Cognitive Radio MIMO Base Station Null Signal Sensing
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Solution Overview
Problem
Cognitive radio communication systems face inefficiencies due to the need for separate sensing times and potential collisions with primary communication systems, leading to wasted resources and inaccurate signal detection.
Innovation Solution
A cognitive radio base station with multiple antennas generates transmission signals that make signals received by sensing terminals null or near-null, allowing for virtual sensing times and adaptive band control to facilitate efficient sensing and data communication without separate quiet times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sensing times are allocated for cognitive radio terminals to detect primary user signals, then sensing accuracy is improved, but system capacity and resource utilization deteriorate due to wasted time resources
Solution Approach 1:
The patent merges the sensing operation with data reception by having the base station transmit data signals to non-sensing terminals while simultaneously transmitting null signals to sensing terminals. This allows sensing to occur during what would otherwise be data transmission time, eliminating separate sensing periods and improving resource utilization.
Solution Approach 2:
The base station applies different signal qualities to different terminals: null signals are transmitted to sensing terminals to create quiet periods for accurate primary user detection, while data signals are transmitted to non-sensing terminals. This localized differentiation allows simultaneous sensing and data transmission without interference.
2Measurement precision
If cognitive radio terminals perform sensing operations, then primary user detection accuracy is improved, but time resources are wasted due to separate sensing periods
Solution Approach 1:
The patent combines sensing time with data transmission time by transmitting null signals to sensing terminals during the same period when data is transmitted to non-sensing terminals. This eliminates the need for separate sensing periods, allowing sensing to occur without time loss.
Solution Approach 2:
The base station maintains continuous data transmission to non-sensing terminals while simultaneously providing continuous null signals to sensing terminals. This ensures that sensing operations do not interrupt the overall data transmission flow, maintaining continuous useful action in the system.
3Measurement precision
If null signals are transmitted to sensing terminals using MIMO channels, then sensing performance is improved by creating virtual sensing times, but signal generation complexity increases
Solution Approach 1:
The base station's MIMO transmission system serves multiple functions simultaneously: it transmits data signals to non-sensing terminals, transmits null signals to sensing terminals, and enables both groups to operate during the same time period. This multi-functionality reduces the need for separate transmission mechanisms.
Solution Approach 2:
The base station changes the signal parameters (amplitude, phase) transmitted to different terminals through the MIMO channels. By adjusting these parameters, the system creates null signals for sensing terminals while maintaining data signals for other terminals, achieving virtual sensing times through parameter manipulation rather than separate transmission periods.
Data Source
AI summary
A cognitive radio communication system using a multiple input multiple output (MIMO) communication technology is provided. A cognitive radio base station includes a plurality of antennas, a group setting unit to set at least one sensing terminal group that includes at least one sensing terminal among a plurality of terminals, and a signal generator to generate a transmission signal to transmit the transmission signal using channels formed between the plurality antennas and the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time.