HARQ Reception Buffer Reordering Without Sequence Numbers
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Solution Overview
Problem
In Hybrid ARQ telecommunication systems, particularly in LTE, there is a challenge in efficiently re-ordering out of order received data blocks without excessive CPU load or memory requirements, especially during parallel Hybrid ARQ processes where time gaps between transmission and acknowledgement lead to disordered reception.
Innovation Solution
The method involves assigning a reception index to each data block based on its scheduled time slot, allowing for re-ordering without relying on sequence numbers from the transmitting end, using reception buffers associated with these indexes, and performing re-ordering and duplicate detection based on these indexes, reducing processing requirements and memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple parallel Hybrid ARQ processes are interleaved to increase data transmission rate, then data transmission rate is improved, but data blocks are received out of order requiring complex re-ordering
Solution Approach 1:
The patent segments the re-ordering problem by creating separate reception buffers for each Hybrid ARQ process ID. Instead of one complex re-ordering operation, multiple simple buffered operations are used, where each buffer handles re-ordering independently for its specific process, reducing overall system complexity while maintaining parallel processing capability
Solution Approach 2:
The patent introduces reception buffers as intermediary storage elements between the parallel Hybrid ARQ processes and the upper layers. These buffers act as mediators that temporarily hold out-of-order data blocks and release them in the correct sequence, simplifying the re-ordering function by providing a buffering mechanism rather than complex real-time re-ordering logic
2Reliability
If sequence number-based re-ordering is used to ensure robust re-ordering, then re-ordering reliability is improved, but CPU load and memory requirements increase excessively
Solution Approach 1:
The patent extracts the re-ordering function from the sequence number processing logic. Instead of using sequence numbers for re-ordering decisions, the system uses reception buffers indexed by Hybrid ARQ process IDs and reception order. This extraction simplifies the re-ordering mechanism by removing the need for complex sequence number comparisons and sorting operations
Solution Approach 2:
The patent uses reception buffers as copies of the transmission order, where each buffer position corresponds to a specific reception sequence. Rather than processing sequence numbers to determine order, the system directly places received blocks into pre-positioned buffer slots that represent the correct transmission sequence, eliminating complex re-ordering calculations
Data Source
AI summary
A method of transmitting data blocks between a user equipment and a station using parallel hybrid automatic repeat request processes. The station includes a scheduler that signals to the user equipment allocations of resources and parameters for transmission and re-transmission of the data blocks, and a set of reception buffers that receive and re-order the data blocks. The scheduler assigns a reception index to the corresponding scheduled reception and assigns reception buffers to received data blocks as a function of the assigned reception indexes identifying time slots scheduled for reception. A newly transmitted data block received in its scheduled time slot is assigned to the reception buffer corresponding to a new reception index. A re-transmitted data block received in a time slot later than its originally scheduled time slot is assigned to the reception buffer corresponding to a same reception index as its originally scheduled reception.