Method and apparatus for SRS antenna switching in carrier aggregation

Abstract

Certain aspects of the present disclosure relate to communication systems, and more particularly, to improving the performance of sounding reference signal (SRS) antenna switching in carrier aggregation (CA). A method for wireless communication, executable by a user equipment (UE), is provided. The method includes determining one or more frequency band combinations for shared antenna switching and sending a list of one or more frequency bands in the one or more frequency band combinations to a base station (BS). The BS receives the list and schedules the UE based on the received list.

Description

[0001] This application is a divisional application of a patent application with an international application date of August 9, 2018, an international application number of PCT / US2018 / 046097, a Chinese national application date of August 9, 2018, an application number of 201880050988.9, and an invention name of “Method and apparatus for SRS antenna switching in carrier aggregation”.

[0002] Cross-references to related applications and priority claims

[0003] This application claims priority to U.S. Application No. 16 / 058,879, filed on August 8, 2018, which claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 62 / 544,648, filed on August 11, 2017, the entire contents of both applications being incorporated herein by reference in their entirety for all applicable purposes.

[0004] public domain

[0005] Aspects of the present disclosure relate to communication systems, and more particularly, to methods and apparatus for improving the performance of sounding reference signal (SRS) antenna switching in carrier aggregation (CA).

[0006] Related technical description

[0007] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name a few.

[0008] In some examples, a wireless multiple access communication system may include several base stations (BSs), each of which is capable of simultaneously supporting communication for multiple communication devices (also referred to as user equipment (UE)). In an LTE or LTE-A network, a set of one or more base stations may define an evolved Node B (eNB). In other examples (e.g., in a next generation, new radio (NR), or 5G network), a wireless multiple access communication system may include several 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 several central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more DUs in communication with a CU may define an access node (e.g., which may be referred to as an NR BS, 5G NB, next generation NB (gNB), transmission reception point (TRP), etc.). A BS or DU may communicate with a set of UEs on downlink channels (eg, for transmissions from the BS to the UEs) and uplink channels (eg, for transmissions from the UEs to the BS or DU).

[0009] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at the city, national, regional, and even global levels. NR is an example of an emerging telecommunications standard. NR is an enhancement to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefixes (CPs) on the downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0010] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should also apply to other multiple access technologies and the telecommunication standards that employ them.

[0011] Brief Overview

[0012] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages, including improved communication between access points and stations in a wireless network.

[0013] Certain aspects provide a method for wireless communication by a user equipment (UE). The method generally includes determining one or more frequency band combinations for shared antenna switching. The UE sends a list of one or more frequency bands in the one or more frequency band combinations to a base station (BS).

[0014] Certain aspects provide a method for wireless communication by a base station. The method generally includes receiving a list of one or more frequency bands of one or more frequency band combinations for shared antenna switching from a UE. The base station schedules the UE based on the received list.

[0015] Certain aspects provide an apparatus for wireless communication, such as a UE. The apparatus generally includes means for determining one or more frequency band combinations for shared antenna switching. The apparatus also includes means for sending a list of one or more frequency bands in the one or more frequency band combinations to a base station.

[0016] Certain aspects provide an apparatus, such as a base station, for wireless communication. The apparatus generally includes means for receiving, from a UE, a list of one or more frequency bands of one or more frequency band combinations for shared antenna switching. The apparatus also includes means for scheduling the UE based on the received list.

[0017] Certain aspects provide an apparatus for wireless communication, such as a user equipment (UE). The apparatus generally includes at least one processor coupled to a memory and configured to determine one or more frequency band combinations for shared antenna switching. The apparatus also includes a transmitter configured to transmit a list of one or more frequency bands in the one or more frequency band combinations to a base station.

[0018] Certain aspects provide an apparatus for wireless communication, such as a base station. The apparatus generally includes a receiver configured to receive, from a UE, a list of one or more frequency bands of one or more frequency band combinations for shared antenna switching. The apparatus includes at least one processor coupled to a memory and configured to schedule the UE based on the received list.

[0019] Certain aspects provide a computer-readable medium having computer-executable code stored thereon for wireless communication. The computer-readable medium generally includes code for determining one or more frequency band combinations for shared antenna switching. The computer-readable medium also includes code for transmitting a list of one or more frequency bands in the one or more frequency band combinations to a base station.

[0020] Certain aspects provide a computer-readable medium having computer-executable code stored thereon for wireless communication. The computer-readable medium generally includes code for receiving, from a UE, a list of one or more frequency bands of one or more frequency band combinations for shared antenna switching. The computer-readable medium also includes code for scheduling the UE based on the received list.

[0021] Aspects generally include methods, apparatus, systems, computer-readable media, and processing systems substantially as described herein with reference to and as illustrated by the accompanying figures.

[0022] To accomplish the foregoing and related ends, one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are indicative of but a few of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order that the manner in which the above-recited features of the present disclosure may be understood in detail, a more particular description of the content briefly summarized above may be obtained by reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain typical aspects of the disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0024] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0025] Figure 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN) in accordance with certain aspects of the present disclosure.

[0026] Figure 3 is a diagram illustrating an example physical architecture of a distributed RAN in accordance with certain aspects of the present disclosure.

[0027] Figure 4 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0028] Figure 5 is a diagram illustrating an example for implementing a communication protocol stack in accordance with certain aspects of the present disclosure.

[0029] Figure 6 Illustrated are examples of frame formats for New Radio (NR) systems, in accordance with certain aspects of the present disclosure.

[0030] Figure 7 Example contiguous carrier aggregation (CA) types are illustrated in accordance with aspects of the present disclosure.

[0031] Figure 8 Example non-contiguous CA types are illustrated in accordance with aspects of the present disclosure.

[0032] Figure 9 is a block diagram illustrating an example UE architecture with shared components for some frequency bands, in accordance with certain aspects of the present disclosure.

[0033] Figure 10 Illustrated are example sounding reference signal (SRS) antenna switching in a subframe in accordance with certain aspects of the present disclosure.

[0034] Figure 11 Illustrated are example operations for wireless communications performed by a UE, in accordance with certain aspects of the present disclosure.

[0035] Figure 12

[0014] Example operations for wireless communications performed by a BS are illustrated in accordance with certain aspects of the present disclosure.

[0036] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation. Detailed description

[0037] Various aspects of the present disclosure provide methods and apparatus for improving the performance of sounding reference signal (SRS) antenna switching in carrier aggregation (CA). SRS antenna switching can be used for a time division duplex (TDD) component carrier (CC) (e.g., a frequency band), and a shared switch or shared filter on the transmit side or the receive side or both may affect communications on another CC (e.g., a CC configured for frequency division duplex (FDD) or 5G communications) that is configured for CA together with the TDD CC and shares antenna switching with the TDD CC. According to certain aspects, a user equipment (UE) can determine the frequency bands that may be affected by SRS antenna switching and send a list of the affected frequency bands to a base station (BS). The BS can use the list of affected frequency bands to determine scheduling for the UE, for example, to avoid or mitigate the impact of antenna switching on those frequency bands. For example, the BS may schedule SRS switching only in special subframes, suppress scheduling SRS switching in affected subframe / band combinations, schedule SRS switching to be aperiodic or to schedule SRS switching with reduced periodicity, avoid scheduling transmissions in affected subframes, schedule shorter TTIs in those subframes, and / or schedule specific modulation schemes or data modes for those subframes.

[0038] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements discussed without departing from the scope of this disclosure. Various examples may appropriately omit, replace, or add various procedures or components. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, the features described with reference to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice a method. In addition, the scope of this disclosure is intended to cover such devices or methods practiced using other structures, functionalities, or structures and functionalities that are supplementary to or in addition to the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be implemented by one or more elements of the claims. The word "exemplary" is used herein to mean used as "an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as being superior to or superior to other aspects.

[0039] The techniques described herein can be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. A TDMA network can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and the like. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS).

[0040] NR is an emerging wireless communication technology being developed in collaboration with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and Advanced LTE (LTE-A) are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, although various aspects may be described herein using terms commonly associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations, such as 5G and later generations, including NR technology.

[0041] NR can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or more), millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or more), massive machine type communication (MTC) targeting non-backward compatible MTC technology, and / or mission-critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet the corresponding quality.

[0042] Example Wireless Communication System

[0043] Figure 1 An example wireless network 100, such as a New Radio (NR) or 5G network, is illustrated in which aspects of the present disclosure may be implemented, for example, to improve the performance of sounding reference signal (SRS) antenna switching in carrier aggregation (CA), as described in more detail below.

[0044] A user equipment (UE) 120 may be configured for CA and SRS antenna switching of a time division duplex (TDD) component carrier (CC) (e.g., frequency band). Antenna switching may affect communications on another CC that is configured for CA along with the TDD CC and shares an antenna with the TDD CC (e.g., configured for frequency division duplex (FDD) or 5G communications). According to certain aspects, the UE 120 may determine frequency bands that are affected (e.g., potentially affected) by SRS antenna switching (e.g., frequency bands that share antenna switching) and send a list of affected frequency bands to the base station (BS) 110. The BS 110 may use the list of affected frequency bands to determine scheduling for the UE 120, for example, to avoid or mitigate the impact of antenna switching on those frequency bands.

[0045] like Figure 1 As illustrated in , the wireless communication network 100 may include several BSs 110 and other network entities. A BS may be a station that communicates with a UE. Each BS 110 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to the coverage area of a Node B (NB) and / or the NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and NR BS, next-generation NB (gNB), transmission reception point (TRP), etc. may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of a cell may move depending on the location of a mobile BS. In some examples, the BSs may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 via various types of backhaul interfaces (such as direct physical connections, wireless connections, virtual networks, or the like using any suitable transport network).

[0046] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, tone, subband, frequency channel, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

[0047] A BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residence, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1In the example shown in FIG, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more (e.g., three) cells.

[0048] The wireless communication network 100 may also include a relay station. A relay station is a station that receives transmissions of data and / or other information from an upstream station (e.g., a BS or a UE) and sends transmissions of the data and / or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions for other UEs. Figure 1 In the example shown in , relay station 110r may communicate with BS 110a and UE 120r to facilitate communication between BS 110a and UE 120r. A relay station may also be referred to as a relay BS, relay, etc.

[0049] The wireless communication network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relays, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless communication network 100. For example, a macro BS may have a high transmit power level (e.g., 20 watts), while a pico BS, a femto BS, and a relay may have a lower transmit power level (e.g., 1 watt).

[0050] The wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, each BS may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, each BS may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0051] A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other, directly or indirectly, for example, via a wireless or wired backhaul.

[0052] UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved / enhanced MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to or to a network (e.g., a wide area network such as the Internet or a cellular network) via, for example, a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0053] Some wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, often referred to as tones, bins, etc. Each subcarrier can be modulated with data. Generally speaking, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the subcarrier spacing can be 15 kHz, and the minimum resource allocation (called a resource block (RB)) can be 12 subcarriers (or 180 kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may be further divided into subbands. For example, a subband may cover 1.08 MHz (ie, 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0054] Although aspects of the examples described herein may be associated with LTE technology, aspects of the present disclosure may be applicable to other wireless communication systems, such as NR. NR may utilize OFDM with CP on both the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and the beam direction may be dynamically configured. MIMO transmission with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas (with multi-layer DL transmission of up to 8 streams) and up to 2 streams per UE. Multi-layer transmission of up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported using up to 8 serving cells.

[0055] In some examples, access to the air interface may be scheduled. For example, a scheduling entity (e.g., a base station) allocates resources for communication between some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. In some examples, for scheduled communications, the subordinate entity utilizes the resources allocated by the scheduling entity. The BS is not the only entity that can act as a scheduling entity. For example, a UE may act as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs use the resources scheduled by the UE for wireless communication. The UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, the UEs may communicate directly with each other in addition to communicating with the scheduling entity. Thus, in a wireless communication network having scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, the scheduling entity and one or more subordinate entities may communicate using the scheduled resources.

[0056] exist Figure 1 In FIG, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and / or uplink. A dashed line with double arrows indicates interfering transmissions between the UE and the BS.

[0057] Figure 2 Illustrated is an example logical architecture 200 of a distributed radio access network (RAN) that can be Figure 1 2. 5G access node 206 may include access node controller (ANC) 202. ANC 202 may be a CU of a distributed RAN. A backhaul interface to a next-generation core network (NG-CN) 204 may terminate at ANC 202. A backhaul interface to a neighboring next-generation access node (NG-AN) 210 may terminate at ANC 202. ANC 202 may include one or more TRPs 208 (e.g., cells, BSs, gNBs, etc.).

[0058] TRP 208 may be a DU. TRP 208 may be connected to a single ANC (e.g., ANC 202) or to more than one ANC (not illustrated). For example, for RAN sharing, Radio as a Service (RaaS), and service-specific ANC deployments, TRP 208 may be connected to more than one ANC. A TRP may include one or more antenna ports. TRP 208 may be configured to serve traffic to a UE individually (e.g., dynamically selected) or jointly (e.g., jointly transmitted).

[0059] The logical architecture 200 can support fronthaul solutions across different deployment types. For example, the logical architecture 200 can be based on transport network capabilities (eg, bandwidth, latency, and / or jitter).

[0060] The logical architecture 200 may share features and / or components with LTE. For example, the NG-AN 210 may support dual connectivity with NR and may share a common fronthaul for LTE and NR.

[0061] The logical architecture 200 may enable collaboration between and among TRPs 208. For example, collaboration may be provisioned within a TRP and / or across TRPs via the ANC 202. There may be no inter-TRP interface.

[0062] Logical functions can be dynamically distributed in the logic architecture 200. Figure 5 Described in more detail, the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the medium access control (MAC) layer, and the physical (PHY) layer can be adaptively placed at the DU (e.g., TRP 208) or the CU (e.g., ANC 202).

[0063] Figure 3 An example physical architecture 300 of a distributed RAN according to aspects of the present disclosure is illustrated. A centralized core network unit (C-CU) 302 can host core network functions. The C-CU 302 can be centrally deployed. C-CU functionality can be offloaded (e.g., to Advanced Wireless Services (AWS)) to handle peak capacity.

[0064] The centralized RAN unit (C-RU) 304 can host one or more ANC functions. In some examples, the C-RU 304 can host core network functions locally. The C-RU 304 can have a distributed deployment. The C-RU 304 can be close to the network edge.

[0065] The DU 306 may host one or more TRPs (edge nodes (EN), edge units (EU), radio heads (RH), smart radio heads (SRH), etc.) The DU may be located at the edge of the network with radio frequency (RF) functionality.

[0066] Figure 4 Explanation Figure 1 The example components of the BS 110 and UE 120 illustrated in FIG. 1 may be used to implement aspects of the present disclosure, such as described herein and with reference to Figure 11 and Figure 12 The operation described.

[0067] At BS 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller / processor 440. The control information may be used for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), or the like. Data may be used for a physical downlink shared channel (PDSCH), or the like. The transmit processor 420 may process (e.g., encode and symbol-map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 420 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). A transmit (Tx) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, and / or reference symbols, as applicable, and may provide output symbol streams to modulators (MODs) 432a through 432t. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 432 may further process (e.g., convert to analog, amplify, filter, and frequency upconvert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 432a through 432t may be transmitted via antennas 434a through 434t, respectively.

[0068] At UE 120, antennas 452a through 452r may receive downlink signals from BS 110 and may provide received signals to demodulators (DEMODs) 454a through 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 454 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all demodulators 454a through 454r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120 to a data sink 460, and provide decoded control information to a controller / processor 480.

[0069] On the uplink, at UE 120, a transmit processor 464 may receive and process data from a data source 462 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 480 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 464 may also generate reference symbols for a reference signal (RS). The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466, where applicable, further processed by modulators 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to BS 110. At BS 110, uplink signals from UE 120 may be received by antenna 434, processed by demodulator 432, detected by MIMO detector 436, where applicable, and further processed by receive processor 438 to obtain decoded data and control information sent by UE 120. Receive processor 438 may provide decoded data to data sink 439 and decoded control information to controller / processor 440 .

[0070] Controllers / processors 440 and 480 may direct the operation at base station 110 and UE 120, respectively. Processor 440 and / or other processors and modules at BS 110 may perform or direct, for example, Figure 12 The processor 480 and / or other processors and modules at the UE 120 may also execute or direct the execution of the functional blocks illustrated in the and / or other processes for the techniques described herein. Figure 11 , and / or execution of the functional blocks illustrated in FIG, and / or other processes for the techniques described herein. Memories 442 and 482 may store data and program codes for BS 110 and UE 120, respectively. Scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0071] Figure 5 Illustrated is a diagram 500 showing an example for implementing a communication protocol stack according to various aspects of the present disclosure. The illustrated communication protocol stack can be implemented by a device operating in a wireless communication system (e.g., wireless communication network 100) (such as an NR system). Diagram 500 illustrates a communication protocol stack including an RRC layer 510, a PDCP layer 515, an RLC layer 520, a MAC layer 525, and a PHY layer 530. In various examples, these layers of the protocol stack can be implemented as separate software modules, parts of a processor or ASIC, parts of non-co-located devices connected by a communication link, or various combinations thereof. Co-located and non-co-located implementations can be used, for example, in a protocol stack for a network access device (e.g., AN, CU, and / or DU) or a UE.

[0072] The first option 505-a shows a split implementation of the protocol stack, where the implementation of the protocol stack is performed on a centralized network access device (e.g., Figure 2 ANC 202 in the ) and distributed network access equipment (e.g., Figure 2 In the first option 505-a, the RRC layer 510 and the PDCP layer 515 may be implemented by a central unit, while the RLC layer 520, the MAC layer 525, and the PHY layer 530 may be implemented by the DU. In various examples, the CU and the DU may be co-located or non-co-located. The first option 505-a may be useful in macrocell, microcell, or picocell deployments.

[0073] The second option 505-b illustrates a unified implementation of the protocol stack, wherein the protocol stack is implemented in a single network access device. In the second option, the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530 can each be implemented by an AN. The second option 505-b can be useful, for example, in a femtocell deployment.

[0074] Regardless of whether the network access device implements part or all of the protocol stack, the UE can implement the entire protocol stack (e.g., RRC layer 510, PDCP layer 515, RLC layer 520, MAC layer 525, and PHY layer 530) as shown in 505-c.

[0075] In LTE, the basic transmission time interval (TTI) or packet duration is a 1ms subframe. In NR, a subframe is still 1ms, but the basic TTI is called a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, ... slots), depending on the subcarrier spacing. An NR RB is 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15 kHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, such as 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

[0076] Figure 6is a diagram illustrating an example of a frame format 600 for NR. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms. Each subframe may include a variable number of slots, depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the subcarrier spacing. The symbol periods in each slot may be assigned an index. A minislot is a subslot structure (e.g., 2, 3, or 4 symbols).

[0077] Each symbol in a slot may indicate the link direction (e.g., DL, UL, or flexible) used for data transmission, and the link direction used for each subframe may be dynamically switched. The link direction may be based on the slot format. Each slot may include DL / UL data and DL / UL control information.

[0078] In NR, a synchronization signal (SS) block is transmitted. The SS block includes PSS, SSS, and two-symbol PBCH. The SS block can be in a fixed time slot position (such as Figure 6 ) is transmitted in the codewords 0-3 shown in . PSS and SSS can be used by UE for cell search and acquisition. PSS can provide half-frame timing, and SS can provide CP length and frame timing. PSS and SSS can provide cell identity. PBCH carries some basic system information (SI), such as downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, system frame number, etc. SS blocks can be organized into SS bursts to support beam sweeping. Further system information (such as remaining minimum system information (RMSI), system information block (SIB), other system information (OSI)) can be transmitted on PDSCH in certain subframes.

[0079] In some cases, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh networks, and / or various other suitable applications. Generally speaking, a sidelink signal may refer to a signal that is communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even though the scheduling entity may be used for scheduling and / or control purposes. In some examples, the sidelink signal may be communicated using licensed spectrum (unlike wireless local area networks, which typically use unlicensed spectrum).

[0080] A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilot signals using a dedicated set of resources (e.g., a radio resource control (RRC) dedicated state, etc.) or a configuration associated with transmitting pilot signals using a shared set of resources (e.g., an RRC shared state, etc.). When operating in the RRC dedicated state, the UE may select a dedicated set of resources for transmitting pilot signals to the network. When operating in the RRC shared state, the UE may select a shared set of resources for transmitting pilot signals to the network. In either case, the pilot signals transmitted by the UE may be received by one or more network access devices (such as an AN, a DU, or portions thereof). Each receiving network access device may be configured to receive and measure pilot signals transmitted on the shared set of resources, and also receive and measure pilot signals transmitted on the dedicated set of resources allocated to the UE, where the network access device is a member of a monitoring set of network access devices for the UE. One or more receiving network access devices, or a CU to which the receiving network access devices transmit pilot signal measurements, may use these measurements to identify the UE's serving cell or initiate a change of the serving cell for one or more UEs.

[0081] Example Carrier Aggregation

[0082] Carrier aggregation (CA) is used in some systems (eg, LTE-Advanced) to increase bandwidth, and therefore bit rate. CA can be used for both FDD and TDD. Figure 8 and 9 An example of FDD CA is illustrated. Each aggregated carrier is referred to as a component carrier (CC).

[0083] In some systems (e.g., LTE-Advanced), a UE can use spectrum with up to 20 MHz bandwidth allocated in a carrier aggregation with up to a total of 100 MHz (5 CCs) for transmission in each direction. Two types of CA include contiguous CA and non-contiguous CA. In contiguous CA, multiple available CCs are adjacent to each other, such as Figure 7 In non-contiguous CA, multiple available CCs are separated along the frequency band, as shown in Figure 8 As shown in . Both non-contiguous CA and contiguous CA aggregate multiple CCs to serve a single UE.

[0084] In some cases, a UE operating in a multi-carrier system (a system supporting carrier aggregation) may be configured to aggregate certain functions (such as control and feedback functions) of multiple carriers on the same carrier, which may be referred to as a "primary carrier" (PCC). The remaining carriers supported by the primary carrier are referred to as associated secondary carriers (SCCs).

[0085] The aggregated CCs may be intra-band (each CC is within the same operating band) or may be inter-band (in which case each CC belongs to a different operating band).

[0086] According to certain aspects, TDD and FDD carriers can be jointly aggregated. TDD-FDD CA can allow the network to improve user throughput by aggregating both TDD and FDD for the same UE. TDD-FDD CA can allow the load to be divided between TDD and FDD frequencies. TDD-FDD CA allows CA to be applied even if spectrum is allocated in both TDD and FDD bands. Thus, the benefits of CA (e.g., flexibility and efficient resource utilization) can be achieved for both TDD and FDD bands.

[0087] According to certain aspects, CA may be applied jointly to the LTE TDD band and a band configured for 5G communications.

[0088] Example methods and apparatus for SRS antenna switching in CA

[0089] In some communication systems (e.g., Long Term Evolution (LTE) and / or New Radio (NR) systems), the spectrum may include frequency bands configured for time division duplexing (TDD) and frequency bands configured for frequency division duplexing (FDD). Certain systems, such as NR systems (e.g., wireless communication network 100), may also include frequency bands configured for NR (e.g., 5G) communications. As described above, carrier aggregation (CA) may be jointly configured for TDD and FDD or for frequency bands configured for 5G.

[0090] In some cases, front-end (FE) components in devices such as user equipment (UE) are shared. For example, some FE components may be shared between TDD and FDD bands, and / or between LTE-configured and 5G-configured bands. For example, FE components may be shared by TDD tx and FDD rx, by TDD tx and FDD tx, or by TDD tx, FDD tx, and FDD tx. Figure 9 is a block diagram illustrating an example UE architecture 900 with shared components for some frequency bands in accordance with certain aspects of the present disclosure. Figure 9As shown in FIG, UE architecture 900 includes a combined FDD and TDD filter 902. The combined FDD and TDD filter 902 has a single output to antenna ports 904 (antenna 0) and 906 (antenna 1) to support CA. The FDD band (e.g., FDD LNA 910 and FDD Tx 912) and the TDD band (e.g., TDD Tx 914 and TDD LNA 916) can share all FE components following the combined FDD and TDD filter 902. It should be noted that although Figure 9 One example of a UE architecture is shown, but other UE architectures may be used within the scope of the present disclosure. Figure 9 Shared components for FDD and TDD bands are illustrated, but in other examples, the UE architecture may include shared components for TDD bands and 5G communication bands.

[0091] The UE can be configured for antenna switching / selection. In some examples, the UE is configured for sounding reference signal (SRS) switching (e.g., antenna selection) for the TDD frequency band for uplink transmission. The UE can use antenna switch 908 (SW A) to switch between antenna ports 904 and 906. Because antenna switch 908 is shared by the TDD and FDD frequency bands, when antenna switch 908 switches an antenna, for example, from antenna 904 to antenna 906 or from antenna 906 to antenna 904, the antenna is also switched for use in the FDD frequency band.

[0092] SRS antenna switching of the TDD band(s) may result in performance loss in other bands (i.e., FDD or 5G bands) that share the antenna. For example, uplink or downlink communications on the FDD or 5G bands may be affected by the SRS antenna switching of the TDD band. The SRS may be transmitted in the last symbol of a subframe. The SRS antenna switching may be performed periodically. For different CA bands (e.g., FDD bands or bands configured with 5G), the last symbol in a subframe may be scheduled on different antennas; therefore, the communication of the symbol may be interrupted by the SRS antenna switching of the TDD band. In the case of timing advance (TA) of other bands (e.g., FDD or 5G bands), two symbols may be affected by the SRS antenna switching of the TDD band. As in Figure 10 As shown in FIG, CC0 is configured as a TDD frequency band, and CC1 is configured as an FDD frequency band, which has a TA relative to the TDD frequency band. Figure 10 As shown in , the antenna is switched from antenna 0 to antenna 1 for SRS transmission on CC0 configured for TDD in the last symbol of the subframe. Figure 10As shown in , since the symbol boundaries of TA, CC0 and CC1 are not aligned, the antenna switching in the last symbol of CC0 affects the last two symbols of CC1.

[0093] Due to different channel conditions between the switched antennas (e.g., antenna 0 and antenna 1), the phase of the affected symbols (e.g., in FDD CC1) may differ from the phase of other symbols in the subframe. This phase difference may result in an increased block error rate (BLER), which may affect throughput (e.g., the DL throughput of the DL Rx subframe of CC1). In some cases, only specific FDD bands that are aggregated with specific TDD bands will be affected by antenna switching. Therefore, it may be desirable for the BS to know which bands may be affected by antenna switching.

[0094] Various aspects of the present disclosure provide methods for improving the performance of SRS switching in carrier aggregation. According to certain aspects, a UE determines frequency bands that may be affected by SRS antenna switching and sends a list of affected frequency bands to a base station. These lists can be used for various frequency band combinations, such as TDD Tx and FDD Rx, TDD Tx and FDD Tx, and / or TDD Tx and FDD Rx and Tx. The base station can use the list of affected frequency bands to determine (e.g., optimize) scheduling for the UE, for example, to avoid or mitigate the impact of antenna switching on those frequency bands.

[0095] Figure 11 Illustrate example operations 1100 for wireless communication according to aspects of the present disclosure. Operations 1100 may be performed by a UE, such as, for example Figure 1 UE 120 in the wireless communication network 100 is shown in FIG.

[0096] Operation 1100 begins at block 1102 by determining one or more frequency band combinations for shared antenna switching (e.g., a combination of frequency bands configured with TDD+FDD CA and / or a combination of frequency bands configured with TDD+5G CA). These frequency bands may be used for uplink, downlink, or both uplink and downlink. These frequency bands may share other components, such as filters. Shared filters may be used for receivers, transmitters, or both between the frequency bands.

[0097] At block 1104, the UE sends a list of one or more frequency bands in the one or more frequency band combinations to the BS. For example, for each uplink frequency band, the UE may send a list of all frequency bands with uplink communications affected by antenna switching and / or a list of all frequency bands with downlink communications affected by antenna switching. For each uplink frequency band (e.g., an uplink frequency band configured for TDD), the UE may send a list of all frequency bands configured with that frequency band for CA.

[0098] According to certain aspects, a UE may decide whether to support antenna switching for one or more frequency bands in a list of one or more frequency band combinations. For example, the UE may decide to ignore (e.g., not comply with) an antenna selectivity command. Thus, the UE may refrain from performing antenna switching for one or more frequency band combinations in certain subframes. According to certain aspects, the UE may send an indication of the decision to the BS. For example, the UE may send the indication in a list, thereby indicating whether antenna selection is supported. Alternatively, the UE may send the indication of the decision separately from the list. Alternatively, the UE may send an indication of the decision instead of sending the list.

[0099] According to certain aspects, the UE may report a list of affected frequency bands and / or a determination of whether antenna selection is supported for the frequency band at the time of UE initialization or after the UE is assigned a frequency band combination (e.g., in response to the UE being assigned a frequency band combination). The UE may report this information at another time.

[0100] In some examples, for each band combination, the UE signals which bands support Tx antenna selection. For each uplink band that supports Tx antenna selection, the UE signals all bands that are switched together for UL (e.g., all bands for which the same port must be enforced) and / or all bands that are switched together for DL (e.g., all bands that introduce "glitch" in DL reception).

[0101] According to certain aspects, as described in greater detail below, a UE may receive scheduling information from a BS based on a frequency band list provided to the BS.

[0102] Figure 12 Illustrate example operations 1200 for wireless communication according to aspects of the present disclosure. Operations 1200 may be performed by a BS, such as, for example Figure 1 Operations 1200 may be performed by the BS complementary to operations 1100 performed by the UE.

[0103] Operations 1200 begin at block 1202 by receiving, from a UE, a list of one or more frequency bands of one or more frequency band combinations for shared antenna switching.

[0104] The BS schedules the UE based on the received list at block 1204. For example, the BS may avoid scheduling the UE in conflicting subframes in which one or more band combinations are configured for communication (eg, and in which SRS antenna switching occurs).

[0105] In another example, the BS may schedule a shorter transmission time interval (TTI) in the conflicting subframes. For example, if the UE supports shortened TTI (sTTI), the BS may schedule sTTI (e.g., 1.14 ms) for those affected subframe / band combinations. If sTTI is assigned in the conflicting subframes, in some cases, only one of six possible sTTIs may be lost.

[0106] According to certain aspects, the BS may reduce the SRS antenna switching rate to reduce disruptions. For example, the BS may schedule the UE for multiple SRS antenna switching only in special subframes (e.g., TDD subframe configuration "special" subframes). Alternatively, the BS may schedule the UE for aperiodic SRS antenna switching. The BS may schedule the UE for SRS antenna switching with reduced periodicity. In another example, the BS may refrain from scheduling the UE for SRS antenna switching (e.g., in conflicting subframes and / or for certain frequency band combinations).

[0107] In another example, the BS may schedule the UE with a more robust modulation scheme and / or data to mitigate the impact of the affected (e.g., lost) symbols. For example, even at a lower data rate, the overall throughput may be increased by using a lower modulation scheme or a specific data pattern for those subframes with collisions.

[0108] Advantageously, the techniques provided herein can enable a device (e.g., a base station (such as a NB, gNB, etc.)) to intelligently schedule a UE based on information received from the UE regarding frequency bands and / or frequency band combinations affected by SRS antenna switching. A further aspect provides that the UE and / or base station decide whether SRS antenna switching should be performed (e.g., supported / scheduled) or not performed at all (e.g., supported / scheduled) for subframes / frequency bands affected by SRS antenna switching. Consequently, performance improvements, such as higher throughput, can be achieved.

[0109] Each method disclosed herein includes one or more steps or actions for implementing the method. These method steps and / or actions may be interchangeable with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of the specific steps and / or actions may be modified without departing from the scope of the claims.

[0110] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including individual members. As an example, "at least one of a, b, or c" is intended to encompass: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0111] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or another data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. "Determining" may also include resolving, selecting, choosing, establishing, and the like.

[0112] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but rather should be granted the full scope consistent with the language of the claims, wherein singular references to elements are not intended to mean "one and only one" (unless specifically stated otherwise) but rather "one or more." Unless specifically stated otherwise, the term "a" refers to one or more. All structural and functional equivalents currently or hereafter known to those of ordinary skill in the art for the various aspects described throughout this disclosure are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be contributed to the public, regardless of whether such disclosure is explicitly stated in the claims. No element of a claim should be interpreted under 35 U.S.C. § 112(f) unless the element is explicitly stated using the phrase "means for..." or, in the case of a method claim, the element is stated using the phrase "step for..."

[0113] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations illustrated in the figures, these operations may have corresponding counterpart means-plus-function components with similar numbering.

[0114] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure 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 commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0115] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement signal processing functions at the PHY layer. In the user terminal 120 (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art and will not be described further. The processor may be implemented using one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry capable of executing software. Those skilled in the art will recognize how to best implement the functionality described with respect to the processing system, depending on the specific application and the overall design constraints imposed on the overall system.

[0116] If implemented in software, each function may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, including any media that facilitates the transfer of a computer program from one location to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to the processor so that the processor can read and write information from / to the storage medium. Alternatively, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separate from the wireless node, all of which may be accessed by the processor via a bus interface. Alternatively or in addition, the machine-readable medium or any portion thereof may be integrated into the processor, such as a cache and / or general register file. As examples, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0117] A software module may include a single instruction or many instructions and may be distributed across several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include several software modules. These software modules include instructions that, when executed by a device (such as a processor), cause a processing system to perform various functions. These software modules may include a transmitting module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded from a hard drive into RAM. During the execution of the software module, the processor may load some instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When describing the functionality of a software module below, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0118] Any connection is also 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 technology (such as infrared (IR), radio, and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Disks, where disks often reproduce data magnetically, and discs reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0119] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having stored (and / or encoded) thereon instructions, which are executable by one or more processors to perform the operations described herein. For example, a computer program product for performing the operations described herein and in Figure 11 and 12 Instructions for the operations explained in .

[0120] In addition, it should be appreciated that the modules and / or other appropriate means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of the means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.) so that once the storage device is coupled to or provided to the user terminal and / or base station, the device can obtain the various methods. In addition, any other suitable technology suitable for providing the methods and techniques described herein to a device can be utilized.

[0121] It will be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: determining one or more frequency band combinations, wherein the one or more frequency band combinations are switched together to the second antenna port when at least one frequency band in a frequency band combination is switched from a first antenna port to a second antenna port; as well as A list is sent to a base station (BS), the list including one or more frequency bands in the one or more frequency band combinations affected by switching from the first antenna port to the second antenna port for one or more uplink frequency bands in the one or more frequency band combinations and the one or more uplink frequency bands.

2. The method of claim 1 , wherein sending the list comprises: For each uplink frequency band in the one or more frequency band combinations, a list of all uplink frequency bands in the one or more frequency band combinations that are affected by the transmit antenna switching is sent.

3. The method of claim 1 , wherein sending the list comprises: For each uplink frequency band in the one or more frequency band combinations, a list of all downlink frequency bands in the one or more frequency band combinations that are affected by switching transmit antennas for use with the uplink frequency band is sent.

4. The method of claim 1, further comprising: determining whether to support transmit antenna switching for the one or more frequency bands in the one or more frequency band combinations, wherein The list includes an indication of the decision to the BS.

5. The method of claim 1 , wherein at least one of the one or more frequency band combinations comprises: A first frequency band configured for time division duplex (TDD) uplink communications using a first transmit receive chain and a second frequency band configured for frequency division duplex (FDD) or 5G communications using a second transmit receive chain, and wherein the first transmit receive chain and the second transmit receive chain share an antenna switch.

6. The method of claim 5, further comprising: On at least one uplink frequency band configured for TDD, switching from the first antenna port to the second antenna port via the antenna switch is performed for transmitting a sounding reference signal (SRS).

7. The method of claim 5, wherein determining the one or more frequency band combinations comprises: One or more downlink FDD frequency bands configured for carrier aggregation (CA) along with one or more uplink frequency bands configured for TDD are determined.

8. The method of claim 7, wherein sending the list comprises: For each uplink frequency band configured for TDD, a list of frequency bands configured for CA together with the uplink frequency band configured for TDD is transmitted.

9. The method of claim 1 , wherein sending the list comprises: The list is sent upon initialization of the UE or in response to the UE receiving an assignment of the one or more frequency band combinations.

10. The method of claim 1, further comprising: Scheduling information is received from the BS based on the list.

11. The method of claim 1 , further comprising: Performing transmit antenna switching for the one or more frequency band combinations is refrained.

12. A method for wireless communication by a base station (BS), comprising: receiving, from a user equipment (UE), a list when at least one frequency band of one or more frequency bands in one or more frequency band combinations is switched from a first antenna port to a second antenna port, the list including the one or more frequency bands in the one or more frequency band combinations affected by switching together to the second antenna port for one or more uplink frequency bands in the one or more frequency band combinations and the one or more uplink frequency bands; as well as The UE is scheduled based on the received list.

13. The method of claim 12, wherein the received list comprises: For each uplink frequency band in the one or more frequency band combinations, the one or more frequency band combinations have a list of all uplink frequency bands for uplink communications affected by the transmit antenna switching.

14. The method of claim 12, wherein the received list comprises: For each uplink frequency band in the one or more frequency band combinations, there is a list of all downlink frequency bands in the one or more frequency band combinations that are affected by switching of transmit antennas for use in the uplink frequency band.

15. The method of claim 12, wherein the received list includes an indication to the BS of a decision as to whether transmit antenna switching is supported for the one or more frequency bands in the one or more frequency band combinations.

16. The method of claim 12, wherein at least one of the one or more frequency band combinations comprises: A first frequency band configured for time division duplex (TDD) uplink communications using a first transmit receive chain and a second frequency band configured for frequency division duplex (FDD) or 5G communications using a second transmit receive chain, and wherein the first transmit receive chain and the second transmit receive chain share an antenna switch.

17. The method of claim 16, wherein the one or more frequency band combinations include: One or more downlink FDD frequency bands are configured for carrier aggregation (CA) along with one or more uplink frequency bands configured for TDD.

18. The method of claim 12, wherein scheduling the UE based on the received list comprises: Scheduling the UE in subframes in which the one or more frequency band combinations are configured for communication is avoided.

19. The method of claim 12, further comprising: determining whether the UE supports shortened transmission time intervals (sTTIs), wherein Scheduling the UE based on the received list includes scheduling the sTTI for communication in a subframe in which the one or more frequency band combinations are configured for communication.

20. The method of claim 12, wherein scheduling the UE based on the received list comprises: At least one of a modulation scheme or a data mode is selected based on the received list for scheduling in subframes in which the one or more frequency band combinations are configured for communication.

21. The method of claim 12, wherein scheduling the UE based on the received list comprises: The UE is scheduled for multiple transmit antenna switching for sounding reference signal (SRS) transmission only in special subframes.

22. The method of claim 12, wherein scheduling the UE based on the received list comprises: The UE is scheduled for aperiodic transmit antenna switching for sounding reference signal (SRS) transmission.

23. The method of claim 12, wherein scheduling the UE based on the received list comprises: The UE is scheduled with reduced periodicity for transmit antenna switching for sounding reference signal (SRS) transmission based on the received list.

24. The method of claim 12, wherein scheduling the UE based on the received list comprises: For the one or more frequency band combinations, scheduling the UE for sounding reference signal (SRS) transmission, suppressing transmit antenna switching.

25. An apparatus for wireless communication by a user equipment (UE), comprising: means for determining one or more frequency band combinations that are to be switched together to a second antenna port when at least one frequency band in a frequency band combination is switched from a first antenna port to a second antenna port; as well as Means for sending a list to a base station (BS), the list including one or more frequency bands in the one or more frequency band combinations affected by switching from the first antenna port to the second antenna port for one or more uplink frequency bands in the one or more frequency band combinations and the one or more uplink frequency bands.

26. The apparatus of claim 25, wherein sending the list comprises: For each uplink frequency band in the one or more frequency band combinations, a list of all uplink frequency bands in the one or more frequency band combinations having uplink communications affected by the transmit antenna switching is sent.

27. The apparatus of claim 25, wherein sending the list comprises: For each uplink frequency band in the one or more frequency band combinations, a list of all downlink frequency bands in the one or more frequency band combinations having downlink communications affected by switching of transmit antennas for use in the uplink frequency band is sent.

28. The apparatus of claim 25, further comprising: means for determining whether to support transmit antenna switching for the one or more frequency bands in the one or more frequency band combinations, wherein The list includes an indication of the decision to the BS.

29. The apparatus of claim 25, wherein at least one of the one or more frequency band combinations comprises: A first frequency band configured for time division duplex (TDD) uplink communications using a first transmit receive chain and a second frequency band configured for frequency division duplex (FDD) or 5G communications using a second transmit receive chain, and wherein the first transmit receive chain and the second transmit receive chain share an antenna switch.

30. The apparatus of claim 29, further comprising: means for switching, via the antenna switch, from the first antenna port to the second antenna port for transmitting a sounding reference signal (SRS) on at least one uplink frequency band configured for TDD.

31. The apparatus of claim 29, wherein determining the one or more frequency band combinations comprises: One or more downlink FDD frequency bands configured for carrier aggregation (CA) along with one or more uplink frequency bands configured for TDD are determined.

32. The apparatus of claim 31 , wherein sending the list comprises: For each uplink frequency band configured for TDD, a list of frequency bands configured for CA together with the uplink frequency band configured for TDD is transmitted.

33. The apparatus of claim 25, wherein sending the list comprises: The list is sent upon initialization of the UE or in response to the UE receiving an assignment of the one or more frequency band combinations.

34. The apparatus of claim 25, further comprising: means for receiving scheduling information from the BS based on the list.

35. The apparatus of claim 25, further comprising: Means for refraining from performing transmit antenna switching for the one or more frequency band combinations.

36. An apparatus for wireless communication by a base station (BS), comprising: means for receiving, from a user equipment (UE), a list when at least one frequency band of one or more frequency bands in one or more frequency band combinations is switched from a first antenna port to a second antenna port, the list including the one or more frequency bands in the one or more frequency band combinations affected by switching together to the second antenna port for one or more uplink frequency bands in the one or more frequency band combinations and the one or more uplink frequency bands; as well as Means for scheduling the UE based on the received list.

37. The apparatus of claim 36, wherein the received list comprises: For each uplink frequency band in the one or more frequency band combinations, the one or more frequency band combinations have a list of all uplink frequency bands for uplink communications affected by the transmit antenna switching.

38. The apparatus of claim 36, wherein the received list comprises: For each uplink frequency band in the one or more frequency band combinations, there is a list of all downlink frequency bands in the one or more frequency band combinations that are affected by switching of transmit antennas for use in the uplink frequency band.

39. The apparatus of claim 36, wherein the received list includes an indication to the BS of a decision as to whether transmit antenna switching is supported for the one or more frequency bands in the one or more frequency band combinations.

40. The apparatus of claim 36, wherein at least one of the one or more frequency band combinations comprises: A first frequency band configured for time division duplex (TDD) uplink communications using a first transmit receive chain and a second frequency band configured for frequency division duplex (FDD) or 5G communications using a second transmit receive chain, and wherein the first transmit receive chain and the second transmit receive chain share an antenna switch.

41. The apparatus of claim 40, wherein the one or more frequency band combinations include: One or more downlink FDD frequency bands are configured for carrier aggregation (CA) along with one or more uplink frequency bands configured for TDD.

42. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: Scheduling the UE in subframes in which the one or more frequency band combinations are configured for communication is avoided.

43. The apparatus of claim 36, further comprising: means for determining whether the UE supports shortened transmission time intervals (sTTIs), wherein Scheduling the UE based on the received list includes scheduling the sTTI for communication in a subframe in which the one or more frequency band combinations are configured for communication.

44. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: At least one of a modulation scheme or a data mode is selected based on the received list for scheduling in subframes in which the one or more frequency band combinations are configured for communication.

45. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: The UE is scheduled for multiple transmit antenna switching for sounding reference signal (SRS) transmission only in special subframes.

46. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: The UE is scheduled for aperiodic transmit antenna switching for sounding reference signal (SRS) transmission.

47. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: The UE is scheduled with reduced periodicity for transmit antenna switching for sounding reference signal (SRS) transmission based on the received list.

48. The apparatus of claim 36, wherein scheduling the UE based on the received list comprises: For the one or more frequency band combinations, scheduling the UE for sounding reference signal (SRS) transmission, suppressing transmit antenna switching.

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