Linear Encoder Output Buffering for Multi-Frame Memory Reduction
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Solution Overview
Problem
Conventional encoder output memory designs in wireless communication systems require significant memory to store entire encoded codewords, leading to complexity and inefficiency, especially in handling extended frame transmissions where encoded bits from different assignments have disparate lifespans.
Innovation Solution
The method involves dividing encoder operations for N sequential frames into N separate operations, each for single frame transmission, and sequentially buffering these in an encoder output buffer, allowing bits from a buffered operation to be read out while the next operation is stored, using a linear memory model to ensure efficient bit management and reduce memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire encoded codeword is stored in encoder memory, then the encoder can provide enough bits for each subpacket, but the memory size becomes very large (around 25 Mbit for UMB FLDCH)
Solution Approach 1:
The encoder output buffer is divided into multiple segments corresponding to different HARQ processes. Each segment stores only the bits needed for a specific HARQ transmission rather than the entire codeword. This segmentation allows the system to maintain sufficient bits for each subpacket while dramatically reducing the total memory size required.
Solution Approach 2:
The encoder pre-generates and stores in the buffer the encoded bits that will be needed for upcoming HARQ transmissions before they are actually required. By performing the encoding action in advance and organizing it by HARQ process, the system ensures bit availability when needed without requiring large memory to hold all possible bits indefinitely.
2Adaptability or versatility
If the encoder stores bits for extended frame transmissions, then it can handle multi-frame assignments, but encoded bits from different assignments have different lifespans causing design complexity
Solution Approach 1:
The buffer is segmented by HARQ process ID, creating separate storage regions for each active HARQ process. This segmentation ensures that bits from different assignments all have the same effective lifespan - they remain in the buffer only as long as their associated HARQ process requires them. When a HARQ process completes or is retransmitted, its buffer segment can be cleared or overwritten, simplifying memory management.
Solution Approach 2:
The buffer structure is made dynamic by associating each buffer segment with a specific HARQ process state. As HARQ processes are activated, retransmitted, or completed, the buffer segments are dynamically allocated, updated, or cleared accordingly. This dynamic approach allows the system to handle varying assignment lengths (single-frame or extended multi-frame) without fixed memory allocation, reducing management complexity.
Data Source
AI summary
Apparatus and methods for using a linear memory model for encoder output buffering are disclosed. The apparatus and method effect linear memory output buffering by dividing an encoder operation having N sequential frames to be encoded by an encoder into N encoder operations each designated for a single frame transmission, such as in the case of extended frame transmissions having multiple frames. Bits of the N encoder operations are then sequentially buffered in an encoder output buffer, wherein bits of each buffered encoder operation of the N encoder operations are read out of the buffer to a multiplexer engine while bits of a next encoder operation of the N encoder operations is being stored in the encoder output buffer.