1. A Mixed Signal MIMO Beamforming Receiver
Richard Tseng, Ada S. Y. Poon, Yun Chiu
Current MIMO Implementations
Proposed Implementation
Large number of analog components
Strong interferers easily saturate the ADCs, rendering any MIMO algorithm useless.
Most research activities focus on the VLSI implementation of various MIMO algorithms and do not solve the critical problem.
Simplify analog circuits, move complexity to the digital domain
Solve dynamic range problem by performing beamforming and signal combining in the analog domain
Many MIMO algorithms still applicable in analog domain, greatly relaxes circuit requirements.
Three Pronged Approach
Digital algorithm
Novel circuits
Scalable Architecture
- in the phase domain
Analog Domain
Digital Domain
Direct Conversion Implementation
Nonlinear
Expansion
Linear
Reconstruction
Decisions
Complex multiplier architecture scales up to multiple LO signals and high frequencies
Core DLL runs at a lower frequency
Edges combined to produce high
frequency LO signals
Quantization algorithm based on frame theory and stochastic approximation.
Signal Combiner
Mixer Core
Transconductance Stage
Accuracy:
MSE α 1/M2
Cost:
M LO Phases
M Mixers/Ant.
Accurate complex multiplication
Insensitive to phase and gain mismatch
Copying of signals allows circuit component reuse
Algorithm MSE can be reduced to
arbitrarily small values
This work is supported by C2S2/DARPA