OFDM Paging Preamble for Low-Power Wireless Acquisition
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Solution Overview
Problem
There is a need in wireless communication systems to efficiently broadcast and utilize control information to improve system performance and terminal operation, particularly in idle states where terminals need to conserve power while still being able to receive paging information efficiently.
Innovation Solution
A base station transmits a preamble in each superframe, including an OFDM symbol for broadcast control and another for paging, allowing terminals to determine receiver gain using the first symbol for improved demodulation of the second symbol, reducing wake-up time and conserving power by processing control information only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminals continuously monitor paging information to ensure reliable reception, then communication reliability is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The terminal operates in periodic cycles, alternating between sleep mode and wake periods. During wake periods, the terminal monitors paging information in superframes according to its assigned paging frame and paging occasion. This periodic operation allows the terminal to balance reliable paging reception with power conservation by remaining in low-power sleep mode between monitoring intervals.
2Reliability
If terminals process control information in every superframe to ensure no paging is missed, then paging detection reliability is improved, but wake-up time increases and power efficiency decreases
Solution Approach 1:
The system structure预先 organizes paging information transmission in specific superframes assigned to each terminal based on terminal ID. The terminal uses this pre-assigned information to wake up only at specific paging occasions rather than monitoring every superframe. This preliminary organization of paging opportunities allows terminals to skip unnecessary wake-ups while ensuring they are present at the correct moments to receive their paging information.
3Reliability
If terminals wake up frequently to monitor all superframes for paging information, then paging information reception is ensured, but power consumption increases
Solution Approach 1:
The paging monitoring function is segmented by assigning different terminals to different paging frames and paging occasions based on terminal identities. Each terminal monitors only its assigned superframes rather than all superframes. This segmentation divides the overall paging monitoring task into separate, non-overlapping intervals for different terminals, allowing each terminal to sleep through unassigned superframes and consume significantly less power.
Data Source
AI summary
Techniques for supporting efficient operation by terminals in a wireless communication system are described. A base station transmits a preamble periodically in each superframe. The preamble includes at least one first OFDM symbol for control information followed by at least one second OFDM symbol for paging information. A terminal receives the first and second OFDM symbols and determines a receiver gain based on the received power of the first OFDM symbol(s), e.g., with an AGC loop having a shorter time constant than the duration of the first OFDM symbol(s). The terminal processes the second OFDM symbol(s) based on the receiver gain to obtain the paging information. The terminal may operate in an idle state, determine superframes assigned to the terminal, sleep between the assigned superframes, and process the first and second OFDM symbols in each assigned superframe to obtain the paging information.