US 11,171,813 B2Granted

Blind distributed multi-user MIMO for decoding multiple concurrent wireless transmissions

AssigneeMicrosoft Technology Licensing, LLC

InventorsKrishna Kant Chintalapudi, Nissanka Arachchige Bodhi Priyantha, Chuhan Gao

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Abstract

Techniques for blind distributed multi-user MIMO enable simultaneous decoding of multiple concurrent wireless transmissions without the need for coordination between wireless devices or a measurement phase. Wireless devices are permitted to transmit independently and at arbitrary times. Concurrent transmissions from wireless devices superimpose in the wireless channel and are received at various base stations. The base stations forward received data samples to a central entity (e.g., a cloud computing service), which uses known preambles to reliably estimate CFOs and channels between the transmitting devices and the receiving base stations while simultaneously recovering the data samples of the individual data streams.

Claims16

Dependent claims

A method, comprising:

receiving data samples from a plurality of base stations, the data samples corresponding to a plurality of signals that are transmitted by a plurality of wireless devices and received at the plurality of base stations;
detecting, based on the data samples, a known preamble indicating a new packet transmission;
using known preamble samples to attempt to simultaneously estimate:
carrier frequency offsets (CFOs) and channel parameters corresponding to the plurality of wireless devices and the plurality of base stations;
and
message data samples corresponding to messages sent by individual wireless devices;
entering a steady state after the CFOs and the channel parameters have been estimated;
while in the steady state, using the estimated CFOs and the estimated channel parameters to estimate the message data samples;
and
entering a blind estimation state in response to detecting another new packet transmission while in the steady state.

7 more elements

A non-transitory computer-readable medium comprising instructions that are executable by one or more processors to cause a computing system to:

receive data samples from a plurality of base stations, wherein the data samples correspond to a plurality of signals that are transmitted by a plurality of wireless devices and received at the plurality of base stations, and wherein the plurality of wireless devices transmit independently and at arbitrary times;
detect, based on the data samples, a known preamble indicating a new packet transmission;
enter a blind estimation state in response to detecting the known preamble;
while in the blind estimation state, using known preamble samples to attempt to simultaneously estimate:
carrier frequency offsets (CFOs) and channel parameters corresponding to the plurality of wireless devices and the plurality of base stations;
and
message data samples corresponding to messages sent by individual wireless devices;
detect that at least one condition that is necessary for successfully performing blind estimation is not satisfied, wherein the at least one condition comprises at least one of a blind estimation sufficiency condition, a minimum number of receivers condition, or a burst limit condition;
and
instruct the plurality of base stations to signal the plurality of wireless devices to temporarily discontinue transmitting.

7 more elements

A system, comprising:

one or more processors;
memory in electronic communication with the one or more processors;
and
instructions stored in the memory, the instructions being executable by the one or more processors to:
receive data samples from a plurality of base stations, wherein the data samples correspond to a plurality of signals that are transmitted by a plurality of wireless devices and received at the plurality of base stations, and wherein the plurality of wireless devices transmit independently and at arbitrary times;
detect, based on the data samples, a known preamble indicating a new packet transmission;
enter a blind estimation state in response to detecting the known preamble;
while in the blind estimation state, using known preamble samples to simultaneously estimate carrier frequency offsets (CFOs), channel parameters corresponding to the plurality of wireless devices and the plurality of base stations, and message data samples corresponding to messages sent by individual wireless devices;
enter a steady state after the CFOs and the channel parameters have been estimated;
and
re-enter the blind estimation state in response to detecting another new packet transmission while in the steady state.

8 more elements

Dependencies are inferred from the claim text.