Two-Step Random Access Control via Multiplexing

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Solution Overview

Problem

In future radio communication systems, such as 5G, the random access procedure is often performed in fewer steps than the traditional four steps, leading to potential deterioration in communication quality due to inadequate control mechanisms.

Innovation Solution

A user terminal is designed with a transmitting section for sending UL signals, a receiving section for responding to these signals, and a control section that applies frequency or time multiplexing to manage the transmission of preamble and message parts, allowing for flexible resource allocation and retransmission control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the random access procedure is performed in fewer steps (e.g., two steps instead of four), then the communication efficiency and speed are improved, but the control precision and reliability of the random access process deteriorate

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidrandom access control reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the random access procedure into distinct phases: preamble transmission phase and message transmission phase. The control section separately manages these phases, applying different multiplexing strategies to each. This segmentation allows the system to maintain simplified two-step operation while implementing precise control mechanisms for each phase, thereby resolving the contradiction between speed and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control by allowing the control section to flexibly switch between frequency multiplexing and time multiplexing based on channel conditions and traffic requirements. This dynamic adaptability enables the system to maintain high communication efficiency while ensuring reliable random access control under varying conditions, resolving the contradiction between speed and reliability.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If frequency multiplexing is applied to separate preamble and message transmissions, then the resource allocation flexibility is improved, but the device complexity increases

Engineering Contradiction:

Improveresource allocation flexibilityVSAvoidtransmission control complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control section is designed as a universal control unit that can perform multiple functions: it manages both frequency multiplexing and time multiplexing, controls preamble transmission, controls message transmission, and adapts to different random access scenarios. This multi-functionality reduces the need for separate dedicated control mechanisms, thereby achieving resource allocation flexibility without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11818754B2Terminal, radio communication method, base station, and system

Publication Date: 2023.11.14 NTT DOCOMO INC

AI summary

A terminal is disclosed including a receiver that receives a synchronization signal block (SSB); a processor that determines, based on the SSB, a time resource for a preamble used for a 2-step random access procedure, and determines, based on the SSB, a time resource for an uplink shared channel (PUSCH) used for the random access procedure; and a transmitter that transmits the preamble and the PUSCH. In other aspects a radio communication method, a base station, and a system are also disclosed.