Beam Load Indicator for Random Access Delay Reduction
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Solution Overview
Problem
In wireless communication networks, especially in 5G New Radio (NR) systems, the random access procedure is affected by unequal load distribution across multiple beams, leading to performance degradation due to the current beam selection methods not accurately reflecting the load situation, resulting in unnecessary delays and congestion.
Innovation Solution
A method where user equipment (UE) receives a backoff indicator in the random access response (RAR) to select an alternative beam with sufficient signal strength, skipping backoff and balancing load across beams, and the radio network node configures UE to skip backoff behavior by indicating beam load conditions, allowing for dynamic beam reselection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE performs backoff operation as indicated in RAR, then collision probability is reduced, but random access delay increases
Solution Approach 1:
The patent applies dynamics by making the backoff operation conditional rather than fixed. The UE dynamically decides whether to perform backoff based on real-time beam load conditions received from the gNB. When the alternative beam has low load, the UE skips backoff; when load is high, backoff is performed. This dynamic adaptation resolves the contradiction between reducing collisions and minimizing delay.
Solution Approach 2:
The patent changes the parameter of backoff behavior from a fixed mandatory operation to a conditional operation based on beam load parameters. The gNB provides beam load information (e.g., RSRP thresholds, load indicators) that the UE uses to adjust its backoff decision. This parameter-based control allows the system to optimize between collision avoidance and access speed based on current network conditions.
2Ease of operation
If UE selects beam based on SS-RSRP only, then beam selection is simple, but load distribution becomes unequal
Solution Approach 1:
The patent implements feedback by having the gNB provide beam load information to the UE. The gNB monitors the actual load on each beam and feeds this information back to UEs through system information or dedicated signaling. UEs use this feedback to adjust their beam selection beyond just SS-RSRP, choosing beams with both good signal quality and acceptable load. This feedback mechanism balances simplicity with effective load distribution.
Solution Approach 2:
The patent adds another dimension to beam selection by incorporating beam load information as an additional criterion alongside SS-RSRP. Instead of selecting beams based solely on signal strength (one dimension), UEs now consider both signal quality and load conditions (two dimensions). This multi-dimensional approach maintains operational simplicity while achieving better load distribution across beams.
3Speed
If UE transmits preamble on overloaded beam, then access speed is fast, but congestion increases
Solution Approach 1:
The patent applies preliminary action by having UEs check beam load conditions before transmitting preambles. The gNB provides beam load information in advance (through system information or RAR), allowing UEs to identify suitable beams with sufficient capacity before attempting access. This preliminary assessment prevents UEs from immediately transmitting on overloaded beams, thereby avoiding congestion while maintaining fast access on underutilized beams.
Solution Approach 2:
The patent uses beam load information as an intermediary between the UE and the beam selection decision. Rather than UEs directly experiencing and reacting to congestion after transmission, the beam load indicator serves as an intermediary that guides UEs to select appropriate beams in advance. This intermediary mechanism allows UEs to avoid congested beams proactively, maintaining both speed and preventing harm.
Data Source
AI summary
Embodiments herein relate to a method performed by a user equipment for handling communication in a wireless communication network. The user equipment receives a RAR comprising an indicator indicating a load of a beam from the radio network node. The user equipment further transmits a preamble in a selected beam selected based on the indicator.