WO2021202036A1

WO2021202036A1 - Superpositioning and transmission of signals using a first radio access technology and a second radio access technology

Info

Publication number: WO2021202036A1
Application number: PCT/US2021/020495
Authority: WO
Inventors: Stelios STEFANATOS; Shuanshuan Wu; Arthur GUBESKYS
Original assignee: Qualcomm Incorporated
Priority date: 2020-04-02
Filing date: 2021-03-02
Publication date: 2021-10-07

Abstract

Certain aspects of the present disclosure provide techniques for wireless communication by a dual-mode wireless device supporting communications using a first radio access technology and a second wireless technology. An example method generally includes identifying a transmit power for transmitting a signal to a receiving device operating on the second radio access technology, identifying a time-frequency resource for transmitting the signal to the receiving device based, at least in part, on the identified transmit power and time-frequency resources used for transmission by devices operating on the first radio access technology, and transmitting a signal to the receiving device using the second radio access technology based, at least in part, on the identified transmit power using the identified time-frequency resource.

Description

SUPERPOSITIONING AND TRANSMISSION OF SIGNALS USING A FIRST RADIO ACCESS TECHNOLOGY AND A SECOND RADIO ACCESS

TECHNOLOGY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of Greece Patent Application No. 20200100166, entitled “Superpositioning and Transmission of Signals Using a First Radio Access Technology and a Second Radio Access Technology”, filed April 2, 2020 and assigned to the assignee hereof, the contents of which are hereby incorporated by reference in its entirety.

BACKGROUND

Field of the Disclosure

[0002] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for transmitting signals using a second radio access technology simultaneously with signals using a first radio access technology in a nondestructive manner.

Description of Related Art

[0003] 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.

[0004] In some examples, a wireless multiple-access communication system may include a number of base stations (BSs), which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). In an 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, a new radio (NR), or 5G 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 DUs, in communication with a CU, may define an access node (e.g., which may be referred to as a BS, 5G NB, next generation NodeB (gNB or gNodeB), transmission reception point (TRP), etc.). A BS or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a BS or DU to a UE) and uplink channels (e.g., for transmissions from a UE to BS or DU).

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. NR (e.g., new radio or 5G) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3 GPP. NR 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). To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] Sidelink communications are communications from one UE to another UE. As the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology, including improvements to sidelink communications. Preferably, these improvements should be applicable to other multi access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

[0007] The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims that follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

[0008] Certain aspects provide a method for wireless communication by a dual-mode wireless device supporting communications using a first radio access technology and a second wireless technology. The method generally includes identifying a transmit power for transmitting a signal to a receiving device operating on the second radio access technology, identifying a time-frequency resource for transmitting the signal to the receiving device based, at least in part, on the identified transmit power and time- frequency resources used for transmission by devices operating on the first radio access technology, and transmitting a signal to the receiving device using the second radio access technology based, at least in part, on the identified transmit power using the identified time-frequency resource.

[0009] Certain aspects provide a method for wireless communication by a dual-mode wireless device supporting communications using a first radio access technology and a second radio access technology. The method generally includes receiving, from a device, on a time-frequency resource, a combined signal including a first signal using a first radio access technology and a second signal using a second radio access technology, decoding and reconstructing the first signal from the combined signal, and recovering the second signal by subtracting the decoded and reconstructed first signal from the combined signal.

[0010] Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.

[0011] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0013] FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

[0014] FIG. 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.

[0015] FIG. 3 is a diagram illustrating an example physical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure.

[0016] FIG. 4 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE), in accordance with certain aspects of the present disclosure.

[0017] FIGs. 5A and 5B show diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure.

[0018] FIG. 6 illustrates an example scenario in which a dual-mode wireless device transmits signaling on time-frequency resources also used by a legacy wireless device, in accordance with certain aspects of the present disclosure.

[0019] FIG. 7 illustrates example operations that may be performed by a dual-mode wireless device to transmit a signal using a second radio access technology that is superpositioned with a signal transmitted by another device using a first radio access technology, in accordance with certain aspects of the present disclosure.

[0020] FIG. 8 illustrates example operations that may be performed by a dual-mode wireless device to process a combined signal received on a time-frequency resource including a first signal using a first radio access technology and a second signal using a second radio access technology, in accordance with certain aspects of the present disclosure.

[0021] FIG. 9 illustrates an example architecture for processing, by a receiving device, a combined signal received on a time-frequency resource including a first signal using a first radio access technology and a second signal using a second radio access technology, in accordance with certain aspects of the present disclosure. [0022] FIG. 10 illustrates messages that may be exchanged between a transmitting wireless device and a receiving wireless device to transmit and process combined signals on a time-frequency resource including a first signal using a first radio access technology and a second signal using a second radio access technology, in accordance with certain aspects of the present disclosure.

[0023] FIG. 11 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

[0024] 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 on other aspects without specific recitation.

DETAILED DESCRIPTION

[0025] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for transmitting a second signal using a second radio access technology such that the second signal is superpositioned over a first signal transmitted by another device using a first radio access technology. Generally, the signal using the second radio access technology may be transmitted using a transmit power that allows receiving devices to decode the first signal and the second signal. To allow for the first signal to be decoded by receiving devices, the second signal may be transmitted with a transmit power that causes the second signal to be treated as noise by devices that communicate using the first radio access technology. For receiving devices that can communicate using the first and the second radio access technologies, the first signal and the second signal may be recovered from the combined signal received on a time- frequency resource. Generally, the superpositioned transmission of signals using the second radio access technology over signals using the first radio access technology on specific time-frequency resource may allow for the coexistence of devices that support communications using only a first radio access technology with devices that support communications using both a first radio access technology and a second radio access technology.

[0026] The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

[0027] The techniques described herein may 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 may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology 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- OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS).

[0028] New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE- Advanced (LTE- A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

[0029] New radio (NR) access (e.g., 5G technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond), millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond), massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

[0030] FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, UEs 120a FIG. 1 may be V2X (vehicle-to-everything) or V2V (vehi cl e-to- vehicle) UEs or include V2X or V2V UEs configured to perform operations described below with reference to FIGs. 7-8 to process signals using a first radio access technology and a second radio access technology in an environment where devices supporting the first radio access technology and dual mode devices supporting the first and second radio access technologies coexist.

[0031] As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) l lOa-z (each also individually referred to herein as BS 110 or collectively as BSs 110) and other network entities. In aspects of the present disclosure, a roadside service unit (RSU) may be considered a type of BS, and a BS 110 may be referred to as an RSU. A BS 110 may provide communication coverage for a particular geographic area, sometimes referred to as a “cell”, which may be stationary or may move according to the location of a mobile BS 110. In some examples, the BSs 110 may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces (e.g., a direct physical connection, a wireless connection, a virtual network, or the like) using any suitable transport network. In the example shown in FIG. 1, the BSs 110a, 110b and 110c may be macro BSs for the macro cells 102a, 102b and 102c, respectively. The BS 1 lOx may be a pico BS for a pico cell 102x. The BSs 1 lOy and 1 lOz may be femto BSs for the femto cells 102y and 102z, respectively. A BS may support one or multiple cells. The BSs 110 communicate with user equipment (UEs) 120a-y (each also individually referred to herein as UE 120 or collectively as UEs 120) in the wireless communication network 100. The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile.

[0032] Wireless communication network 100 may also include relay stations (e.g., relay station 1 lOr), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE 120 or a BS 110), or that relays transmissions between UEs 120, to facilitate communication between devices.

[0033] A network controller 130 may couple to a set of BSs 110 and provide coordination and control for these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

[0034] The 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, 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 computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wristband, smartjewelry (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 machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices. The UEs illustrated in FIG. 1 may be, in some embodiments, V2X UEs or vehicles including UEs that can perform the operations illustrated in FIGs. 7 or 8 discussed below.

[0035] Certain 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 partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB)) may be 12 subcarriers (or 180 kHz). Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

[0036] While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. [0037] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among 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. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function 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 may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer- to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

[0038] In FIG. 1, 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 finely dashed line with double arrows indicates interfering transmissions between a UE and a BS.

[0039] FIG. 2 illustrates an example logical architecture of a distributed Radio Access Network (RAN) 200, which may be implemented in the wireless communication network 100 illustrated in FIG. 1. A 5G access node 206 may include an access node controller (ANC) 202. ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the Next Generation Core Network (NG-CN) 204 may terminate at ANC 202. The backhaul interface to neighboring next generation access Nodes (NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or more TRPs 208 (e.g., cells, BSs, gNBs, etc.).

[0040] The TRPs 208 may be a distributed unit (DU). TRPs 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not illustrated). For example, for RAN sharing, radio as a service (RaaS), and service specific AND deployments, TRPs 208 may be connected to more than one ANC. TRPs 208 may each include one or more antenna ports. TRPs 208 may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE. [0041] The logical architecture of distributed RAN 200 may support fronthauling solutions across different deployment types. For example, the logical architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter).

[0042] The logical architecture of distributed RAN 200 may share features and/or components with LTE. For example, next generation access node (NG-AN) 210 may support dual connectivity with NR. and may share a common fronthaul for LTE and NR.

[0043] The logical architecture of distributed RAN 200 may enable cooperation between and among TRPs 208, for example, within a TRP and/or across TRPs via ANC 202. An inter- TRP interface may not be used.

[0044] Logical functions may be dynamically distributed in the logical architecture of distributed RAN 200. The Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202).

[0045] FIG. 3 illustrates an example physical architecture of a distributed RAN 300, according to aspects of the present disclosure. A centralized core network unit (C-CU) 302 may host core network functions. C-CU 302 may be centrally deployed. C-CU 302 functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity.

[0046] A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have distributed deployment. The C-RU 304 may be close to the network edge.

[0047] A DU 306 may host one or more TRPs (Edge Node (EN), an Edge Unit (EU), a Radio Head (RH), a Smart Radio Head (SRH), or the like). The DU may be located at edges of the network with radio frequency (RF) functionality.

[0048] FIG. 4 illustrates example components of BS 110a and UE 120a (as depicted in FIG. 1), which may be used to implement aspects of the present disclosure. For example, antennas 452, processors 466, 458, 464, and/or controller/processor 480 of the UE 120a and/or antennas 434, processors 420, 430, 438, and/or controller/processor 440 of the BS 110a may be used to perform the various techniques and methods described herein with reference to FIGs. 8-9. [0049] At the BS 110a, 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 for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and 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, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the 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 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

[0050] At the TIE 120a, the antennas 452a through 452r may receive the downlink signals from the base station 110a and may provide received signals to the demodulators (DEMODs) in transceivers 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 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 the demodulators 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink 460, and provide decoded control information to a controller/processor 480.

[0051] On the uplink, at UE 120a, a transmit processor 464 may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source 462 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 480. The transmit processor 464 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)). The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators in transceivers 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the base station 110a. At the BS 110a, the uplink signals from the UE 120a may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120a. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller/processor 440.

[0052] The controllers/processors 440 and 480 may direct the operation at the BS 110a and the UE 120a, respectively. The processor 440 and/or other processors and modules at the BS 110a may perform or direct the execution of processes for the techniques described herein. For example, as shown in FIG. 4, the controller/processor 440 of the BS 110a has a sidelink recovery manager 441 that may be configured for receiving a plurality of sidelink communications, each sidelink communication between two user equipments (UEs); and for transmitting recovery information in a recovery slot, wherein the recovery information is for recovery of at least one of the sidelink communications by the two UEs or other UEs that transmitted when at least one of the sidelink communications occurred and wherein the recovery slot is for transmission of the recovery information, according to aspects described herein. As shown in FIG. 2, the controller/processor 480 of the UE 120a has a sidelink manager 481 that may be configured for transmitting a sidelink communication to another UE; and for receiving recovery information in a recovery slot, wherein the recovery information is for recovery of at least one of the sidelink communications by other UEs that transmitted when the sidelink communication occurred and wherein the recovery slot is for transmission of the recovery information; and for determining another sidelink communication transmitted by a wireless node, based on the sidelink communication and the recovery information, according to aspects described herein. Although shown at the controller/processor 480 and controller/processor 440, other components of the UE 120a and BS 110a may be used performing the operations described herein. The memories 442 and 482 may store data and program codes forBS 110a and UE 120a, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and/or uplink. [0053] In some circumstances, 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 relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS), even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks (WLANs), which typically use an unlicensed spectrum).

[0054] FIGs. 5A and 5B show diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure. For example, the vehicles shown in FIGs. 5A and 5B may communicate via sidelink channels and may perform sidelink CSI reporting as described herein.

[0055] The V2X systems, provided in FIGs. 5A and 5B provide two complementary transmission modes. A first transmission mode, shown by way of example in FIG. 5A, involves direct communications (for example, also referred to as side link communications) between participants in proximity to one another in a local area. A second transmission mode, shown by way of example in FIG. 5B, involves network communications through a network, which may be implemented over a Uu interface (for example, a wireless communication interface between a radio access network (RAN) and a UE).

[0056] Referring to FIG. 5A, a V2X system 500 (for example, including vehicle-to- vehicle (V2V) communications) is illustrated with two vehicles 502, 504. The first transmission mode allows for direct communication between different participants in a given geographic location. As illustrated, a vehicle can have a wireless communication link 506 with an individual (i.e., vehicle to person (V2P), for example, via a UE) through a PC5 interface. Communications between the vehicles 502 and 504 may also occur through a PC5 interface 508. In a like manner, communication may occur from a vehicle 502 to other highway components (for example, roadside service unit 510), such as a traffic signal or sign (i.e., vehicle to infrastructure (V2I)) through a PC5 interface 512. With respect to each communication link illustrated in FIG. 5 A, two-way communication may take place between elements, therefore each element may be a transmitter and a receiver of information. The V2X system 500 may be a self-managed system implemented without assistance from a network entity. A self-managed system may enable improved spectral efficiency, reduced cost, and increased reliability as network service interruptions do not occur during handover operations for moving vehicles. The V2X system may be configured to operate in a licensed or unlicensed spectrum, thus any vehicle with an equipped system may access a common frequency and share information. Such harmonized/common spectrum operations allow for safe and reliable operation.

[0057] FIG. 5B shows a V2X system 550 for communication between a vehicle 552 and a vehicle 554 through a network entity 556. These network communications may occur through discrete nodes, such as a base station (for example, an eNB or gNB), that sends and receives information to and from (for example, relays information between) vehicles 552, 554. The network communications through vehicle to network (V2N) links 558 and 510 may be used, for example, for long-range communications between vehicles, such as for communicating the presence of a car accident a distance ahead along a road or highway. Other types of communications may be sent by the node to vehicles, such as traffic flow conditions, road hazard warnings, environmental/weather reports, and service station availability, among other examples. Such data can be obtained from cloud-based sharing services.

[0058] In some circumstances, two or more subordinate entities (for example, UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via a sidelink. When a UE is transmitting a sidelink communication on a sub-channel of a frequency band, the UE is typically unable to receive another communication (e.g., another sidelink communication from another UE) in the frequency band. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. Generally, a sidelink may refer to a direct link between one subordinate entity (for example, UE1) and another subordinate entity (for example, UE2). As such, a sidelink may be used to transmit and receive a communication (also referred to herein as a “sidelink signal”) without relaying the communication through a scheduling entity (for example, a BS), even though the scheduling entity may be utilized for scheduling or control purposes. In some examples, a sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0059] Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable proximal devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configurations and other parameters used for data transmissions, and the PSSCH may carry the data transmissions.

[0060] For the operation regarding PSSCH, a UE performs either transmission or reception in a slot on a carrier. A reservation or allocation of transmission resources for a sidelink transmission is typically made on a sub-channel of a frequency band for a period of a slot. NR sidelink supports for a UE a case where all the symbols in a slot are available for sidelink, as well as another case where only a subset of consecutive symbols in a slot is available for sidelink.

Example Superposition Transmission of Signals Using a Second Radio Access Technology over Signals Transmitted Using a First Radio Access Technology

[0061] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for superposition transmission of signals using a second radio access technology over signals transmitted by other devices using a first radio access technology. In environments in which devices that support a first radio access technology (e.g., LTE) coexist with dual-mode devices that support both the first radio access technology and a second radio access technology (e.g., NR), the devices may communicate using a set of time-frequency resources. For example, in an autonomous vehicle scenario, some vehicles may support communications using LTE and may broadcast information that is applicable to any device in the network, such as information in a basic safety message (BSM). Other vehicles may support communications using NR and may transmit additional information beyond that in a BSM, such as sensor information for sensor sharing applications and the like, in broadcast or unicast transmissions (e.g., transmissions directed to a specific device).

[0062] Because dual-mode devices may not operate on separate resources from legacy devices that support the first radio access technology, a channel co-existence scenario may arise from the deployment of legacy devices that support the first radio access technology and dual-mode devices. Generally, a channel co-existence scenario may exist when legacy devices and dual -mode devices communicate using different radio access technologies on a same channel or set of channels. Generally, to provide for co existence of these devices and communications on a same channel or set of channels using different radio access technologies, operations by dual-mode devices should not negatively impact operations by legacy devices (e.g., cause interference to signals transmitted between legacy devices on the first radio access technology). In some cases, because dual-mode devices may be aware of the existence and structure of signals transmitted using the first radio access technology coexistence of legacy and dual-mode devices may be achieved if the dual-mode devices adjust transmissions to utilize the same time-frequency resources as those used by the legacy devices without degrading the performance of the legacy devices, as discussed in further detail below.

[0063] One technique that may allow for the coexistence of legacy devices and dual mode devices may be for dual-mode devices to sense spectrum usage by the legacy devices and dynamically utilize spectrum that is not used by the legacy devices. Doing so may prevent signals using the second radio access technology from colliding with signals using the first radio access technology. Meanwhile, legacy devices may detect high interference on the resources on which the signals using the second radio access technology are transmitted and avoid using those resources. Transmitting signals using the first radio access technology and the second radio access technology on different resources may minimize interference, since signals on different radio access technologies may not overlap on the same time-frequency resources. However, the legacy devices and dual-mode devices may only use some of the available resources for communications, which may not be an efficient use of the available resources in a wireless communications system. [0064] To improve resource utilization in a coexistence scenario, legacy devices and dual-mode devices may coexist using multiuser superposition transmission. In multiuser superposition transmission, both the legacy and dual-mode devices can perform transmissions using the same resources. As discussed in further detail below, signals using the second radio access technology may be transparent to legacy devices, which may not have knowledge of signaling using the second radio access technology or those superpositioned over signals using the first radio access technology. For example, signals using the second radio access technology may be filtered out as noise by legacy devices so that the legacy devices are capable of decoding signals using the first radio access technology without encountering destructive interference from at least signals transmitted using the second radio access technology. Dual-mode devices may decode both signals using the first radio access technology and signals using the second radio access technology using a single-antenna or multiple-antenna system.

[0065] FIG. 6 illustrates an example scenario in which legacy and dual-mode devices coexist. In this scenario, a dual-mode device may transmit a unicast signal using the second radio access technology to another dual-mode device in the vicinity. The unicast signal may include, for example, sensor sharing information, and the recipient may be in close range, which allows for the use of a low transmit power to successfully transmit the signal to the recipient Because the transmit power needed to transmit the signal from the transmitting dual-mode device to the recipient dual-mode device is relatively small, resource utilization may be increased by transmitting the signal on time-frequency resources that are already occupied by a higher power signal using the first radio access technology. The resulting interference to the signal using the first radio access technology may be small, due to the low power of the signal using the second radio access technology, and may not impact the ability of other devices (both legacy devices and dual-mode devices) from decoding the signal using the first radio access technology.

[0066] Legacy devices may decode the signal using the first radio access technology as if the transmitting dual-mode device did not transmit a signal on the same time- frequency resources. For example, legacy devices can treat the signal using the second radio access technology as noise at a small enough power that may not adversely impact the ability of the legacy devices to decode the signal using the first radio access technology. To allow for coexistence and multiuser superposition transmission of signals using the first and the second radio access technologies, the signal using the second radio access technology may be aligned temporally (e.g., at the subframe level) with the signals using the first radio access technology and may have a signal power that is sufficiently smaller than the signal power of the signal using the first radio access technology. Time synchronization may be achieved when both legacy and dual-mode devices use a common time synchronization source (e.g., timing information from a satellite positioning system, such as NAVSTAR GPS, GALILEO, GLONASS, etc.; timing information from a central time server; etc.) and use a matching numerology (e.g., the 15 KHz numerology in NR, which matches with a numerology used in LTE).

[0067] Dual-mode devices that are aware of the presence of a superpositioned signal using the second radio access technology may employ an interference cancellation scheme to recover the signal using the second radio access technology. The signal using the first radio access technology may be treated as a “base” layer, and the signal using the second radio access technology may be treated as the “second” layer for interference cancellation purposes. For example, the base layer may be cancelled from the signal to obtain the second layer in which the signal using the second radio access technology is transmitted. To decode the second layer, a minimum transmit power may be needed so that a signal can be successfully recovered.

[0068] FIG. 7 illustrates example operations 700 that may be performed by a dual mode wireless device supporting a first radio access technology and a second radio access technology to transmit signals using the second radio access technology.

[0069] As illustrated, operations 700 begin at block 702, where the device identifies a transmit power for transmitting a signal to a receiving device operating on the second radio access technology. As discussed in further detail below, the transmit power identified for transmitting the signal to the receiving device may be based on information about the received power on one or more of a plurality of time-frequency resources. The transmit power may be calculated based on an expected pathloss between the device and the receiving device so that the signal transmitted to the receiving device is received at a power that does not cause destructive interference to signals on a first radio access technology (e.g., transmitted by a base station to the receiving device).

[0070] At block 704, the device identifies a time-frequency resource for transmitting the signal to the receiving device. The time-frequency resource may be identified based, at least in part, on the identified transmit power and time-frequency resources used for transmission by devices operating on the first radio access technology. For example, the identified resources in the time domain may be downlink subframes or symbols in a subframe where a receiving user equipment is expecting to receive data from one or more transmitting devices. The frequency resources may be one or more frequency bands or portions thereof on which the receiving device communicates with a base station.

[0071] At block 706, the device transmits a signal to the receiving device using the second radio access technology. The transmission may be based, at least in part, on the identified transmit power and may use the identified time-frequency resources for transmission.

[0072] FIG. 8 illustrates example operations 800 that may be performed by a dual mode wireless device supporting a first radio access technology and a second radio access technology to receive signals using the second radio access technology.

[0073] As illustrated, operations 800 begin at block 802, where the device receives, on a time-frequency resource, a combined signal. The combined signal generally includes a first signal using a first radio access technology and a second signal using a second radio access technology. The first signal may be received from a first device (e.g., a legacy device, such as a legacy device capable of communicating using the first radio access technology but not capable of communicating using the second radio access technology), and the second signal may be received on the same time-frequency resource from a second device (e.g., a dual-mode device capable of communicating using one or both of the first radio access technology and the second radio access technology)

[0074] At block 804, the device decodes and reconstructs the first signal from the combined signal.

[0075] At block 808, the device recovers the second signal by subtracting the decoded and reconstructed first signal from the combined signal.

[0076] As discussed, for legacy devices that support communications using the first radio access technology, the superpositioning of signals using the second radio access technology may be transparent to these legacy devices. Thus, to recover the first signal, legacy devices need not perform additional processing and may decode the combined signal on the time-frequency resource as the device would decode other signals. [0077] FIG. 9 illustrates a decoding pipeline for a dual-mode device that recovers a signal using a first radio access technology and a signal using a second radio access technology included in a combined signal. As illustrated, the decoding pipeline may receive a combined signal, represented as s_LTE + s_NR + noise , where s_LTE represents the signal using the first radio access technology, s_NR represents the signal using the second radio access technology, and noise represents other extraneous signals included in the combined signal. At block 902, the device decodes s_LTE as a legacy device would decode s_LTE and reconstructs the signal.

[0078] At block 904, the device subtracts the decoded and reconstructed signal from the combined signal. This subtraction block generally treats s_LTE as interference to be cancelled from the combined signal, resulting in an interference-free signal defined as s_NR + noise.

[0079] At block 906, the system decodes the signal using the second radio access technology from the interference-free signal generated at block 904. In some embodiments, multiple receive antennas may be used to improve the decoding probability for a low-power signal using the second radio access technology.

[0080] To determine a transmit power needed to successfully transmit a signal using the second radio access technology, the dual-mode device may track the received power (e.g., the reference signal received power, RSRP) of signals using the first radio access technology and link path loss between dual-mode devices. The dual-mode device can receive information about the received power of signals using the first radio access technology by decoding broadcast signals from legacy devices and reading resource reservation information in control information received from other devices in a network. The control information may be, for example, a sidelink control information (SCI) message. In some embodiments, the dual-mode device may receive additional information about the received power of signals using the first radio access technology by querying nearby dual-mode devices to report their observed received power measurements for signals using the first radio access technology.

[0081] To track link path loss between dual-mode devices, the dual-mode device can obtain path loss or a minimum transmit power needed for a signal using the second radio access technology to be successfully decoded at a dual-mode receiver. This information may be obtained by exploiting channel reciprocity and/or by explicitly requesting feedback using resources reserved for signals using the second radio access technology.

[0082] Based on the received power of signals using the first radio access technology and the transmit power needed to successfully transmit a signal using the second radio access technology, a dual-mode device can identify time-frequency resources on which a signal using the second radio access technology can be superpositioned over a signal using the first radio access technology. The time-frequency resources may be identified based on a comparison of the received power of a signal using the first radio access technology to a threshold value based on the minimum transmit power needed to successfully transmit the signal using the second radio access technology. Generally, where a higher transmit power is needed to transmit a signal using the second radio access technology, the signal using the first radio access technology should have a correspondingly high received power such that the signal using the second radio access technology is not destructive to the signal using the first radio access technology on which the signal using the second radio access technology is superpositioned. The dual-mode device can randomly select an identified time-frequency resource on which a signal using the first radio access technology is transmitted and may transmit the signal using the second radio access technology using a minimum required transmit power. Where no resources exist that allow for a successful superpositioning of the signal using the second radio access technology over the signal using the first radio access technology, the signal using the second radio access technology may be transmitted on an available resource that is not already reserved for signals using the first radio access technology.

[0083] In some embodiments, a dual-mode device may announce the selection of a time-frequency resource for superpositioned transmission of a signal using a second radio access technology over a signal using a first radio access technology. By announcing the selection, dual-mode devices that are the intended receivers of the signal may decode the received, combined signal as discussed above with respect to FIG. 9, and other dual-mode devices can defer from using the same time-frequency resource to avoid causing interference to the signal using the second radio access technology. The announcement may be transmitted to the intended receivers when the number of time-frequency resources on which the signal using the second radio access technology can be superpositioned exceeds a threshold and/or the available resources for transmissions using only the second radio access technology is above a threshold. The announcement may be carried on an existing link in, for example, a control message (e.g., sidelink control information), in data carried on a shared channel (e.g., on the physical sidelink shared channel. PSSCH), or in a medium access control (MAC) control element (CE) of the signal. Where the number of applicable time-frequency resources is less than the threshold and/or the available resources for transmissions using only the second radio access technology is below a threshold, the announcement may be broadcast on a resource exclusive to signaling using the second radio access technology. For example, the announcement may be included in a control message (e.g., sidelink control information) or data carried on a shared channel (e.g., the PSSCH). In some embodiments, resources may be reserved for announcing the superpositioning of signals using the second radio access technology over signals using the first radio access technology.

[0084] FIG. 10 is a call flow diagram illustrating example messages that may be exchanged between a transmitting device 1002 and a receiving device 1004 for transmitting and processing combined signals on a time-frequency resource including a first signal using a first radio access technology and a second signal using a second radio access technology, in accordance with certain aspects of the present disclosure.

[0085] As illustrated, transmitting device 1002 can transmit time-frequency resource identification 1010 to receiving device 1004. The time-frequency resource identification 1010 generally identifies time-frequency resources on which a signal using a second radio access technology can be superimposed on a signal using a first radio access technology. The time-frequency resources may be, for example, subframes or symbols within a subframe on which a signal using a second radio access technology can be superimposed on a signal using a first radio access technology. The receiving device 1004 can use this information to determine when to attempt to recover the signal using the second radio access technology from a received signal in which the signal using the second radio access technology is superimposed on a signal using the first radio access technology.

[0086] At block 1012, the transmitting device 1002 determines a transmission power to use for transmitting a superimposed signal using the second radio access technology. The transmitting device 1002 can use power information reported to the transmitting device 1002 (e.g., by receiving device 1004 or a base station or other network entity having received this information from the receiving device 1004) to determine the transmission power for the superimposed signal using the second radio access technology. Generally, the transmission power may be a power that, after having accounted for pathloss between the transmitting device 1002 and the receiving device 1004, results in the superimposed signal using the second radio access technology being treated as non destructive noise to the signal using the first radio access technology.

[0087] Based on the transmission power determined at block 1012, transmitting device 1002 transmits a signal 1014 using the second radio access technology. The signal 1014 may be superimposed on a signal using the first radio access technology. At block 1016, the receiving device 1004 decodes the signal using the first radio access technology.

[0088] As discussed, because the signal 1014 using the second radio access technology is transmitted at a power level that does not cause destructive interference to the signal using the first radio access technology, the receiving device 1004 may not need to pre-process the combined signal in order to remove the noise introduced by the signal 1014. Subsequently, at block 1018, the UE recovers the superimposed signal using the second radio access technology. To recover the superimposed signal, the UE can subtract the signal using the first radio access technology from a combined signal. The resulting signal, after subtracting the signal using the first radio access technology, may be a combination of the signal using the second radio access technology and noise in the communication channel. The receiving device 1004 may process the resulting signal to retrieve the data transmitted by transmitting device 1002 using the second radio access technology.

[0089] FIG. 11 illustrates a communications device 1100 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIGs. 7 and/or 8. The communications device 1100 includes a processing system 1102 coupled to a transceiver 1108. The transceiver 1108 is configured to transmit and receive signals for the communications device 1100 via an antenna 1110, such as the various signals as described herein. The processing system 1102 may be configured to perform processing functions for the communications device 1100, including processing signals received and/or to be transmitted by the communications device 1100.

[0090] The processing system 1102 includes a processor 1104 coupled to a computer- readable medium/memory 1112 via a bus 1106. In certain aspects, the computer-readable medium/memory 1112 is configured to store instructions (e.g., computer-executable code) that when executed by the processor 1104, cause the processor 1104 to perform the operations illustrated in FIGs. 7 and/or 8, or other operations for performing the various techniques discussed herein for transmitting superpositioned signals using a second radio access technology over signals transmitted by other devices using a first radio access technology on a given time-frequency resource and/or recovering a superpositioned signal using a second radio access technology from receiving a combined signal on a time-frequency resource. In certain aspects, computer-readable medium/memory 1112 stores code for identifying a transmit power 1140, code for identifying time-frequency resources 1142, code for transmitting a signal 1144, code for receiving a signal 1146, code for decoding and recovering a first signal 1148, and code for recovering a second signal 1150. In certain aspects, the processor 1104 has circuitry configured to implement the code stored in the computer-readable medium/memory 1112. The processor 1104 includes circuitry for identifying a transmit power 1120, circuitry for identifying time- frequency resources 1122, circuitry for transmitting a signal 1124, circuitry for receiving a signal 1126, circuitry for decoding and recovering a first signal 1128, and circuitry for recovering a second signal 1130.

Example Clauses

[0091] Clause 1: A method for wireless communications by a dual-mode wireless device supporting communications using a first radio access technology and a second radio access technology, comprising: identifying a transmit power for transmitting a signal to a receiving device operating on the second radio access technology; identifying a time-frequency resource for transmitting the signal to the receiving device based, at least in part, on the identified transmit power and time-frequency resources used for transmission by devices operating on the first radio access technology; and transmitting a signal to the receiving device using the second radio access technology based, at least in part, on the identified transmit power using the identified time-frequency resource.

[0092] Clause 2: The method of Clause 1, wherein the signal transmitted to the receiving device is superimposed over signals transmitted using the time-frequency resource for the first radio access technology and comprises nondestructive interference to signals transmitted using the time-frequency resource by the devices operating on the first radio access technology. [0093] Clause 3: The method of Clauses 1 or 2, wherein identifying the time- frequency resource for transmitting the signal to the device operating on the second radio access technology comprises: identifying time-frequency resources on which a signal transmitted by a device operating on the first radio access technology has a received power greater than a threshold power level.

[0094] Clause 4: The method of Clause 3, wherein the threshold power level is determined based on the identified transmit power.

[0095] Clause 5: The method of Clauses 1 or 2, wherein identifying the time- frequency resource for transmitting the signal to the device operating on the second radio access technology comprises: determining that a number of time-frequency resources used for signals transmitted using the first radio access technology having a received power that is greater than a threshold power level is less than a threshold number of time- frequency resources; and selecting a time-frequency resource that is reserved for signals transmitted using the first radio access technology based on the determination.

[0096] Clause 6: The method of any of Clauses 1 through 5, wherein the time- frequency resources used for transmission by devices operating on the first radio access technology comprise time-frequency resources identified from information included in control messages about signals transmitted using the first radio access technology.

[0097] Clause 7: The method of any of Clauses 1 through 6, wherein the time- frequency resources used for transmission by devices operating on the first radio access technology comprise time-frequency resources identified from received power on time- frequency resources reserved for signals using the first radio access technology reported by other devices operating on the second radio access technology.

[0098] Clause 8: The method of any of Clauses 1 through 7, wherein identifying the transmit power for transmitting a signal to a device operating on the second radio access technology comprises: determining a path loss between the transmitting device and the receiving device.

[0099] Clause 9: The method of any of Clauses 1 through 8, further comprising: transmitting, to the receiving device, information about the identified time-frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is greater than a first threshold number of time-frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is greater than a second threshold number of time- frequency resources.

[0100] Clause 10: The method of any of Clauses 1 through 9, further comprising: broadcasting, to the receiving device and one or more other devices operating on the second radio access technology, information about the identified time-frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is less than a first threshold number of time-frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is less than a second threshold number of time- frequency resources.

[0101] Clause 11 : A method for communications using a first radio access technology and a second radio access technology, comprising: receiving, on a time-frequency resource, a combined signal including a first signal using a first radio access technology and a second signal using a second radio access technology; decoding and reconstructing the first signal from the combined signal; and recovering the second signal by subtracting the decoded and reconstructed first signal from the combined signal.

[0102] Clause 12: The method of Clause 11, further comprising: reporting, to the device, information about time-frequency resources on which signals are received using the first radio access technology.

[0103] Clause 13 : The method of Clause 12, wherein the information about the time- frequency resources on which signals are received using the first radio access technology is reported in a control message.

[0104] Clause 14: The method of Clause 12, wherein the information about the time- frequency resources on which signals are received using the first radio access technology comprises received power for each of the time-frequency resources.

[0105] Clause 15: The method of any of Clauses 11 through 14, further comprising: receiving, from the device, information identifying the time-frequency resource.

[0106] Clause 16: The method of Clause 15, wherein the information identifying the time-frequency resource is received in a broadcast transmission from the device.

[0107] Clause 17: An apparatus for wireless communications, comprising: a memory; and a processor configured to perform the operations of any of Clauses 1 through 10. [0108] Clause 18: An apparatus for wireless communications, comprising: a memory; and a processor configured to perform the operations of any of Clauses 11 through 16.

[0109] Clause 19: An apparatus for wireless communications, comprising: means for performing the operations of any of Clauses 1 through 10.

[0110] Clause 20: An apparatus for wireless communications, comprising means for performing the operations of any of Clauses 11 through 16.

[0111] Clause 21: A computer-readable medium having instructions stored thereon which, when executed by a processor, performs the operations of any of Clauses 1 through 10

[0112] Clause 22: A computer-readable medium having instructions stored thereon which, when executed by a processor, performs the operations of any of Clauses 11 through 16.

Additional Considerations

[0113] The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged 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 specific steps and/or actions may be modified without departing from the scope of the claims.

[0114] As used herein, a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0115] As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

[0116] The previous 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 generic principles defined herein may be applied to other aspects. 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 of the 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.” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”

[0117] The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component s) and/or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components. For example, various operations shown in FIGs. 7-8 may be performed by various processors shown in FIG. 4, such as processors 466, 458, 464, and/or controller/processor 480 of the UE 120a.

[0118] The various illustrative logical blocks, modules and circuits described in connection 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, e.g., 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. [0119] If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1), a user interface (e.g., 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 therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0120] If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine- readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, 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 medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

[0121] A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into 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 referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

[0122] Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0123] Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIGs. 8-9.

[0124] Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

[0125] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes 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

WHAT IS CLAIMED IS:

1. A method for wireless communications by a dual -mode wireless device supporting communications using a first radio access technology and a second radio access technology, comprising: identifying a transmit power for transmitting a signal to a receiving device operating on the second radio access technology; identifying a time-frequency resource for transmitting the signal to the receiving device based, at least in part, on the identified transmit power and time-frequency resources used for transmission by devices operating on the first radio access technology; and transmitting a signal to the receiving device using the second radio access technology based, at least in part, on the identified transmit power using the identified time-frequency resource.

2. The method of claim 1, wherein the signal transmitted to the receiving device is superimposed over signals transmitted using the time-frequency resource for the first radio access technology and comprises nondestructive interference to signals transmitted using the time-frequency resource by the devices operating on the first radio access technology.

3. The method of claim 1, wherein identifying the time-frequency resource for transmitting the signal to the device operating on the second radio access technology comprises: identifying time-frequency resources on which a signal transmitted by a device operating on the first radio access technology has a received power greater than a threshold power level.

4. The method of claim 3, wherein the threshold power level is determined based on the identified transmit power.

5. The method of claim 1, wherein identifying the time-frequency resource for transmitting the signal to the device operating on the second radio access technology comprises: determining that a number of time-frequency resources used for signals transmitted using the first radio access technology having a received power that is greater than a threshold power level is less than a threshold number of time-frequency resources; and selecting a time-frequency resource that is reserved for signals transmitted using the first radio access technology based on the determination.

6. The method of claim 1, wherein the time-frequency resources used for transmission by devices operating on the first radio access technology comprise time- frequency resources identified from information included in control messages about signals transmitted using the first radio access technology.

7. The method of claim 1, wherein the time-frequency resources used for transmission by devices operating on the first radio access technology comprise time- frequency resources identified from received power on time-frequency resources reserved for signals using the first radio access technology reported by other devices operating on the second radio access technology.

8. The method of claim 1, wherein identifying the transmit power for transmitting a signal to a device operating on the second radio access technology comprises: determining a path loss between the dual-mode wireless device and the receiving device.

9. The method of claim 1, further comprising: transmitting, to the receiving device, information about the identified time- frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is greater than a first threshold number of time-frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is greater than a second threshold number of time-frequency resources.

10. The method of claim 1, further comprising: broadcasting, to the receiving device and one or more other devices operating on the second radio access technology, information about the identified time-frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is less than a first threshold number of time-frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is less than a second threshold number of time- frequency resources.

11. A method for communications using a first radio access technology and a second radio access technology, comprising: receiving, on a time-frequency resource, a combined signal including a first signal using a first radio access technology and a second signal using a second radio access technology; decoding and reconstructing the first signal from the combined signal; and recovering the second signal by subtracting the decoded and reconstructed first signal from the combined signal.

12. The method of claim 1, further comprising: reporting, to the device, information about time-frequency resources on which signals are received using the first radio access technology.

13. The method of claim 12, wherein the information about the time-frequency resources on which signals are received using the first radio access technology is reported in a control message.

14. The method of claim 12, wherein the information about the time-frequency resources on which signals are received using the first radio access technology comprises received power for each of the time-frequency resources.

15. The method of claim 11, further comprising: receiving, from the device, information identifying the time-frequency resource.

16. The method of claim 15, wherein the information identifying the time-frequency resource is received in a broadcast transmission from the device.

17. An apparatus for wireless communications by a dual-mode wireless device supporting communications using a first radio access technology and a second radio access technology, comprising: a processor configured to: identify a transmit power for transmitting a signal to a receiving device operating on the second radio access technology, identify a time-frequency resource for transmitting the signal to the receiving device based, at least in part, on the identified transmit power and time-frequency resources used for transmission by devices operating on the first radio access technology, and transmit a signal to the receiving device using the second radio access technology based, at least in part, on the identified transmit power using the identified time-frequency resource; and a memory.

18. The apparatus of claim 17, wherein the signal transmitted to the receiving device is superimposed over signals transmitted using the time-frequency resource for the first radio access technology and comprises nondestructive interference to signals transmitted using the time-frequency resource by the devices operating on the first radio access technology.

19. The apparatus of claim 17, wherein identifying the time-frequency resource for transmitting the signal to the device operating on the second radio access technology comprises: identifying time-frequency resources on which a signal transmitted by a device operating on the first radio access technology has a received power greater than a threshold power level.

20. The apparatus of claim 19, wherein the threshold power level is determined based on the identified transmit power.

21. The apparatus of claim 17, wherein the processor is configured to identify the time-frequency resource for transmitting the signal to the device operating on the second radio access technology by: determining that a number of time-frequency resources used for signals transmitted using the first radio access technology having a received power that is greater than a threshold power level is less than a threshold number of time-frequency resources; and selecting a time-frequency resource that is reserved for signals transmitted using the first radio access technology based on the determination.

22. The apparatus of claim 17, wherein the time-frequency resources used for transmission by devices operating on the first radio access technology comprise time- frequency resources identified from information included in control messages about signals transmitted using the first radio access technology.

23. The apparatus of claim 17, wherein the time-frequency resources used for transmission by devices operating on the first radio access technology comprise time- frequency resources identified from received power on time-frequency resources reserved for signals using the first radio access technology reported by other devices operating on the second radio access technology.

24. The apparatus of claim 17, wherein the processor is configured to identify the transmit power for transmitting a signal to a device operating on the second radio access technology by: determining a path loss between the dual -mode wireless device and the receiving device.

25. The apparatus of claim 17, wherein the processor is further configured to: transmit, to the receiving device, information about the identified time-frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is greater than a first threshold number of time- frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is greater than a second threshold number of time-frequency resources.

26. The apparatus of claim 17, wherein the processor is further configured to: broadcast, to the receiving device and one or more other devices operating on the second radio access technology, information about the identified time-frequency resource, where a number of time-frequency resources used for signals transmitted using a first radio access technology is less than a first threshold number of time-frequency resources or a number of time-frequency resources reserved for signals transmitted using a second radio access technology is less than a second threshold number of time- frequency resources.

27. An apparatus for wireless communications by a dual-mode wireless device supporting communications using a first radio access technology and a second radio access technology, comprising: a processor configured to: receive, on a time-frequency resource, a combined signal including a first signal using a first radio access technology and a second signal using a second radio access technology, decode and reconstruct the first signal from the combined signal, and recover the second signal by subtracting the decoded and reconstructed first signal from the combined signal; and a memory.

28. The apparatus of claim 27, wherein the processor is further configured to: report, to the device, information about time-frequency resources on which signals are received using the first radio access technology.

29. The apparatus of claim 28, wherein: the information about the time-frequency resources on which signals are received using the first radio access technology is reported in a control message; and the information about the time-frequency resources on which signals are received using the first radio access technology comprises received power for each of the time-frequency resources.

30. The apparatus of claim 27, wherein the processor is further configured to: receive, from the device, information identifying the time-frequency resource.