SPMT Switch Sharing Phase Shifter and VGA in Massive MIMO
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Solution Overview
Problem
Massive MIMO wireless communication systems face increased hardware complexity and energy consumption due to the need for numerous antennas, phase shifters, and variable gain amplifiers, which becomes impractical and costly, especially in channels with small angular spread.
Innovation Solution
The system shares analog hardware resources by using a single-pole-M-throw analog switch to connect a phase shifter and variable gain amplifier to each antenna sequentially, allowing reuse across multiple antennas, decoupling time dependency through principles from digital signal processing, and employing band-pass filters for signal reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each antenna is connected to a dedicated phase shifter and variable gain amplifier for beamforming transmission, then beamforming performance is maintained, but hardware complexity and cost increase significantly
Solution Approach 1:
The patent merges the phase shifter and variable gain amplifier resources by implementing time-division multiplexing, where a single phase shifter and VGA are shared across multiple antenna elements. The controller sequentially connects the shared phase shifter-VGA unit to different antenna elements through switching matrices, allowing one set of components to serve multiple antennas at different time intervals, thereby reducing hardware complexity while preserving beamforming capability
Solution Approach 2:
The patent employs periodic time-division multiplexing where the shared phase shifter and VGA are periodically allocated to different antenna elements in a sequential manner. The controller implements periodic switching cycles that connect the shared components to each antenna element for predetermined time slots, enabling resource reuse across the antenna array while maintaining the ability to perform beamforming operations
2Device complexity
If the number of phase shifters and variable gain amplifiers is reduced by sharing hardware resources, then hardware cost decreases, but the ability to perform concurrent transmission from multiple antennas is limited
Solution Approach 1:
The patent implements periodic time-division multiplexing where the shared phase shifter and VGA are allocated to different antenna elements in sequential time slots. The controller manages periodic switching cycles that enable each antenna element to access the shared components for predetermined durations, allowing the system to support multiple transmission streams over time while using fewer hardware components
Solution Approach 2:
The patent introduces dynamic resource allocation through a controller that manages the switching matrices and time-division multiplexing scheme. The system dynamically adjusts the connection between the shared phase shifter-VGA unit and different antenna elements based on transmission requirements, enabling flexible resource sharing and maintaining adaptability in beamforming operations despite hardware constraints
3Use of energy by moving object
If a single phase shifter and variable gain amplifier are shared across multiple antennas, then energy consumption is reduced, but the system must sequentially connect components rather than concurrently
Solution Approach 1:
The patent implements periodic time-division multiplexing that efficiently cycles the shared phase shifter and VGA through different antenna elements. The controller manages periodic switching at optimized frequencies that minimize connection transition time while maximizing resource utilization, allowing the system to reduce energy consumption from fewer active components while maintaining acceptable transmission throughput
Solution Approach 2:
The patent ensures continuous useful action by implementing overlapping time-division multiplexing schedules where the shared phase shifter-VGA unit transitions between antenna elements with minimal idle time. The controller coordinates switching operations to maintain continuous beamforming functionality across the antenna array, reducing the impact of sequential connection time while preserving energy efficiency
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 hardware costs and energy consumption while maintaining beamforming performance by enabling efficient reuse of phase shifters and variable gain amplifiers across multiple antennas, effectively addressing the impracticality of concurrent transmission requirements in massive MIMO systems.
Implementation Method 1
A phase shifter to shift a phase of an input signal
Implementation Method 2
a variable gain amplifier to change an amplitude of the input signal
Implementation Method 3
employing band-pass filters for signal reconstruction
Implementation Method 4
Beamforming can be achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference, while others experience destructive interference
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A transmitter or receiver including at least one radio-frequency (RF) chain. The RF chain including an array of transmitting elements, each transmitting element includes a band-pass filter and an antenna connected in series for transmitting an analog signal using a beamforming with an angle of departure (AOD) defined by phase shifts of analog signals received by different transmitting elements within the array. A phase shifter to shift a phase of an input signal. A variable gain amplifier (VGA) to change an amplitude of the input signal. A switcher to connect the phase shifter and the VGA to each transmitting element in the array. Wherein at most one transmitting element is connected to the phase shifter and the VGA at a given point of time, such that the switcher is a single-pole-M-throw (SPMT) analog switch. A controller to control the phase shifter, the VGA and the switcher.