RSSI Measurement Timing in Wireless TDMA Devices
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Solution Overview
Problem
In wireless communications using TDMA, higher multislot classes face challenges in scheduling Received Signal Strength Indication (RSSI) measurements due to the time required for phase-locked loop (PLL) stabilization, making it difficult to fit RSSI measurements within available timeslots, especially in devices with advanced PLL designs or additional receivers being costly and power-intensive.
Innovation Solution
Implementing a method where RSSI signal samples are collected prior to complete PLL stabilization, allowing parallel stabilization and sampling, enabling RSSI measurements in a dedicated low-power mode within the available timeslots, thus allowing higher multislot classes without additional receivers or advanced PLL designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSSI measurement is scheduled within available timeslots in higher multislot classes, then measurement precision is improved, but the time required for PLL stabilization causes the measurement to miss the available slot
Solution Approach 1:
The patent applies preliminary action by initiating the PLL stabilization process before the RSSI measurement slot begins. The receiver is configured to start stabilizing the PLL in advance, so that by the time the measurement slot arrives, the PLL is already stabilized or close to stabilization, eliminating the need to wait for stabilization during the measurement window.
Solution Approach 2:
The patent maintains continuity of useful action by keeping the receiver in a low-power monitoring mode between active timeslots. Instead of completely powering down the receiver, it maintains a ready state that allows rapid PLL stabilization when the next measurement slot arrives, ensuring continuous capability to perform measurements without full re-initialization delays.
2Productivity
If a highly advanced PLL design is implemented to reduce stabilization time, then productivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies dynamics by making the receiver operational mode flexible and adaptive. The system dynamically switches between different operational states (active reception, low-power monitoring, measurement mode) based on the TDMA frame structure and availability of timeslots. This dynamic operation allows standard PLL designs to achieve fast stabilization by optimizing the timing and sequence of operations rather than relying on complex hardware.
3Measurement precision
If more than one receiver is employed to perform RSSI measurement, then measurement precision is improved, but device bulk and cost increase
Solution Approach 1:
The patent applies universality by making the single receiver multi-functional. The same receiver that performs primary data reception in active timeslots is also used for RSSI measurements in measurement slots. The receiver is configured to switch between reception mode and measurement mode, eliminating the need for a dedicated second receiver while still achieving accurate signal strength measurements for handover decisions.
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 approach reduces the time required for RSSI measurements, enabling their scheduling within existing timeslots, allowing devices to operate in higher multislot classes with standard PLL designs and single receivers, while reducing power consumption and device bulk.
Implementation Method 1
the time required to stabilize the phase-locked loop of the receiver
Data Source
AI summary
A wireless communications device having a fast-receive mode for measuring received signal strength indication (RSSI) enables the device to handle higher time division multiple access (TDMA) multislot classes without requiring that the device include either a second receiver or a receiver with a more advanced and expensive phase-locked loop (PLL) design. The time to complete an RSSI measurement is reduced by initiating the sampling of signal strength before the radio transceiver is fully stabilized in the downlink mode. By initiating sampling before PLL stabilization is complete, the overall time to complete an RSSI measurement is reduced sufficiently to enable scheduling of an RSSI measurement in each GSM frame.