Reciprocal Geometric Precoding for Wireless Network Overhead Reduction

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Solution Overview

Problem

Current wireless communication networks face challenges in managing bandwidth and providing high-quality service due to the exponential growth in wireless data traffic and user devices.

Innovation Solution

The proposed solution involves a method for precoding signal transmissions in wireless networks based solely on the channel state determined for the reverse direction of transmissions, using a precoding scheme that is completely defined by the uplink channel state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If downlink channel state information is obtained through explicit feedback from user devices, then channel state accuracy for precoding is improved, but network overhead and latency increase

Engineering Contradiction:
Improvechannel state accuracyVSAvoidnetwork overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent inverts the traditional approach by obtaining channel state information through uplink reference signal transmissions instead of downlink explicit feedback. The network device determines uplink channel state from reference signals transmitted by user devices, and uses this uplink channel state to define the precoding scheme for downlink transmissions, eliminating the need for downlink channel feedback while maintaining channel state accuracy through channel reciprocity

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

User devices self-transmit uplink reference signals that enable the network device to autonomously determine the channel state without requiring external feedback from the user devices. The network device performs self-service by using the uplink channel measurements to generate precoding schemes, eliminating dependency on downlink feedback mechanisms

Inventive Principle:
Principle #25Self-service

2Measurement precision

If downlink channel state information is obtained through explicit feedback from user devices, then channel state accuracy for precoding is improved, but service latency increases

Engineering Contradiction:
Improvechannel state accuracyVSAvoidservice latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The network device performs preliminary channel state determination by measuring uplink reference signal transmissions from user devices before downlink data transmissions occur. This preliminary action of obtaining channel state information through uplink measurements eliminates the need for subsequent feedback transmission, reducing service latency while maintaining channel state accuracy for precoding

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If channel state information is obtained from multiple directions, then precoding accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveprecoding accuracyVSAvoidchannel measurement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The uplink reference signal transmissions serve multiple functions: they enable channel state determination, provide channel reciprocity information for precoding, and eliminate the need for separate downlink channel measurement and feedback mechanisms. This multi-functionality achieves precoding accuracy while reducing overall system complexity by consolidating channel information gathering into a single uplink measurement process

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3981082B1Reciprocal geometric precoding
Publication Date: 2025.01.29 COHERE TECHNOLOGIES INC
  • EP3981082B1 patent drawingFigure 1A
  • EP3981082B1 patent drawingFigure 1B
  • EP3981082B1 patent drawingFigure 1C

AI summary

Methods, systems and devices for reciprocal geometric precoding are described. One example method includes determining, by a network device, an uplink channel state using reference signal transmissions received from multiple user devices, and generating a precoded transmission waveform for transmission to one or more of the multiple user devices by applying a precoding scheme that is based on the uplink channel state, wherein the uplink channel state completely defines the precoding scheme. In some embodiments, the reference signal transmissions and the precoded transmission waveform are multiplexed using either time-domain multiplexing or frequency-domain multiplexing.