Dual-Receive RF Architecture for Parallel WRAN Spectrum Sensing
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Solution Overview
Problem
Current RF architectures for spectrum access networks, such as IEEE 802.22 WRANs, lack the capability to efficiently perform opportunistic out-of-band spectrum sensing and signal reception while maintaining data transmission, especially in scenarios where CPEs need to receive data from unsubscribed systems without disrupting their subscribed channels.
Innovation Solution
The proposed RF architecture incorporates an out-of-band sensing circuit and a WRAN signal receiving circuit, featuring a sensing antenna, pre-selective filter, low noise amplifier, mixer, local oscillator, channel filter, and WRAN synchronization module, allowing for parallel opportunistic spectrum sensing and data transmission, with separate directional and omni-directional antennas for independent tuning and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single receive chain is used for WRAN communication, then the device complexity is reduced, but the system cannot perform out-of-band spectrum sensing and receive external signals simultaneously while maintaining transmission on subscribed channel
Solution Approach 1:
The RF architecture is segmented into multiple independent receive chains: one dedicated to WRAN communication and another for out-of-band spectrum sensing. Each chain has its own antenna, LNA, mixer, and signal processing path, allowing simultaneous operation without interference and enabling versatile spectrum monitoring while maintaining communication functionality.
Solution Approach 2:
The dual receive chain architecture provides multi-functionality by enabling the system to simultaneously perform WRAN communication, out-of-band spectrum sensing, and reception of external signals from other systems. This universal design allows the CPE to adapt to multiple operational modes and spectrum access scenarios.
2Adaptability or versatility
If the CPE focuses on transmission on subscribed channel, then transmission reliability is improved, but the system cannot receive data from outside systems
Solution Approach 1:
The RF system is divided into separate transmit and receive paths, with the transmit path dedicated to maintaining reliable communication on the subscribed WRAN channel while the receive path simultaneously monitors external signals and out-of-band spectrum. This segmentation ensures that transmission reliability is not compromised by external signal reception activities.
Solution Approach 2:
A dual receive chain architecture acts as an intermediary, allowing the CPE to passively monitor external systems and out-of-band spectrum without interfering with the primary transmission operations. The separate receive chains enable the system to gather external information while maintaining stable communication with its subscribed base station.
3Measurement precision
If quiet periods are extended for spectrum sensing, then sensing accuracy is improved, but the system productivity decreases
Solution Approach 1:
The system implements periodic out-of-band spectrum sensing using the secondary receive chain, which can operate continuously or periodically without interrupting primary data transmission. This periodic monitoring provides accurate spectrum awareness while maintaining high productivity, as the sensing operations are performed in parallel rather than requiring extended quiet periods that would halt communication.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This architecture enables CPEs to detect and decode signals from neighboring systems while maintaining normal transmission and reception on subscribed channels, optimizing RF paths for spectrum detection and minimizing quiet periods, thus enhancing the overall efficiency and coexistence of WRAN systems.
Implementation Method 1
a sensing antenna coupled to a pre-selective filter
Implementation Method 2
a pre-selective filter coupled to a low noise amplifier
Implementation Method 3
A low noise amplifier is coupled to the pre-selective filter
Implementation Method 4
a mixer is coupled to the low noise amplifier, local oscillator
Implementation Method 5
A local oscillator and a channel filter are coupled to the mixer
Implementation Method 6
A local oscillator and a channel filter are coupled to the mixer
Data Source
AI summary
Radio frequency (RF) architectures for spectrum access networks are provided. Embodiments of the invention generally provide a radio frequency (RF) architecture for customer premise equipment (CPE) for use in, for example, IEEE 802.22 wireless regional area networks (WRANs). In some embodiments, the CPE RF architecture includes two receive chains with a directional antenna and an omni-directional antenna, respectively. The CPE RF architecture facilitates opportunistic out-of-band spectrum sensing and WRAN signal receiving that are performed in parallel with data transmission.