OFDM I/Q Interleaving Segmentation for Lower-Latency Transmission
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Solution Overview
Problem
Current wireless communications networks face inefficiencies in data transmission and reception due to high memory requirements for interleaving and de-interleaving in OFDM systems, which increase complexity and latency, making it difficult to support low-latency communications.
Innovation Solution
The implementation of a transmitter and receiver system that segments modulation symbols into smaller segments for transmission on an integer number of OFDM symbols or part thereof, with separate interleaving of real and imaginary components, reducing the size of the interleaver memory and improving data integrity by applying phase rotation and I/Q interleaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If modulation symbols are interleaved using conventional methods in OFDM systems, then data transmission reliability is improved, but memory requirements and system complexity increase significantly
Solution Approach 1:
The patent divides the interleaving process into two separate operations: one for real components and one for imaginary components of modulation symbols. This segmentation allows each interleaver to process only one component type, reducing the memory required at any given time while maintaining the diversity benefits of full interleaving.
Solution Approach 2:
The patent extracts the real and imaginary components of modulation symbols separately and processes them through independent interleaving paths. By separating the interleaving of I and Q components into distinct processing streams, the system reduces the peak memory requirements of the interleaver while achieving effective diversity.
2Reliability
If conventional interleaving methods are used to ensure data integrity, then transmission reliability improves, but transmission latency increases
Solution Approach 1:
By segmenting the interleaving operation into separate real and imaginary component processing, the system can process components independently and in parallel, reducing the overall processing time required for interleaving while maintaining data integrity through comprehensive diversity.
Solution Approach 2:
The patent applies phase rotation to modulation symbols before interleaving, and uses predetermined interleaving patterns that are established in advance. This preliminary processing prepares the data for efficient interleaving operations that can be executed with reduced latency.
3Reliability
If phase rotation and separate I/Q interleaving are applied, then data integrity is enhanced, but processing complexity increases
Solution Approach 1:
The patent segments the complex interleaving task into manageable parts: phase rotation followed by separate real and imaginary interleaving. This segmentation makes the processing complexity more tractable by breaking down a single complex operation into simpler, independent stages that can be implemented efficiently.
Data Source
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AI summary
A transmitter or an infrastructure equipment of a wireless communications network for transmitting data to and receiving data from communications devices is configured to transmit data to one or more of the communications devices via a wireless access interface having a time divided structure of repeating time units, each of the time units comprising a predetermined number of resource elements disposed in time and frequency. The transmitter includes modulator circuitry comprising modulation symbol generator circuitry configured to receive the data and to generate modulation symbols representing the data, each modulation symbol for modulating a corresponding sub-carrier of one or more OFDM symbols in accordance with a modulation scheme, segmentation circuitry configured to receive the modulation symbols representing the data and to divide the modulation symbols into segments of modulation symbols for transmission, each segment of the modulation symbols for transmission via an integer number of the one or more OFDM symbols or part thereof. Modulation rotation circuitry is configured to receive the modulation symbols of one segment and to rotate each modulation symbol by an angle dependent on the choice of modulation scheme, I/Q interleaver circuitry, is configured to receive each of the segments of rotated modulation symbols and for each segment to separate real and imaginary components of the rotated modulation symbols for the segment and to interleave the real components of the rotated modulation symbols of the segment differently to the imaginary components of the rotated modulation symbols of the segment, and I/Q combiner circuitry is configured to re-combine the real and imaginary interleaved components of the rotated modulation symbols of each segment and to form from the real and imaginary components modulation cells. Each modulation cell modulates one of the plurality of sub-carriers of each of the integer number of one or more OFDM symbols or part thereof for the segment to be transmitted. By dividing the modulation symbols into segments of modulation symbols for transmission on an integer number of OFDM symbols or part thereof, which may be less than a number of OFDM symbols in each time- unit allocated to the communications device for receiving the data then a delay in transmitting and receiving the data can be reduced and the size of an interleaver memory for interleaving and de- interleaving can be reduced.