HARQ Controller Physical Layer Decentralization
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Solution Overview
Problem
Current mobile communication systems face challenges in efficiently managing Hybrid Automatic Repeat reQuest (HARQ) operations due to high CPU load, power consumption, and processing delays, especially in mobile stations with limited processing speed and power, which affects data transmission rates and reliability.
Innovation Solution
A HARQ control apparatus and method that decentralizes HARQ operations by moving control functions from the upper layer to the physical layer, utilizing a HARQ controller to decode control messages, update Walsh masks, and perform demodulation and decoding, thereby reducing CPU load and power consumption while supporting multiple channels and varying ACK/NAK delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ operations are performed in the MAC layer (upper layer), then protocol error checking and retransmission control are implemented, but CPU load increases and processing speed decreases
Solution Approach 1:
The patent segments HARQ operations into two distinct parts: physical layer operations (demodulation, decoding, soft combining) and MAC layer operations (error checking, retransmission control). By moving time-critical operations to the physical layer, the system maintains reliability while reducing CPU load and improving processing speed.
Solution Approach 2:
The patent introduces a physical layer HARQ controller as an intermediary between the physical layer and MAC layer. This intermediary handles the computationally intensive tasks independently, allowing the MAC layer to focus on higher-level protocol control without being bottlenecked by processing speed constraints.
2Productivity
If HARQ operations are moved to the physical layer for fast processing, then processing speed improves, but device complexity increases
Solution Approach 1:
The patent designs the physical layer HARQ controller to perform multiple functions: demodulation, decoding, soft combining, and coordination with the MAC layer. By consolidating these functions into a single multi-functional controller, the system achieves fast processing without proportionally increasing complexity.
Solution Approach 2:
The patent implements soft combining by storing and reusing previous received signal information (soft bits) in memory. This copying of historical data allows the physical layer controller to perform efficient retransmission processing without requiring complete re-decoding, thereby reducing computational complexity while maintaining high processing speed.
3Productivity
If multiple HARQ channels are supported for parallel processing, then data transmission rate increases, but number of turbo decoders and controllers must increase
Solution Approach 1:
The patent implements dynamic resource allocation where the number of active turbo decoders and controllers is adjusted based on the actual number of HARQ channels in use. When fewer channels are active, the system dynamically reduces the number of active processing units, thereby avoiding unnecessary complexity while still supporting multiple channels when needed for high data transmission rates.
Data Source
AI summary
A Hybrid Automatic Repeat reQuest (HARQ) control apparatus and method for detecting a message received over a packet data control channel in a mobile communication system are provided in which a base station transmits a packet data control message over at least one packet data control channel and transmits packet data to a mobile station over a packet data channel. A control channel decoder decodes a control message received over the packet data control channel. Based on the decoded control message, the HARQ controller determines at least one of whether to perform demodulation and decoding on a packet received over the packet data channel, whether to update a Walsh mask, and whether to perform state transition on the mobile station. The HARQ controller based on the determination performs at least one of the following functions: outputs demodulation and decoding parameters, updates a Walsh mask, and outputs a state transition value to an upper layer. A data channel demodulator demodulates packet data received over the packet data channel upon receiving a demodulation parameter from the HARQ controller. A decoder decodes the packet data demodulated by the data channel demodulator upon receiving a decoding parameter from the HARQ controller.