HARQ Process Configuration for Centralized BBU Delay Management
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Solution Overview
Problem
Centralized processing architectures in mobile communication systems introduce delays due to the distance between centralized BaseBand Units (BBUs) and Remote Radio Heads (RRHs), affecting the round-trip latency and peak data rate, especially in HARQ protocols where strict timing is required for acknowledgement packets.
Innovation Solution
A configurable number of HARQ processes is implemented to adapt the Round-Trip Time (RTT) according to the base station implementation, allowing for flexible configuration of transmission cycles to manage delays and support longer fiber lengths, which can include synchronous or asynchronous HARQ protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centralized processing architecture is used to concentrate intelligence at centralized entities, then processing efficiency is improved and costs are reduced, but transmission delays are introduced due to increased distance between centralized BBU and transmission points
Solution Approach 1:
The system segments the transmission cycle into multiple parallel HARQ processes. Each process handles independent data packets with their own timing, allowing the system to manage the inherent transmission delays of centralized architecture by distributing packets across multiple time-divided processes rather than requiring all packets to meet strict timing requirements in a single process.
Solution Approach 2:
The system dynamically configures the number of HARQ processes and their timing parameters based on the actual fiber length and round-trip delay characteristics. This dynamic adaptation allows the system to optimize performance for different centralized architecture deployments, adjusting the transmission cycle configuration to match the specific delay conditions introduced by the fiber length between BBU and transmission points.
2Adaptability or versatility
If fiber length is increased to support more distant centralized BBU locations, then system flexibility is improved, but round-trip latency increases affecting HARQ timing
Solution Approach 1:
The system changes the parameter of HARQ process count and timing configuration based on the fiber length and resulting latency. By adjusting these parameters, the system can accommodate varying fiber lengths and centralized BBU locations while maintaining acceptable performance, thus supporting greater system flexibility without being constrained by fixed timing requirements.
3Reliability
If strict timing is enforced for HARQ acknowledgement packets, then reliability is improved, but peak data rate is reduced due to transmission gaps
Solution Approach 1:
The system segments the data transmission into multiple parallel HARQ processes, where each process maintains its own strict timing for reliability. By distributing the overall data flow across multiple such processes, the system preserves the timing-critical nature of individual HARQ exchanges while achieving higher aggregate throughput that would be impossible with a single timing-constrained process.
Data Source
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AI summary
Embodiments provide an apparatus, a base station transceiver, a mobile station transceiver, methods, and computer programs for configuring a delay for a transmission cycle. The apparatus 10 is operable to configure a delay for a transmission cycle. A transmission cycle corresponds to a process of transmitting a payload data packet from a transmitter 20 and receiving an associated acknowledgement packet from a receiver 30 at the transmitter 20. The apparatus 10 is operable to provide information on the delay between the transmitting of the payload data packet and the receiving of the associated acknowledgement packet to the transmitter 20 and to the receiver 30.