RA-RNTI Calculation for Random Access Collision Avoidance
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Solution Overview
Problem
The existing random access procedures in wireless communication systems, such as LTE, face challenges in differentiating between random access preamble transmissions from User Equipment (UE) on the same PRACH resource but in different radio frames, leading to increased contention probability and potential collisions during the random access procedure.
Innovation Solution
The User Equipment (UE) calculates a modified Random Access-Radio Network Temporary Identifier (RA-RNTI) by incorporating the index of the first radio frame of the specified PRACH, ensuring distinct RA-RNTI values for each radio frame, thereby preventing collisions and improving contention resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing random access procedure uses a standard RA-RNTI calculation without incorporating radio frame index, then the procedure is simple and easy to implement, but UEs transmitting on the same PRACH resource in different radio frames cannot be differentiated, leading to increased contention probability and potential collisions
Solution Approach 1:
The patent segments the RA-RNTI calculation by introducing the radio frame index as a distinct parameter component. Instead of using a single unified calculation, the system now considers multiple dimensions (PRACH resource index and radio frame index) separately, allowing differentiation of UEs across different radio frames while maintaining clear modular calculation structure.
Solution Approach 2:
The patent adds another dimension (radio frame index) to the RA-RNTI calculation space. By incorporating the time dimension of radio frame indexing alongside the frequency/resource dimension, the system creates a multi-dimensional identification space that prevents collisions between UEs using the same PRACH resource in different radio frames.
2Reliability
If the RA-RNTI calculation incorporates the index of the first radio frame of the specified PRACH, then distinct RA-RNTI values are generated for each radio frame, but the calculation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the RA-RNTI calculation formula that incorporates radio frame index before the actual random access procedure begins. The calculation methodology is established in advance through system information broadcast, so UEs can autonomously compute their RA-RNTI values without real-time complex processing during the random access attempt.
Solution Approach 2:
The patent changes the parameters used in RA-RNTI calculation from the traditional format to a new format that includes radio frame index. This parameter expansion transforms the calculation from using only resource indices to using a composite of resource index and time index, fundamentally changing the identification mechanism while maintaining calculation efficiency.
3Productivity
If multiple UEs transmit random access preambles on the same PRACH resource in different radio frames, then resource utilization is maximized, but without modified RA-RNTI calculation, Msg3 collisions occur between these UEs
Solution Approach 1:
The patent implements feedback through the modified RA-RNTI calculation that provides implicit feedback about the radio frame of transmission. The RA-RNTI value itself carries information about which radio frame the preamble was sent in, allowing the network to differentiate and properly route responses, and enabling UEs to correctly identify their own random access responses without confusion.
Data Source
Figure 1~2A
Figure 2B
Figure 3(a)~4
AI summary
The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for performing a random access procedure in wireless communication system, the method comprising: transmitting a random access preamble (RAP) on a physical random access channel (PRACH) resource in a radio frame; calculating a random access-radio network temporary identifier (RA-RNTI) by considering time-frequency resource associated with the PRACH resource and an index of a first radio frame of the PRACH resource; and monitoring a physical downlink control channel (PDCCH) identified by the calculated RA-RNTI for RAR reception during a RAR window.