Random Access Synchronization Using Shifted PRACH Detection Windows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional base station configurations struggle with synchronization failures due to large round-trip delays in distributed antenna systems (DAS), particularly when only PRACH short preamble formats are used, leading to incorrect PRACH preamble detection and round-trip delay estimation issues.
Innovation Solution
A method involving delaying the PRACH detection window by a shift value based on stored network device delay, estimating the first round-trip delay, and determining a timing advance to ensure uplink communications are received within the uplink receive window, thereby extending the supported round-trip delay range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PRACH short preamble formats are used in conventional base station configurations, then device complexity is reduced, but synchronization reliability deteriorates due to large round-trip delays in distributed antenna systems
Solution Approach 1:
The patent applies parameter changes by modifying the PRACH detection window timing parameter. Specifically, the detection window is delayed by a shift value that compensates for the round-trip delay in DAS systems. This timing adjustment allows the base station to correctly detect PRACH preambles even when large round-trip delays are present, thereby maintaining synchronization reliability without increasing device complexity.
2Reliability
If the PRACH detection window is delayed by a shift value to accommodate large round-trip delays, then synchronization reliability is improved, but measurement precision of round-trip delay deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the shift value in the base station before the synchronization process begins. The shift value is determined based on the known round-trip delay characteristics of the DAS system and is applied in advance to the PRACH detection window timing. This preliminary adjustment ensures that the detection window is correctly positioned to receive preambles from UEs with large round-trip delays, while the base station can still measure the actual round-trip delay for timing advance calculation.
Solution Approach 2:
The patent uses the shifted detection window as an intermediary mechanism that bridges the gap between the base station's timing reference and the UE's transmission timing. By introducing the shift value as an intermediary parameter, the system can accommodate large round-trip delays without losing measurement precision. The shift value acts as a compensating factor that allows accurate measurement of the actual round-trip delay while maintaining reliable synchronization.
3Adaptability or versatility
If the detection window is extended to accommodate larger round-trip delays, then adaptability to different DAS configurations is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the PRACH detection window timing adjustable rather than fixed. The detection window can be dynamically shifted by a configurable value that adapts to different DAS configurations and round-trip delay characteristics. This dynamic adjustment mechanism allows the base station to adapt to various DAS topologies and delay conditions without requiring complex reconfiguration of the entire system. The shift value can be modified based on the specific deployment scenario, providing versatility while keeping the overall device complexity manageable.
Data Source
AI summary
A method of synchronizing a user equipment (UE) with a network device, the method comprising: using at least one computer hardware processor to perform: receiving, at the network device, a synchronization request for establishing a data transmission session between the network device and the UE, wherein a detection window for the synchronization request is delayed by a shift value at the network device, the shift value being based on a stored network device delay; determining an estimated first round-trip delay between the UE and the network device based on the synchronization request received by the network device; determining a timing advance for the UE based on the estimated first round-trip delay and a shift value; and monitoring, by the network device, for an uplink communication with the determined timing advance applied at the UE for the uplink communication.