Cognitive Communications

Project Description:

Figure 1. The full-duplex modes for the causal cognitive interference channel.

Figure 1. The full-duplex modes for the causal cognitive interference channel.

The causal cognitive interference channel (CCIC) has two sender-receiver pairs, in which the second sender obtains information from the first sender causally. The second sender assists the first sender’s transmission, in addition to transmitting its own information. In this project, we study both the full- and half-duplex modes. In each mode, we propose two new coding schemes built successively upon one another to illustrate the impact of different coding techniques.

 

Transmission Scheme:

The first scheme, called partial decode-forward binning (PDF-binning), combines the ideas of partial decode-forward relaying and Gelfand-Pinsker binning. The second scheme, called Han-Kobayashi partial decode-forward binning (HK-PDF-binning), combines PDF-binning with Han-Kobayashi coding by further splitting rates and applying superposition coding, conditional binning, and relaxed joint decoding.

Figure 2. Coding structure for the full-duplex PDF-binning scheme at block i. (SP stands for superposition, Bin stands for binning.)

Figure 2. a) Coding structure for the full-duplex PDF-binning scheme at block i.
(SP stands for superposition, Bin stands for binning. b) Coding structure for the full-duplex Han-Kobayashi PDF-binning scheme at block i.)

Numerical Results

Figure 4 shows the comparison in the full-duplex mode among the Han-Kobayashi scheme, PDF-binning, HK-PDF-binning, and the outer bound. As illustrated by the figure, the proposed HD-PDF-binning scheme contains both the Han-Kobayashi and the PDF-binning rate regions.

Figure 5 compares the HK-PDF-binning schemes with existing half-duplex schemes for the CCIC in Devroye2006TIT, ChatterjeeISIT2010. It’s evident that HK-PDF-binning is strictly better than all existing schemes.

Figure 4. Rate regions for full-duplex schemes in the Gaussian causal cognitive interference channel.

Figure 3. a) Rate regions for full-duplex schemes in the Gaussian causal cognitive interference channel; b) Comparison of the HK-PDF-binning schemes with existing schemes.

Publications:

  1. A Half-Duplex Transmission Scheme for the Gaussian Causal Cognitive Interference Channel,
    Z. Wu and M. Vu, IEEE International Conf. on Comm. (ICC), June 2013.
  2. Partial Decode-Forward Binning for Full-Duplex Causal Cognitive Interference Channels,
    Z. Wu and M. Vu, IEEE Int’l Symposium on Info. Theory (ISIT), July 2012.