Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a radio unit (RU) may receive, from a user equipment (UE), a demodulation reference signal (DMRS) associated with a channel. The RU may perform a channel estimation associated with the channel using the DMRS to obtain channel estimation information. The RU may transmit, to a distributed unit (DU), information that is based at least in part on the channel estimation information. Numerous other aspects are described.

Abstract: Various aspects of the disclosure relate to managing ephemeris information. Provisions are made for providing ephemeris information to a user terminal (UT). Messages are defined for sending ephemeris information and for requesting ephemeris information. Ephemeris information for a subset of the satellites in a constellation may be sent to a UT to reduce signaling load. A UT may manage a database of ephemeris information to ensure freshness of the ephemeris information.

Abstract: Aspects of the present disclosure generally relate to techniques and apparatus that may help improve greatly reduce the implementation complexity of the ground station, and ground base-station user capacity by utilizing a subband beamformer for processing uplink signals received from aircraft at ground base stations, in an air-to-ground (ATG) system. The techniques presented herein may allow for dynamic subband allocation to different airborne devices with multi-user beamforming and subband combining.

Abstract: Various aspects of the disclosure relate to managing ephemeris information. Provisions are made for providing ephemeris information to a user terminal (UT). Messages are defined for sending ephemeris information and for requesting ephemeris information. Ephemeris information for a subset of the satellites in a constellation may be sent to a UT to reduce signaling load. A UT may manage a database of ephemeris information to ensure freshness of the ephemeris information.

Abstract: Managing handover procedures of two or more modems from a serving base station to a target base station includes receiving at least one message indicative of at least one measurement report of radio conditions from at least one modem of the two or more modems; determining, based on the at least one message, whether to handover the two or more modems from the serving base station to the target base station; and upon determining to handover the two or more modems from the serving base station to the target base station, indicating to each of the two or more modems to send to the serving base station a measurement report configured to trigger a respective handover procedure from the serving base station to the target base station.

Abstract: Methods, systems, and devices are described for implementing timing advances in which a propagation delay may exceed a time period of a portion of a radio frame. In some examples, a transmitter may identify a timing advance indicating a time to initiate wireless uplink transmission of a subframe. Such a timing advance may compensate for a propagation delay between the transmitter and a receiver of the wireless uplink transmission. The timing advance may be applied as an integer component and a fractional component in relation to a duration of the subframe, to adjust the time to initiate the wireless uplink transmission of the subframe. The integer component may be used to adjust one or more subframe characteristics, and the fractional component that may be used to adjust the time to initiate the wireless uplink transmission of the subframe.

Abstract: Methods, systems, and devices are described for transmitting across a broad azimuth using an antenna array. In one example, a method is described that includes forming two subarrays from an antenna array. Beamforming weights are selected for each subarray to cause the radiation patterns to be complementary over a range of the azimuth of a cell. The beamforming weights may be selected according to a recursive relation based on the number of antenna elements in each subarray. Information may be encoded, scrambled, and mapped to modulation symbols. A Space Frequency Block Code (SFBC) such as an Alamouti Code may then be used to form two signals to be transmitted over the two subarrays.

Abstract: Methods, systems, and devices are described for establishing a wireless communications link at an aircraft terminal (AT). An AT may determine a timing offset based on the propagation delay between the AT and a ground station, which in some cases may be more than 100 kilometers away. The AT may then transmit an initial access message to the ground station based on the determined timing offset. In some embodiments, the AT may receive an access response message from the ground station that includes a timing alignment value and adjust the timing offset based on this value. The AT may transmit a connection message to the ground station that includes AT location information. This information may be used by the ground station to facilitate beamforming.

Abstract: Aspects of the present disclosure generally relate to techniques and apparatus that may help improve greatly reduce the implementation complexity of the ground station, and ground base-station user capacity by utilizing a subband beamformer for processing uplink signals received from aircraft at ground base stations, in an air-to-ground (ATG) system. The techniques presented herein may allow for dynamic subband allocation to different airborne devices with multi-user beamforming and subband combining.

Abstract: Managing handover procedures of two or more modems from a serving base station to a target base station includes receiving at least one message indicative of at least one measurement report of radio conditions from at least one modem of the two or more modems; determining, based on the at least one message, whether to handover the two or more modems from the serving base station to the target base station; and upon determining to handover the two or more modems from the serving base station to the target base station, indicating to each of the two or more modems to send to the serving base station a measurement report configured to trigger a respective handover procedure from the serving base station to the target base station.

Abstract: Methods, systems, and devices are described for implementing timing advances in which a propagation delay may exceed a time period of a portion of a radio frame. In some examples, a transmitter may identify a timing advance indicating a time to initiate wireless uplink transmission of a subframe. Such a timing advance may compensate for a propagation delay between the transmitter and a receiver of the wireless uplink transmission. The timing advance may be applied as an integer component and a fractional component in relation to a duration of the subframe, to adjust the time to initiate the wireless uplink transmission of the subframe. The integer component may be used to adjust one or more subframe characteristics, and the fractional component that may be used to adjust the time to initiate the wireless uplink transmission of the subframe.

Abstract: Methods, systems, and devices are described for establishing a wireless communications link at an aircraft terminal (AT). An AT may determine a timing offset based on the propagation delay between the AT and a ground station, which in some cases may be more than 100 kilometers away. The AT may then transmit an initial access message to the ground station based on the determined timing offset. In some embodiments, the AT may receive an access response message from the ground station that includes a timing alignment value and adjust the timing offset based on this value. The AT may transmit a connection message to the ground station that includes AT location information. This information may be used by the ground station to facilitate beamforming.

Abstract: The connection management entity apparatus determines a set of modems within coverage of a particular area. Each modem of the set of modems is associated with a particular aircraft and one carrier of a plurality of carriers. The apparatus allocates subsets of modems to each eNB of a set of eNBs. The allocation allows each eNB to communicate with the allocated subset of modems. Each eNB operates on a different carrier. The apparatus may be a eNB. The eNB determines a set of modems within coverage of the eNB. The set of modems is associated with one carrier of a plurality of carriers. The eNB operates on the one carrier. Each modem in the set of modems is associated with a different aircraft. The eNB sends information indicating the set of modems and receives an allocation of a second set of modems in response to the sent information.

Abstract: Methods, systems, and devices are described for transmitting across a broad azimuth using an antenna array. In one example, a method is described that includes forming two subarrays from an antenna array. Beamforming weights are selected for each subarray to cause the radiation patterns to be complementary over a range of the azimuth of a cell. The beamforming weights may be selected according to a recursive relation based on the number of antenna elements in each subarray. Information may be encoded, scrambled, and mapped to modulation symbols. A Space Frequency Block Code (SFBC) such as an Alamouti Code may then be used to form two signals to be transmitted over the two subarrays.

Abstract: A method of wireless communication includes communicating with a base station using an extended special subframe. Communicating with the base station using the extended special subframe may be performed by disabling an uplink pilot time slot and an adjacent uplink subframe.

Abstract: A method of wireless communication includes communicating with a base station using a special subframe that extends a guard period over an uplink pilot time slot and one or more disabled, adjacent uplink subframes. The method also includes associating a control information subframe with a specific downlink subframe while accounting for both cell radius extension and loss of the one or more disabled, adjacent uplink subframes used to communicate the extended special subframe.

Abstract: Methods, systems, devices, and apparatuses are described for location tracking in which each tag used to track an asset or person in an indoor environment transmits ranging waveforms used to estimate a location of the tag. Multiple tags may concurrently transmit without interfering with each other by having each tag use a distinct frequency shift for the ranging waveforms. Access points may be deployed throughout the indoor environment as part of a wireless network (e.g., ultra-wideband or UWB network) that tracks the assets. The access points may receive the ranging waveforms transmitted by the tags and may perform measurements based on the ranging waveforms. The measurements may be sent to a tracking management server to estimate the location of the tags. The server may also determine and assign the distinct frequency shifts used by the tags and may modify the assignment when the number of tags being tracked changes.

Abstract: Synchronized broadcast transmits a same broadcast content using a same waveform from multiple transmitters. Transmitters each apply a same spreading code for broadcast transmissions. In a spread-spectrum communication system having a time division multiplexed forward link, a synchronized broadcast transmission is inserted into a broadcast slot. One embodiment employs an Orthogonal Frequency Divisional Multiplex (OFDM) waveform for the synchronized broadcast. An OFDM receiver is then used to process the received synchronized broadcast transmission. An alternate embodiment implements a broadcast Pseudo-random Noise (PN) code for use by multiple transmitters. An equalizer is then employed to estimate the synchronized broadcast transmission.

Abstract: In a synchronous application to control forward link (FL) data rates in a satellite system, user equipment (UE) repeatedly transmits a quality control measurement (QCM) index during a QCM period. During this QCM period, the data rate cannot change. The associated satellite transmits at a new rate corresponding to the QCM index. The UE knows that it will begin receiving new data at the new rate after a QCM delay. In an asynchronous application, a satellite transmits a rate change signal over a FL rate indication channel (RICH). A UE monitors the FL RICH for this signal. When the signal quality is to be low, the satellite sends only a single bit of the QCM index over a first orthogonal channel. When the signal quality is not low, the satellite transmits each bit of the QCM index in a separate orthogonal channel of the FL RICH.

Abstract: Synchronized broadcast transmits a same broadcast content using a same waveform from multiple transmitters. Transmitters each apply a same spreading code for broadcast transmissions. In a spread-spectrum communication system having a time division multiplexed forward link, a synchronized broadcast transmission is inserted into a broadcast slot. One embodiment employs an Orthogonal Frequency Divisional Multiplex (OFDM) waveform for the synchronized broadcast. An OFDM receiver is then used to process the received synchronized broadcast transmission. An alternate embodiment implements a broadcast Pseudo-random Noise (PN) code for use by multiple transmitters. An equalizer is then employed to estimate the synchronized broadcast transmission.