 2011 19
Thank You! Samar Agnihotri Email: samar@ie. cuhk. edu. hk Web: http: //personal. ie. cuhk. edu. hk/~samar/ https: //sites. google. com/site/samaragnihotri / ITW 2011 20
