WO2019169526A1

WO2019169526A1 - Wireless devices pairing for downlink mu-mimo transmission

Info

Publication number: WO2019169526A1
Application number: PCT/CN2018/078002
Authority: WO
Inventors: Qiaoyu Li; Yu Zhang; Chao Wei; Chenxi HAO; Liangming WU; Hao Xu
Original assignee: Qualcomm Incorporated
Priority date: 2018-03-05
Filing date: 2018-03-05
Publication date: 2019-09-12

Abstract

Methods, systems, and devices for wireless communications are described. A first wireless device may be paired with a second wireless device to receive a downlink transmission from a base station, the downlink transmission including a signal for the first wireless device and a signal for the second wireless device encoded based on channel state information of the devices. The first wireless device may be geographically closer to the base station than the second wireless device and receive, from the base station, configuration information for the second wireless device. The first wireless device may decode the signal for the second wireless device based on the configuration information, then decode the signal for the first wireless device based on decoding the signal for the second wireless device. For example, the first wireless device may use successful interference cancellation of the signal for the second wireless device to decode the other signal.

Description

WIRELESS DEVICES PAIRING FOR DOWNLINK MU-MIMO TRANSMISSION

BACKGROUND

The following relates generally to wireless communications, and more specifically to wireless devices pairing for downlink MU-MIMO transmission.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform-spread-OFDM (DFT-S-OFDM) . A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

A base station may serve many machine-type communications (MTC) wireless devices in addition to mobile broadband (MBB) UEs. An MTC device and an MBB UE may communicate using different frequency resources if the base station is communicating with both simultaneously. The base station may allocate separate resources for the MBB UEs and the many MTC devices. Allocating separate resources may use a large amount of frequency resources to serve both types of wireless devices, causing poor spectral efficiency.

SUMMARY

A base station may serve a massive number of machine type communications (MTC) devices as well as multiple mobile broadband (MBB) user equipments (UEs) simultaneously using multiple-user (MU) multiple-input, multiple-output (MIMO) (MU-MIMO) communications. In some cases, the base station may reuse frequency resources allocated to MTC devices for MBB communications to UEs. For example, if an MBB UE and an MTC device are in a same spatial direction, the base station may transmit MBB transmissions for the MBB UE over MTC transmissions for the MTC device. The MBB signal and the MTC signal may be encoded using a same spatial precoder and transmitted in a single downlink transmission in the direction of the MBB UE and MTC UE. Transmitting two signals encoded using the same frequency and time resources may be referred to as superposition encoding the signals. In some cases, the two signals may be encoded with the same spatial precoder. The transmission carrying both signals may be referred to as a superposition encoded transmission. The base station may transmit the superposition encoded transmission on a subband based on channel state information (CSI) of the two wireless devices. The base station may adjust a power ratio between the MTC signal and the MBB signal such interference or decoding errors for the MTC device can be avoided. The UE may have a high enough channel gain to decode both the MBB signal and the MTC signal from the superposition encoded transmission. The base station may transmit MCS information for the MTC device to the MBB UE, which the MBB UE may use to decode the MTC signal. The MBB UE may then decode the MBB signal based on successive interference cancellation of the MTC signal.

Two wireless devices receiving a superposition coded transmission may be referred to as paired. In the above example, an MBB UE is paired with an MTC device, as an MBB signal for the MBB UE is superposition encoded over the MTC signal for the MTC device. In some other examples, one MBB UE may be paired with multiple MTC devices, or one MBB UE may be paired with multiple, other MBB UEs. In another example, one MTC device may be paired with multiple MBB UEs, or one MTC device may be paired with multiple MTC devices. The base station may transmit MCS information to whichever wireless device is geographically closer in proximity to the base station. For example, if a close MBB device is paired with multiple far MBB devices, the base station may indicate MCS information for each of the far MBB devices to the close MBB device. The base station may superposition encode an MBB signal for the close MBB UE over an MBB signal for each of the far MBB UEs. The close MBB UE may use the MCS information of each far MBB device to decode each MBB signal intended for the close MBB UE.

The base station may transmit superposition encoded signals to multiple pairs of wireless devices in different directions. The base station may reuse frequency subbands for the pairs of wireless devices in different directions by spatially multiplexing superposition encoded transmissions on the same frequency subbands. The base station may indicate MCS information to the closer device in a pair of wireless devices in a spatially multiplexed and frequency selective manner.

A method of wireless communications is described. The method may include identifying, at a first UE, a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, receiving, from the base station, configuration information associated with the second UE, receiving a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE, and decoding the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.

An apparatus for wireless communications is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify, at a first UE, a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, receive, from the base station, configuration information associated with the second UE, receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE, and decode the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.

Another apparatus for wireless communications is described. The apparatus may include means for identifying, at a first UE, a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, means for receiving, from the base station, configuration information associated with the second UE, means for receiving a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE, and means for decoding the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.

A non-transitory computer-readable medium storing code for wireless communications is described. The code may include instructions executable by a processor to identify, at a first UE, a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, receive, from the base station, configuration information associated with the second UE, receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE, and decode the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, decoding the downlink transmission comprises decoding the second signal for the second UE based at least in part on the configuration information associated with the second UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for decoding the first signal for the first UE based at least in part on successive interference cancelling of the second signal for the second UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration information associated with the second UE comprises an MCS for the second UE and a power ratio between the first signal and the second signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an MCS update and a power ratio update for the second UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying an updated MCS and an updated power ratio for the second UE based at least in part on the MCS update and the power ratio update, wherein decoding the downlink transmission comprises decoding a first set of symbols of the downlink transmission according to the MCS for the second UE and decoding a second set of symbols of the downlink transmission according to the updated MCS and the updated power ratio for the second UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal for the second UE may be transmitted for the first set of symbols and not the second set of symbols, and the MCS update and the power ratio update may be received based at least in part on early termination of the second signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal for the second UE may be transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update may be received based at least in part on the base station starting to transmit to the second UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal may be transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, wherein the MCS update and the power ratio update may be received based at least in part on the base station switching from transmitting to the second UE to transmitting to the third UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying, at the first UE, a third UE geographically located at a third distance from the base station, the third distance being greater than the first distance. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station, a second configuration information associated with the third UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a second downlink transmission, wherein the second downlink transmission comprises a third signal for the first UE and a fourth signal for the third UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for decoding the second downlink transmission based at least in part on the second configuration information associated with the third UE to obtain the third signal for the first UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first and second signals occupy a first frequency subband, and the third and fourth signals occupy a second frequency subband.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first signal and the second signal may be encoded using a same spatial precoder.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal for the second UE may be transmitted using more power than the first signal for the first UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration information associated with the second UE may be received in downlink control information or via radio resource control (RRC) signaling.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first UE may be an MBB UE or an MTC UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second UE may be an MBB UE or an MTC UE.

A method of wireless communications is described. The method may include identifying, at a base station, a first UE and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, transmitting, to the first UE, configuration information associated with the second UE, encoding a first signal for the first UE and a second signal for the second UE to generate a downlink transmission, and transmitting the downlink transmission based at least in part on CSI of the first UE and the second UE.

An apparatus for wireless communications is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify, at a base station, a first UE and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, transmit, to the first UE, configuration information associated with the second UE, encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission, and transmit the downlink transmission based at least in part on CSI of the first UE and the second UE.

Another apparatus for wireless communications is described. The apparatus may include means for identifying, at a base station, a first UE and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, means for transmitting, to the first UE, configuration information associated with the second UE, means for encoding a first signal for the first UE and a second signal for the second UE to generate a downlink transmission, and means for transmitting the downlink transmission based at least in part on CSI of the first UE and the second UE.

A non-transitory computer-readable medium storing code for wireless communications is described. The code may include instructions executable by a processor to identify, at a base station, a first UE and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, transmit, to the first UE, configuration information associated with the second UE, encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission, and transmit the downlink transmission based at least in part on CSI of the first UE and the second UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an MCS update and a power ratio update for the second UE, wherein a first set of symbols of the downlink transmission may be encoded based at least in part on a first MCS and a first power ratio and a second set of symbols of the downlink transmission may be encoded based at least in part on a second MCS and a second power ratio.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal for the second UE may be transmitted for the first set of symbols and not the second set of symbols, wherein the MCS update and the power ratio update may be transmitted based at least in part on early termination of the second signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal for the second UE may be transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update may be transmitted based at least in part the base station starting to transmit to the second UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second signal may be transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, wherein the MCS update and the power ratio update may be transmitted based at least in part on the base station switching from transmitting to the second UE to transmitting to the third UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a third UE and a fourth UE, wherein the third UE may be geographically located at a third distance from the base station and the fourth UE may be geographically located at a fourth distance from the base station, the fourth distance being greater than the third distance. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the third UE, a second configuration information associated with the fourth UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for encoding a third signal for the third UE and a fourth signal for the fourth UE based at least in part on CSI of the third UE and the fourth UE to generate a second downlink transmission.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for spatially multiplexing the first downlink transmission and the second downlink transmission on a same frequency subband.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a third UE, wherein the third UE may be geographically located at a third distance from the base station, the third distance being greater than the first distance, the first UE and the third UE being in a second same spatial direction from the base station. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the first UE, a second configuration information associated with the third UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for encoding a third signal for the first UE and a fourth signal for the third UE based at least in part on the CSI of the first UE and CSI of the third UE to generate a second downlink transmission.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a third UE, wherein the third UE may be geographically located at a third distance from the base station, the second distance being greater than the third distance, and the third UE and the second UE being in a second same spatial direction from the base station. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting to the third UE, the configuration information associated with the second UE. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for encoding a third signal for the third UE and a fourth signal for the second UE using a second same spatial precoder to generate a second downlink transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration information associated with the second UE may be transmitted in downlink control information or via RRC signaling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communication that supports wireless devices pairing for downlink multi-user (MU) multiple input, multiple output (MIMO) (MU-MIMO) transmission in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of superposition coding in a frequency subband that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of superposition coded signals on multiple frequency subbands that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a modulation and coding scheme (MCS) update that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of an MCS update that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIGs. 7 through 9 show block diagrams of a device that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 10 illustrates a block diagram of a system including a user equipment (UE) that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIGs. 11 through 13 show block diagrams of a device that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIG. 14 illustrates a block diagram of a system including a base station that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

FIGs. 15 through 17 illustrate methods for wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

A base station may serve a large number of machine type communications (MTC) devices. A user equipment (UE) may be an example of an MTC device, for example, or any wireless device configured for MTC. The base station may allocate a spatially multiplexed frequency subband to each served MTC device. The base station may also serve a number of UEs configured for mobile broadband (MBB) communications (e.g., MBB UEs) . The base station may reuse resources allocated to one wireless device for another wireless device, which may increase spectral efficiency. For example, the base station may encode a downlink signal for a first wireless device and a downlink signal for a second wireless device using a same spatial precoder if the first wireless device and the second wireless device are in the same direction. The base station may transmit the two downlink signals in a single downlink transmission in the direction of the wireless devices.

For example, the base station may encode MBB signals and MTC signals using a same spatial precoder if an MBB UE and an MTC device are in a same spatial direction. The base station may frequency selectively transmit a downlink signal with the encoded signals on a frequency subband used by the MBB UE and the MTC device. The downlink transmission including the MBB signal and the MTC signal occupying the same frequency and time resources may be referred to as a superposition encoded transmission, with the MBB signal supersposition encoded over the MTC signal. Two wireless devices may be referred to as “paired” if receiving a superposition encoded transmission. The base station may superposition encode a downlink transmission based on hierarchical modulation. For example, the MBB signal may be modulated by 16 quadrature amplitude modulation (QAM) , and the MTC signal may be modulated by quadrature phase-shift keying (QPSK) . The base station may adjust a transmission power ratio between the MBB signal and the MTC signal such that the MBB UE, with a greater channel gain, can decode the MBB signal while the MBB signal is transparent to the MTC device.

The MBB UE may use successive interference cancellation to cancel out the MTC signal and decode the downlink MBB signal from the superposition encoded transmission. The base station may transmit an indication of modulation and coding scheme (MCS) information associated with the paired MTC device to the MBB UE. The MBB UE may receive the superposition encoded transmission, decode the MTC signal based on the MCS information of the MTC device, and decode the MBB signal upon decoding the MTC signal. The MTC device may decode the MTC signal without observing substantial interference from the MBB signal based on the power ratio between the MBB signal and the MTC signal.

In some cases, the base station may transmit an updated MCS to the MBB UE. For example, if an MTC device joins a subband in the same spatial direction as the MBB UE, the base station may begin superposition encoding MBB signals over MTC signals of the joined MTC device. The base station may indicate updated MCS information for the newly paired MTC device. In other example, an MTC device may terminate its downlink transmission early, or the base station may select a different MTC device to use for superposition encoding. If there is a new MTC device paired to the MBB UE, the base station may transmit an MCS update to the MBB UE indicating a new MCS to use for decoding an MTC signal of the newly paired MTC device. If downlink transmission for an MTC device is terminated early, the MCS update may indicate that there is no superposition encoded signal (e.g., no MTC signal on the subband) .

The base station may implement described techniques for distinct paired wireless devices. For example, the base station may spatially multiplex frequency subbands for multiple MBB UEs in different directions. For example, a second MBB UE in a different direction from the base station than the first MBB UE may use the same frequency subbands as the first MBB UE to receive superposition encoded transmissions. The base station may superposition encode MBB signals for the second MBB UE over MTC signals to a second set of MTC devices in the same as the second MBB UE. Based on the MBB UEs being in different directions, there may not be interference introduced to one MBB UE from transmissions to the other MBB UE.

In the above example, an MBB UE is paired with an MTC device, as an MBB signal for the MBB UE is superposition encoded over the MTC signal for the MTC device. In some other examples, one MBB UE may be paired with multiple MTC devices, or one MBB UE may be paired with multiple, other MBB UEs. In another example, one MTC device may be paired with multiple MBB UEs, or one MTC device may be paired with multiple MTC devices. The base station may transmit MCS information to whichever wireless device of the pair is geographically closer in proximity to the base station. For example, if a close MBB device is paired with multiple far MBB devices, the base station may indicate MCS information for each of the far MBB devices to the close MBB device. The base station may superposition encode an MBB signal for the close MBB UE over an MBB signal for each of the far MBB UEs. The close MBB UE may use the MCS information of each far MBB device to decode each MBB signal intended for the close MBB UE.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to wireless devices pairing for downlink MU-MIMO transmission.

FIG. 1 illustrates an example of a wireless communications system 100 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation Node B or giga-nodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 108 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 108 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 108 for a base station 105 may be divided into sectors making up only a portion of the geographic coverage area 108, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 108. In some examples, different geographic coverage area 108 associated with different technologies may overlap, and overlapping geographic coverage area 108 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage area 108.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 108 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 108 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 108 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1 or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2 or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that can tolerate interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving devices are equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105. Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) . The single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .

In some cases, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may in some cases perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical (PHY) layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an E-UTRA absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as OFDM or DFT-s-OFDM) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR, etc. ) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that can support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A UE 115 may be configured with multiple downlink CCs and one or more uplink CCs according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In some cases, an eCC may utilize a different symbol duration than other CCs, which may include use of a reduced symbol duration as compared with symbol durations of the other CCs. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc. ) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across frequency) and horizontal (e.g., across time) sharing of resources.

A base station 105 may reuse frequency resources allocated to MTC devices 110 for MBB communications to UEs 115. For example, if a UE 115 and an MTC device 110 are in a same spatial direction, the base station 105 may encode MTC signals and MBB signals using a same spatial precoder and transmit both signals in a single downlink transmission in the spatial direction of the UE 115 and the MTC device 110. Transmitting the two signals encoded using the same frequency and time resources may be referred to as superposition encoding the signals. The base station 105 may adjust a power ratio between the MTC signal and the MBB signal such that the MBB signal does not affect the MTC device 110. The UE 115 may have a high enough channel gain to decode both the MBB signal and the MTC signal from the superposition encoded transmission. The base station may transmit MCS information for the MTC device 110 to the UE 115. The UE 115 may decode the MTC signal using the MCS information for the MTC device 110, then decode the MBB signal based on successive interference cancellation of the MTC signal.

The base station 105 may transmit superposition encoded transmissions to the UE 115 on multiple frequency subbands, if there are MTC devices 110 in a similar direction to the UE 115 and operating on those frequency subbands. The base station 105 may supply MCS information for each of the MTC devices 110 on the frequency subbands in a frequency selective and spatially multiplexed manner. The UE 115 may decode MBB signals from the base station 105 on each frequency subband based on decoding the corresponding MTC signal in the superposition encoded transmission. Furthermore, the base station 105 may transmit superposition encoded transmissions to multiple UEs 115. For example, a second UE 115 in a different direction from the base station may also receive superposition encoded transmissions, carrying MBB signals for the second UE 115 and MTC signals for MTC devices in the same direction as the second UE 115. The base station 105 may reuse the frequency subbands from the first UE 115 and spatially multiplex the superposition encoded transmissions on the frequency subbands. As described, base station 105 may frequency selectively transmit spatially multiplexed MBB signals superposition encoded over MTC signals.

In the above example, an MBB UE (e.g., a UE 115) is paired with an MTC device 110, as an MBB signal for the UE 115 is superposition encoded over the MTC signal for the MTC device 110. In some other examples, one UE 115 may be paired with multiple MTC devices 110, or one UE 115 may be paired with multiple, other UEs 115. In another example, one MTC device 110 may be paired with multiple UEs 115, or one MTC device 110 may be paired with multiple MTC devices 110. The base station 105 may transmit MCS information to whichever wireless device is geographically closer in proximity to the base station 105. For example, if a close UE 115 is paired with multiple far UEs 115, the base station 105 may indicate MCS information for each of the far UEs 115 to the close UE 115. The base station 105 may superposition encode an MBB signal for the close UE 115 over an MBB signal for each of the far UEs 115. The close UE 115 may use the MCS information of each far UE 115 to decode each MBB signal intended for the close UE 115.

FIG. 2 illustrates an example of a wireless communication system 200 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. In some examples, wireless communication system 200 may implement aspects of wireless communication system 100. Wireless communications system 200 may include base station 105-a, which may be an example of a base station 105 as described herein. Wireless communications system 200 may also include UE 115-a and UE 115-b, which may each be an example of a UE 115 as described herein. UE 115-a and UE 115-b may be examples of MMB UEs, or UEs 115 capable of MMB communications. In some cases, base station 105-a, UE 115-a, and UE 115-b may each be capable of MIMO communications, such as multiuser massive-MIMO (MU-mMIMO) communications.

Wireless communications system 200 may also include MTC devices 110-a, 110-b, 110-c, 110-d, 110-e, and 110-f. The MTC devices 110 may be MTC UEs or another device capable of MTC. An MTC device 110 may receive repeated transmissions of information. In some cases, the MTC devices 110 may be examples of massive-MTC devices, and the UEs 115 may be MBB UEs supported by enhanced MBB systems.

Base station 105-a may support a large number of MTC devices 110. The MTC devices 110 may be single-antenna devices multiplexed over various frequency resources. For example, if base station 105-a is multiplexing

MTC devices 110 in each of

orthogonal frequency resources, base station 105-a may support U _MTC total MTC devices 110. For example, base station 105-a may support other MTC devices 110 not shown in various locations or directions. Base station 105-a may use spatial beamforming based on a large amount of channel state information (CSI) acquisitions with respect to the different MTC devices 110.

Base station 105-a may reuse frequency resources for MBB transmissions and MTC transmissions. For example, base station 105-a may superposition encode signals for MBB devices (e.g., UEs 115) on top of signals for MTC devices (e.g., MTC devices 110) . In some cases, a single-device downlink transmission rate of MBB communications may be greater than the downlink transmission rate for MTC communication. Therefore, the base station 105-a may use a subset of the frequency resources allocated for MTC communications to transmit MBB information by superposition encoding the MBB signal on top of the MTC signal. A UE 115 which is receiving superposition coded signals corresponding to an MTC device 110 may be referred to as paired with that MTC device 110. For example, UE 115-a is paired with MTC devices 110-a, 110-b, and 110-c. UE 115-b is paired with MTC devices 110-d, 110-e, and 110-f. UE 115-a may be an example close UE, and MTC devices 110-a, 110-b, and 110-c may be examples of far UEs. As shown, UE 115-a may be geographically closer to base station 105-a than MTC devices 110-a, 110-b, and 110-c.

For example, base station 105-a may transmit an MTC signal 205 on a first frequency subband to MTC device 110-a. When UE 115-a is scheduled downlink MBB information, base station 105-a may superposition encode an MBB signal 210 on top of the MTC signal 205. There may be other MTC devices 110 in a similar direction receiving MTC communications on different frequency subbands. For example, base station 105-a may transmit an MTC signal 215 to MTC device 110-b and transmit MTC signal 225 to MTC device 110-c. In some cases, when UE 115-a is scheduled downlink MBB information, base station 105-a may superposition encode MBB information over MTC information across multiple frequency subbands. For example, base station 105-a may superposition encode an MBB signal 220 over the MTC signal 215 and an MBB signal 230 over the MTC signal 225.

Using MIMO communications, base station 105-a may transmit the superposition encoded signals using multiple antennae, and UE 115-a may receive the superposition encoded signals also using multiple antennae. Base station 105-a may use the same spatial coder for an MTC signal and an MBB signal on a same frequency subband. For example, base station 105-a may use the same spatial beamforming precoder for the MTC signal 205 and the MBB signal 210. In some cases, by using the same spatial beamforming precoder originally used for MTC device 110-a, there may be little additional spatial interference from MTC device 110-a to UE 115-a. Base station 105-a may use another beamforming precoder for both the MTC signal 215 and the MBB signal 220, which are transmitted together, superposition encoded on a second frequency subband. (e.g., a different beamforming precoder than the one used for the MTC signal 205 and the MBB signal 210) .

A UE 115 may have a greater channel gain than an MTC device 110. Base station 105-a may transmit the MTC signals with a greater power allocation than the MBB signals. An MTC device 110 may not have high enough channel gain to detect the MBB signals. Therefore, the MBB superposition coding may be transparent to the MTC devices 110. Base station 105-a may adjust a superposition power ratio between a UE 115 and an MTC device 110 based on a QoS of an MTC device 110. Thus, the MTC device may still successfully decode its downlink MTC information without additional information from base station 105-a.

For example, base station 105-a may transmit the MBB signal 210 superposition encoded over the MTC signal 205, but base station 105-a may allocate less power for the MBB signal 210 than MTC signal 205. UE 115-a may have a channel gain high enough to receive both the MTC signal 205 and the MBB signal 210, but MTC device 110-a may only detect and receive the MTC signal 205. Therefore, transmission of the MBB signal 210 on the same frequency subband as the MTC signal 205 may be transparent to MTC device 110-a. Based on the different spatial precoders for frequency subband 1, frequency subband 2, and frequency subband 3, MTC device 110-a may receive the MTC signal 205 transparent of the MBB signal 210 or other MTC signals, MTC device 110-b may receive the MTC signal 215 transparent of the MBB signal 220 or other MTC signals, and MTC device 110-c may receive the MTC signal 225 transparent of the MBB signal 230 or other MTC signals.

To assist in decoding the superposition coded signals, base station 105-a may indicate MCS information for each MTC device 110 paired to a UE 115. For example, base station 105-a may indicate MCS information for MTC devices 110-a, 110-b, and 110-c to UE 115-a. A UE 115 receiving the superposition coded transmission may decode the MBB signals from the superposition encoded transmission. To perform successive interference canceling, UE 115-a may decode the MTC signal 205 from the superposition coded transmission on frequency subband 1. UE 115-a may then decode the MBB signal 210 after decoding the MTC signal 205 based on successive interference cancellation of the MTC signal 205. For example, UE 115-a may decode

MBB signals

210, 220, and 230 based on a successive interference cancellation of the MTC signals 205, 215, and 225, respectively. UE 115-a may use similar techniques to decode

MBB signals

220 and 230 from superposition coded signals on

frequency subband

2 and 3.

Base station 105-a may be triggered to transmit updated MCS information for an MTC device 110 paired to a UE 115. For example, an MTC signal to the MTC device 110 may be terminated early. The MTC device 110 may indicate receipt of MTC information repeatedly transmitted and the MTC signal may be terminated early. Or, in another example, an MTC device 110 may attach to base station 105 and be in a similar spatial direction to the UE 115, so the MTC device 110 may pair with the UE 115. Or, in other examples, the MTC device 110 or the UE 115 may move such that the MTC device 110 is a good candidate for pairing with the UE 115 (e.g., a similar spatial direction) , and the MTC device 110 may pair with the UE 115. Or, the MTC device 110 or the UE 115 may move such that the MTC device 110 is no longer in a similar spatial direction as the UE 115, and the MTC device 110 may be unpaired with the UE 115. In any of these situations and others not described, the MCS information for the MTC device 110 may be updated.

The UE 115 may receive the updated MCS message and determine how to decode an MBB signal. For example, the UE 115 may perform successive interference canceling with an MTC signal transmitted to a newly paired MTC device 110, or the UE 115 may determine that the MBB signal is not superposition coded on an MTC signal. In some cases, the UE 115 may determine that the MBB signal is still superposition coded on an MTC signal, but the MTC signal may be for a new MTC device 110 which uses the updated MCS information. The MCS information may include a modulation order, channel coding information, and a power ratio between the paired MTC device 110 and UE 115.

Base station 105-a may frequency selectively transmit MCS updates to UE 115-a. For example, if there is an MCS update for MTC device 110-b, base station 105-a may transmit an MCS update on frequency subband 2 to UE 115-a. In some cases, the MCS update may be transmitted UE 115-a in downlink control information (DCI) . By transmitting updated MCS information in DCI, the MSC information at UE 115-a may be more frequently up-to-date, and decoding performance at UE 115-a may be improved. In some other examples, the MCS update may be transmitted via RRC signaling. By transmitting the MCS updates via RRC signaling, updating MCS may not increase a transmission load on the control channel. Furthermore, by implementing appropriate pairing of MTC devices 110 and UEs 115 (e.g., pairing MTC devices 110 and UEs 115 with low mobility) , updating MCS information via RRC signaling due to MTC device starting or switching or termination may be reduced, reducing the amount of MCS update overhead. In some cases, base station 105-a may indicate MCS updates for an MTC device termination by RRC signaling, and base station 105-a may update MCS for new pairings or switching devices in DCI.

Base station 105-a may implement the described techniques for multiple UEs 115. For example, UE 115-b may also have MTC devices 110 in a similar spatial direction from base station 105-a. Base station 105-a may superposition encode MBB data onto MTC data for the MTC devices 110 in the same direction as UE 115-b. For example, base station 105-a may superposition encode MBB signal 240 over MTC signal 235, MBB signal 250 over MTC signal 245, and MBB signal 260 over MTC signal 255. Base station 105-a may indicate MCS information for MTC device 110-d, 110-e, and 110-f to UE 115-b as described, as well as transmit any MCS updates for a paired MTC device upon a trigger described above. As depicted, base station 105-a may also superposition encode MBB signals over MTC signals for one additional UE 115 (e.g., UE 115-b) , but base station 105-a may superposition encode MBB signals over MTC signals on multiple frequency subbands for multiple UEs 115 in different directions. MCS information for the MTC devices 110 may be beamformed and multicast in multiple spatial directions to the multiple UEs 115. The number of UEs 115 may be controlled to provide sufficient throughput performance for MBB communications.

Base station 105-a may reuse frequency spectrum subbands for UE 115-a and UE 115-b, spatially multiplexing the frequency subbands for the UEs 115. For example, the MTC signals 205 and 235 may be spatially multiplexed on frequency subband 1, the MTC signals 215 and 245 may be spatially multiplexed on the frequency subband 2, and the MTC signals 225 and 255 may be spatially multiplexed on the frequency subband 3. Base station 105-a may select UEs 115 with significantly different channel direction (e.g., CSI directions) , which may avoid overlap of the reused frequency spectrum subbands.

In some other examples, base station 105-a may not implement superposition encoding for massive MU-MIMO beamforming. For example, base station 105-a may use spatial and frequency selective beamforming for multiple MTC devices 110 and UEs 115 without superposition encoding.

In the above example, UEs 115 are paired with MTC devices 110, as MBB signals for the UEs 115 are superposition encoded over MTCs signal for corresponding MTC devices 110. In some other examples, an UE 115 may be paired with multiple, other UEs 115. In another example, an MTC device 110 may be paired with multiple UEs 115, or an MTC device 110 may be paired with multiple MTC devices 110. A base station 105 may transmit MCS information to whichever wireless device is geographically closer in proximity to the base station 105. As shown in this example, UE 115-a is geographically closer to base station 105-a than MTC devices 110-a, 110-b, or 110-c. In another example, if a close UE 115 is paired with multiple far UEs 115, the base station 105 may indicate MCS information for each of the far UEs 115 to the close UE 115. The base station 105 may superposition encode an MBB signal for the close UE 115 over an MBB signal for each of the far UEs 115. The close UE 115 may use the MCS information of each far UE 115 to decode each MBB signal intended for the close UE 115.

In another example, a first MTC device 110 may be paired with a second MTC device 110, a third MTC device 110, and a fourth MTC device 110, where the first MTC device 110 is closer to the base station than the other three MTC devices 110 (e.g., the second MTC device 110, the third MTC device 110, and the fourth MTC device 110) . The first MTC device 110 may be an example of a close UE, and the other three MTC devices 110 may be examples of UEs which are geographically located farther away from the base station 105. The second, third, and fourth MTC devices may be in relatively close proximity and may be in a similar direction from the base station 105 as the first MTC device 110. For example, there may be distinct spatial directions to the second, third, and fourth MTC devices 110 which are also in the same direction as the first MTC device 110, for example due to the first MTC device being closer to the base station 105. The base station 105 may indicate MCS information of the second, third, and fourth MTC devices to the first MTC device and generate downlink transmissions for the paired devices by using three different spatial precoders (e.g., a first spatial precoder for signals in the direction of the first and second MTC devices 110, a second spatial precoder for signals in the direction the first and third MTC devices 110, and a third spatial precoder for signals in the direction of the first and fourth MTC devices 110) . The base station 105 may provide MCS information for the second, third, and fourth MTC devices 110 to the first MTC device 110. The first MTC device may decode the MTC signals for the second, third, and fourth MTC devices 110 and use successive interference cancelling with these signals to obtain MTC signals intended for the first MTC device 110.

FIG. 3 illustrates an example of superposition coding in a frequency subband 300 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. In some examples, superposition coding in a frequency subband 300 may implement aspects of wireless communication system 100. Superposition coding in a frequency subband 300 may include base station 105-b and UE 115-c, which may be respective examples of a base station 105 and a UE 115 as described herein. Superposition coding in a frequency subband 300 may also include MTC device 110-g and MTC device 110-h, which may be examples of MTC devices 110 as described herein, such as MTC UEs.

UE 115-c and MTC device 110-g may be paired for superposition coding, and base station 105-b may transmit an MBB signal superposition encoded over MTC signals in a frequency subband 305 in the direction of UE 115-c and MTC device 110-g. Base station 105-b may transmit MTC information for MTC device 110-g and MBB information for UE 115-c in the superposition encoded signal. UE 115-c may have MCS information for MTC device 110-g, which may have been provided by base station 105-b in DCI or by RRC signaling.

UE 115-c may have a higher channel gain than MTC device 110-g. Base station 105-b may transmit the MTC signal with a higher power than the MBB signal, such that the MTC device 110-g is unaffected by the superposition encoded MBB signal, but UE 115-c receives both the MBB signal and the MTC signal. UE 115-c may be an example of a close UE, while MTC device 110-g may be an example of a UE which is geographically farther away from the base station..

Base station 105-b may transmit the MTC signal and the MBB signal using radio bearers associated with different layers. For example, base station 105-b may transmit the MTC signal on the base layer 310 and transmit the MBB signal on the enhanced layer 315. MTC device 110-g may receive the MTC signal on the base layer 310, and UE 115-c may receive both the MTC signal and the MBB signal on the enhanced layer 315. UE 115-c may decode the MTC signal based on the MCS information of MTC device 110-g. UE 115-c may then cancel out the decoded MTC signal from superposition encoded signal to decode the MBB signal.

The superposition coding may implement a hierarchical modulation scheme. For example, base station 105-b may transmit the MBB signal using 16QAM and transmit the MTC signal using quadrature phase-shift keying (QPSK) . MTC device 110-g, with a lower channel gain, may decode a QPSK symbol 320 in the base layer 310. UE 115-c, with a higher channel gain, may decode the QPSK symbol 320 and a 16QAM symbol 325 in the enhanced layer 315. UE 115-c may decode the QPSK symbol 320 and use successive interference cancelling to cancel out the MTC signal from the superposition encoded signal. UE 115-c may then decode the 16QAM symbol 325 after canceling out the MTC signal. In some cases, base station 105-b may adjust a power ratio (e.g., the ratio of d ₁ 330 to d ₂ 335, such as

) between UE 115-c and MTC device 110-g to meet QoS criteria for one or more of UE 115-c and MTC device 110-g.

Shown is a single frequency subband corresponding to a pairing of UE 115-c and MTC device 110-g. In some examples, UE 115-c may be paired with other MTC devices 110 on other frequency subbands. Base station 105-b may spatially multiplex the frequency subband to transmit superposition encoded signals to a UE 115 and MTC device 110 in another direction. Additionally, or alternatively, base station 105-b may transmit MCS updates to UE 115-c if triggered to as described in FIGs. 2 and 5-6.

FIG. 4 illustrates an example of superposition coded signals on multiple frequency subbands 400 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. In some examples, superposition coded signals on multiple frequency subbands 400 may implement aspects of wireless communication system 100.

As described herein, a base station 105 may transmit MBB information to a UE 115 and MTC information to an MTC device 110. In some cases, the base station 105 may superposition encode MBB signals on top of MTC signals, which may increase spectral reuse and efficiency while introduce very little interference to the MTC devices. In some cases, the UE 115 may be paired with one or more MTC devices 110, where the UE 115 and the MTC devices 110 are in a similar direction from the base station 105. When the UE 115 is scheduled for downlink MBB information in a slot 405, the base station 105 may superposition encoded an MBB signal 410 for the UE 115 over an MTC signal for an MTC device 110 during the slot 405. The UE 115 may be paired with multiple MTC devices 110, and the base station 105 may superposition encode the MBB transmission 410 over multiple MTC transmissions on different frequency subbands.

For example, as shown, base station 105 may spatially multiplex MTC signals on three frequency subbands in three different directions (e.g., nine MTC devices 110) . In other examples, base station 105 may transmit MTC signals on another number of frequency subbands and spatially multiplex the other number of frequency subbands in another number of directions. For example, MTC signals 415 may be spatially multiplexed and transmitted on a first frequency subband (e.g., frequency subband 1) , MTC signals 420 may be spatially multiplexed and transmitted on a second frequency subband (e.g., frequency subband 2) , and MTC signals 425 may be spatially multiplexed and transmitted on a third frequency subband (e.g., frequency subband 3) .

On frequency subband 1, the base station 105 may transmit MTC signal 415-a, MTC signal 415-b, and MTC signal 415-c. In some cases, the UE 115 may be in the same direction as an MTC device 110 receiving the MTC signal 415-c. The UE 115 may be paired with and be in the same spatial direction as an MTC device 110 receiving MTC signal 415-c. On frequency subband 2, the base station 105 may transmit MTC signal 420-a, MTC signal 420-b, and MTC signal 420-c. The UE 115 may be paired with and be in the same spatial direction as an MTC device 110 receiving MTC signal 420-b. On frequency subband 3, the base station 105 may transmit MTC signal 425-a, MTC signal 425-b, and MTC signal 425-c. The UE 115 may be paired with and in the same spatial direction as an MTC device 110 receiving MTC signal 425-a.

The UE 115 may be scheduled for MBB transmission during the slot 405. The base station may superposition encode MBB signal 410-a over MTC signal 415-c, MBB signal 410-b over MTC signal 420-b, and MBB signal 410-c over MTC signal 425-a. Transmission of the MBB signals over the MTC signals may be transparent to the MTC devices 110 receiving the MTC signals based on the superposition coding techniques described in FIG. 3.

The UE 115 receiving the superposition encoded signals may decode MTC signal 415-c, MTC signal 420-b, and MTC signal 425-a. The UE 115 may then user successive interference canceling techniques to cancel out the MTC signals and decode a frequency selective transmission 435. For example, the MBB signal 410-a may be transmitted in a first, second, fourth, and fifth symbol period 430 on the first frequency subband. The MBB signal 410-b may be transmitted in the first, third, fourth, fifth, sixth, and seventh symbol periods 430 on the second frequency subband, and the MBB signal 410-c may be transmitted on the first, third, fourth, fifth, sixth, and seventh symbol periods 430 on the third frequency subband.

FIG. 5 illustrates an example of an MCS update 500 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. In some examples, MCS update 500 may implement aspects of wireless communication system 100.

MCS update 500 may include a similar configuration as the superposition coded signals on multiple frequency subbands 400 of FIG. 4. For example, MTC signals 515, including MTC signals 515-a, 515-b, and 515-c, may be spatially multiplexed and transmitted on a first frequency subband (e.g., frequency subband 1) . MTC signals 520, including MTC signals 520-a, 520-b, and 520-c, may be spatially multiplexed and transmitted on a second frequency subband (e.g., frequency subband 2) . MTC signals 525, including MTC signals 525-a, 525-b, and 525-c, may be spatially multiplexed and transmitted on a third frequency subband (e.g., frequency subband 3) . In some cases, the UE 115 may be in the same direction as MTC devices 110 receiving MTC signals 515-c, 520-b, and 525-a.

However, in MCS update 500, MTC devices 110 may be paired to a UE 115 during the MBB signal 510, or MTC devices 110 may be unpaired (e.g., due to early termination of an MTC signal) from the UE 115 during the MBB signal 510. The base station 105 may transmit an MCS update to the UE 115 such that the UE 115 may decode the MTC signal of a newly paired MTC device 110, or such that the UE 115 may determine not to attempt to decode an MTC signal if the MTC signal is terminated early.

For example, at 540, an MTC device 110 receiving MTC signal 520-b may terminate its downlink transmission early. In some cases, there may not be other MTC devices 110 operating on the second frequency subband in the same spatial direction. the base station 105 may update an MCS for the UE 115 receiving the MBB signal 510-b, which indicates there’s no superposition coding applied on subband 2 in the spatial direction of the UE 115. For example, the UE 115 may not decode an MTC signal for the sixth and seventh symbol periods 530 of the slot 505. Therefore, decoding performance for the UE 115 may be improved for these symbol periods. In some cases, the base station 105 may transmit the MCS update related to the early termination to the UE 115 in an RRC notification.

At 545, an MTC device 110 may be paired to the UE 115. During the first two symbol periods 530 of the slot 505, there may not be an MTC device 110 on the third subband in the same spatial direction as the UE 115. The base station 105 may transmit MBB signal 510-c to the UE 115 on the third subband during a first and second symbol period 530 without superposition encoding it on an MTC signal. However, by the third symbol period 530, either an MTC device 110 may be operating on the third subband and in the same spatial direction as the UE 115. The MTC device 110 may pair to the UE 115, and the base station 105 may superposition encode MBB signal 510-c over MTC signal 525-a. In some cases, the MTC device 110 may be paired to the UE 115 based on movement of either the MTC device 110 or the UE 115 or activation of the MTC device 110. In some cases , the base station 105 may transmit the MCS update to the UE 115 related to starting MTC transmission to the MTC device 110 in downlink control information.

The UE 115 may decode MTC signal 515-c, MTC signal 520-b, and MTC signal 525-a. The UE 115 may then user successive interference canceling techniques to cancel out the MTC signals and decode a frequency selective transmission 535. For example, the MBB signal 510-a may be transmitted in a first, second, fourth, and fifth symbol period 530 on the first frequency subband. The MBB signal 510-b may be transmitted in the first, third, fourth, fifth, sixth, and seventh symbol periods 530 on the second frequency subband. A first set of symbols (e.g., symbols one, three, four, and five) ) of the MBB signal 510-b may be decoded by the MBB UE 115 by first decoding the MTC signal 525-a. A second set of symbols in the MBB signal 510-b may be decoded based on an MCS for the MBB UE 115, as the MBB signal 510-b may not be superposition encoded over an MTC signal for the second set of symbols. The MBB signal 510-c may be transmitted on the first, third, fourth, fifth, sixth, and seventh symbol periods 530 on the third frequency subband. A first set of symbols of the MBB signal 510-c (e.g., the first symbol) may be decoded based on the MCS of the MBB UE 115 and not based on decoding an MTC signal. When MTC transmission begins for a second set of symbols, the MBB UE 115 may decode the second set of symbols (e.g., symbols three, four, five, six, and seven) based also on decoding the MTC signals 525-a.

FIG. 6 illustrates an example of an MCS update 600 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. In some examples, MCS update 600 may implement aspects of wireless communication system 100.

MCS update 600 may include a similar configuration as the superposition coded signals on multiple frequency subbands 400 of FIG. 4 and the MCS update 500 of FIG. 5. For example, MTC signals 615, including MTC signals 615-a, 615-b, and 615-c, may be spatially multiplexed and transmitted on a first frequency subband (e.g., frequency subband 1) . MTC signals 620, including MTC signals 620-a, 620-b, and 620-c, may be spatially multiplexed and transmitted on a second frequency subband (e.g., frequency subband 2) . MTC signals 625, including MTC signals 625-a, 625-b, and 625-c, may be spatially multiplexed and transmitted on a third frequency subband (e.g., frequency subband 3) . In some cases, the UE 115 may be in the same direction as MTC devices 110 receiving MTC signals 615-c, 620-b, and 625-a.

At 640, a UE 115 may switch from being paired to a first MTC device 110 on frequency subband 2 to a second MTC device 110 on frequency subband 2 over an MBB signal 610, or an MBB transmission. The base station 105 may superposition encode MBB signal 610-b on MTC signal 625-b from the first symbol period 630 to the fifth symbol period 630. The base station may switch to superposition encoding the MBB signal 610-b on MTC signal 625-a for the sixth and seventh symbol periods. The base station 105 may transmit an MCS update to the UE 115 indicating MCS information for the second MTC device 110, such that the UE 115 may continue to decode the superposition encoded signal. In some cases, the base station 105 may switch MTC signals based on the second MTC device 110 and the UE 115 being in a more similar spatial direction. For example, the UE 115 may move away from the first MTC device 110, or the MTC device 110 may move away from the UE 115. In some cases , the base station 105 may transmit the MCS update related to MTC device switching to the UE 115 in DCI.

The UE 115 may decode MTC signal 615-c, a first set of symbol in MTC signal 620-b, a second set of symbols in MTC signal 625-a, and MTC signal 625-a. The UE 115 may then user successive interference canceling techniques to cancel out the MTC signals and decode a frequency selective transmission 635. For example, the MBB signal 610-a may be transmitted in a first, second, fourth, and fifth symbol period 630 on the first frequency subband. The MBB signal 610-b may be transmitted in the first, third, fourth, fifth, sixth, and seventh symbol periods 630 on the second frequency subband, and the MBB signal 610-c may be transmitted on the first, third, fourth, fifth, sixth, and seventh symbol periods 630 on the third frequency subband.

FIG. 7 shows a block diagram 700 of a UE 705 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. UE 705 may be an example of aspects of a UE 115 as described herein. UE 705 may include receiver 710, communications manager 715, and transmitter 720. UE 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to wireless devices pairing for downlink MU-MIMO transmission, etc. ) . Information may be passed on to other components of the device. The receiver 710 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The receiver 710 may utilize a single antenna or a set of antennas.

Communications manager 715 may be an example of aspects of the communications manager 1010 described with reference to FIG. 10.

Communications manager 715 and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions of the communications manager 715 and/or at least some of its various sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. The communications manager 715 and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, communications manager 715 and/or at least some of its various sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, communications manager 715 and/or at least some of its various sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

Communications manager 715 may identify, at a first UE, a second UE, where the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, receive, from the base station, configuration information associated with the second UE, receive a downlink transmission, where the downlink transmission includes a first signal for the first UE and a second signal for the second UE, and decode the downlink transmission based on the configuration information associated with the second UE to obtain the first signal for the first UE.

Transmitter 720 may transmit signals generated by other components of the device. In some examples, the transmitter 720 may be collocated with a receiver 710 in a transceiver module. For example, the transmitter 720 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The transmitter 720 may utilize a single antenna or a set of antennas.

FIG. 8 shows a block diagram 800 of a UE 805 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. UE 805 may be an example of aspects of a UE 705 or a UE 115 as described with reference to FIGs. 1 and 705. UE 805 may include receiver 810, communications manager 815, and transmitter 840. UE 805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to wireless devices pairing for downlink MU-MIMO transmission, etc. ) . Information may be passed on to other components of the device. The receiver 810 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The receiver 810 may utilize a single antenna or a set of antennas.

Communications manager 815 may be an example of aspects of the communications manager 1010 described with reference to FIG. 10. Communications manager 815 may also include UE identifier 820, UE configuration component 825, downlink transmission receiver 830, and decoding component 835.

UE identifier 820 may identify, at a first UE, a second UE, where the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance. In some cases, the first UE and the second UE may be in a same spatial direction from the base station. UE configuration component 825 may receive, from the base station, configuration information associated with the second UE.

Downlink transmission receiver 830 may receive a downlink transmission, where the downlink transmission includes a first signal for the first UE and a second signal for the second UE. Decoding component 835 may decode the downlink transmission based on the configuration information associated with the second UE to obtain the first signal for the first UE.

Transmitter 840 may transmit signals generated by other components of the device. In some examples, the transmitter 840 may be collocated with a receiver 810 in a transceiver module. For example, the transmitter 840 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The transmitter 840 may utilize a single antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a communications manager 905 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The communications manager 905 may be an example of aspects of a communications manager 715, a communications manager 815, or a communications manager 1010 described with reference to FIGs. 7, 8, and 10. The communications manager 905 may include UE identifier 910, UE configuration component 915, downlink transmission receiver 920, and decoding component 925. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

UE identifier 910 may identify, at a first UE, a second UE, where the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance. In some cases, the first UE and the second UE may be in a same spatial direction from the base station. In some cases, the first UE is an MBB UE or an MTC UE. In some cases, the second UE is an MBB UE or an MTC UE. In some cases, UE identifier 910 may identify, at the first UE, a third UE geographically located at a third distance from the base station, the third distance being greater than the first distance, and the first UE and the third UE being in a second same spatial direction from the base station.

UE configuration component 915 may receive, from the base station, configuration information associated with the second UE. In some cases, the configuration information associated with the second UE includes an MCS for the second UE and a power ratio between the first signal and the second signal. In some cases, the configuration information associated with the second UE is received in downlink control information or via RRC signaling. In some examples, UE configuration component 915 may receive an MCS update and a power ratio update for the second UE and identify an updated MCS and an updated power ratio for the second UE based on the MCS update and the power ratio update, where decoding the downlink transmission includes decoding a first set of symbols of the downlink transmission according to the MCS for the second UE and decoding a second set of symbols of the downlink transmission according to the updated MCS for the second UE. In some examples, UE configuration component 915 may receive, from the base station, a second configuration information associated with the third UE.

Downlink transmission receiver 920 may receive a downlink transmission, where the downlink transmission includes a first signal for the first UE and a second signal for the second UE. In some cases, downlink transmission receiver 920 may receive a second downlink transmission, where the second downlink transmission includes a third signal for the first UE and a fourth signal for the third UE. In some cases, the first and second signals may occupy a first frequency subband, and the third and fourth signals occupy a second frequency subband. In some cases, the second signal for the second UE is transmitted for the first set of symbols and not the second set of symbols, and the MCS update and the power ratio update may be received based on early termination of the second signal. In some cases, the second signal for the second UE is transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update are received based on the base station starting to transmit to the second UE. In some cases, the second signal for the second UE is transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, where the MCS update and the power ratio update are received based on the base station switching from transmitting to the second UE to transmitting to the third UE.

Decoding component 925 may decode the downlink transmission based on the configuration information associated with the second UE to obtain the first signal for the first UE. In some cases, the first signal and the second signal are encoded using a same spatial precoder. In some cases, the second signal for the second UE is transmitted using more power than the first signal for the first UE. In some examples, decoding component 925 may decode the second signal for the second UE based at least in part on the configuration information associated with the second UE, and decode the first signal for the first UE based at least in part on successive interference cancelling of the second signal for the second UE. In some examples, decoding component 925 may decode the second downlink transmission based on the second configuration information associated with the third UE to obtain the third signal for the first UE.

FIG. 10 shows a diagram of a system 1000 including a device 1005 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. Device 1005 may be an example of or include the components of UE 705, UE 805, or a UE 115 as described above, e.g., with reference to FIGs. 7 and 8. Device 1005 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including communications manager 1010, I/O controller 1015, transceiver 1020, antenna 1025, memory 1030, and processor 1040. These components may be in electronic communication via one or more buses (e.g., bus 1045) .

I/O controller 1015 may manage input and output signals for device 1005. I/O controller 1015 may also manage peripherals not integrated into device 1005. In some cases, I/O controller 1015 may represent a physical connection or port to an external peripheral. In some cases, I/O controller 1015 may utilize an operating system such as

or another known operating system. In other cases, I/O controller 1015 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, I/O controller 1015 may be implemented as part of a processor. In some cases, a user may interact with device 1005 via I/O controller 1015 or via hardware components controlled by I/O controller 1015.

Transceiver 1020 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1020 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1020 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1025. However, in some cases the device may have more than one antenna 1025, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

Memory 1030 may include RAM and ROM. The memory 1030 may store computer-readable, computer-executable software 1035 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1030 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

Processor 1040 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, processor 1040 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor 1040. Processor 1040 may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting wireless devices pairing for downlink MU-MIMO transmission) .

FIG. 11 shows a block diagram 1100 of a base station 1105 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. Base station 1105 may be an example of aspects of a base station 105 as described herein. Base station 1105 may include receiver 1110, communications manager 1115, and transmitter 1120. Base station 1105 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to wireless devices pairing for downlink MU-MIMO transmission, etc. ) . Information may be passed on to other components of the device. The receiver 1110 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The receiver 1110 may utilize a single antenna or a set of antennas.

Communications manager 1115 may be an example of aspects of the communications manager 1410 described with reference to FIG. 14.

Communications manager 1115 and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions of the communications manager 1115 and/or at least some of its various sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. The communications manager 1115 and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, communications manager 1115 and/or at least some of its various sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, communications manager 1115 and/or at least some of its various sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

Communications manager 1115 may identify a first UE and a second UE, where the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance, transmit, to the first UE, configuration information associated with the second UE, encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission, and transmit the downlink transmission based on CSI of the first UE and the second UE.

Transmitter 1120 may transmit signals generated by other components of the device. In some examples, the transmitter 1120 may be collocated with a receiver 1110 in a transceiver module. For example, the transmitter 1120 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The transmitter 1120 may utilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a base station 1205 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. Base station 1205 may be an example of aspects of a base station 1105 or a base station 105 as described with reference to FIGs. 1 and 1105. Base station 1205 may include receiver 1210, communications manager 1215, and transmitter 1240. Base station 1205 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 1210 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to wireless devices pairing for downlink MU-MIMO transmission, etc. ) . Information may be passed on to other components of the device. The receiver 1210 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The receiver 1210 may utilize a single antenna or a set of antennas.

Communications manager 1215 may be an example of aspects of the communications manager 1410 described with reference to FIG. 14.

Communications manager 1215 may also include UE identifier 1220, UE configuration component 1225, encoding component 1230, and directional transmitting component 1235.

UE identifier 1220 may identify, at a base station, a first UE and a second UE, where the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance.

UE configuration component 1225 may transmit, to the first UE, configuration information associated with the second UE.

Encoding component 1230 may encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission. Directional transmitting component 1235 may transmit the downlink transmission based on CSI of the first UE and the second UE.

Transmitter 1240 may transmit signals generated by other components of the device. In some examples, the transmitter 1240 may be collocated with a receiver 1210 in a transceiver module. For example, the transmitter 1240 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The transmitter 1240 may utilize a single antenna or a set of antennas.

FIG. 13 shows a block diagram 1300 of a communications manager 1305 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The communications manager 1305 may be an example of aspects of a communications manager 1115, a communications manager 1215, or a communications manager 1410 described with reference to FIGs. 11, 12, and 14. The communications manager 1305 may include UE identifier 1310, UE configuration component 1315, encoding component 1320, and directional transmitting component 1325. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

UE identifier 1310 may identify, at a base station, a first user equipment (UE) and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance. In some cases, the first UE is an MBB UE or an MTC UE. In some cases, the second UE is an MBB UE or an MTC UE.

In some cases, the UE identifier 1310 may identify a third UE and a fourth UE, wherein the third UE is geographically located at a third distance from the base station and the fourth UE is geographically located at a fourth distance from the base station, the fourth distance being greater than the third distance, the third UE and the fourth UE being in a second same spatial direction from the base station, and the second same spatial direction being different from the first same spatial direction.

In some examples, the UE identifier 1310 may identify a third UE, wherein the third UE is geographically located at a third distance from the base station, the third distance being greater than the first distance, the first UE and the third UE being in a second same spatial direction from the base station. In another example, the UE identifier 1310 may identify a third UE, wherein the third UE is geographically located at a third distance from the base station, the second distance being greater than the third distance. In some cases, the third UE and the second UE may be in a second same spatial direction from the base station.

UE configuration component 1315 may transmit, to the first UE, configuration information associated with the second UE. In some cases, UE configuration component 1315 may an MCS update and a power ratio update for the second UE, where a first set of symbols of the downlink transmission are encoded based on a first MCS and a second set of symbols of the downlink transmission are encoded based on a second MCS. In some examples, UE configuration component 1315 may transmit, to the third UE, a second configuration information associated with the fourth UE. In some cases, the UE configuration component 1315 may transmit, to the first UE, a second configuration information associated with the third UE. In some examples, UE configuration component 1315 may transmit to the third UE, the configuration information associated with the second UE. In some cases, the configuration information associated with the second UE includes an MCS for the second UE and a power ratio between the first signal and the second signal. In some cases, the configuration information associated with the second UE is transmitted in downlink control information or via RRC signaling.

Encoding component 1320 may encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission. In some cases, the encoding component 1320 may encode a third signal for the third UE and a fourth signal for the fourth UE to generate a second downlink transmission. In some examples, the encoding component 1320 may spatially multiplex the first downlink transmission and the second downlink transmission on a same frequency subband. The encoding component 1320 may encode a third signal for the first UE and a fourth signal for the third UE to generate a second downlink transmission. In some cases, the encoding component 1320 may encode a third signal for the third UE and a fourth signal for the second UE to generate a second downlink transmission.

Directional transmitting component 1325 may transmit the downlink transmission based on CSI of the first UE and the second UE. In some cases, the directional transmitting component 1325 may transmit the second downlink transmission in the second same spatial direction of the third UE and the fourth UE. In some cases, the directional transmitting component 1325 may transmit the second downlink transmission in the second same spatial direction of the first UE and the third UE. In some examples, the directional transmitting component 1325 may transmit the second downlink transmission in the second same spatial direction as the third UE and the second UE. In some cases, the second signal for the second UE is transmitted for the first set of symbols and not the second set of symbols, where the MCS update and the power ratio update are transmitted based on early termination of the second signal. In some cases, the second signal for the second UE is transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update are transmitted based at least in part the base station starting to transmit to the second UE. In some cases, the second signal for the second UE is transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, where the MCS update and the power ratio update are transmitted based on the base station switching from transmitting to the second UE to transmitting to the third UE.

FIG. 14 shows a diagram of a system 1400 including a device 1405 that supports wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. Device 1405 may be an example of or include the components of base station 1105, base station 1205, or a base station 105 as described above, e.g., with reference to FIGs. 11 and 12. Device 1405 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including communications manager 1410, network communications manager 1415, transceiver 1420, antenna 1425, memory 1430, processor 1440, and inter-station communications manager 1445. These components may be in electronic communication via one or more buses (e.g., bus 1450) .

Network communications manager 1415 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1415 may manage the transfer of data communications for client devices, such as one or more UEs 115.

Transceiver 1420 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1420 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1420 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1425. However, in some cases the device may have more than one antenna 1425, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

Memory 1430 may include RAM and ROM. The memory 1430 may store computer-readable, computer-executable software14 35 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1430 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

Processor 1440 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, processor 1440 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor 1440. Processor 1440 may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting wireless devices pairing for downlink MU-MIMO transmission) .

Inter-station communications manager 1445 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1445 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, inter-station communications manager 1445 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

FIG. 15 shows a flowchart illustrating a method 1500 for wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a UE or its components as described herein. The UE may be an example of a UE 115 as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 7 to 10. In some examples, a UE may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE may perform aspects of the functions described below using special-purpose hardware.

At 1505 the first UE may identify a second UE, where the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance. The operations of 1505 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1505 may be performed by an UE identifier as described with reference to FIGs. 7 to 10.

At 1510 the first UE may receive, from the base station, configuration information associated with the second UE. The operations of 1510 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1510 may be performed by a UE configuration component as described with reference to FIGs. 7 to 10.

At 1515 the first UE may receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE. The operations of 1515 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1515 may be performed by a downlink transmission receiver as described with reference to FIGs. 7 to 10.

At 1520 the first UE may decode the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE. The operations of 1520 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1520 may be performed by a decoding component as described with reference to FIGs. 7 to 10.

FIG. 16 shows a flowchart illustrating a method 1600 for wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a UE or its components as described herein. For example, the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 7 to 10. In some examples, a UE may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE may perform aspects of the functions described below using special-purpose hardware.

At 1605 a first UE may identify a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically at a second distance from the base station, the second distance being greater than the first distance. The operations of 1605 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1605 may be performed by an UE identifier as described with reference to FIGs. 7 to 10.

At 1610 the first UE may receive, from the base station, configuration information associated with the second UE. The operations of 1610 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1610 may be performed by a UE configuration component as described with reference to FIGs. 7 to 10.

At 1615 the first UE may receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE. The operations of 1615 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1615 may be performed by a downlink transmission receiver as described with reference to FIGs. 7 to 10.

At 1620 the first UE may decode the second signal for the second UE based at least in part on the configuration information associated with the second UE. The operations of 1620 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1620 may be performed by a decoding component as described with reference to FIGs. 7 to 10.

At 1625 the first UE may decode the first signal for the first UE based at least in part on successive interference cancelling of the second signal for the second UE. The operations of 1625 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1625 may be performed by a decoding component as described with reference to FIGs. 7 to 10.

FIG. 17 shows a flowchart illustrating a method 1700 for wireless devices pairing for downlink MU-MIMO transmission in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a base station or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 11 to 14. In some examples, a base station may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station may perform aspects of the functions described below using special-purpose hardware.

At 1705 the base station may identify a first UE and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance. The operations of 1705 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1705 may be performed by an UE identifier as described with reference to FIGs. 11 to 14.

At 1710 the base station may transmit, to the first UE, configuration information associated with the second UE. The operations of 1710 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1710 may be performed by a UE configuration component as described with reference to FIGs. 11 to 14.

At 1715 the base station may encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission. The operations of 1715 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1715 may be performed by an encoding component as described with reference to FIGs. 11 to 14.

At 1720 the base station may transmit the downlink transmission based on CSI of the first UE and the second UE. The operations of 1720 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1720 may be performed by a directional transmitting component as described with reference to FIGs. 11 to 14.

It should be noted that the methods described above describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A small cell may be associated with a lower- powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs 115 having an association with the femto cell (e.g., UEs 115 in a closed subscriber group (CSG) , UEs 115 for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications system 100 or systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may comprise random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications, comprising:

identifying, at a first user equipment (UE) , a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

receiving, from the base station, configuration information associated with the second UE;

receiving a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE; and

decoding the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.
The method of claim 1, wherein the configuration information associated with the second UE comprises a modulation and coding scheme (MCS) for the second UE and a power ratio between the first signal and the second signal.
The method of claim 2, further comprising:

receiving an MCS update and a power ratio update for the second UE; and

identifying an updated MCS and an updated power ratio for the second UE based at least in part on the MCS update and the power ratio update, wherein decoding the downlink transmission comprises decoding a first set of symbols of the downlink transmission according to the MCS for the second UE and decoding a second set of symbols of the downlink transmission according to the updated MCS and the updated power ratio for the second UE.
The method of claim 3, wherein the second signal for the second UE is transmitted for the first set of symbols and not the second set of symbols, and the MCS update and the power ratio update are received based at least in part on early termination of the second signal.
The method of claim 3, wherein the second signal for the second UE is transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update are received based at least in part on the base station starting to transmit to the second UE.
The method of claim 3, wherein the second signal is transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, wherein the MCS update and the power ratio update are received based at least in part on the base station switching from transmitting to the second UE to transmitting to the third UE.
The method of claim 1, wherein decoding the downlink transmission comprises:

decoding the second signal for the second UE based at least in part on the configuration information associated with the second UE; and

decoding the first signal for the first UE based at least in part on successive interference cancelling of the second signal for the second UE.
The method of any one of claims 1 to 7, further comprising:

identifying, at the first UE, a third UE geographically located at a third distance from the base station, the third distance being greater than the first distance;

receiving, from the base station, a second configuration information associated with the third UE;

receiving a second downlink transmission, wherein the second downlink transmission comprises a third signal for the first UE and a fourth signal for the third UE; and

decoding the second downlink transmission based at least in part on the second configuration information associated with the third UE to obtain the third signal for the first UE.
The method of claim 8, wherein the first and second signals occupy a first frequency subband, and the third and fourth signals occupy a second frequency subband.
The method of any one of claims 1 to 7, wherein the first signal and the second signal are encoded using a same spatial precoder.
The method of any one of claims 1 to 7, wherein the second signal for the second UE is transmitted using more power than the first signal for the first UE.
The method of any one of claims 1 to 7, wherein the configuration information associated with the second UE is received in downlink control information or via radio resource control (RRC) signaling.
The method of any one of claims 1 to 7, wherein the first UE is a mobile broadband (MBB) UE or a machine-type communications (MTC) UE.
The method of any one of claims 1 to 7, wherein the second UE is a mobile broadband (MBB) UE or a machine-type communications (MTC) UE.
A method for wireless communications, comprising:

identifying, at a base station, a first user equipment (UE) and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

transmitting, to the first UE, configuration information associated with the second UE;

encoding a first signal for the first UE and a second signal for the second UE to generate a downlink transmission; and

transmitting the downlink transmission based at least in part on channel state information (CSI) of the first UE and the second UE.
The method of claim 15, wherein the configuration information associated with the second UE comprises a modulation and coding scheme (MCS) for the second UE and a power ratio between the first signal and the second signal.
The method of claim 16, further comprising:

transmitting an MCS update and a power ratio update for the second UE, wherein a first set of symbols of the downlink transmission are encoded based at least in part on a first MCS and a first power ratio and a second set of symbols of the downlink transmission are encoded based at least in part on a second MCS and a second power ratio.
The method of claim 17, wherein the second signal for the second UE is transmitted for the first set of symbols and not the second set of symbols, wherein the MCS update and the power ratio update are transmitted based at least in part on early termination of the second signal.
The method of claim 17, wherein the second signal for the second UE is transmitted for the second set of symbols and not the first set of symbols, and the MCS update and the power ratio update are transmitted based at least in part the base station starting to transmit to the second UE.
The method of claim 17, wherein the second signal is transmitted to the second UE for the first set of symbols and transmitted to a third UE for the second set of symbols, wherein the MCS update and the power ratio update are transmitted based at least in part on the base station switching from transmitting to the second UE to transmitting to the third UE.
The method of any one of claims 15 to 20, further comprising:

identifying a third UE and a fourth UE, wherein the third UE is geographically located at a third distance from the base station and the fourth UE is geographically located at a fourth distance from the base station, the fourth distance being greater than the third distance;

transmitting, to the third UE, a second configuration information associated with the fourth UE;

encoding a third signal for the third UE and a fourth signal for the fourth UE based at least in part on CSI of the third UE and the fourth UE to generate a second downlink transmission.
The method of claim 21, further comprising:

spatially multiplexing the first downlink transmission and the second downlink transmission on a same frequency subband.
The method of any one of claims 15 to 20, further comprising:

identifying a third UE, wherein the third UE is geographically located at a third distance from the base station, the third distance being greater than the first distance, the first UE and the third UE being in a second same spatial direction from the base station;

transmitting, to the first UE, a second configuration information associated with the third UE; and

encoding a third signal for the first UE and a fourth signal for the third UE based at least in part on the CSI of the first UE and CSI of the third UE to generate a second downlink transmission.
The method of any one of claims 15 to 20, further comprising:

identifying a third UE, wherein the third UE is geographically located at a third distance from the base station, the second distance being greater than the third distance, and the third UE and the second UE being in a second same spatial direction from the base station;

transmitting to the third UE, the configuration information associated with the second UE; and

encoding a third signal for the third UE and a fourth signal for the second UE using a second same spatial precoder to generate a second downlink transmission.
The method of any one of claims 15 to 20, wherein the configuration information associated with the second UE is transmitted in downlink control information or via Radio Resource Control (RRC) signaling.
The method of any one of claims 15 to 20, wherein the first UE is a mobile broadband (MBB) UE or a machine-type communications (MTC) UE.
The method of any one of claims 15 to 20, wherein the second UE is a mobile broadband (MBB) UE or a machine-type communications (MTC) UE.
An apparatus for wireless communications, comprising:

means for identifying, at a first user equipment (UE) , a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

means for receiving, from the base station, configuration information associated with the second UE;

means for receiving a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE; and

means for decoding the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.
An apparatus for wireless communications, comprising:

means for identifying, at a base station, a first user equipment (UE) and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

means for transmitting, to the first UE, configuration information associated with the second UE;

means for encoding a first signal for the first UE and a second signal for the second UE to generate a downlink transmission; and

means for transmitting the downlink transmission based at least in part on cannel state information (CSI) of the first UE and the second UE.
An apparatus for wireless communications, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:

identify, at a first user equipment (UE) , a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

receive, from the base station, configuration information associated with the second UE;

receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE; and

decode the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.
An apparatus for wireless communications, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:

identify, at a base station, a first user equipment (UE) and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

transmit, to the first UE, configuration information associated with the second UE;

encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission; and

transmit the downlink transmission based at least in part on cannel state information (CSI) of the first UE and the second UE.
A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to:

identify, at a first user equipment (UE) , a second UE, wherein the first UE is geographically located at a first distance from a base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

receive, from the base station, configuration information associated with the second UE;

receive a downlink transmission, wherein the downlink transmission comprises a first signal for the first UE and a second signal for the second UE; and

decode the downlink transmission based at least in part on the configuration information associated with the second UE to obtain the first signal for the first UE.
A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to:

identify, at a base station, a first user equipment (UE) and a second UE, wherein the first UE is geographically located at a first distance from the base station and the second UE is geographically located at a second distance from the base station, the second distance being greater than the first distance;

transmit, to the first UE, configuration information associated with the second UE;

encode a first signal for the first UE and a second signal for the second UE to generate a downlink transmission; and

transmit the downlink transmission based at least in part on cannel state information (CSI) of the first UE and the second UE.