Abstract: Technical solutions provide setup sequences for multi access point (AP) coordinated beamforming (CBF) at a transmission opportunity (TXOP) stage. A first AP can transmit, to a second AP capable of participating in CBF and a first station of the first AP, a notification indicative of a CBF TXOP. The first AP can receive, from at least the first station, responsive to the notification, a first response identifying a first capability of the first station. The first AP can receive, from the second AP associated with a second one or more stations, responsive to the notification, a second response identifying a second capability of at least one of the second AP or a second station of the second one or more stations. The first AP can communicate data to the first station during the CBF TXOP according to at least one of the first capability or the second capability.

Abstract: Technical solutions providing setup sequences for multi-access point (AP) coordinated beamforming (CBF). A system can include a first access point (AP) configured to transmit, to a second AP that is capable of participating in coordinated beamforming (CBF), a first notification frame comprising a first set of stations of the first AP to participate in a CBF transmission. The first AP can be configured to receive, from the second AP, responsive to the first notification frame, a first response frame comprising a second set of stations of the second AP to participate in the CBF transmission. The first AP can be configured to transmit data in the CBF transmission to at least one station of the first set of stations or the second set of stations, responsive to the first response frame.

Abstract: Technical solutions include systems and methods for multi-access-point (AP) coordination of coordinated beamforming (CBF) for nulling of mutual interferences. A first AP can be configured to identify a second AP that is capable of participating in coordinated beamforming (CBF), select one or more candidate stations of the first AP and identify capabilities of at least one of the first AP or the one or more candidate stations. The first AP can be configured to determine one or more stations of the one or more candidate stations to participate in CBF based at least on the capabilities and perform a sequence with the second AP to exchange, between the first AP and the second AP, a set of stations of the first AP and the second AP to participate in CBF. The first AP can identify to the second AP the determined one or more stations as participating in CBF.

Abstract: The technical solutions are directed to coordinated beamforming per-TXOP frame sequence negotiation. A first access point (AP) can transmit, to a second AP and a first candidate set of stations, a first message to initiate transmission opportunity (TXOP) and a CBF request. The second AP can transmit a second message to a second candidate set of stations of the second AP identified to participate in the TXOP with a CBF response responsive to the CBF request. The first AP, responsive to receiving the CBF response, can transmit to the second AP a third message having a CBF trigger comprising information to synchronize a CBF transmission to be communicated during the TXOP.

Abstract: At least one aspect of the technical solutions can be directed to a system. The system can include a first access point (AP) that can be configured to transmit, to a second AP that can be capable of participating in coordinated beamforming (CBF) and a first candidate set of stations of the first AP, a first message to initiate transmission opportunity (TXOP). The second AP can be configured to transmit a second message to the first AP and a second candidate set of stations of second AP identified to participate in the TXOP. The second AP can be configured to transmit a third message having a CFB response to the first AP. The first AP can be configured to transmit a fourth message to second AP having a CBF trigger that can include information on a preamble of a CBF transmission to be communicated during the TXOP.

Abstract: To more efficiently compensate for modulation imbalance, a mobile device modulates and demodulates a calibration tone and generates digital data representing modulation imbalance effects on the calibration tone. Using digital data enables modulation imbalance effects to be quickly estimated using digital signal processing techniques, increasing the number of estimates of modulation imbalance effects calculated. The modulation imbalance estimates are used to refine one or more compensation parameters which are applied to transmitted and/or received signals to compensate for errors caused by modulation.

Abstract: Two dimensional interpolation techniques are used to compensate for time-varying channel gain H in an OFDM system. The channel gain can be reasonably estimated at various times and at various frequencies due, for example, to the use of pilot tones. These channel estimates are used to estimate the channel gain at other times and/or frequencies by two-dimensional interpolation, interpolating first with respect to time (e.g., with respect to a symbol index s) and then with respect to frequency (e.g., with respect to a sub-carrier index c).

Abstract: To more efficiently compensate for modulation imbalance, a mobile device modulates and demodulates a calibration tone and generates digital data representing modulation imbalance effects on the calibration tone. Using digital data enables modulation imbalance effects to be quickly estimated using digital signal processing techniques, increasing the number of estimates of modulation imbalance effects calculated. The modulation imbalance estimates are used to refine one or more compensation parameters which are applied to transmitted and/or received signals to compensate for errors caused by modulation.

Abstract: Architectures of multi-stage sample rate converters are disclosed. According to one aspect of the present invention, a received signal with a higher sampling rate is converted to a lower sampling rate. To prevent aliasing in the resultant signal, an anti-aliasing filter is introduced. The passband of the anti-aliasing filter is so adjusted according to the conversation rate of a sample rate converter. To keep the implementation relatively simple, the coefficients of the filter are kept constant. Therefore, the conversation rate of a sample rate converter is constrained in a limited range, thus requiring only a constant anti-aliasing filter. A series of halfband filters are then used to convert the signal to a desired sampling rate.