Uplink Downlink BWP Linkage for Random Access Latency

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Solution Overview

Problem

In 5G mobile communication systems, user equipment (UE) needs to switch back to initial uplink and downlink bandwidth parts (BWP) for random access, leading to increased loading and signal transmission collisions, which hampers resource utilization and increases transmission latency.

Innovation Solution

A BWP configuration mechanism that allows UE to transmit preambles on active uplink BWPs and receive random access response messages on corresponding active downlink BWPs, reducing the need to switch back to initial BWPs and minimizing signal transmission collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE switches back to initial uplink BWP to transmit preamble, then BS can receive the preamble on initial uplink BWP, but UE must switch BWP which increases transmission latency and causes resource utilization imbalance

Engineering Contradiction:

Improvepreamble transmission reliabilityVSAvoidtransmission latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The base station pre-configures multiple uplink BWPs and establishes correspondence relationships between them before random access occurs. This preliminary configuration allows the UE to directly transmit preambles on the currently activated uplink BWP without needing to switch back to the initial uplink BWP, thereby reducing transmission latency while ensuring reliable preamble reception at the base station

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically activates different uplink BWPs based on UE requirements and establishes flexible correspondence relationships with downlink BWPs. This dynamic approach allows the UE to transmit preambles on whichever uplink BWP is currently activated, eliminating the need for BWP switching and reducing transmission latency while maintaining reliable communication

Inventive Principle:

Principle #15Dynamics

2Reliability

If all UEs switch back to initial uplink BWP for random access, then BS can reliably receive preambles, but resource loading on initial uplink BWP increases causing signal transmission collisions

Engineering Contradiction:

Improvepreamble reception reliabilityVSAvoidsignal transmission collisions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The uplink bandwidth is divided into multiple uplink BWPs (first, second, third, etc.), each capable of independently receiving preambles. The base station configures correspondence relationships between different uplink BWPs, allowing UEs to distribute their random access transmissions across multiple segmented bandwidth parts. This segmentation reduces the concentration of signal transmissions on a single initial uplink BWP, thereby reducing signal transmission collisions while maintaining reliable preamble reception

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different uplink BWPs are configured with different properties and correspondence relationships with downlink BWPs. The system allows specific local characteristics (such as which uplink BWP corresponds to which downlink BWP) to be customized, enabling UEs to transmit preambles on locally optimal uplink BWPs rather than forcing all UEs to use the initial uplink BWP, thus reducing collisions while maintaining reliability

Inventive Principle:

Principle #3Local quality

3Reliability

If BS transmits random access response message on every downlink BWP, then all UEs can receive the message, but BS loading increases

Engineering Contradiction:

Improverandom access response message deliveryVSAvoidBS transmission loading

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The base station pre-establishes correspondence relationships between uplink BWPs and downlink BWPs before random access occurs. When a UE transmits a preamble on a specific uplink BWP, the base station can directly transmit the random access response message on the pre-configured corresponding downlink BWP without needing to transmit on all downlink BWPs. This preliminary configuration reduces base station transmission loading while ensuring that UEs can reliably receive their response messages on the correct downlink BWP

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The correspondence relationship between uplink and downlink BWPs acts as an intermediary that links the transmission and reception sides. Instead of the base station transmitting random access response messages on all downlink BWPs, the correspondence relationship enables targeted transmission on the specific downlink BWP that corresponds to the uplink BWP where the preamble was received, reducing BS loading while maintaining reliable message delivery

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10791578B2User equipment and base station for mobile communication system having a linkage between uplink BWPS and downlink BWPS

Publication Date: 2020.09.29 INSTITUTE FOR INFORMATION INDUSTRY

AI summary

A user equipment (UE) and a base station (BS) for a mobile communication system are provided. The UE transmits a preamble to the BS on a physical random access channel of an active uplink bandwidth part of a plurality of uplink bandwidth parts and receives a random access response message from the BS on an active downlink bandwidth part of a plurality of downlink bandwidth parts according to a linkage. The linkage defines that the active downlink bandwidth part corresponds to the active uplink bandwidth part.