Relay Node Association in Multi-Hop Wireless Networks

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Solution Overview

Problem

Wireless networks face challenges in extending communication range without increasing overhead, particularly in systems with relay nodes, where legacy receivers may disregard or fail to decrypt retransmitted frames due to modifications in MAC headers for encryption keys.

Innovation Solution

The method involves indicating a network address of an access point to clients through a relay, forwarding association requests, encrypting messages based on original and final destination addresses, and transmitting encrypted messages through relays for delivery, while determining association success or failure and filtering subsequent messages as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If relay devices are used to extend wireless network range, then communication coverage is improved, but overhead such as association, encryption, and filtering increases

Engineering Contradiction:
Improvenetwork coverage areaVSAvoidoverhead complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent introduces a relay node as an intermediary device that forwards data frames between stations and access points. The relay node acts as a mediator that receives frames from stations, modifies their MAC headers to indicate relayed status, and forwards them to the appropriate access point, thereby extending network coverage without requiring direct station-to-AP connectivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies specific parameters in the MAC header of data frames, particularly the Duration/ID field and Address fields, to indicate that a frame has been relayed. These parameter changes allow receiving devices to properly handle relayed frames, distinguish them from direct frames, and manage their transmission queues appropriately, thus managing the complexity introduced by relay operations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If MAC header fields are modified for encryption key generation, then security is improved, but legacy receivers cannot decrypt retransmitted frames

Engineering Contradiction:
Improveencryption securityVSAvoidreceiver compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extracts the encryption-related header modifications from the visible MAC header structure that legacy devices can interpret. By using specific fields (such as the Duration/ID field) that legacy devices typically ignore or treat as non-critical, the patent allows modern devices to derive encryption keys from header contents without preventing legacy devices from functioning, as they simply cannot decrypt the payload but can still process the frame structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary encryption of data frames before they are transmitted through the relay node. The encryption keys are generated based on modifications to MAC header fields, and this encryption is applied in advance. When frames are retransmitted, the encryption is already in place, and legacy receivers that cannot decrypt simply disregard these frames, while modern receivers can properly process them.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If association requests are forwarded through relays, then network connectivity is improved, but association overhead increases

Engineering Contradiction:
Improvenetwork connectivityVSAvoidassociation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The relay node serves as an intermediary that forwards association requests between stations and access points. Instead of requiring stations to directly associate with distant access points, the relay node receives association requests from stations, forwards them to the appropriate access point, and relays responses back, enabling connectivity in multi-hop scenarios.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The relay node performs multiple functions: it acts as a forwarding device for data frames, serves as an intermediary for association requests, and provides network topology information to stations. By consolidating these multiple functions in a single node, the patent reduces the need for separate dedicated association infrastructure, thereby reducing overall association overhead.

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

Data Source

PatentEP2893733B1Systems, apparatus, and methods for association in multi-hop networks
Publication Date: 2021.03.17 QUALCOMM INC
  • EP2893733B1 patent drawingFigure 1
  • EP2893733B1 patent drawingFigure 2A
  • EP2893733B1 patent drawingFigure 2B

AI summary

Systems, methods, and devices for communicating data in a wireless communications network are described herein. One aspect of the present disclosure includes a method of communicating in a wireless network. The method includes encrypting a message based, at least in part, on an original source address, and a final destination address (805). The method further includes transmitting the encrypted message to a relay ((107a), (107b), (107c)) for delivery to the final destination address (806).