OFDMA Interleaving Algorithm for Burst Error Reduction
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Solution Overview
Problem
Current OFDMA-based communication systems, such as the proposed UTRA downlink, lack an interleaving/deinterleaving structure to effectively manage varying sub-carrier assignments and transmission rates, leading to potential burst errors due to non-uniform data distribution across sub-carriers.
Innovation Solution
Implementing an interleaving and deinterleaving algorithm in base stations and user devices that pseudo-randomly distributes coded bits across sub-carriers, accommodating varying transmission rates and sub-carrier assignments, using two permutations to map coded bits into non-overlapping sub-carriers and modulation constellations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data is transmitted using varying sub-carrier assignments and transmission rates in OFDMA-based systems, then system adaptability and transmission efficiency are improved, but data distribution becomes non-uniform across sub-carriers leading to burst errors
Solution Approach 1:
The patent applies preliminary action by performing interleaving operations before data transmission. The interleaver pseudo-randomly distributes coded bits across sub-carriers in advance, creating a uniform distribution pattern that prevents burst errors from occurring during transmission with varying sub-carrier assignments and transmission rates.
Solution Approach 2:
The patent introduces an interleaver as an intermediary component between the channel encoder and the transmission medium. This interleaver acts as a mediator that transforms the non-uniform data distribution caused by varying sub-carrier assignments into a uniform distribution, thereby preventing burst errors while maintaining system adaptability.
2Device complexity
If interleaving is not implemented in OFDMA-based systems with varying sub-carrier assignments, then system complexity is reduced, but burst errors increase due to non-uniform data distribution
Solution Approach 1:
The patent applies dynamics by implementing a flexible interleaving structure that adapts to varying sub-carrier assignments and transmission rates. The interleaver uses parameters such as interleaver size, interleaver type, and pseudo-random seed that can be dynamically adjusted based on the current transmission conditions, allowing the system to maintain low complexity while effectively preventing burst errors.
Solution Approach 2:
The patent utilizes parameter changes by modifying interleaving parameters (interleaver size, interleaver type, pseudo-random seed) based on varying transmission conditions. These parameter changes allow the interleaving structure to adapt to different sub-carrier assignments and transmission rates without requiring a completely different interleaving design for each scenario.
Data Source
AI summary
In an exemplary embodiment, a base station includes an antenna for transmitting signals on a downlink to a plurality of user devices. The base station also includes a processor, and memory in electronic communication with the processor. Interleaving instructions are stored in the memory. The interleaving instructions are executable by the processor to interleave coded data in accordance with an interleaving algorithm in order to generate interleaved data. The interleaving algorithm is configured to accommodate use of different transmission bandwidths for data transmission. OFDMA processing instructions are also stored in the memory. The OFDMA processing instructions are executable by the processor to perform OFDMA processing on the interleaved data. The OFDMA processing facilitates the use of a varying number of sub-carriers for channel transmission.