wiki:Projects/Rice_FullDuplex

Rice University Full Duplex Communication Example

Rice University has posted an example of a full-duplex implementation using WARP. The design, copyright Rice University, is provided under the WARP Project License.

Description

Current deployed wireless communication systems employ devices which use either a time-division or frequency-division approach for wireless transmission and reception of signals. This requires dividing the temporal and/or spectral resources into orthogonal resources and results in an orthogonalization of the transmissions and receptions performed by a wireless device. Consequently, all currently deployed wireless devices operate in half-duplex fashion, where same frequency simultaneous transmission and reception of signals is not possible. The key challenge in achieving full-duplex wireless communications, where a device can transmit and receive signals over-the-air at the same time and in the same frequency band, is the large power differential between the self-interference created by a device's own wireless transmissions and the received signal of interest coming from a distant transmitting antenna. This large power differential is due to the fact that the self-interference signal has to travel much shorter distances than the signal-of-interest. The large self-interference spans most of the dynamic range of the Analog to Digital Converter (ADC) in the received signal processing path, which in turn dramatically increases the quantization noise for the signal-of-interest. Thus to achieve full-duplex it is essential to suppress the self-interference before the analog received signal is sampled by the ADC.

Current wireless network designs have assumed that the power differential between the self-interference and the signal of interest is such that it is impossible to cancel the self-interference enough in order to make full-duplex wireless communications feasible. However, recent work in self-interference cancellation and full-duplex implementation has demonstrated that it is possible to implement self-interference cancellation mechanisms that can sufficiently attenuate the self-interference such that the resulting full-duplex wireless system can achieve higher rates than a half-duplex system.

The code and explanations provided in this release will help the user get a full-duplex setup running. If a user is interested in reproducing this example in the lab we recommend to carefully follow the instructions below. There is a risk of permanently damaging the radios if the radios are connected in the wrong way. The user should use the code and explanation provided below in this document at his/her own risk.

Full Duplex Laboratory Setup

User Guide

Full Duplex User Guide (pdf)

Hardware Compatibility

The full duplex project from Rice University was constructed on a modified version of the WARPLab v5.2 Reference Design for WARP v1 hardware. The modifications to this design are provided in the design files posted below. For newer hardware, these changes can be used as a starting point for modifying more recent releases of the WARPLab Reference Design.

Design Files

Download Design Files: Rice_FullDuplex.zip

Related WARP Publications

Last modified 6 years ago Last modified on Apr 29, 2013, 6:50:54 PM

Attachments (2)

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