OFDM Stream Scheduling for Intercell Interference Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cellular wireless networks experience reduced data rates due to intercell interference, especially at cell edges, and MIMO systems struggle with low signal-to-noise-plus-interference ratios (SNIR), leading to inefficient data stream transmission.
Innovation Solution
A controller adjusts the number of data streams based on channel quality, coordinating base stations to align single-stream transmissions in interfering cells with those in serving cells, allowing receivers to cancel interference and improve data reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency reuse of one is used to maximize time/frequency resources, then resource utilization is improved, but intercell interference increases
Solution Approach 1:
The system dynamically changes the number of data streams transmitted based on channel quality indicators (CQI) and signal-to-interference-plus-noise ratio (SINR). When interference is high, the system reduces the number of streams to maintain link reliability, and when interference is low, it increases streams to maximize throughput.
Solution Approach 2:
The MIMO system dynamically adapts between single-stream and multi-stream transmission modes based on real-time channel conditions. The scheduler adjusts the number of spatial streams transmitted to each user equipment (UE) according to varying interference levels and channel quality, enabling flexible response to changing network conditions.
2Productivity
If multiple simultaneous data streams are transmitted over MIMO channels, then data rate is improved, but performance degrades in low SNIR conditions
Solution Approach 1:
The system changes the number of active data streams based on measured channel conditions including SNIR and CQI. When SNIR is low, the system reduces the number of streams to ensure reliable decoding, and when SNIR is high, it increases streams to exploit the full MIMO capacity.
Solution Approach 2:
The system uses feedback from channel quality indicators (CQI) and buffer status reports (BSR) to adjust transmission parameters. The UE measures channel conditions and reports CQI back to the base station, which then adjusts the number of data streams accordingly, creating a closed-loop control system.
3Reliability
If single-stream transmission is used in low SNIR conditions, then link reliability is improved, but data rate is reduced
Solution Approach 1:
The system dynamically switches between single-stream and multi-stream transmission modes based on real-time channel conditions. This dynamic adaptation allows the system to maximize data rate when conditions permit while ensuring minimum reliability requirements are met when interference is high.
Solution Approach 2:
The scheduler adjusts the number of spatial streams as a variable parameter based on channel quality. By changing this parameter dynamically rather than using a fixed configuration, the system can optimize the trade-off between reliability and data rate for each user and time slot.
Data Source
AI summary
A user equipment (UE) comprising a receiver, a transmitter, and a processor are configured to simultaneously receive a plurality of orthogonal frequency division multiplex (OFDM) streams from a first base station and detect data from the received plurality of streams. Further, the UE, based on detected data from the first base station, receive and detect data from an OFDM stream from the first base station and an OFDM stream from a second base station. The UE is further configured to transmit channel quality information to the first base station and the second base station and receive and detect data from the at least one OFDM stream from the first base station and the at least one OFDM stream from the second base station is based on the transmitted channel quality information.