Frequency Hopping Mirroring Pattern Adjustment for LTE HARQ Diversity
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Solution Overview
Problem
Current wireless communication systems, such as LTE, face a reduction in frequency diversity gain due to the limited randomization of frequency hopping patterns during Hybrid Automatic Repeat Request (HARQ) retransmissions, especially when using the mirroring technique, as the retransmissions are performed in units of 8 subframes while a radio frame includes 10 subframes.
Innovation Solution
The proposed solution involves modifying the mirroring pattern for frequency hopping by adjusting the frequency hopping interval based on the packet transmission number, using equations like fm(i) = └i/G┘ mod 2, where G is an adjustable integer greater than two subframes and equal to or less than the HARQ retransmission interval, to achieve frequency diversity gain in both initial and retransmitted data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ retransmission is performed in unit of 8 subframes, then the retransmission timing is standardized, but the frequency hopping randomization is reduced
Solution Approach 1:
The patent introduces dynamic adjustment of the mirroring parameter G based on the packet transmission number. Instead of using a fixed mirroring pattern, the system dynamically changes G values (e.g., G=3 for initial transmission, G=5 for retransmission) to adapt to different transmission scenarios, thereby maximizing frequency hopping randomization while maintaining standardized retransmission timing.
Solution Approach 2:
The patent changes the parameter G in the mirroring equation fm(i) = └i/G┘ mod 2 based on the packet transmission number. By adjusting G dynamically (different G values for different transmission attempts), the system achieves different frequency hopping patterns for initial transmission and retransmission, improving both randomization and reception reliability.
2Ease of manufacture
If fixed mirroring pattern is used for frequency hopping, then the implementation is simple, but the frequency diversity gain is reduced
Solution Approach 1:
The patent transforms the static mirroring pattern into a dynamic one by making parameter G dependent on the packet transmission number. This dynamic approach maintains implementation simplicity (still using the same basic mirroring equation) while significantly improving frequency diversity gain through adaptive pattern selection.
Solution Approach 2:
The patent modifies the mirroring parameter G based on transmission context (initial transmission vs. retransmission). This parameter change allows the system to achieve better frequency diversity without complicating the fundamental mirroring mechanism, balancing simplicity and performance.
Data Source
AI summary
A method and an apparatus are provided for transmitting and receiving uplink data in a wireless communication system. The method includes transmitting an uplink grant including resource allocation information and frequency hopping information; determining a resource for the uplink data based on the resource allocation information and a packet transmission number, if the frequency hopping information indicates that a predefined hopping pattern is enabled; and receiving the uplink data mapped on the determined resource. Mirroring is alternatively applied for determining the resource based on the packet transmission number.