Transmit/receive compensation in a time division duplex system

Claim 2

In a highly bandwidth-efficient communications method, including the steps of: receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; testing a transmit path at said base station during said first time period and compiling transmit compensation weights; spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; applying said transmit compensation weights to said second data signal during said second time period; transmitting said second spread signal during said second time period; testing said receive path at said base station during said second time period and compiling new receive compensation weights; in a first TDD interval, testing the receive path of a first antenna during a base station transmission period; applying a multitone signal to the input of a receive amplifier in the receive path; compiling receive path compensation weights and storing them in a receive path compensation buffer; and applying the receive path compensation weights in later TDD receive periods.

Claim 3

In the highly bandwidth-efficient communications method of claim 1, wherein said first and second time periods are part of a time division duplex interval.

Claim 4

In the highly bandwidth-efficient communications method of claim 1, wherein said compensation measurements are made for the transmission path during the receive portion of a time division duplex cycle and compensation measurements are made for the receive path during the transmit portion of the TDD cycle.

Claim 5

In the highly bandwidth-efficient communications method of claim 1, wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications.

Claim 6

In the highly bandwidth-efficient communications method of claim 4, wherein each said antenna has its own transmission path components and receive path components.

Claim 7

In the highly bandwidth-efficient communications method of claim 5, wherein a transmit amplifier in the transmit path and a receive amplifier in the receive path tend to drift in their characteristics over time.

Claim 8

In the highly bandwidth-efficient communications method of claim 5, wherein said compensation steps further comprise: managing sequential testing of each respective transmission path and receive path for each antenna; measuring a drift of the transmit path components and the receive path components and preparing compensating weights to be applied to signals processed in each path.

Claim 9

In a highly bandwidth-efficient communications method, including the steps of: receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; testing a transmit path at said base station during said first time period and compiling transmit compensation weights, spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; applying said transmit compensation weights to said second data signal during said second time period; transmitting said second spread signal during said second time period; and testing said receive path at said base station during said second time period and compiling new receive compensation weights; wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications; wherein each said antenna has its own transmission path components and receive path components; wherein said compensation steps further comprise: managing sequential testing of each respective transmission path and receive path for each antenna; measuring a drift of the transmit path component and the receive path components and preparing compensating weights to be applied to signals processed in each path; wherein in a first TDD interval, testing the receive path of a first antenna during a base station transmission period; applying a multitone signal to the input of a receive amplifier in the receive path; compiling receive path compensation weights and storing them in a receive path compensation buffer; applying the receive path compensation weights in later TDD receive periods.

Claim 10

In a highly bandwidth-efficient communications method, including the steps of: receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; testing a transmit path at said base station during said first time period and compiling transmit compensation weights, spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; applying said transmit compensation weights to said second data signal during said second time period; transmitting said second spread signal during said second time period; and testing said receive path at said base station during said second time period and compiling new receive compensation weights; wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications; wherein each said antenna has its own transmission path components and receive path components; wherein said compensation steps further comprise: managing sequential testing of each respective transmission path and receive path for each antenna; measuring a drift of the transmit path component and the receive path components and preparing compensating weights to be applied to signals processed in each path; wherein in a first TDD interval, testing the receive path of a first antenna during a base station transmission period; applying a multitone signal to the input of a receive amplifier in the receive path; compiling receive path compensation weights and storing them in a receive path compensation buffer; applying the receive path compensation weights in later TDD receive periods.

Claim 11

In the highly bandwidth-efficient communications method of claim 8, wherein in the base receive period applying a multitone test signal output to a transmitter in the transmit path to an input of a test receiver; processing the received test signal applied by the test receiver; compiling transmit path compensation weights and storing them in a transmit path compensation buffer; applying the transmit path compensation weights thereafter to signals transmitted from the base station.

Claim 12

In the highly bandwidth-efficient communications method of claim 9, wherein repeating said testing and compensation steps for a second antenna in the next consecutive TDD interval.

Claim 13

In a highly bandwidth-efficient communications system, comprising: means for receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; means for compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; means for testing a transmit path at said base station during said first time period and compiling transmit compensation weights; means for spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; means for applying said transmit compensation weights to said second data signal during said second time period; means for transmitting said second spread signal during said second time period; means for testing said receive path at said base station during said second time period and compiling new receive compensation weights; means for testing in a first TDD interval the receive path of a first antenna during a base station transmission period; means for applying a multitone signal to the input of a receive amplifier in the receive path; means for compiling receive path compensation weights and storing them in a receive path compensation buffer; and means for applying the receive path compensation weights in later TDD receive periods.

Claim 14

In a highly bandwidth-efficient communications system, comprising: means for receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; means for compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; means for testing a transmit path at said base station during said first time period and compiling transmit compensation weights; means for spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; means for applying said transmit compensation weights to said second data signal during said second time period; means for transmitting said second spread signal during said second time period; means for testing said receive path at said base station during said second time period and compiling new receive compensation weights; means for testing in a first TDD interval the receive path of a first antenna during a base station transmission period; means for applying a multitone signal to the input of a receive amplifier in the receive path; means for compiling receive path compensation weights and storing them in a receive path compensation buffer; and means for applying the receive path compensation weights in later TDD receive periods.

Claim 15

In the highly bandwidth-efficient communications system of claim 11, wherein said first and second time periods are part of a time division duplex interval.

Claim 16

In the highly bandwidth-efficient communications system of claim 11, wherein said compensation measurements are made for the transmission path during the receive portion of a time division duplex cycle and compensation measurements are made for the receive path during the transmit portion of the TDD cycle.

Claim 17

In the highly bandwidth-efficient communications system of claim 11, wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications.

Claim 18

In the highly bandwidth-efficient communications system of claim 14, wherein each said antenna has its own transmission path components and receive path components.

Claim 19

In the highly bandwidth-efficient communications system of claim 15, wherein a transmit amplifier in the transmit path and a receive amplifier in the receive path tend to drift in their characteristics over time.

Claim 20

In the highly bandwidth-efficient communications system of claim 15, which further comprises: means for managing sequential testing of each respective transmission path and receive path for each antenna; means for measuring a drift of the transmit path components and the receive path components and preparing compensating weights to be applied to signals processed in each path.

Claim 21

In a highly bandwidth efficient communications system, comprising: means for receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; means for compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; means for testing a transmit path at said base station during said first time period and compiling transmit compensation weights; means for spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; means for applying said transmit compensation weights to said second data signal during said second time period; means for transmitting said second spread signal during said second time period; means for testing said receive path at said base station during said second time period and compiling new receive compensation weights; wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications; wherein each said antenna has its own transmission path components and receive path components; means for managing sequential testing of each respective transmission path and receive path for each antenna; means for measuring a drift of the transmit path components and the receive path components and preparing compensating weights to be applied to signals processed in each path; means for testing in a first TDD interval, the receive path of a first antenna during a base station transmission period; means for applying a multitone signal to the input of a receive amplifier in the receive path; means for compiling receive path compensation weights and storing them in a receive path compensation buffer; and means for applying the receive path compensation weights in later TDD receive periods.

Claim 22

In a highly bandwidth efficient communications system, comprising: means for receiving in a receive path at a base station during a first time period a first spread signal comprising a first data signal spread over a plurality of discrete tones; means for compensating for drift in said receive path during said first time period by applying receive compensation weights to said first spread signal; means for testing a transmit path at said base station during said first time period and compiling transmit compensation weights; means for spreading a second data signal at the base station with a spreading code that distributes the second data signal over a plurality of discrete tones during a second time period; means for applying said transmit compensation weights to said second data signal during said second time period; means for transmitting said second spread signal during said second time period; means for testing said receive path at said base station during said second time period and compiling new receive compensation weights; wherein said base station has multiple antennas for spatial spreading and despreading of discrete multitone spread spectrum (DMT-SS) communications; wherein each said antenna has its own transmission path components and receive path components; means for managing sequential testing of each respective transmission path and receive path for each antenna; means for measuring a drift of the transmit path components and the receive path components and preparing compensating weights to be applied to signals processed in each path; means for testing in a first TDD interval, the receive path of a first antenna during a base station transmission period; means for applying a multitone signal to the input of a receive amplifier in the receive path; means for compiling receive path compensation weights and storing them in a receive path compensation buffer; and means for applying the receive path compensation weights in later TDD receive periods.

Claim 23

In the highly bandwidth-efficient communications system of claim 18, wherein means for applying in the base receive period, a multitone test signal output to a transmitter in the transmit path to an input of a test receiver; means for processing the received test signal applied by the test receiver; means for compiling transmit path compensation weights and storing them in a transmit path compensation buffer; and means for applying the transmit path compensation weights thereafter to signals transmitted from the base station.

Claim 24

In the highly bandwidth-efficient communications system of claim 19, which further comprises: means for repeating said testing and compensation steps for a second antenna in the next consecutive TDD interval.