Node having an adaptive space-spectrum whiteniner and multi-user rake receiver for use in a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission with cooperative beamforming and adaptive space-spectrum whitening

Patent metadata

Field	Value
Publication number	US-11050458-B2
Application number	US-201916661917-A
Country	US
Kind code	B2
Filing date	Oct 23, 2019
Priority date	Mar 25, 2019
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A node is provided for a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission. The node includes antennas and a waveform module having a receiver processing chain that can include an adaptive space-spectrum whitener (ASSW) module and a multi-user RAKE (mRAKE) receiver. Each antenna can receive output a channel that includes direct-sequence spread-spectrum signals received from other nodes and multi-path components of those transmissions. The ASSW module can perform adaptive space-spectrum whitening to detect and remove interference signals received from each of the channels by performing a covariance analysis to generate channelized signals. The ASSW module can include modified Discrete Fourier Transform (MDFT) analysis and synthesis modules that generate an interference mitigated time-domain channelized signals. The mRAKE receiver, when performing demodulation processing, can combine the interference mitigated time-domain channelized signals to generate fingers that combine components of transmissions received from the other nodes.

First claim

What is claimed is:

1. A node configured to communicate in a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission using a direct-sequence spread-spectrum (DSSS) waveform, the node comprising: a first antenna configured to receive a first plurality of DSSS signals from other nodes on a first particular channel, and output a first channel that includes the first plurality of DSSS signals, wherein the first plurality of DSSS signals include transmissions that are directly received from other nodes and multi-path components of those transmissions; a second antenna configured to receive a second plurality of DSSS signals from the other nodes on a second particular channel, and output a second channel that includes the second plurality of DSSS signals, wherein the second plurality of DSSS signals include transmissions that are directly received from the other nodes and multi-path components of those transmissions; and:
a waveform module having a receiver processing chain comprising:
one or more hardware-based processors and memory comprising processor-executable instructions encoded on a non-transient processor-readable media, wherein the one or more hardware-based processors are configurable by the processor-executable instructions to implement:
an adaptive space-spectrum whitener (ASSW) module that is configured to: perform adaptive space-spectrum whitening to detect and remove interference signals received from each of the first and second channels by performing a covariance analysis to generate a plurality of channelized signals comprising: a first channelized signal that comprises transformed beam samples for the first channel and a second channelized signal that comprises transformed beam samples for the second channel,
wherein the ASSW module comprises: a modified Discrete Fourier Transform (MDFT) analysis module comprising: a plurality of an MDFT analysis banks, wherein each MDTF analysis bank corresponds to one of the first and second antennas and is configured to: receive a beam from one of the first and second antennas in the spectral domain,
wherein each beam comprises a digitized spatial stream of frequency channelized RF samples that are digitized to preserve spatial diversity; and channelize the beam to generate a channelized beam of frequency samples, wherein each channelized beam comprises multiple spectral channels,
wherein the channelized beams collectively comprise a number of spectral-spatial channels equal to the product of the number of channelized beams and the multiple spectral channels,
wherein the channelized beams collectively form a spatial-spectral matrix (Z) of time-frequency samples across the different antennas;
an adaptive interference mitigation space-frequency whitener module configured to: apply a whitening matrix (W) to the spatial-spectral matrix (Z) to remove interference and generate an interference-mitigated whitened matrix (WZ) that comprises a plurality of interference-mitigated spatial-spectral domain channels; and
a MDFT synthesis module comprising: a plurality of MDFT synthesis banks that collectively re-construct the interference-mitigated whitened matrix (WZ) back to a time-domain matrix (Y) that comprises a plurality of interference mitigated time-domain channelized signals,
wherein each MDFT synthesis bank is configured to perform a MDFT synthesis operation on one of the spatial-spectral domain channels to generate an interference mitigated time-domain channelized signal of reconstructed beam samples, wherein each interference mitigated time-domain channelized signal represents a respective spatial channel; and
a multi-user RAKE receiver is configured to: combine, when performing demodulation processing, the plurality of interference mitigated time-domain channelized signals to generate a subset (1 . . . F) of fingers that combine components of a plurality of transmissions directly received from the other nodes and multipath components of transmissions received from the other nodes.

2. The node according to claim 1 , wherein each row of the spatial-spectral matrix (Z) represents spatial-spectral samples unique to one of the channelized beams, and wherein each column of the spatial-spectral matrix (Z) represents time indices.

3. The node according to claim 2 , wherein the adaptive interference mitigation space-frequency whitener module is configured to calculate auto-correlation matrices across rows of the spatial-spectral matrix (Z) such that the resulting whitened matrix (WZ) is a diagonal correlation matrix.

4. The node according to claim 1 , wherein the one or more hardware-based processors are further configurable by the processor-executable instructions to implement:
a de-hop module configured to: de-hop each of the received DSSS signals by tuning to a particular frequency to receive each DSSS signal and then channelizing input spectrum for each of the received DSSS signals to generate beam samples for each channelized signal.

5. The node according to claim 1 , wherein the multi-user RAKE receiver comprises: first and second correlation modules and a finger selection module, and wherein the one or more hardware-based processors are further configurable by the processor-executable instructions to implement: the first and second correlation modules each being configured to receive the first and second channelized signals output by the ASSW module, wherein each of the first and second channelized signals is a spatial stream, wherein each of the first and second correlation modules comprises: correlator blocks for each of the plurality of nodes (1, . . . , N), wherein each correlator block is driven by a unique scramble code that identifies transmissions from a particular node and performs correlation for that particular node by processing a spatial stream received from the ASSW module and the unique scramble code for that particular node to determine channel-multipath correlations and generate one or more candidate fingers multipath location and respective complex weight, wherein each finger corresponds to a specific channel-signal pair for that particular node or a specific channel-multipath component pair for that particular node; and the finger selection module configured to receive the fingers output from each correlator block and to select the subset (1 . . . F) of the fingers having sufficient correlation by selecting which nodes contribute to the F total largest signal multipath components received.

6. The node according to claim 5 , wherein the unique scramble code is a first code that is unique for that particular node that is logically combined with a security code.

7. The node according to claim 5 , wherein the one or more hardware-based processors are further configurable by the processor-executable instructions to implement: a maximum likelihood ratio combiner module configured to: maximally ratio combine aligned symbols for each of a subset (1 . . . F) of fingers on a per channel basis to generate a soft decision across each of the multiple channels; and combine the soft decisions into a joint soft decision.

8. The node according to claim 7 , wherein the maximum likelihood ratio combiner module comprises: a plurality of processing modules comprising: a processing module for each of the other nodes that processes signals for that node, wherein each processing module comprises: a coherent combine module for that node that is configured to receive a number of the subset of fingers from the finger selection module, and coherently combine that number of the subset of fingers to generate an output signal; a descrambler for that node that is configured to descramble the output signal received from that coherent combine module using a unique descramble code for t

Assignees

• General Dynamics Mission Systems Inc

Inventors

• Blanchard Scott David
• Lee David Kunil

Classifications

• Y02D30/70

  in wireless communication networks · CPC title

• H04W88/04

  adapted for relaying to or from another terminal or user · CPC title

• H04B1/7115 Primary

  Constructive combining of multi-path signals, i.e. RAKE receivers · CPC title

• H04B1/692 Primary

  Hybrid techniques using combinations of two or more spread spectrum techniques · CPC title

• H04L27/26524

  Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation · CPC title