Uplink Data Transmission CPRB Collision Prevention
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Solution Overview
Problem
In wireless communication systems, collisions occur during the transmission and reception of uplink data due to the selection of the same CPRB (Contention PUSCH Resource Block) by terminals, leading to errors in error correction responses (HARQ ACK/NACK) and demodulation-reference signal (DMRS) collisions.
Innovation Solution
A method is introduced where a cyclic shift value is allocated based on CPRB indication information to differentiate CPRB resources, allowing terminals to transmit uplink data without an UL grant, and receive HARQ responses through a physical hybrid ARQ indicator channel (PHICH), thereby preventing collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terminals select the same CPRB for uplink data transmission, then transmission efficiency is improved, but collisions occur causing transmission errors
Solution Approach 1:
The patent segments the CPRB resources by introducing cyclic shift values to differentiate between multiple terminals using the same CPRB. Each terminal is assigned a unique cyclic shift value, which divides the transmission space and prevents collisions while maintaining efficient resource utilization.
Solution Approach 2:
The patent applies local quality by assigning different cyclic shift values to different terminals based on their identification information. This creates locally differentiated transmission characteristics for each terminal while using the same overall CPRB resource, enabling simultaneous collision-free transmissions.
2Reliability
If cyclic shift values are allocated based on CPRB indication information, then collisions are prevented, but system complexity increases
Solution Approach 1:
The patent implements self-service by enabling terminals to autonomously determine their cyclic shift values based on their own identification information and the allocated CPRB resources. Each terminal independently calculates its transmission parameters without requiring complex centralized coordination, reducing overall system complexity.
Solution Approach 2:
The patent uses parameter changes by varying the cyclic shift value as a key parameter to differentiate terminals. This simple parameter modification provides effective collision prevention without requiring complex resource allocation mechanisms, as the cyclic shift values can be derived from terminal identification information.
3Productivity
If HARQ ACK/NACK is mapped to the same resource as DMRS, then resource utilization is optimized, but demodulation errors occur
Solution Approach 1:
The patent segments the resource elements within the CPRB by introducing cyclic shift differentiation. This segmentation separates the DMRS and HARQ ACK/NACK signals in the signal space, allowing both to use the same time-frequency resources while preventing demodulation errors through distinct cyclic shift patterns.
Data Source
AI summary
A method for transmitting uplink (UL) data requiring low latency in a wireless communication system according to the present invention, the method performed by a user equipment comprises transmitting contention PUSCH resource block (CPRB) indication information used for identifying a particular UE and/or particular data to an eNB; transmitting UL data to the eNB through CPRB resources of a contention based PUSCH (CP) zone; and receiving a hybrid automatic retransmit request (HARQ) response with respect to the UL data from the eNB through a physical hybrid ARQ indicator channel (PHICH).