Two-Step Random Access Procedure for Wireless Signaling Efficiency
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Solution Overview
Problem
Current wireless communication systems, such as LTE and 5G NR, face inefficiencies in the four-step random access procedure, particularly in distinguishing between user equipment during contention-based access, leading to unsuccessful access attempts due to the reliance on user IDs in the fourth step.
Innovation Solution
A two-step random access procedure is introduced, merging the random access preamble and Msg3 into MsgA and combining contention resolution and responses in MsgB, using BPSK or π/2-BPSK modulation with CP-OFDM waveform, allowing for more efficient signaling and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a four-step random access procedure is used, then user equipment can establish connection with the network, but signaling overhead increases and power consumption rises
Solution Approach 1:
The patent merges the four-step random access procedure into a two-step procedure by combining Message 1 and Message 3 into a single MsgA transmission, and combining Message 2 and Message 4 into a single MsgB transmission. This reduces the number of uplink transmissions required from four to two, directly reducing power consumption while maintaining connection establishment reliability
Solution Approach 2:
The patent segments the random access procedure into two distinct phases: MsgA containing the preamble and uplink data, and MsgB containing the random access response and contention resolution. This segmentation allows for more efficient resource allocation and reduced signaling overhead compared to the traditional four-step approach
2Reliability
If four-step random access procedure is used, then user equipment can transmit data, but signaling efficiency decreases
Solution Approach 1:
The patent combines multiple signaling functions into fewer messages: MsgA combines the random access preamble and uplink data transmission, while MsgB combines the random access response and contention resolution. This merging reduces the total number of signaling exchanges from four to two, improving signaling efficiency while maintaining data transmission capability
Solution Approach 2:
MsgA serves multiple functions simultaneously: it acts as both the random access preamble and the uplink data transmission vehicle. Similarly, MsgB serves dual purposes as both the random access response and the contention resolution message. This multi-functionality reduces signaling overhead and improves efficiency
3Reliability
If four-step random access procedure is used, then user equipment can complete access, but access time increases
Solution Approach 1:
By merging the four-step procedure into two steps where MsgA contains both the preamble and uplink data, and MsgB contains both the response and contention resolution, the patent reduces the number of round-trip transmissions required. This directly reduces access time while ensuring complete access through the integrated contention resolution in MsgB
Solution Approach 2:
The patent performs contention resolution preliminarily within MsgB rather than requiring a separate fourth step. This preliminary action allows the access procedure to complete in just two steps, reducing access time while maintaining reliable access completion through embedded contention resolution
Data Source
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AI summary
Methods, systems, and devices for a two-step random access procedure in mobile communication technology are described. An exemplary method for wireless communication includes receiving, by a network node, a random access message that comprises at least one of a radio network temporary identifier (RNTI), an identity of the wireless device, an establishment cause, uplink control information (UCI) or beam information, and transmitting, to a wireless device, a contention resolution message, wherein at least a portion of the random access message is modulated using a first modulation scheme selected from a modulation group that comprises binary phase shift keying (BPSK) and π/2-BPSK.