TY - JOUR
T1 - Dependence balance based outer bounds for gaussian networks with cooperation and feedback
AU - Tandon, Ravi
AU - Ulukus, Sennur
N1 - Funding Information:
Manuscript received December 10, 2008; revised August 16, 2010; accepted December 21, 2010. Date of current version June 22, 2011. This work was supported by NSF Grants CCF 04-47613, CCF 05-14846, CNS 07-16311, and CCF 07-29127, and was presented in part at the IEEE International Conference on Communications, Dresden, Germany, June 2009, the IEEE Information Theory Workshop, Volos, Greece, June 2009, and the IEEE International Symposium on Information Theory, Seoul, South Korea, June 2009.
PY - 2011/7
Y1 - 2011/7
N2 - We obtain new outer bounds on the capacity regions of the two-user multiple access channel with generalized feedback (MAC-GF) and the two-user interference channel with generalized feedback (IC-GF). These outer bounds are based on the idea of dependence balance which was proposed by Hekstra andWillems. To illustrate the usefulness of our outer bounds, we investigate three different channel models. We first consider a Gaussian MAC with noisy feedback (MAC-NF), where transmitter k, k = 1,2, receives a feedback YFk, which is the channel output corrupted with additive white Gaussian noise Z k. For this channel model, the cut-set outer bound is not sensitive to the feedback noise variances. We demonstrate that our outer bound improves upon the cut-set bound for all nonzero values of the feedback noise variances. Moreover, in the limit as σ2Zk → ∞, k = 1,2, our outer bound collapses to the capacity region of the Gaussian MAC without feedback. Secondly, we investigate a Gaussian MAC with user-cooperation (MAC-UC), where each transmitter receives an additive white Gaussian noise corrupted version of the channel input of the other transmitter. For this channel model, the cut-set bound is sensitive to the cooperation noises, but not sensitive enough. For all nonzero values of cooperation noise variances, our outer bound strictly improves upon the cut-set outer bound. Moreover, as the cooperation noises become large, our outer bound collapses to the capacity region of the Gaussian MAC without cooperation. Thirdly,we investigate a Gaussian IC with user-cooperation (ICUC). For this channel model, the cut-set bound is again sensitive to cooperation noise variances as in the case of MAC-UC channel model, but not sensitive enough. We demonstrate that our outer bound strictly improves upon the cut-set bound for all nonzero values of cooperation noise variances.
AB - We obtain new outer bounds on the capacity regions of the two-user multiple access channel with generalized feedback (MAC-GF) and the two-user interference channel with generalized feedback (IC-GF). These outer bounds are based on the idea of dependence balance which was proposed by Hekstra andWillems. To illustrate the usefulness of our outer bounds, we investigate three different channel models. We first consider a Gaussian MAC with noisy feedback (MAC-NF), where transmitter k, k = 1,2, receives a feedback YFk, which is the channel output corrupted with additive white Gaussian noise Z k. For this channel model, the cut-set outer bound is not sensitive to the feedback noise variances. We demonstrate that our outer bound improves upon the cut-set bound for all nonzero values of the feedback noise variances. Moreover, in the limit as σ2Zk → ∞, k = 1,2, our outer bound collapses to the capacity region of the Gaussian MAC without feedback. Secondly, we investigate a Gaussian MAC with user-cooperation (MAC-UC), where each transmitter receives an additive white Gaussian noise corrupted version of the channel input of the other transmitter. For this channel model, the cut-set bound is sensitive to the cooperation noises, but not sensitive enough. For all nonzero values of cooperation noise variances, our outer bound strictly improves upon the cut-set outer bound. Moreover, as the cooperation noises become large, our outer bound collapses to the capacity region of the Gaussian MAC without cooperation. Thirdly,we investigate a Gaussian IC with user-cooperation (ICUC). For this channel model, the cut-set bound is again sensitive to cooperation noise variances as in the case of MAC-UC channel model, but not sensitive enough. We demonstrate that our outer bound strictly improves upon the cut-set bound for all nonzero values of cooperation noise variances.
KW - Dependence balance
KW - generalized feedback
KW - noisy feedback
KW - user cooperation
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U2 - 10.1109/TIT.2011.2145150
DO - 10.1109/TIT.2011.2145150
M3 - Article
AN - SCOPUS:79959535770
SN - 0018-9448
VL - 57
SP - 4063
EP - 4086
JO - IEEE Transactions on Information Theory
JF - IEEE Transactions on Information Theory
IS - 7
M1 - 5895096
ER -