Pilot Signal Scheduling for Inter-Cell Interference Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-cell TDD communication systems, the limited length of pilot signals leads to significant inter-cell interference (ICI) when reused across cells, resulting in inaccurate channel estimation and reduced data transmission performance, especially for user devices with high mobility.
Innovation Solution
A method for scheduling pilot signals in a control node-managed network cluster, where a wireless device transmits a first pilot signal at specific time slots and alternately transmits a second pilot signal with opposite sign at other time slots, effectively eliminating ICI and increasing the signal-to-noise ratio (SNR) by doubling the effective transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the length of the pilot signal is limited, then the throughput is improved, but the number of orthogonal pilot signals available for assignment decreases
Solution Approach 1:
The patent applies periodic action by having wireless devices transmit pilot signals with opposite signs in alternating time slots. Specifically, a device transmits a pilot signal in one time slot, then transmits a pilot signal with opposite sign in the next time slot, creating a periodic pattern that enables interference cancellation at the base station through signal processing of these alternating transmissions.
2Area of stationary object
If pilot signals are reused in different cells, then the coverage is improved, but inter-cell interference increases
Solution Approach 1:
The patent converts the harmful inter-cell interference into a beneficial signal for cancellation. By having devices transmit pilot signals with opposite signs in alternating time slots, the interference from other cells becomes predictable and cancelable. The base station uses the known opposite-sign pattern to subtract the interfering signals, transforming the harmful ICI into a removable component that actually improves channel estimation accuracy.
3Adaptability or versatility
If the length of the coherent time block is shortened for high mobility devices, then the adaptability to channel changes is improved, but the data transmission time decreases
Solution Approach 1:
The patent applies periodic action by having wireless devices transmit pilot signals with opposite signs in alternating time slots. Specifically, a device transmits a pilot signal in one time slot, then transmits a pilot signal with opposite sign in the next time slot, creating a periodic pattern that enables interference cancellation at the base station through signal processing of these alternating transmissions.
Data Source
AI summary
A method for scheduling a pilot signal, a control node and a wireless device are proposed. The control node manages an i-th cell among N cells of a network cluster. The method includes: dividing a training time into at least (N) time slots; scheduling a wireless device of the i-th cell to transmit a first pilot signal at a j-th time slot and a (j+1)-th time slot, or scheduling the wireless device of the i-th cell to transmit a second pilot signal at the j-th time slot and the (j+1)-th time slot; scheduling the wireless device to alternately transmit the first pilot signal and the second pilot signal at residual time slots other than the j-th time slot and the (j+1)-th time slot, wherein the first pilot signal and the second pilot signal have opposite signs.