Pilot Insertion for Intra-Frequency Full Duplex Delay Compensation
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Solution Overview
Problem
Intra-frequency full duplex (IFD) systems face challenges in channel estimation due to relative delays caused by different signal transmission distances, preventing effective channel initialization and phase noise suppression.
Innovation Solution
The method involves inserting first and second pilots into local and peer transmit signals, respectively, with specific time intervals and durations to align delays, ensuring orthogonality and simultaneous reception at the receiver, allowing for accurate channel estimation and phase noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If offline delay alignment is used to compensate for transmission delays, then signal timing alignment is improved, but system complexity increases and cannot resolve relative delay between local and peer signals
Solution Approach 1:
The patent applies preliminary action by inserting pilots at specifically calculated positions before signal transmission. The first pilot is inserted at position T1+T2-D1 in the local signal, and the second pilot is inserted at position T1+T2-D3 in the peer signal. This pre-positioning of pilots ensures that after transmission and reception, the pilots arrive at the receiver at the same time, enabling delay compensation without complex offline alignment procedures.
2Measurement precision
If pilots are inserted at different positions in local and peer signals, then channel estimation becomes feasible, but signal orthogonality deteriorates
Solution Approach 1:
The patent applies local quality by making the pilot insertion positions signal-specific rather than uniform. The first pilot in the local signal is inserted at position T1+T2-D1, while the second pilot in the peer signal is inserted at position T1+T2-D3. These different local positions are carefully chosen to ensure that after transmission, the pilots arrive simultaneously at the receiver, enabling channel estimation while maintaining signal orthogonality through the specific mathematical relationship between the positions.
3Reliability
If multiple pilots are inserted with specific time intervals, then delay compensation and channel estimation are enabled, but signal processing complexity increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the insertion positions of pilots based on transmission delay parameters. The first pilot is inserted at position T1+T2-D1 and the second pilot at position T1+T2-D3, where T1 and T2 are transmission distances and D1 and D3 are device-specific delays. By changing the pilot position parameters according to the specific delay characteristics of each signal path, the system enables reliable channel estimation while keeping processing complexity manageable through a systematic parameter-based approach.
Data Source
AI summary
The present invention discloses an information processing method and apparatus, including: obtaining a local to-be-transmitted signal by using a local transmitter, and inserting first pilots and second pilots, where the first pilots are inserted from a first position of the local to-be-transmitted signal, the second pilots are inserted from a second position of the local to-be-transmitted signal; obtaining a local transmit signal; obtaining a peer transmit signal, where the peer transmit signal is sent after third pilots and fourth pilots are inserted, the third pilots are inserted from a third position of the peer transmit signal, the fourth pilots are inserted from a fourth position of the peer transmit signal, the first pilot is orthogonal to the fourth pilot, and the second pilot is orthogonal to the third pilot; and parsing the local transmit signal and the peer transmit signal by using the local receiver.