Coordinated UE Silencing for Spectrum Sensing in Unlicensed Bands
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Solution Overview
Problem
Current wireless devices face interference issues when using unlicensed communication bands, such as TV whitespace and ISM bands, due to uncoordinated usage by multiple users, which affects the ability to detect primary and secondary users and manage spectrum occupancy effectively.
Innovation Solution
The implementation of a measuring gap schedule that coordinates user equipment (UE) to measure license-exempt bands by determining specific measurement times when UEs withhold transmissions, allowing them to sense the spectrum for primary and secondary users, using a broadcast-GAP, multicast-GAP, or hybrid-GAP approach, and reporting back to the HeNB for spectrum management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple user equipment (UE) devices transmit and receive communications simultaneously in unlicensed bands, then communication activity and data throughput are improved, but interference between devices increases and spectrum sensing accuracy deteriorates
Solution Approach 1:
The patent implements periodic measurement gaps in the radio frame structure, where UEs periodically suspend transmissions to perform spectrum sensing. These measurement gaps occur at regular intervals (e.g., every 40ms or 80ms) and allow devices to detect primary users and assess spectrum occupancy without continuous interference, thereby maintaining communication activity while reducing harmful interference through time-division multiplexing.
Solution Approach 2:
The patent segments the radio frame into distinct functional portions: communication slots and measurement gap slots. By dividing the time domain into these separate segments, the system allows UEs to alternate between transmitting/receiving data and performing spectrum sensing. This segmentation resolves the contradiction by ensuring that sensing and communication occur in different time segments, eliminating mutual interference while maintaining both functions.
2Measurement precision
If user equipment (UE) performs spectrum sensing to detect primary users, then detection accuracy is improved, but communication time and data transmission are reduced
Solution Approach 1:
The patent applies partial action by implementing measurement gaps that cover only the minimum necessary duration to perform accurate spectrum sensing. Rather than requiring UEs to stop communication entirely or for extended periods, the system allocates specific partial time slots (e.g., a few milliseconds within each measurement gap) dedicated solely to sensing. This allows adequate detection accuracy while minimizing the loss of communication time.
Solution Approach 2:
The patent uses periodic measurement gaps that recur at defined intervals (such as every 40ms or 80ms based on measurement gap repetition periods). This periodic structure ensures that spectrum sensing occurs regularly enough to maintain detection accuracy for identifying primary users, while the intervals between gaps preserve substantial communication time. The periodicity balances sensing requirements with communication continuity.
3Reliability
If user equipment (UE) continuously monitors unlicensed bands for primary users, then spectrum awareness is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic monitoring through measurement gaps that occur at predetermined intervals rather than continuous monitoring. UEs suspend normal communications during these periodic gaps to perform spectrum sensing, then resume communications afterward. This periodic approach maintains spectrum awareness by regularly checking for primary users while significantly reducing energy consumption compared to continuous monitoring, as the radio transceiver remains active for communication most of the time and only switches to sensing mode during brief periodic intervals.
Solution Approach 2:
The patent enables UEs to autonomously perform spectrum sensing during their allocated measurement gaps without requiring continuous network control or coordination for each sensing opportunity. Once the measurement gap pattern is configured by the network, UEs independently execute sensing operations during their periodic gaps, manage their own energy consumption, and report findings to the network. This self-service approach reduces overall system energy usage while maintaining reliable spectrum awareness.
Data Source
AI summary
Systems, methods, and instrumentalities are disclosed to schedule user equipment (UE) measurements. An HeNB may identify a first cluster of UEs and a second cluster of UEs. The HeNB may determine a measuring gap schedule relating to the first cluster of UEs and the second cluster of UEs. The measuring gap schedule may indicate a measurement time for each cluster. The measurement time may indicate that UEs in a cluster withhold a transmission during the measurement time. The UEs in the cluster may measure a spectrum (e.g., frequency, channel, etc.) associated with a supplementary cell during the measurement time. The HeNB may send the measuring gap schedule to the first cluster of UEs and the second cluster of U Es. The HeN B may receive spectrum measurements of the supplementary cell from the first cluster of UEs and the second cluster of UEs, e.g., in accordance with the measuring gap schedule.