Massive-MIMO Transceiver Single Master Clock Architecture
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Solution Overview
Problem
The commercial deployment of massive-MIMO systems is hindered by the complexity and high cost of radio-frequency (RF) hardware, which increases significantly with the number of antennas, making conventional RF equipment prohibitive for commercial applications.
Innovation Solution
A MIMO transceiver design that uses a single master clock to generate sampling-clock signals and multiple electrical local-oscillator signals, employing frequency dividers and filters to generate signals with different frequencies, reducing complexity and cost while improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional RF equipment is used in M-MIMO systems with hundreds of antennas, then the system can achieve high capacity and coverage, but the hardware complexity and cost become prohibitive
Solution Approach 1:
The patent merges multiple independent RF signal generation paths into a single integrated architecture. A single master clock and single local oscillator (LO) signal are shared across multiple antenna channels through frequency division and phase shifting networks, eliminating the need for separate RF generators per antenna. This combining approach maintains the ability to serve multiple antennas while dramatically reducing hardware complexity and cost.
Solution Approach 2:
The single master clock and LO signal structure serves multiple functions across all antenna channels simultaneously. The frequency divider network generates multiple frequency components from one clock source, and the phase shifter network distributes the single LO signal to multiple channels with different phase offsets. This multi-functional design allows one set of RF components to support hundreds of antennas, resolving the contradiction between system capacity and hardware complexity.
2Reliability
If the number of antennas in M-MIMO system is increased to improve performance, then system capacity and coverage are enhanced, but the cost and complexity of RF equipment rise dramatically
Solution Approach 1:
The patent segments the RF signal generation function into distinct modular components: a master clock generator, frequency division network, single LO signal generator, and per-channel phase shifters. This segmentation allows the complex task of generating signals for hundreds of antennas to be divided into manageable functional blocks, where the complex frequency and phase manipulation is centralized in the first two stages, while individual channels only require simple phase adjustment. This modular segmentation maintains system performance while controlling overall complexity.
Solution Approach 2:
The patent introduces intermediate frequency (IF) conversion as a mediator between the baseband digital domain and the RF domain. Instead of directly generating RF signals for each antenna, the system first converts digital signals to IF, then uses a single LO to upconvert all channels to RF. This intermediate step decouples the complexity of multi-channel RF signal generation from the baseband processing, allowing independent optimization of each domain and reducing the overall system complexity.
3Reliability
If separate RF signal generation is used for each antenna channel, then signal quality is maintained, but the transceiver size and cost increase significantly
Solution Approach 1:
The patent combines the RF signal generation function into a single centralized unit that serves all antenna channels. The master clock and LO signal are shared resources that are distributed to multiple channels through frequency and phase manipulation networks. This merging eliminates redundant RF generators, mixers, and oscillators that would otherwise be required for each channel, dramatically reducing transceiver size while maintaining signal quality through careful design of the sharing networks.
Solution Approach 2:
The patent changes the frequency and phase parameters of the shared LO signal to generate the required signal variations for different antenna channels. Instead of using separate oscillators with different frequencies and phases, the system uses a single LO whose frequency is divided and whose phase is shifted electronically for each channel. This parameter manipulation approach maintains signal quality while avoiding the physical size of multiple independent RF signal generation chains.
Data Source
AI summary
An embodiment of the disclosed MIMO transceiver uses a single master clock to generate (i) the sampling-clock signals for the analog-to-digital and digital-to-analog converters and (ii) the multiple electrical local-oscillator signals that are used in various channels of the transceiver's analog down- and up-converters to translate signals between the corresponding intermediate-frequency and RF bands. The MIMO transceiver may employ a plurality of interconnected frequency dividers configured to variously divide the master-clock frequency to generate the sampling-clock signals and the multiple local-oscillator signals in a manner that causes these signals to have different respective frequencies. In embodiments designed for operating in the mmW band, the MIMO transceiver may also employ a frequency multiplier configured to multiply the master-clock frequency to generate an additional local-oscillator signal for translating signals between the mmW and RF bands.