MIMO Clock Divider Synchronization Using Phase Detection
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Solution Overview
Problem
Communication devices operating in MIMO systems face challenges in maintaining timing synchronization between multiple transmit chains, which is crucial for efficient data transmission and reception.
Innovation Solution
The solution involves generating a clock inhibit signal and a divided clock signal based on a clock select signal and the clock inhibit signal to synchronize clock signals across different regions within a wireless device, using a common clock synthesizer and phase detection to adjust and synchronize clock phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple wireless transmitters and receivers are used to increase communication bandwidth in MIMO systems, then data transmission capacity and spectral efficiency are improved, but timing synchronization between multiple transmit chains becomes more difficult to maintain
Solution Approach 1:
The patent divides the clock distribution system into multiple independent regions, each with its own clock buffer and control circuitry. This segmentation allows each region to be independently synchronized while maintaining overall system coherence, resolving the synchronization difficulty caused by multiple transmit chains.
Solution Approach 2:
The patent implements preliminary clock phase adjustment by inserting delay elements and control circuits that pre-synchronize clock signals before they reach multiple transmit chains. This preliminary action ensures that all transmit chains start with synchronized clocks, preventing timing drift during operation.
2Area of stationary object
If clock signals are distributed throughout the communication device through dividers, buffers, and repeaters, then clock signal coverage is improved, but clock phase synchronization across different regions deteriorates
Solution Approach 1:
The patent employs feedback mechanisms where clock phase detectors monitor the phase relationships between distributed clock signals and generate control signals that adjust delay elements. This closed-loop feedback ensures that even as clock signals are distributed across large areas, phase synchronization is continuously maintained.
Solution Approach 2:
The patent makes the clock distribution system dynamic by introducing controllable delay elements and adjustable buffer circuits that can adapt their characteristics based on measured phase differences. This dynamic adjustment capability allows the system to maintain synchronization despite variations in distribution path lengths and loading conditions.
Data Source
AI summary
An apparatus and a method are disclosed for synchronizing clock signals distributed within a wireless device. In some embodiments, a local oscillator (LO) clock signal is buffered and distributed to two or more transceivers within the wireless device. Each transceiver may include a configurable clock divider to divide the distributed LO clock signal and generate an output clock signal. A phase detector compares output clock signals from each of the configurable clock dividers and generates an output signal in accordance with a determined phase difference. The phase detector output signal may cause at least one of the configurable clock dividers to modify its respective output clock signal, and thereby synchronize output clock signals between different configurable clock dividers. In some embodiments, a clock signal from a configurable clock divider may be modified (shifted) by approximately 90 or 180 degrees.