Access Point Backhaul Delay Compensation for Coordinated Scheduling
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Solution Overview
Problem
In wireless communication networks, the transmission delay introduced by longer backhaul connections in relaxed coordination schemes limits the performance, especially for time-critical services like VoLTE, as the scheduling decisions are not efficiently synchronized between access points, leading to suboptimal resource allocation and interference management.
Innovation Solution
A method where the first access point determines the backhaul connection delay and adjusts the transmission scheduling to account for both the processing time of the wireless device and the backhaul delay, ensuring that the second access point receives the scheduling indication at the correct time instance, thereby enabling coordinated multipoint transmission and improving network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relaxed coordination scheme is used with longer backhaul connections, then coordination between access points is achieved, but transmission delay increases limiting performance for time-critical services
Solution Approach 1:
The system performs preliminary actions by determining the backhaul delay in advance and using this information to adjust scheduling decisions. The first access point calculates the backhaul delay and communicates it to the second access point before actual data transmission occurs, enabling the second access point to prepare appropriate scheduling decisions that account for the known delay, thus reducing the impact of transmission delay on time-critical services
Solution Approach 2:
The backhaul delay value acts as an intermediary parameter that mediates between the first and second access points. This delay information is transmitted as a separate control signal that enables the second access point to compensate for the backhaul delay when making scheduling decisions, effectively decoupling the coordination function from the harmful delay effect
2Adaptability or versatility
If scheduling decisions are exchanged between access points over backhaul connection, then coordinated multipoint transmission is enabled, but synchronization accuracy deteriorates due to backhaul delay
Solution Approach 1:
The system changes the parameter of scheduling timing by adjusting it based on the determined backhaul delay. The second access point modifies its scheduling decisions by compensating for the known backhaul delay, effectively changing the timing parameter to maintain synchronization accuracy despite the presence of backhaul delay in the coordination process
3Productivity
If backhaul delay is compensated by adjusting scheduling, then resource allocation efficiency improves, but system complexity increases due to additional delay determination and adjustment mechanisms
Solution Approach 1:
The backhaul delay is determined in advance as a preliminary step, and this delay value is stored and reused for multiple scheduling decisions. This preliminary determination avoids the need for continuous complex delay measurements and adjustments for each scheduling event, thereby improving resource allocation efficiency while limiting the increase in system complexity to the initial delay measurement and storage mechanisms
Data Source
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AI summary
Embodiments herein relate to a method performed by a first access point (12) out of at least two access points for handling communication of a wireless device (10) served by the first access point (12) in a wireless communication network (1). The first access point (12) coordinates communication with a second access point (13) out of the at least two access points in the wireless communication network (1), which coordination is performed over a backhaul connection between the first access point (12) and the second access point (13). The first access point determines a delay of the backhaul connection to the second access point (13). The first access point (12) schedules a transmission to or from the wireless device (10) based on the determined delay, wherein the transmission from or to the wireless device (10) is delayed.