MIMO OTA Channel Emulation with Reduced Transmit Antennas

The patent transforms the channel emulation problem from a spatial configuration problem to a signal parameter problem. By changing the parameters of the transmitted signals (amplitude, phase, frequency) rather than changing the physical positions of transmit elements, the system achieves accurate channel emulation with fewer transmit elements. The signal parameters are adjusted to match the desired channel characteristics, allowing the same physical transmit elements to emulate different channel conditions.

The patent creates virtual copies of the desired channel response through signal processing. Instead of physically positioning transmit elements to replicate channel paths, the system uses signal copying and synthesis to create multiple virtual signal paths from a limited number of physical transmit elements. Each physical transmit element can represent multiple virtual paths by modulating its signal with different characteristics.

The patent reduces cost by changing the approach from hardware proliferation to software-based signal parameter adjustment. Instead of purchasing and positioning multiple expensive transmit elements, the system uses a limited number of transmit elements with programmable signal characteristics. The channel emulation is achieved through digital signal processing that adjusts amplitude, phase, and frequency parameters, which is much cheaper than acquiring additional physical hardware.

The patent creates multiple virtual channel paths through signal copying and synthesis rather than using multiple physical transmit elements. By copying and combining signals with different characteristics from a limited set of physical elements, the system emulates the effect of having many transmit elements at a fraction of the cost.

The patent changes the fundamental approach from physical signal generation to digital signal parameter modulation. By adjusting signal parameters (amplitude, phase, frequency) rather than increasing the number of physical transmit elements, the system avoids the harmful reflections that would be generated by additional transmit elements in the anechoic chamber. The same physical transmit elements are used with different signal characteristics to achieve the desired channel emulation.

The patent creates multiple virtual signal paths through digital signal copying and synthesis rather than using multiple physical transmit elements. This approach maintains the anechoic chamber's reflective characteristics while still achieving accurate channel emulation through software-based signal combination and manipulation.