System and method for device random access in a beamformed communications system

A method for communicating with an access node includes receiving measurement table information from the access node, wherein the measurement table information is derived from measurements of communications channels between access nodes and user equipments (UEs) served by the access nodes, determining an access strategy and an associated access parameter for a shared communications channel in accordance with the measurement table information, and transmitting an uplink transmission on the shared communications channel in accordance with the associated access parameter after obtaining access to the shared communications channel.

TECHNICAL FIELD

The present disclosure relates generally to a system and method for digital communications, and, in particular embodiments, to a system and method for device random access in a beamformed communications system.

BACKGROUND

Future wireless communications systems are operating at ever higher carrier frequencies in a quest to find greater bandwidth and less interference. These wireless communications systems may operate at frequencies of 6 GHz and above, millimeter wavelength (mmWave) frequencies, for example, to exploit greater available bandwidth and less interference then what is available at the congested lower frequencies. However, pathloss is a significant issue. Beamforming may be used to overcome the high pathloss.

SUMMARY

Example embodiments provide a system and method for device random access in a beamformed communications system.

In accordance with an example embodiment, a method for communicating with an access node is provided. The method includes receiving, by a user equipment (UE), measurement table information from the access node, wherein the measurement table information is derived from measurements of communications channels between access nodes and UEs served by the access nodes, determining, by the UE, an access strategy and an associated access parameter for a shared communications channel in accordance with the measurement table information, and transmitting, by the UE, an uplink transmission on the shared communications channel in accordance with the associated access parameter after obtaining access to the shared communications channel.

Optionally, in any of the preceding embodiments, the method further comprises receiving, by the UE, communications beam scheduling information from the access node, wherein the access strategy is also determined in accordance with the communications beam scheduling information.

Optionally, in any of the preceding embodiments, wherein the measurement table information includes at least one of indications of communications beams of the access node, indications of communications of neighboring access nodes detectable by UEs served by the access node, indications of communications beams of the UEs served by the access node, indications of communications beams of the UEs served by the access node detectable by the neighboring access nodes.

Optionally, in any of the preceding embodiments, wherein determining the access strategy comprises determining, by the UE, a value for the associated access parameter in accordance with a transmission probability.

Optionally, in any of the preceding embodiments, wherein the associated access parameter comprises one or more of a listen before talk (LBT) threshold, a contention window size, wait time before contention, or a carrier sense multiple access (CSMA) threshold.

In accordance with an example embodiment, a method for communicating with a UE is provided. The method includes generating, by an access node, measurement table information in accordance with channel measurements of communications channels between the access node and UEs served by the access node, signaling, by the access node, the measurement table information to the UEs served by the access node, and receiving, by the access node, an uplink transmission from the UE on a shared communications channel.

Optionally, in any of the preceding embodiments, wherein generating the measurement table information comprises deriving, by the access node, the measurement table information from measurement reports received from the UEs served by the access node.

Optionally, in any of the preceding embodiments, wherein generating the measurement table information comprises measuring, by the access node, the communications channels in accordance with signals received from the UEs served by the access node, and deriving, by the access node, the measurement table information from the measurements of the communications channels.

Optionally, in any of the preceding embodiments, wherein the method further comprises signaling, by the access node, communications beam scheduling information to the UEs served by the access node.

Optionally, in any of the preceding embodiments, wherein the method further comprises sharing, by the access node, the measurement table information with neighboring access nodes.

Optionally, in any of the preceding embodiments, wherein sharing the measurement table information comprises sending, by the access node, the measurement table information to the neighboring access nodes, receiving, by the access node, neighboring measurement table information from the neighboring access nodes, and updating, by the access node, the measurement table information in accordance with the neighboring measurement table information.

In accordance with an example embodiment, a UE is provided. The UE includes one or more processors, and a computer readable storage medium storing programming for execution by the one or more processors. The programming including instructions to configure the UE to receive measurement table information from an access node, wherein the measurement table information is derived from measurements of communications channels between access nodes and UEs served by the access nodes, determine an access strategy and an associated access parameter for a shared communications channel in accordance with the measurement table information, and transmit an uplink transmission on the shared communications channel in accordance with the associated access parameter after obtaining access to the shared communications channel.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the UE to receive communications beam scheduling information from the access node, and wherein the access strategy is also determined in accordance with the communications beam scheduling information.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the UE to determine a value for the associated access parameter in accordance with a transmission probability.

Optionally, in any of the preceding embodiments, wherein the measurement table information includes at least one of indications of communications beams of the access node, indications of communications of neighboring access nodes detectable by UEs served by the access node, indications of communications beams of the UEs served by the access node, indications of communications beams of the UEs served by the access node detectable by the neighboring access nodes.

In accordance with an example embodiment, an access node is provided. The access node includes one or more processors, and a computer readable storage medium storing programming for execution by the one or more processors. The programming including instructions to configure the access node to generate measurement table information in accordance with channel measurements of communications channels between the access node and UEs served by the access node, signal the measurement table information to the UEs served by the access node, and receive an uplink transmission from the UE on a shared communications channel.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the access node to derive the measurement table information from measurement reports received from the UEs served by the access node.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the access node to measure the communications channels in accordance with signals received from the UEs served by the access node, and derive the measurement table information from measurements of the communications channels.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the access node to signal communications beam scheduling information to the UEs served by the access node.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the access node to share the measurement table information with neighboring access nodes.

Optionally, in any of the preceding embodiments, wherein the programming includes instructions to configure the access node to send the measurement table information to the neighboring access nodes, receive neighboring measurement table information from the neighboring access nodes, and update the measurement table information in accordance with the neighboring measurement table information.

Practice of the foregoing embodiments enables user equipment operating in a beamforming environment to randomly access a shared communications channel based on signal measurement information and communications beam information that are collaboratively obtained. The use of the signal measurement information and communications beam information helps to reduce interference caused by the random access transmissions of the user equipment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1illustrates an example wireless communications system100. Communications system100includes a first access node (access node_1)105and a second access node (access node_2)107, as well as a plurality of user equipments (UEs), such as UE no, UE112, UE114, UE116, and UE118. In one communications mode commonly referred to as cellular mode, communications intended for or originating from a UE pass through an access node serving the UE. In another communications mode commonly referred to as random access, a UE with a transmission to make can randomly access a shared communications channel and make the transmission as long as the UE has checked the status of the shared communications channel and has determined that the shared communications channel is not occupied by another transmitting device.

Access nodes are also commonly referred to as NodeBs, evolved NodeBs (eNBs), next generation (NG) NodeBs (gNBs), master eNBs (MeNBs), secondary eNBs (SeNBs), master gNBs (MgNBs), secondary gNBs (SgNBs), base stations, access points, remote radio heads, and so on. Similarly, UEs are also commonly referred to as mobiles, mobile stations, stations, terminals, subscribers, users, and the like. While it is understood that communications systems may employ multiple access nodes capable of communicating with a number of UEs, only two access nodes, and five UEs are illustrated for simplicity.

In non-beamformed communications systems, when a device has a transmission to make on a shared communications channel (which may be on an unlicensed carrier), the device usually needs to perform a listen-before-talk procedure before making the transmission. The listen-before-talk procedure (sometimes referred to as a listen-before-transmit procedure) typically involves the device sensing its radio environment to determine if the shared communications channel is idle before the device commences its transmission. If the detected energy on the shared communications channel is below a specified threshold, the device determines that the shared communications channel is idle and may proceed with its transmission. If the detected energy on the shared communications channel is above the specified threshold, the device determines that the shared communications channel is busy and holds its transmission. IEEE 802.11 (Wi-Fi) compliant communications use a variation of listen-before-talk referred to as carrier sense multiple access with collision detect (CSMA/CD) where a Wi-Fi station senses the state of the shared communications channel to determine if the shared communications channel is idle before transmitting.

Legacy communications systems supporting listen-before-talk random access normally support devices that receive using omnidirectional receive antennas. However, in a beamformed communications system, where devices communicate using directional communications beams, listen-before-talk may be insufficient in preventing transmission collisions.FIG. 2illustrates a beamformed communications system200highlighting the insufficiency of listen-before-talk. Beamformed communications system200includes an access node205making a transmission to a first UE (UE1)210using transmit beam212. While access node205is transmitting to UE1210, a second UE (UE2)215has a transmission intended for a third UE (UE3)220. Therefore, UE2215performs a listen-before-talk procedure using receive beam222. Because transmit beam212is directed away from UE2215and because UE2215is using receive beam222to perform the listen-before-talk procedure, it is very likely that UE2215is unable to detect the transmission taking place between access node205and UE1210. Hence, the detected energy level on the shared communications channel may be below the specified threshold and the shared communications channel is deemed to be idle. Therefore, UE2215is free to transmit to UE3220using a transmit beam that corresponds to receive beam222. The transmission may cause interference to the transmission taking place between access node205and UE1210.

Therefore, there is a need for systems and methods for supporting transmitting device random access in a beamformed communications system.

According to an example embodiment, a system and method for supporting transmitting device random access in a beamformed communications system utilizing signal measurement information is provided. A transmitting device, such as a UE, uses the signal measurement information to determine an access strategy for randomly accessing the shared communications channel without causing undue interference to other devices operating in the vicinity. Determination of the access strategy also includes determining associated access parameters of the access strategy. The signal measurement information indicates which receive beam of a first device is capable of detecting a transmitted signal from a second device, for example. An access node (or a network entity maintaining the signal measurement information) may provide the signal measurement information to the transmitting device. Examples of access parameters include contention window sizes, listen-before-talk thresholds, CSMA thresholds, minimum wait time before contention, maximum wait time before contention, wait time before contention, and so on.

The signal measurement information may be in the form of single-bit values indicating if a particular receive beam of a first device is able to detect a transmitted signal from a second device. Alternatively, the signal measurement information may be in the form of multiple-bit values indicating a quantized received signal strength of a transmitted signal from a second device received by a particular receive beam of a first device. Alternatively, the signal measurement information may be in the form of a received signal strength of a transmitted signal from a second device received by a particular receive beam of a first device. The examples of the signal measurement information presented herein are for illustrative purposes only and are not intended to be limiting to either the scope or the spirit of the example embodiments.

According to an example embodiment, a system and method for supporting transmitting device random access in a beamformed communications system utilizing collaboratively gathered signal measurement information and communications beam scheduling information is used to support device random access in a beamformed communications system. A transmitting device, such as a UE, uses the signal measurement information and communications beam scheduling information to determine an access strategy for randomly accessing the shared communications channel, as well as associated access parameters therefor, without causing undue interference to other devices operating in the vicinity. The communications beam scheduling information indicates a time, a time interval, a time slot, and so forth, that a first device will be using a particular communications beam to transmit (using the particular transmit beam) to a second device or to receive (using the particular receive beam) from a second device, for example. An access node (or a network entity maintaining the communications beam scheduling information) may provide the communications beam scheduling information to the transmitting device.

The communications beam scheduling information may be in the form of a sequence of communications beams of a first device and a time, time interval, time slot, and so forth, for each communications beam indicating when the first device will use the communications beam. Alternatively, communications beam scheduling information may be in the form of a sequence of communications beams of a first device with the ordering of the sequence implicitly indicating when the first device will use the communications beam. As an illustrative example, if the communications beam scheduling information comprises sequence: 2, 4, 1, 3, then communications beam 2 will be used in a first time slot or interval, then communications beam 4 will be used in a second time slot or interval, followed by communications beam 1 in a third time slot or interval and communications beam 3 in a fourth time slot or interval. The examples of the communications beam scheduling information presented herein are for illustrative purposes only and are not intended to be limiting to either the scope or the spirit of the example embodiments.

For discussion purposes, the following communications system deployment is utilized:The communications system includes a plurality of access nodes, denoted A, B, C, and so on, and a plurality of UEs, denoted UE_1, UE_2, UE_3, and so forth.Each UE is served by a particular access node. As an example, UE_1is served by access node B, which is a neighbor of access node A.Each access node supports beamforming in both transmission and reception. As an example, the beams of access node A are denoted beams A(i), i=1, . . . , NA, where NA is the number of communications beams of access node A. Similarly, the beams of access node B are denoted beams B(i), i=1, . . . , NB, where NB is the number of communications beams of access node A.For simplicity, the beams of an access node may be used for transmitting and receiving. The situation where an access node has different transmit and receive beam configurations are also supported by the example embodiments presented herein but are not considered in this discussion to maintain simplicity.For simplicity, the UEs utilize omnidirectional transmissions. The situation where a UE uses beamformed transmissions is also supported by the example embodiments presented herein but is not considered in this discussion to maintain simplicity.Beam calibration is used.If a UE can detect a transmission from an access node transmitting with an i-th transmit beam, then the access node can detect a transmission from the UE using the i-th receive beam.

FIG. 3illustrates a diagram300of communications exchanged between devices participating in transmitting device random access in a beamformed communications system. Diagram300displays communications exchanged between access nodes (access node A305and access node B307) and UEs (UE1310and UE2312) as the devices participate in transmitting device random access in a beamformed communications system.

In order to support signal measurements, some of the devices transmit beamformed signals (such as reference signals, measurement reference signals, normal transmissions, and so on) while other devices measure an amount of energy that they are able to detect on the communications channel while the signals are being transmitted. As shown inFIG. 3, access node A305transmits a beamformed reference signal (RS) in one or more network resources for measurement purposes (event315), while UE1310and UE2312make measurements of detectable energy in the one or more network resources. The RS may broadcast by access node A305or the RS may be individually transmitted to UE1310and UE2312. As an example, the RS may be addressed to a UE group that includes UE1310and UE2312or the RS may be addressed to UE1310and UE2312separately. Access node B307also transmits a beamformed RS in one or more network resources for measurement purposes (event317), while UE1310and UE2312make measurements of detectable energy in the one or more network resources. The RS transmitted by access node A305may be the same as the RS transmitted by access node B307. Alternatively, the access nodes may transmit different RSs. The access nodes may transmit their respective RSs simultaneously or separately, depending upon the capabilities of the UEs, for example.

AlthoughFIG. 3illustrates a situation where the access nodes transmit and the UEs measure (downlink channel measurements), a similar situation is possible where the UEs transmit and the access nodes measure (uplink channel measurements). In certain communications systems, such as those that use time division duplexing (TDD), uplink channel measurements and downlink channel measurements are substantially equal.

The UEs measure the amount of energy that they are able to detect in network resources used to convey the RS. Because the access nodes are using beamforming, in order to accurately assess the detectability of signals transmitted by the access nodes using different transmission beams, the access nodes should transmit the beamformed RS using each of their available transmission beams. This is referred to as beam sweeping. As an example, at a first time, access node A305transmits the beamformed RS using transmit beam A(1), at a second time, access node A305transmits the beamformed RS using transmit beam A(2), and so on, for all transmit beams of access node A305. It is noted that in a situation where the UEs are using receive beams (i.e., the UE is also using beamforming), the dwell time of each beamformed RS transmission should be sufficiently long to allow the UE to detect the energy in the communications channel using each of its receive beams.

The UEs report the amount of energy detected for each of the transmit beams of each of the access nodes in measurement reports (events319and321). In an embodiment, each UE reports the detected energies associated with all of the access nodes to a single access node (e.g., the access node serving the UE). In another embodiment, each UE reports the detected energies with each access node separately to each access node.

The access nodes exchange the information in the measurement reports and update their signal measurement information (event323). The signal measurement information may be stored in tabular form. A discussion of an example tabular arrangement of the signal measurement information is presented below. The access nodes share the detected energies associated with their own transmissions, as well as detected energies associated with transmissions made by other access nodes, with neighboring access nodes. As shown inFIG. 3, access node A305receives a measurement report from UE1310that includes detected energies for beamformed RSs transmitted by both access node A305and access node B307. Access node A305shares the detected energies with access node B307. Similarly, access node B307receives a measurement report from UE2312that includes detected energies for beamformed RSs transmitted by both access node B307and access node A305. Access node B307shares the detected energies with access node A305.

In addition to the information in the measurement reports, the access nodes share communications beam scheduling information (event323). The communications beam scheduling information indicates a time, a time interval, a time slot, and so forth, that an access node will be using a particular communications beam to transmit (using the particular transmit beam) to a device or to receive (using the particular receive beam) from a device, for example. As an example, the communications beam scheduling information of access node A305informs access node B307when access node A305will use a particular communications beam (either a transmit beam or a receive beam) to communicate. Access node B307may then schedule a transmission or a reception or to remain silent during that time to not cause interference to access node A305or receive interference from access node A305.

The access nodes signal the signal measurement information to the UEs (events325and327). The access nodes signal the signal measurement information to the UEs that they serve. In an embodiment, the access nodes also signal the communications beam scheduling information to the UEs. The UEs determine an access strategy, as well as associated access parameters, in accordance with the signal measurement information and optionally, the communications beam scheduling information. The UEs perform channel access in accordance with their respective access strategy (events329and331).

FIG. 4illustrates an example arrangement of signal measurement information400. Signal measurement information400is arranged in tabular form. Other arrangements of the signal measurement information are possible. As shown inFIG. 4, signal measurement information400includes information for communications beams of two access nodes, access node A405and access node B407. Access node A405has four communications beams (A(1), . . . , A(4)) and access node B407has four communications beams (B(1), . . . , B(4)). Each communications beam of the two access nodes is represented as columns of the table. As an example, column415corresponds to communications beam A(1), column417corresponds to communications beam A(2), and column419corresponds to communications beam A(3), and so on.

Signal measurement information400includes detected signal strength values for four UEs, including UE1410, and UE3412, with a first value (e.g., “1”) representing a detected signal strength that exceeds a specified threshold and a second value (e.g., “0”) representing a detected signal strength that does not exceed the specified threshold. As an example, value420represents that the signals detected by UE1410for a transmission made on communications beam A(1) (i.e., transmit beam A(1)) by access node A405exceeded the specified threshold. Similarly, value422represents that the signals detected by UE3412for a transmission made on communications beam A(1) by access node A405exceeded the specified threshold. However, values425and427represent that the signals detected by UE1410and UE3412for transmissions made on communications beam A(2) of access node A405do not exceed the specified threshold. Furthermore, value430represents that the signals detected by UE1410for a transmission made on communications beam A(3) of access node A405does not exceed the specified threshold.

Conversely, the detected signal strength values represent that detected signals corresponding to a transmission made by a particular UE as received by a communications beam (i.e., a receive beam) meets (e.g., value=“1”) or does not meet (e.g., value=“0”) the specified threshold. As an example, value420represents that signals from UE1410, as detected by communications beam A(1) of access node A405, exceed the specified threshold, while value425represents that signals from UE1410, as detected by communications beam A(2) of access node A405, does not exceed the specified threshold. Therefore, for a UE and access node pairing associated with a particular entry in signal measurement information400that is equal to “1”, then when the UE is transmitting to a nearby device, the transmission from the UE will cause interference to the access node.

It is noted that the discussion of signal measurement information400presents a configuration where a one-bit value (either 1 or 0) is used to represent if the detected signals meet a threshold. Other configurations are possible. As an illustrative example, a multi-bit value is used to represent the detected signals. In such a configuration, a first value may indicate that the detected signal does not meet a threshold, while a plurality of values may indicate a magnitude of how much the detected signal exceeds the threshold. For example, a two-bit value is used, where value “00” represents the detected signal not meeting the threshold, value “01” represents the detected signal meeting the threshold by a small margin, value “10” represents the detected signal meeting the threshold by a medium margin, and value “11” represents the detected signal meeting the threshold by a large margin. The multi-valued signal measurement information may allow UEs to finely tune their access strategy. As an example, a UE may decide to go ahead with a high priority transmission even if the signal measurement information indicates that its transmission will cause a small amount of interference to other devices, while stopping a low priority transmission under the same circumstances.

FIG. 5Aillustrates a communications system500highlighting a first example communications beam scenario. Communications system500includes an access node A505serving UE1510, and an access node B507serving UE2512. Access node A505and access node B507are neighboring access nodes. As shown inFIG. 5A, access node A505has four communications beams A(1)515, A(2)516, A(3)517, and A(4)518, while access node B507has four communications beams B(1)520, B(2)521, B(3)522, and B(4)523. The access nodes communicate using their respective communications beams in an order as shown. UE1510is located at the coverage edge of access node A505and spatially between communications beams A(1)515and A(4)518, while UE2512is located at the coverage edge of access node B507and spatially between communications beams B(2)521and B(3)522.

FIG. 5Billustrates a first example arrangement550of signal measurement and communications beam scheduling information. Arrangement550includes both signal measurement information and communications beam scheduling information. Arrangement550is presented in tabular form, but other arrangements are possible.

Arrangement550includes a first portion555that includes communications beam scheduling information. The columns of arrangement550correspond to times, time intervals, time slots, and so on, associated with the communications beams. As an example, with respect to first portion555, column557corresponds to a first time, when access node A505is communicating using communications beam A(1) and access node B507is communicating using communications beam B(1), while column559corresponds to a second time, when access node A505is communicating using communications beam A(2) and access node B507is communicating using communications beam B(2), and so on.

Arrangement550includes a second portion560that includes signal measurement information. The columns of arrangement550correspond to times, time intervals, time slots, and so on, associated with the communications beams. As an example, with respect to second portion560, column557corresponds to a first time, when a particular access node communicates using a first communications beam, while column559corresponds to a second time, when the particular access node communicates using a second communications beam. A value in a cell of arrangement550corresponds to a particular time (associated with a particular column of the cell) and one or more access nodes (associated with a particular row of the cell) and indicates if a transmission made by the UE will be detectable by the one or more access nodes. As an illustrative example, cell562represents signal measurement information for UE1510for a first time (column557) and access node A505(row564). As shown inFIG. 5B, cell562has value “1” representing that a transmission by UE1510would be detectable by access node A505, while cell566has a value “0” representing that a transmission by UE1510would not be detectable by access node A505. Similarly, cell562represents that a transmission by access node A505would be detectable by UE1510at the first time, while cell566represents that a transmission by access node A505would not be detectable by UE510at the second time. Row568presents signal measurement information for UE1510I.C.O. both access nodes A505and B507. The values of cells of in row568are basically a logical AND operation of the values of cells associated with UE1510and the individual access nodes.

FIG. 6Aillustrates communications system600highlighting a second example communications beam scenario. Communications system600includes an access node A605serving UE1610, and an access node B607serving UE2612. Access node A605and access node B607are neighboring access nodes. As shown inFIG. 6A, access node A605has four communications beams A(1)615, A(2)616, A(3)617, and A(4)618, while access node B607has four communications beams B(1)620, B(3)621, B(2)622, and B(4)623. The access nodes communicate using their respective communications beams in an order as shown. UE1610is located at the coverage edge of access node A605and spatially between communications beams A(1)615and A(4)618, while UE2612is located at the coverage edge of access node B607and spatially between communications beams B(4)623and B(3)621.

FIG. 6Billustrates a second example arrangement650of signal measurement and communications beam scheduling information. Arrangement650includes both signal measurement information and communications beam scheduling information. Arrangement550is presented in tabular form, but other arrangements are possible.

Arrangement650includes a first portion655that includes communications beam scheduling information. The columns of arrangement650correspond to times, time intervals, time slots, and so on, associated with the communications beams. As an example, with respect to first portion655, column657corresponds to a first time, when access node A605is communicating using communications beam A(1) and access node B607is communicating using communications beam B(1), while column659corresponds to a second time, when access node A605is communicating using communications beam A(2) and access node B607is communicating using communications beam B(3), and so on.

Arrangement650includes a second portion660that includes signal measurement information. The columns of arrangement650correspond to times, time intervals, time slots, and so on, associated with the communications beams. As an example, with respect to second portion660, column657corresponds to a first time, when a particular access node communicates using a first communications beam, while column659corresponds to a second time, when the particular access node communicates using a second communications beam. A value in a cell of arrangement650corresponds to a particular time (associated with a particular column of the cell) and one or more access nodes (associated with a particular row of the cell) and indicates if a transmission made by the UE will be detectable by the one or more access nodes. As an illustrative example, cell662represents signal measurement information for UE1610for a first time (column657) and access node A605(row664). As shown inFIG. 6B, cell662has value “1” representing that a transmission by UE1610would be detectable by access node A605, while cell666has a value “0” representing that a transmission by UE1610would not be detectable by access node A605. Similarly, cell662represents that a transmission by access node A605would be detectable by UE1610at the first time, while cell666represents that a transmission by access node A605would not be detectable by UE610at the second time. Row668presents signal measurement information for UE1610I.C.O. both access nodes A605and B607. The values of cells of in row668are basically a logical AND operation of the values of cells associated with UE1610and the individual access nodes.

According to an example embodiment, a UE determines its access strategy and associated access parameters based on signal measurement information. Signal measurement information, such as shown inFIG. 4, may be used to set a transmission probability for a UE, for example. In a situation when transmissions by a UE are not causing interference to an access node when the access node is using a particular communications beam (e.g., when a value associated with the UE/access node/communications beam combination is “0”), the UE may set or select its access strategy to increase the transmission probability. Conversely, when transmissions by the UE are causing interference to the access node when the access node is using a particular communications beam (e.g., when a value associated with the UE/access node/communications beam combination is “1”), the UE may set or select its access strategy to decrease the transmission probability. As an illustrative example, a contention window size is used to set the transmission probability, with smaller contention window sizes increasing the transmission probability and larger contention window sizes decreasing the transmission probability. As another illustrative example, a CSMA listen-before-talk (LBT) threshold is used to set the transmission probability, with larger CSMA LBT thresholds increasing the transmission probability and smaller CSMA LBT thresholds decreasing the transmission probability.

According to an example embodiment, a UE determines its access strategy and associated access parameters based on signal measurement information and communications beam scheduling information. Signal measurement information and communications beam scheduling information (such as shown inFIGS. 5B and 6B) may be used to set a transmission probability for a UE, for example. In a situation when transmissions by a UE are not causing interference to an access node at a time when the access node is using a particular communications beam (e.g., when a value associated with the UE/access node/communications beam combination is “0”), the UE may set its access strategy to increase the transmission probability. Conversely, when transmissions by the UE are causing interference to the access node at a time when the access node is using a particular communications beam (e.g., when a value associated with the UE/access node/communications beam combination is “1”), the UE may set its access strategy to decrease the transmission probability. As an illustrative example, a contention window size is used to set the transmission probability. As another illustrative example, a CSMA LBT threshold is used to set the transmission probability.

According to an example embodiment, in a situation where an access node serves multiple UEs, each of the UEs independently determine its own access strategy and associated access parameters based on signal measurement information. According to an example embodiment, in a situation where an access node serves multiple UEs, each of the UEs independently determine its own access strategy and associated access parameters based on signal measurement information and communications beam scheduling information.

It is noted that in a situation where multiple UEs may simultaneously transmit, a collision may occur and collision resolution is needed. Any of a variety of contention resolution techniques may be used. As an illustrative example, a contention resolution technique involving a random backoff period may be used. As another illustrative example, a contention resolution technique involving a random backoff period and increased contention window size may be used.

FIG. 7illustrates a flow diagram of example operations700occurring in an access node. Operations700may be indicative of operations occurring in an access node as the access node receives a transmission from a UE.

Operations700begin with the access node generating signal measurement information (block705). The access node may generate the signal measurement information by deriving the signal measurement information from measurement reports received from UEs. Alternatively, the access node may generate the signal measurement information by measuring signals transmitted by UEs and deriving the signal measurement information from the measurements. The signal measurement information may be generated from detected signal levels from the measurement reports received from the UEs or from actual measurements made by the access node. The access node shares the signal measurement information with other access nodes (block707). The access node shares its signal measurement information with other access nodes. In some embodiments, each UE reports measurement reports that include measurements for more than one access node. In such a situation, the access node provides the measurements for the other access nodes to the other access nodes, in addition to its signal measurement information. The access node shares communications beam schedule information with other access nodes (block709). The access node shares a schedule of how its communications beams are used to other access nodes. The access node maintains the signal measurement information (block711). The access node updates the signal measurement information based on the signal measurement information and/or the communications beam scheduling information received from other access nodes. The access node signals the signal measurement information and/or the communications beam scheduling information to the UEs that it serves (block713). The access node receives an uplink transmission from a UE (block715). The access node receives an uplink transmission from one of its served UEs.

FIG. 8illustrates a flow diagram of example operations800occurring in a UE. Operations800may be indicative of operations occurring in a UE as the UE uses signal measurement information and/or communications beam scheduling information to determine an access strategy and uses the access strategy to transmit a transmission to an access node serving the UE.

Operations800being with the UE receiving signal measurement information and/or communications beam scheduling information from the access node serving the UE (block805). The UE uses the signal measurement information and/or the communications beam scheduling information to determine an access strategy (block807). In addition to the access strategy, the UE determines associated access parameters of the access strategy. The UE uses the access strategy to transmit a transmission to the access node (block809).

FIG. 9illustrates an example communication system900. In general, the system900enables multiple wireless or wired users to transmit and receive data and other content. The system900may implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), or non-orthogonal multiple access (NOMA).

In this example, the communication system900includes electronic devices (ED)910a-910c, radio access networks (RANs)920a-920b, a core network930, a public switched telephone network (PSTN)940, the Internet950, and other networks960. While certain numbers of these components or elements are shown inFIG. 9, any number of these components or elements may be included in the system900.

The EDs910a-910care configured to operate and/or communicate in the system900. For example, the EDs910a-910care configured to transmit and/or receive via wireless or wired communication channels. Each ED910a-910crepresents any suitable end user device and may include such devices (or may be referred to) as a user equipment/device (UE), wireless transmit/receive unit (WTRU), mobile station, fixed or mobile subscriber unit, cellular telephone, personal digital assistant (PDA), smartphone, laptop, computer, touchpad, wireless sensor, or consumer electronics device.

The RANs920a-920bhere include base stations970a-970b, respectively. Each base station970a-970bis configured to wirelessly interface with one or more of the EDs910a-910cto enable access to the core network930, the PSTN940, the Internet950, and/or the other networks960. For example, the base stations970a-970bmay include (or be) one or more of several well-known devices, such as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNodeB), a Home NodeB, a Home eNodeB, a site controller, an access point (AP), or a wireless router. The EDs910a-910care configured to interface and communicate with the Internet950and may access the core network930, the PSTN940, and/or the other networks960.

In the embodiment shown inFIG. 9, the base station970aforms part of the RAN920a, which may include other base stations, elements, and/or devices. Also, the base station970bforms part of the RAN920b, which may include other base stations, elements, and/or devices. Each base station970a-970boperates to transmit and/or receive wireless signals within a particular geographic region or area, sometimes referred to as a “cell.” In some embodiments, multiple-input multiple-output (MIMO) technology may be employed having multiple transceivers for each cell.

The base stations970a-970bcommunicate with one or more of the EDs910a-910cover one or more air interfaces990using wireless communication links. The air interfaces990may utilize any suitable radio access technology.

It is contemplated that the system900may use multiple channel access functionality, including such schemes as described above. In particular embodiments, the base stations and EDs implement LTE, LTE-A, and/or LTE-B. Of course, other multiple access schemes and wireless protocols may be utilized.

The RANs920a-920bare in communication with the core network930to provide the EDs910a-910cwith voice, data, application, Voice over Internet Protocol (VoIP), or other services. Understandably, the RANs920a-920band/or the core network930may be in direct or indirect communication with one or more other RANs (not shown). The core network930may also serve as a gateway access for other networks (such as the PSTN940, the Internet950, and the other networks960). In addition, some or all of the EDs910a-910cmay include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and/or protocols. Instead of wireless communication (or in addition thereto), the EDs may communicate via wired communication channels to a service provider or switch (not shown), and to the Internet950.

AlthoughFIG. 9illustrates one example of a communication system, various changes may be made toFIG. 9. For example, the communication system900could include any number of EDs, base stations, networks, or other components in any suitable configuration.

FIGS. 10A and 10Billustrate example devices that may implement the methods and teachings according to this disclosure. In particular,FIG. 10Aillustrates an example ED1010, andFIG. 10Billustrates an example base station1070. These components could be used in the system900or in any other suitable system.

As shown inFIG. 10A, the ED1010includes at least one processing unit1000. The processing unit1000implements various processing operations of the ED1010. For example, the processing unit1000could perform signal coding, data processing, power control, input/output processing, or any other functionality enabling the ED1010to operate in the system900. The processing unit1000also supports the methods and teachings described in more detail above. Each processing unit1000includes any suitable processing or computing device configured to perform one or more operations. Each processing unit1000could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

The ED1010also includes at least one transceiver1002. The transceiver1002is configured to modulate data or other content for transmission by at least one antenna or NIC (Network Interface Controller)1004. The transceiver1002is also configured to demodulate data or other content received by the at least one antenna1004. Each transceiver1002includes any suitable structure for generating signals for wireless or wired transmission and/or processing signals received wirelessly or by wire. Each antenna1004includes any suitable structure for transmitting and/or receiving wireless or wired signals. One or multiple transceivers1002could be used in the ED1010, and one or multiple antennas1004could be used in the ED1010. Although shown as a single functional unit, a transceiver1002could also be implemented using at least one transmitter and at least one separate receiver.

The ED1010further includes one or more input/output devices1006or interfaces (such as a wired interface to the Internet950). The input/output devices1006facilitate interaction with a user or other devices (network communications) in the network. Each input/output device1006includes any suitable structure for providing information to or receiving/providing information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.

In addition, the ED1010includes at least one memory1008. The memory1008stores instructions and data used, generated, or collected by the ED1010. For example, the memory1008could store software or firmware instructions executed by the processing unit(s)1000and data used to reduce or eliminate interference in incoming signals. Each memory1008includes any suitable volatile and/or non-volatile storage and retrieval device(s). Any suitable type of memory may be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, and the like.

As shown inFIG. 10B, the base station1070includes at least one processing unit1050, at least one transceiver1052, which includes functionality for a transmitter and a receiver, one or more antennas1056, at least one memory1058, and one or more input/output devices or interfaces1066. A scheduler, which would be understood by one skilled in the art, is coupled to the processing unit1050. The scheduler could be included within or operated separately from the base station1070. The processing unit1050implements various processing operations of the base station1070, such as signal coding, data processing, power control, input/output processing, or any other functionality. The processing unit1050can also support the methods and teachings described in more detail above. Each processing unit1050includes any suitable processing or computing device configured to perform one or more operations. Each processing unit1050could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

Each transceiver1052includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each transceiver1052further includes any suitable structure for processing signals received wirelessly or by wire from one or more EDs or other devices. Although shown combined as a transceiver1052, a transmitter and a receiver could be separate components. Each antenna1056includes any suitable structure for transmitting and/or receiving wireless or wired signals. While a common antenna1056is shown here as being coupled to the transceiver1052, one or more antennas1056could be coupled to the transceiver(s)1052, allowing separate antennas1056to be coupled to the transmitter and the receiver if equipped as separate components. Each memory1058includes any suitable volatile and/or non-volatile storage and retrieval device(s). Each input/output device1066facilitates interaction with a user or other devices (network communications) in the network. Each input/output device1066includes any suitable structure for providing information to or receiving/providing information from a user, including network interface communications.

FIG. 11is a block diagram of a computing system1100that may be used for implementing the devices and methods disclosed herein. For example, the computing system can be any entity of UE, access network (AN), mobility management (MM), session management (SM), user plane gateway (UPGW), and/or access stratum (AS). Specific devices may utilize all of the components shown or only a subset of the components, and levels of integration may vary from device to device. Furthermore, a device may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc. The computing system1100includes a processing unit1102. The processing unit includes a central processing unit (CPU)1114, memory1108, and may further include a mass storage device1404, a video adapter1110, and an I/O interface1112connected to a bus1120.

The bus1120may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, or a video bus. The CPU1114may comprise any type of electronic data processor. The memory1108may comprise any type of non-transitory system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or a combination thereof. In an embodiment, the memory1108may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs.

The mass storage1104may comprise any type of non-transitory storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via the bus1120. The mass storage1104may comprise, for example, one or more of a solid state drive, hard disk drive, a magnetic disk drive, or an optical disk drive.

The video adapter1110and the I/O interface1112provide interfaces to couple external input and output devices to the processing unit1102. As illustrated, examples of input and output devices include a display1118coupled to the video adapter1110and a mouse/keyboard/printer1116coupled to the I/O interface1112. Other devices may be coupled to the processing unit1102, and additional or fewer interface cards may be utilized. For example, a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide an interface for an external device.

The processing unit1102also includes one or more network interfaces1106, which may comprise wired links, such as an Ethernet cable, and/or wireless links to access nodes or different networks. The network interfaces1106allow the processing unit1102to communicate with remote units via the networks. For example, the network interfaces1106may provide wireless communication via one or more transmitters/transmit antennas and one or more receivers/receive antennas. In an embodiment, the processing unit1102is coupled to a local-area network1122or a wide-area network for data processing and communications with remote devices, such as other processing units, the Internet, or remote storage facilities.

It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a generating unit/module, a signaling unit/module, a deriving unit/module, a measuring unit/module, an updating unit/module, and/or a sharing unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).