Cyclic Advance Diversity for OFDM Packet Error Rate
Solution Overview
Problem
Legacy receivers in wireless communication systems, such as SISO receivers, face challenges in handling multiple-antenna transmitters due to issues like destructive interference from multi-path signals, and existing techniques like cyclic delay diversity can spoof the FFT placement, leading to erroneous results.
Innovation Solution
Implementing cyclic advance diversity by cyclically advancing sections of OFDM packets between transmit antennas, with the duration of the advance being less than the guard interval, to create intentional multi-path and improve packet error rate performance in legacy receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic delay diversity is used to create intentional multi-path, then packet error rate performance is improved, but FFT placement is spoofed leading to erroneous results
Solution Approach 1:
The patent inverts the conventional cyclic delay diversity approach by using cyclic advance diversity instead. Instead of delaying signal sections to create multi-path effects, the invention advances the signal sections cyclically. This inversion resolves the contradiction because the advance duration is kept less than the guard interval, preventing the FFT placement spoofing that occurs with delay-based approaches while still creating the necessary intentional multi-path effects for diversity combining.
2Object-affected harmful factors
If linear delay diversity is used to avoid destructive interference, then multi-path interference is mitigated, but guard intervals are consumed
Solution Approach 1:
The patent changes the key parameter from time delay to cyclic advance duration. By setting the advance duration to be less than the guard interval duration, the invention maintains the protective function of the guard interval while still achieving the desired diversity effect. This parameter change allows the system to avoid destructive interference without consuming the guard interval, resolving the contradiction between interference mitigation and time loss.
Data Source
AI summary
Embodiments of cyclic diversity systems and methods are disclosed. One system embodiment, among others, comprises a logic configured to cyclically advance, or perform the periodic equivalent of the same, one or more sections of an orthogonal frequency division multiplexing (OFDM) packet relative to the OFDM packet to be transmitted on a first transmit antenna, the packet having the one or more cyclically advanced sections to be transmitted on a second transmit antenna, the duration of the cyclic advance having a duration less than a guard interval.