Patent Description:
In some examples, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). In LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation or <NUM>th generation (<NUM>) network), a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with a number of central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., a new radio base station (NR BS), a new radio node-B (NR NB), a network node, <NUM> NB, eNB, etc.). A base station or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit).

NR generally refers to a set of enhancements to the LTE mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) as well as support beamforrning, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a desire for further improvements in NR technology. <CIT> discloses a communications system communicating data to/from a communications terminal including infrastructure equipment forming a mobile communications network to transmit/receive data to/from the communications terminal via a wireless access interface, the communications terminal configured to transmit/receive data to/from the infrastructure equipment. <CIT> relates to a method in a user equipment for handling a scheduling request, SR, wherein the user equipment is served by a base station in a cellular communications network. The user equipment receives a first message from the base station. The first message comprises a first assignment of SR resources. The first message is received using a first protocol. The first assignment of SR resources is semi-static. The user equipment further receives a second message from the base station. The second message comprising a second assignment of SR resources. The second message is received using a second protocol. The second protocol is associated with a layer that is lower than a layer associated with the first protocol. The user equipment then applies the SR resources according to the first assignment and the SR resources according to the second assignment at the same time or separately. <CIT> discloses a method implemented in a user equipment UE for use in a wireless system for single carrier frequency division multiple access SC-FDMA, the method including receiving an assignment of a scheduling request resource in the wireless system comprising a plurality of subcarriers. <CIT> being prior art under Art. <NUM> (<NUM>) discloses that an UE includes receiving circuitry configured to receive, from a base station apparatus, a radio resource control (RRC) message(s) comprising one or more scheduling request (SR) configurations, wherein each SR configuration is associated with one or more PUCCH resources and the SR configuration is corresponding to any one or more of the following: one or more logical channels (LCH), one or more logical channel groups (LCG), one or more priority, one or more numerology, one or more services, and/or one or more bandwidth part (BWP).

Certain aspects provide a method for wireless communications by a base station (BS). The method generally includes configuring at least one user equipment (UE) with multiple scheduling request (SR) resources, receiving an SR from the UE requesting an uplink grant for sending traffic, and inferring at least one parameter of the traffic based on which of the multiple SR resources the UE used to send the SR.

Certain aspects provide a method for wireless communications by a user equipment (UE). The method generally includes selecting a scheduling request (SR) resource, from multiple scheduling request (SR) resources configured for the UE, for requesting an uplink grant from a base station for sending traffic, wherein the selection is based on a parameter of the traffic and sending the SR using the selected SR resource.

Aspects of the present disclosure relate to methods and apparatus for multiplexing scheduling requests (SRs). As will be described in greater detail below, one or more UEs may each be allocated different resources for transmitting SRs. The choice of SR may, for example, indicate a priority of corresponding traffic. As a result, a base station receiving the SR may infer the priority (or some feature or attribute) of the traffic to be sent, from the resources used to send the SR. This may help the base station make scheduling decisions, for example, by considering the priority of traffic if multiple UEs request a grant at the same time.

NR may support various wireless communication services, such as Enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g. <NUM> beyond), millimeter wave (mmW) targeting high carrier frequency (e.g. <NUM>), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low latency communications (URLLC).

<FIG> illustrates an example wireless network <NUM>, such as a new radio (NR) or <NUM> network, in which aspects of the present disclosure may be performed.

As illustrated in <FIG>, the wireless network <NUM> may include a number of BSs <NUM> and other network entities. A BS may be a station that communicates with UEs. Each BS <NUM> may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to a coverage area of a Node B and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and eNB, Node B, <NUM> NB, AP, NR BS, NR BS, or TRP may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in the wireless network <NUM> through various types of backhaul interfaces such as a direct physical connection, a virtual network, or the like using any suitable transport network.

A network controller <NUM> may be coupled to a set of BSs and provide coordination and control for these BSs. The BSs <NUM> may also communicate with one another, e.g., directly or indirectly via wireless or wireline backhaul.

A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered evolved or machine-type communication (MTC) devices or evolved MTC (eMTC) devices. Some UEs may be considered Internet-of-Things (IoT) devices.

For example, the spacing of the subcarriers may be <NUM> and the minimum resource allocation (called a 'resource block') may be <NUM> subcarriers (or <NUM>). Consequently, the nominal FFT size may be equal to <NUM>, <NUM>, <NUM>, <NUM> or <NUM> for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM> megahertz (MHz), respectively. For example, a subband may cover <NUM> (i.e., <NUM> resource blocks), and there may be <NUM>, <NUM>, <NUM>, <NUM> or <NUM> subbands for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, respectively.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using time division duplex (TDD). A single component carrier bandwidth of <NUM> may be supported. NR resource blocks may span <NUM> sub-carriers with a sub-carrier bandwidth of <NUM> over a <NUM> duration. Each radio frame may consist of <NUM> subframes with a length of <NUM>. Consequently, each subframe may have a length of <NUM>. Each subframe may indicate a link direction (i.e., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. UL and DL subframes for NR may be as described in more detail below with respect to <FIG>. Alternatively, NR may support a different air interface, other than an OFDM-based. NR networks may include entities such CUs and/or DUs.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., eNB, <NUM> Node B, Node B, transmission reception point (TRP), access point (AP)) may correspond to one or multiple BSs. NR cells can be configured as access cell (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover. In some cases DCells may not transmit synchronization signals-in some case cases DCells may transmit SS. NR BSs may transmit downlink signals to UEs indicating the cell type. Based on the cell type indication, the UE may communicate with the NR BS. For example, the UE may determine NR BSs to consider for cell selection, access, handover, and/or measurement based on the indicated cell type.

<FIG> illustrates example components of the BS <NUM> and UE <NUM> illustrated in <FIG>, which may be used to implement aspects of the present disclosure. As described above, the BS may include a TRP. One or more components of the BS <NUM> and UE <NUM> may be used to practice aspects of the present disclosure. For example, antennas <NUM>, Tx/Rx <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the operations described herein and illustrated with reference to FIGs. <NUM>-<NUM>.

At the base station <NUM>, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. The control information may be for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), etc. The data may be for the Physical Downlink Shared Channel (PDSCH), etc. The processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor <NUM> may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. For example, the TX MIMO processor <NUM> may perform certain aspects described herein for RS multiplexing.

For example, MIMO detector <NUM> may provide detected RS transmitted using techniques described herein. According to one or more cases, CoMP aspects can include providing the antennas, as well as some Tx/Rx functionalities, such that they reside in distributed units. For example, some Tx/Rx processings can be done in the central unit, while other processing can be done at the distributed units. For example, in accordance with one or more aspects as shown in the diagram, the BS mod/demod <NUM> may be in the distributed units.

The processor <NUM> and/or other processors and modules at the base station <NUM> may perform or direct, e.g., the execution of the functional blocks illustrated in FIGs. <NUM>-<NUM>, and/or other processes for the techniques described herein. The processor <NUM> and/or other processors and modules at the UE <NUM> may also perform or direct processes for the techniques described herein. The memories <NUM> and <NUM> may store data and program codes for the BS <NUM> and the UE <NUM>, respectively.

The DL-centric subframe may also include a common UL portion <NUM>. The common UL portion <NUM> may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms. The common UL portion <NUM> may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion <NUM> may include feedback information corresponding to the control portion <NUM>. Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The common UL portion <NUM> may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. As illustrated in <FIG>, the end of the DL data portion <NUM> may be separated in time from the beginning of the common UL portion <NUM>. One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

<FIG> is a diagram <NUM> showing an example of an UL-centric subframe. The UL -centric subframe may include a control portion <NUM>. The control portion <NUM> may exist in the initial or beginning portion of the UL-centric subframe. The control portion <NUM> in <FIG> may be similar to the control portion described above with reference to <FIG>. The UL-centric subframe may also include an UL data portion <NUM>. The UL data portion <NUM> may sometimes be referred to as the payload of the UL-centric subframe. The UL data portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS). In some configurations, the control portion <NUM> may be a physical DL control channel (PDCCH).

As illustrated in <FIG>, the end of the control portion <NUM> may be separated in time from the beginning of the UL data portion <NUM>. The UL-centric subframe may also include a common UL portion <NUM>. The common UL portion <NUM> in <FIG> may be similar to the common UL portion <NUM> described above with reference to <FIG>. The common UL portion <NUM> may additionally or alternatively include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilots using a dedicated set of resources (e.g., radio resource control (RRC) dedicated state, etc.) or a configuration associated with transmitting pilots using a common set of resources (e.g., an RRC common state, etc.).

As noted above, aspects of the present disclosure may allow a base station to determine attributes or features of traffic a UE has to send, based on resources that UE uses to send a scheduling request for a grant to send that traffic.

In certain systems, there may be constraints placed on which particular resources are allocated to a UE for sending scheduling requests (SRs). In LTE, for example, each UE is provided a single SR resource for requesting an UL grant. If eNB receives the SR, it allocates a UL grant for the UE. At this point, however, the eNB is not sure what priority class the traffic belongs to. In other words, the eNB may learn of the priority only after the UE transmits an indication of BSR and logical channel (Priority class) in a Medium Access Control (MAC) Control Element (CE). At that point, the eNB then schedules traffic based on the priority.

Unfortunately, in this scenario, the eNB has to wait for MAC CE before scheduling traffic. Thus, no special privilege is given to the SR resource based on traffic class.

Aspects of the present disclosure, however, provide techniques for multiplexing of SR that may take into account different UE traffic classes and corresponding objectives, such as reliability and latency requirements. As will be described in greater detail below, a UE may be configured with multiple SR resource configurations. A UE may select a configuration based on the type of the traffic for which a grant is requested by the SR. Each configuration, for example, may specify a set of time/frequency resources (for sending an SR request), as well as a periodicity. For example, a periodicity may indicate how often an SR request is sent (e.g., once a slot, twice a slot, etc as in accordance with the claims).

As used herein, the term slot (or time slot) generally refers to a transmission time interval (TTI) that may be less than a subframe. For example, there may be two. <NUM> slots in a <NUM> subframe.

<FIG> illustrates example operations <NUM> for multiplexing SR by a base station (BS), such as BS <NUM> shown in <FIG>, in accordance with aspects of the present disclosure.

Operations <NUM> begin, at <NUM>, by configuring at least one user equipment (UE) with multiple scheduling request (SR) resources. At <NUM>, the BS receives an SR from the UE requesting an uplink grant for sending traffic. At <NUM>, the BS infers at least one parameter of the traffic based on which of the multiple SR resources the UE used to send the SR.

<FIG> illustrates example operations <NUM> for wireless communications by a user equipment (UE), such as UE <NUM> shown in <FIG>, in accordance with aspects of the present disclosure. For example, a UE may perform operations <NUM> to send an SR to a BS performing operations <NUM>.

Operations <NUM> begin, at <NUM>, by selecting a scheduling request (SR) resource, from multiple scheduling request (SR) resources configured for the UE, for requesting an uplink grant from a base station for sending traffic, wherein the selection is based on a parameter of the traffic. At <NUM>, the UE sends the SR using the selected SR resource.

As noted above, a base station (eNB) may configure multiple SR resources or resource sets per UE. Each SR resource may be configured with its own periodicity, time and frequency resource, and sequence. The SR resource choice (by the UE) might be a function of latency/reliability requirement.

In some cases, the eNB may configure rules for the UE to identify the SR resource to use (for sending SR). For example, one rule may for identifying the SR resource to use may be a function of priority class of traffic, latency requirement, signal to noise ratio (SNR), and the like.

SR resources may be dedicated or shared. For example, at least one of the SR resources may be dedicated to a UE, while one or more SR resources may be shared by other UEs. The sharing may be based on time, frequency, and/or sequence resources. In some cases, exactly how many SR resources are dedicated and how many SR resources are shared may depend on how crowded a network is. For example, if there are relatively few UEs, there may be little need for shared resources.

In cases, in accordance with the claims, where a UE sends an SR using an SR resource shared by multiple UEs, a compressed UE identity is added to the SR payload to uniquely identify the UE. In some cases, the compressed UE identity (carried in the SR payload) can be explicitly configured by eNB. In other cases, the compressed UE identity may be implicitly obtained, for example, as a hashing function of some unique UE identity (know to the eNB), such as a C-RNTI, GUTI, IMSI, or TMSI. In some cases, orthogonal cover codes may be used to identify UEs sending an SR.

In a simple example scenario when an eNB configures two SRS resources, one dedicated and one shared, an SR sent using the dedicated resource has no UE identity and hence higher coverage. In the shared SR resource, the UE has to indicate a (compressed) UE ID and might have lower reliability and/or coverage.

To further illustrate possible utility of the techniques described herein, if a UE has a high priority traffic to be sent, the UE may use a dedicated resource to send SR. In that case, the UE identifies that the UE traffic corresponds to high priority/low latency traffic and may immediately schedule an UL grant with sufficient resources. The UE may then transmit its data in the UL grant.

On the other hand, if the UE has low priority traffic to send, it may use the shared SR resource. In this case, the UE provides an indication of its (compressed) UE identity and this SR might have lower reliability/coverage. The eNB identifies the UE from the compressed UE identity and allocates an UL grant to the UE.

One benefit of sharing SR resources is that SR periodicity may still be kept relatively high (for shared SR resources). In contrast, SR periodicity for dedicated SR resource may be relatively low, resulting in reduction in latency. The actual periodicities of each, of course, come at a tradeoff between latency and coverage loss.

In some cases, SR configurations may be such that, with the same slot (or other TTI), multiple SR opportunities (time/frequency resources) may overlap (or collide"). In this case, the UE may need to decide which to use, for example, if it has two or more types of traffic to send. In some case, the UE may be configured (or allowed) to only send SR on one of the (overlapping) sets of resources. In some cases, the UE may decide to send an SR for only the traffic with a highest priority.

In some cases, in addition to overlapping SR resources within a same slot, one or more SR opportunities may overlap with a physical uplink control channel (PUCCH) used to send uplink control information (UCI) other than as SR, such as acknowledgment information or channel quality feedback. In such cases, if a PUCCH (with non-SR UCI) overlaps with resources for an SR, a UE may be configured to send only the PUCCH and not send the SR.

In some cases, the UE may still convey different types of SR information even in the event of an overlap with PUCCH. For example, a UE may include (e.g., append) bits to the PUCCH payload to effectively indicate different SR resource selections. In some cases, a bit may be included for each SR configuration, allowing every possible combination of SR resource configuration to be selected. In other cases, fewer bits may be included to indicate less than all possible combinations. For example, if a UE is restricted to indicating only one SR resource selection, one of up to four "active" SR resource sets may be indicated with only two bits (e.g., with '<NUM>' indicating SR resource <NUM>, '<NUM>' indicating SR resource <NUM>, etc.).

Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more.

For example, means for transmitting and/or means for receiving may comprise one or more of a transmit processor <NUM>, a TX MIMO processor <NUM>, a receive processor <NUM>, or antenna(s) <NUM> of the base station <NUM> and/or the transmit processor <NUM>, a TX MIMO processor <NUM>, a receive processor <NUM>, or antenna(s) <NUM> of the user equipment <NUM>. Additionally, means for generating, means for multiplexing, and/or means for applying may comprise one or more processors, such as the controller/processor <NUM> of the base station <NUM> and/or the controller/processor <NUM> of the user equipment <NUM>.

Claim 1:
A method (<NUM>) for wireless communications by a base station (<NUM>), comprising:
configuring (<NUM>) at least one user equipment, UE, (<NUM>) with multiple scheduling request, SR, resources configurations associated with different periodicities for the at least one UE to send an SR, wherein each periodicity of the different periodicities indicates how often an SR is sent within a time slot;
receiving (<NUM>) an SR from the at least one UE requesting an uplink grant for sending traffic; and
inferring (<NUM>) at least one parameter of the traffic based on which of the multiple SR resources configurations the at least one UE used to send the SR;
wherein the SR is sent using an SR resource shared by multiple DEs; and
wherein a payload of the SR carries a compressed identity, ID, of the at least one UE.