Radio Transmission Apparatus Interference Cancellation
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Solution Overview
Problem
Existing radio communication systems, particularly in mobile communication, face challenges in efficiently canceling interference signals due to the requirement for a large number of antennas, which complicates miniaturization and increases complexity in multipath environments.
Innovation Solution
A radio transmitting apparatus and multicarrier signal generating method that utilize a configuration with an encoding section, repetition section, modulation section, and generating section to create a multicarrier signal with same symbols mapped on subcarriers, allowing for efficient interference cancellation using MMSE processing, similar to the adaptive array antenna technique, but with a reduced number of antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adaptive array antenna technique is used to cancel interference signals, then interference cancellation performance is improved, but the number of antennas required increases significantly
Solution Approach 1:
The patent transforms the spatial dimension (multiple antennas) into a frequency dimension (multiple subcarriers). By mapping the same symbol to multiple subcarriers and utilizing frequency-domain processing, the system achieves interference cancellation functionality without requiring multiple physical antennas, thus resolving the contradiction between interference cancellation performance and antenna quantity.
Solution Approach 2:
The patent creates multiple copies of the same symbol across different subcarriers. These replicated symbols serve as virtual observations that enable interference cancellation through MMSE processing, replacing the need for multiple physical antennas with frequency-domain replicas.
2Reliability
If multiple antennas are used for interference cancellation, then interference signals can be canceled effectively, but device complexity and miniaturization difficulty increase
Solution Approach 1:
The invention shifts the solution from spatial complexity (multiple antennas) to frequency-domain complexity (multiple subcarriers with same symbol mapping). This dimensional transformation reduces physical device complexity while maintaining interference cancellation capability, as frequency-domain processing can be implemented with simpler circuitry.
3Volume of moving object
If the number of antennas is reduced for miniaturization, then device size is decreased, but interference cancellation performance deteriorates
Solution Approach 1:
The patent compensates for reduced spatial resources (fewer antennas) by utilizing the frequency dimension. By mapping symbols to multiple subcarriers and performing MMSE processing in the frequency domain, the system achieves interference cancellation with a single antenna, thus maintaining performance while enabling miniaturization.
Data Source
AI summary
A base station allowing mobile stations to efficiently remove interference signals. In this base station, an encoding part performs an error correction encoding of transport data to generate a bit sequence comprising systematic bits and parity bits; a repetition part repeats, as a repetition subject, only the parity bits out of the plurality of bits included in the bit sequence, which is generated by the encoding part, so as to perform a rate matching; a modulating part modulates, after the repetition, the bit sequence to generate symbols; an S/P part parallel converts the symbols serially inputted from the modulating part (103) and then outputs them to an IFFT part; and the IFFT part performs an IFFT processing of the symbols inputted from the S/P part and then maps them onto subcarriers in accordance with a predetermined mapping pattern, thereby generating OFDM symbols.