OFDM Data Vector Transformation for Interference-Resilient Capacity
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Solution Overview
Problem
Current OFDM/OFDMA-based communication systems face challenges in minimizing noise and interference while maximizing signal strength, particularly in non-ideal channels, leading to suboptimal system capacity and performance.
Innovation Solution
The method involves transforming data vectors using Fourier transforms and Butler matrices, inserting pilot symbols, and transmitting these transformed vectors across multiple sub-carriers, allowing for channel estimation and optimal signal processing to mitigate interference and enhance capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OFDM/OFDMA systems use standard transmission methods, then system implementation is straightforward, but noise and interference are not adequately minimized and signal strength is not maximized
Solution Approach 1:
The patent applies preliminary action by performing transformations (Fourier transform, Butler matrix) on the data vector before transmission. This pre-processing prepares the signal in advance to be more robust against noise and interference during transmission, resolving the contradiction by enhancing reliability through advance signal preparation without requiring complex real-time processing during transmission.
2Productivity
If matched filter principles are used to maximize signal acquisition, then desired signal strength is maximized, but system capacity is limited without advanced transformation techniques
Solution Approach 1:
The patent applies parameter changes by transforming the data vector using Fourier transform and/or Butler matrix operations, which change the signal representation parameters. This enables the system to achieve higher capacity by exploiting additional signal dimensions and properties, resolving the contradiction between increased productivity and device complexity through mathematical transformations that enhance signal utilization.
3Measurement precision
If pilot symbols are inserted into transformed vectors, then channel estimation accuracy is improved, but transmission overhead increases
Solution Approach 1:
The patent uses transformed vectors as intermediaries that carry both data and channel information more efficiently. By transforming the data vector before inserting pilot symbols, the system creates an intermediate representation that allows for more accurate channel estimation with reduced overhead, as the transformation spreads channel information across multiple dimensions, resolving the contradiction between measurement precision and quantity of transmission resources.
Data Source
AI summary
Numerous embodiments are provided that may be used to provide enhanced capacity and/or Quality-of-Service for OFDM-based systems such as LTE and/or WiMAX. Various service/device modes and/or applications are also provided. According to embodiments of the invention, a transformation may be performed on a data vector by a transmitter, prior to the transmitter transmitting the data vector, to distribute elements of the data vector over an available frequency space, thus providing robustness to channel anomalies such as fading and/or interference. The transformation may be based upon a Fourier transform or a truncated Butler matrix. At a receiver, an inverse of the transformation may be applied to recover data. The receiver and/or transmitter may be configured with an antenna array that may comprise a two-dimensional lattice of antenna elements, and may further be configured to estimate a number of resolvable signal paths and to form a spatial filter/rake that is matched to the number of resolvable signal paths. Embodiments relating to architectures, systems, methods, devices, software, firmware and/or computer program products are provided.