Random Access Channel Purpose ID for Control Overhead Reduction

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Solution Overview

Problem

Conventional random access channels (RACH) in mobile communication systems require multiple transmissions of control channels (CCH) for uplink and downlink, increasing communication overhead due to limited information transmission.

Innovation Solution

Incorporating a 'purpose ID' in the random access channel (RACH) and control channel to facilitate resource allocation based on the content of subsequent control channels, reducing the number of CCH transmissions by determining resource allocation dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional random access channel (RACH) transmits only limited information indicating data transmission request, then the random access channel structure remains simple, but the number of control channel (CCH) transmissions increases and communication overhead increases

Engineering Contradiction:
Improverandom access channel structureVSAvoidnumber of control channel transmissions
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by including the purpose ID in the RACH transmission before the actual data transmission. This allows the base station to pre-allocate resources and determine the type of subsequent control channel needed, eliminating the need for multiple CCH transmissions. The purpose ID is embedded in the RACH message itself, enabling the base station to understand the transmission purpose (e.g., initial access, scheduling request, handover) and prepare appropriate resources in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the communication process by dividing the RACH transmission into distinct purpose categories using the purpose ID. Each purpose ID represents a specific transmission intent (initial access, scheduling request, handover, etc.), allowing the system to handle different types of communications separately and efficiently. This segmentation enables targeted resource allocation and reduces the need for generic multiple CCH transmissions.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple control channel (CCH) transmissions are performed following RACH, then resource allocation can be confirmed, but communication overhead increases and transmission efficiency decreases

Engineering Contradiction:
Improveresource allocation confirmationVSAvoidcommunication efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements feedback by using the purpose ID in the RACH transmission to provide the base station with information about the user's transmission intent. The base station uses this feedback to make immediate resource allocation decisions without requiring multiple back-and-forth CCH transmissions. The purpose ID acts as a feedback mechanism that conveys essential information (user ID allocation status, transmission purpose) enabling the base station to confirm resource allocation in a single step.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

By including the purpose ID that indicates whether a user ID is uniquely allocated and the transmission purpose, the system performs preliminary resource allocation planning before actual data transmission. The base station can pre-determine the appropriate control channel type and allocate resources accordingly, eliminating the need for multiple confirmatory transmissions and improving overall communication efficiency.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If limited information is transmitted in RACH, then the RACH message size remains small, but subsequent control channel transmissions increase communication overhead

Engineering Contradiction:
ImproveRACH message sizeVSAvoidnumber of transmissions
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The purpose ID serves multiple functions simultaneously: it indicates whether a user ID is uniquely allocated, specifies the transmission purpose (initial access, scheduling request, handover, etc.), and enables resource allocation decisions. This multi-functionality allows the RACH message to convey essential information without significantly increasing message size, while reducing the need for subsequent CCH transmissions and improving overall communication efficiency.

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

Data Source

PatentEP2699047B1Base station and method in mobile communication system
Publication Date: 2015.03.18 NTT DOCOMO INC
  • EP2699047B1 patent drawingFigure 1
  • EP2699047B1 patent drawingFigure 2
  • EP2699047B1 patent drawingFigure 3

AI summary

A disclosed user apparatus includes a random access channel generating unit configured to generate a random access channel; a control channel generating unit configured to generate a control channel in accordance with scheduling information received from a base station; and an uplink transmission signal generating unit configured to generate an uplink transmission signal including the random access channel or the control channel. Further, the purpose ID indicating at least whether there is a user ID uniquely allocated by the base station is included in the random access channel or the control channel.