Abstract:
A personal identification device may conserve power by delegating one or more operations to another device. For example, the one or more operations may be associated with the authentication of the personal identification device. In one example, the personal identification device may determine an amount of power greater than a power threshold will be consumed by the personal identification device to perform the one or more operations. The personal identification device may determine it can communicate with a mobile device that is capable of performing the one or more operations, and may then delegate the one or more operations to the mobile device to conserve power. In one example, the personal identification device may receive the results of the one or more operations from the mobile device, and may provide data associated with the results to a personal identification device detector for authentication of the personal identification device.
Abstract:
In a multiple-input, multiple-output (MIMO) system, a wireless node's receive chain demodulation function is enhanced to include phase tracking. VHT Long Training Fields (LTFs) embedded in a frame preamble are used for phase tracking. Single stream pilot tones are added during transmission of VHT-LTFs. A receiver estimates the channel using the pilot tones in a first set of LTFs. A second set of LTFs are used to estimate the phase of the pilot tones using the estimated channel. The phase estimation is continuously applied to other received data tones throughout the VHT-LTFs of data symbols. Phase errors due to PLL mismatches and phase noise are reduced at reception, leading to better signal to noise ratio for different levels of drift and frequency offset. Further, MIMO channel estimation is more accurate, improving the overall wireless network when the accurate MIMO channel estimation data participates in calibration and handshake between wireless nodes.
Abstract:
A method of adjusting single-stream transmissions by a wireless device based on channel state information (CSI). The wireless device generates a sounding packet formatted for transmission via multiple spatial streams, and transmits the sounding packet to a receiving device via a single one of the multiple spatial streams. For example, the wireless device may be a single-antenna device. The wireless device further receives channel state information (CSI) from the receiving device based at least in part on the sounding packet. The wireless device then adjusts one or more characteristics of single-stream transmissions to the receiving device based at least in part on the received CSI.
Abstract:
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may be communicating on a radio frequency spectrum band of a first radio access technology (RAT) using a set of antennas. The UE may reconfigure at least one antenna of the set of antennas to perform a first scan on the radio frequency spectrum band of a second RAT. The UE may determine, based on the first scan, whether to reconfigure a remaining portion of the antennas of the set of antennas to perform a second scan on the radio frequency spectrum band of the second RAT.
Abstract:
A method for determining uplink channel information includes sending a trigger frame from an access point of a wireless network to a plurality of stations in the wireless network. The method also includes receiving an uplink transmission from at least one station of the plurality of stations in response to sending the trigger frame. The method further includes determining uplink channel data based on the uplink transmission. The method also includes sending the uplink channel data to the at least one station. The uplink channel data is usable by the at least one station to send data to the access point.
Abstract:
A method of providing rate adaptation in a multi-user wireless communication system including single-user beamforming (SU-BF) and multi-user multiple-input multiple-output (MU-MIMO) is described. In this method, a master rate, which is a modulation and coding scheme (MCS) for the SU-BF, is determined. An MCS for each transmit mode is derived from the master rate using a rate mapping. Using the results from the mapping, the master rate, instead of the MCS for each transmit mode, is tracked. In one embodiment, a mapping calibration is periodically performed.
Abstract:
A method of providing rate adaptation in a multi-user wireless communication system including single-user beamforming (SU-BF) and multi-user multiple-input multiple-output (MU-MIMO) is described. In this method, a master rate, which is a modulation and coding scheme (MCS) for the SU-BF, is determined. An MCS for each transmit mode is derived from the master rate using a rate mapping. Using the results from the mapping, the master rate, instead of the MCS for each transmit mode, is tracked. In one embodiment, a mapping calibration is periodically performed.
Abstract:
A method of providing feedback on channel observations to a transmitter includes observing a channel at a receiver based on received signals from the transmitter and determining whether a packet error rate (PER) is rising based on the observing. The receiver determines whether a rising PER is caused by channel noise or interference, and transmits a message to the transmitter indicating the cause of the rising PER. The cause may be encoded in reserved bits of a block acknowledgement (BA) frame or an Acknowledge (ACK) frame, or in a modulation coding scheme (MCS) used to transmit the message. The cause may be detected in response to SNR/RSSI level of received signals, or a number of receiver restarts. The transmitter may change the transmit rate adaptation algorithm to use a lower MCS if channel noise causes the rising PER, and a higher MCS if interference causes the rising PER.
Abstract:
In a semi-open loop rate adaptation scheme for a multiple-input multiple-output (MIMO) system, a transmitter can advantageously use one or more quality metrics of an uplink as well as knowledge of device characteristics of both ends to perform fast and accurate rate adaptation.
Abstract:
A wireless device may be configured to operate in one of two modes where each mode uses a different channel list to perform operations in accordance with the IEEE 802.11 standard. In a first mode, the wireless device operates as an access point that sets up channels using one channel list in order to facilitate communications within a basic service set (BSS). In a second mode, the wireless device uses a second channel list to operate as a station and scan for a BSS. The first channel list contains a subset of the channels contained in the second channel list. The channels in each respective channel list may be reconfigured to adapt to changes in the configuration of a BSS and the devices communicating therein.