CN108886699B - Apparatus and method for radio resource measurement and CSI measurement for licensed assisted access UE - Google Patents

Abstract

Systems and methodologies are generally described that provide DRS measurements in unlicensed frequency bands. The UE determines whether a DRS power level of a DRS transmission is already different from a power level of a previously received DRS transmission. If so, the UE does not report DRS measurements or adjust DRS measurements for RRM measurements. In either case, the CSI measurement results are still reported. If the DRS measurement falls outside a predetermined range from the mean, the DRS measurement is averaged with the previous DRS measurement. The UE determines DRS power level changes through DRS measurement changes via an indication from the eNB or other characteristics of DRS transmissions resulting from use of the unlicensed frequency band.

Description

Apparatus and method for radio resource measurement and CSI measurement for licensed assisted access UE

Priority declaration

The present application claims priority benefits of U.S. provisional patent application serial No. 62/320,998 entitled "APPARATUS AND METHOD for RADIO RESOURCE MEASUREMENT AND CSI MEASUREMENT for licensed assisted access to a UE" (LICENSED ASSISTED ACCESS US RADIO RESOURCE MEASUREMENT AND CSI MEASUREMENT associated with METHOD) "filed on 11/4/2016, the entire contents of which are incorporated herein by reference.

Technical Field

Embodiments relate to radio access networks. Some embodiments relate to reference signal measurements in various cellular and Wireless Local Area Network (WLAN) networks, including third generation partnership project long term evolution (3GPP LTE) networks and LTE-advanced (LTE-a) networks, as well as 4 th generation (4G) networks and 5 th generation (5G) networks. Some embodiments relate to various types of measurements in License Assisted Access (LAA) networks.

Background

The use of 3GPP LTE systems, including LTE and LTE-a systems, has increased due to the increase in device types of User Equipment (UE) that use network resources, as well as the amount of data and bandwidth (e.g., video streaming) used by various applications. LTE networks typically operate in multiple Radio Frequency (RF) bands licensed to wireless operators, where base stations (evolved node bs (enbs)) communicate with an increasing number and variety of types of User Equipment (UEs). Communications are typically limited to licensed bands regulated by the federal government; however, the increase in network usage of user equipment and Machine Type Communication (MTC) devices has exceeded the limits of licensed frequency bands.

To alleviate the pressure on licensed bands, operators have turned to using unlicensed spectrum, such as the industrial, scientific, and medical RF spectrum (ISM band), in Licensed Assisted Access (LAA) communications. While only LTE systems can legally operate in the LTE band, other systems, such as Wireless Local Area Network (WLAN) systems, coexist with LAA systems in unlicensed spectrum. The use of unlicensed spectrum comes at the cost of increased complexity and various issues related to accessing the unlicensed spectrum, as the spectrum is shared by various radio access technologies. For example, when the LAA spectrum is used to transmit reference signals, certain assumptions in reference signal measurements may no longer hold. This may lead to problems with respect to the characteristics determined based on the reference signal measurements made at the UE.

Drawings

In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

Fig. 1 illustrates an example of a portion of an end-to-end network architecture of an LTE network, in accordance with some embodiments.

FIG. 2 illustrates components of a communication device according to some embodiments.

Fig. 3 illustrates a block diagram of a communication device, in accordance with some embodiments.

Fig. 4 illustrates another block diagram of a communication device in accordance with some embodiments.

Fig. 5 illustrates reference signal fluctuations in the LAA spectrum, according to some embodiments.

Fig. 6 illustrates a flow diagram of reference signal reporting, according to some embodiments.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of others. Embodiments set forth in the claims encompass all available equivalents of those claims.

Fig. 1 illustrates an example of a portion of an end-to-end network architecture of an LTE network, in accordance with some embodiments. As used herein, LTE networks refer to LTE and LTE-advanced (LTE-a) networks, as well as other releases of LTE networks to be developed. Network 100 may include a Radio Access Network (RAN) (e.g., an E-UTRAN or evolved universal terrestrial radio access network as depicted) 101 and a core network 120 (e.g., shown as an Evolved Packet Core (EPC)) coupled together by an SI interface 115. For convenience and brevity, only a portion of the core network 120 and the RAN 101 are shown in this example.

The core network 120 may include a Mobility Management Entity (MME)122, a serving gateway (serving GW)124, and a packet data network gateway (PDN GW) 126. RAN 101 may include an evolved node b (enb)104 (which may serve as a base station) for communicating with User Equipment (UE) 102. The enbs 104 may include a macro eNB 104a and a Low Power (LP) eNB 104 b. Other elements, such as a Home Location Register (HLR)/Home Subscriber Server (HSS), a database including subscriber information of the 3GPP network that may perform configuration storage, identity management, and user status storage, and a Policy and Charging Rules Function (PCRF) that performs policy decisions to dynamically apply quality of service (QoS) and charging policies on a per-flow basis, are not shown for convenience.

The MME 122 may be similar in function to the control plane of a conventional Serving GPRS Support Node (SGSN). The MME 122 may manage mobility aspects in access, such as gateway selection and tracking area list management, performing Mobility Management (MM), and Session Management (SM). The non-access stratum (NAS) is part of the control plane between the UE 102 and the MME 122. NAS is used for signaling between UE 102 and EPC in the LTE UMTS protocol stack. The NAS supports UE mobility and session management for establishing and maintaining an IP connection between the UE 102 and the PDN GW 126.

The serving GW 124 may terminate (terminate) the user plane interface towards the RAN 101 and route data packets between the RAN 101 and the core network 120. In addition, the serving GW 124 may be a local mobility anchor for inter-eNB handover and may also provide an anchor for inter-3 GPP mobility. Other responsibilities may include lawful interception, charging and policy enforcement, packet routing, idle mode packet buffering, and triggering the MME to page the UE. The serving GW 124 and MME 122 may be implemented in one physical node or in separate physical nodes.

The PDN GW 126 may terminate the SGi interface towards a Packet Data Network (PDN). The PDN GW 126 may route data packets between the EPC 120 and the external PDN, and may perform policy enforcement and charging data collection, UE IP address allocation, packet screening, and filtering. The PDN GW 126 may also provide an anchor point for mobile devices with non-LTE access. The external PDN may be an IP Multimedia Subsystem (IMS) domain and any other type of IP network. The PDN GW 126 and the serving GW 124 may be implemented in one physical node or in separate physical nodes.

The eNB 104 (macro and micro enbs) may terminate the air interface protocol and may be the first contact point for the UE 102. In some embodiments, the eNB 104 may implement various logical functions of the RAN 101 including, but not limited to, RNCs (radio network controller functions), such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. According to an embodiment, the UE 102 may be configured to communicate Orthogonal Frequency Division Multiplexed (OFDM) communication signals with the eNB 104 over a multicarrier communication channel in accordance with an OFDMA communication technique. The OFDM signal may include a plurality of orthogonal subcarriers.

S1 interface 115 may be an interface separating RAN 101 and EPC 120. The S1 interface 115 may be divided into two parts: S1-U and S1-MME, where S1-U may carry traffic data between the eNB 104 and the serving GW 124, and S1-MME may be the signaling interface between the eNB 104 and the MME 122. The X2 interface may be an interface between enbs 104. The X2 interface may include two parts: X2-C and X2-U. X2-C may be a control plane interface between eNBs 104, while X2-U may be a user plane interface between eNBs 104.

With cellular networks, LP cell 104b may generally be used to extend coverage to indoor areas where outdoor signals do not reach well, or to increase network capacity in heavily used areas. In particular, it may be desirable to use different sized cells (macro, micro, pico, and femto cells) to enhance the coverage of a wireless communication system, thereby improving system performance. The different sized cells may operate on the same frequency band or may operate on different frequency bands (with each cell operating on a different frequency band or only different sized cells operating on different frequency bands). As used herein, the term LP eNB refers to any suitable opposing LP eNB for implementing a smaller cell (smaller than a macro cell), such as a femto cell, pico cell, or micro cell. A femto cell eNB may typically be provided by a mobile network operator to its residential or enterprise customers. Femto cells may typically be the size of a residential gateway or smaller and are typically connected to broadband lines. Femto cells may connect to the mobile operator's mobile network and provide additional coverage typically ranging from 30 meters to 50 meters. Thus, LP eNB 104b may be a femto cell eNB. In some embodiments, when the LP eNB 104b is a home eNB (HeNB), a HeNB gateway may be provided between the HeNB and the MME/serving gateway. The HeNB gateway may control multiple henbs and provide user data and signal traffic from the henbs to the MME/serving gateway. Similarly, a pico cell may be a wireless communication system that typically covers a small area, e.g., in a building (office building, mall, train station, etc.), or more recently in an airplane. A picocell eNB may typically connect to another eNB (e.g., a macro eNB) through an X2 link, through its Base Station Controller (BSC) functionality, and/or to an MME/serving gateway via an S1 interface. Thus, since the LP eNB may be coupled to the macro eNB 104a via an X2 interface, the LP eNB may be implemented with a pico eNB. The pico eNB or other LP eNB 104b may contain some or all of the functionality of the macro eNB LP eNB 104 a. In some cases, this may be referred to as an access point base station or an enterprise femtocell.

The eNB 104 may provide periodic reference signaling messages for various purposes. The reference signaling messages may include cell-specific reference signals (CRS), which may be used for cell search and initial acquisition of communications with the eNB, downlink channel quality measurements, and downlink channel estimation for coherent demodulation or detection. Channel Quality Indicators (CQIs) may be used to indicate measurements of channel quality, including carrier level Received Signal Strength Indicators (RSSI) and Bit Error Rates (BER). Channel state information reference signals (CSI-RS) may be used to estimate the channel and report channel quality information. The Discovery Reference Signal (DRS) may include one or more of the above-described signals (synchronization and reference signals) and may be specific to a single UE. The use of DRS is introduced in LTE release 12 to facilitate fast transition of small cells (e.g., femto or pico cells) from an OFF state to an ON state by transmitting a low duty cycle signal for Radio Resource Management (RRM) measurements during the OFF state. Transmission of DRSs allows UEs to discover and measure dormant cells, among other uses.

FIG. 2 illustrates components of a communication device according to some embodiments. The communication device 200 may be a UE, eNB, or other network component as described herein. The communication device 200 may be a fixed non-mobile device or may be a mobile device. In some embodiments, the UE 200 may include application circuitry 202, baseband circuitry 204, Radio Frequency (RF) circuitry 206, front-end module (FEM) circuitry 208, and one or more antennas 210 coupled together at least as shown. At least some of the baseband circuitry 204, RF circuitry 206, and FEM circuitry 208 may form a transceiver. In some embodiments, other network elements (e.g., MMEs) may include some or all of the components shown in fig. 2.

The application or processing circuitry 202 may include one or more application processors. For example, the application circuitry 202 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

The baseband circuitry 204 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 204 may include one or more baseband processors and/or control logic to process baseband signals received from the receive signal path of RF circuitry 206 and to generate baseband signals for the transmit signal path of RF circuitry 206. The baseband processing circuitry 204 may interface with the application circuitry 202 for the generation and processing of baseband signals and control the operation of the RF circuitry 206. For example, in some embodiments, the baseband circuitry 204 may include a second generation (2G) baseband processor 204a, a third (3G) baseband processor 204b, a fourth generation (4G) baseband processor 204c, and/or other baseband processor(s) 204d for other existing generations, generations in development, or generations to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 204 (e.g., one or more of the baseband processors 204 a-d) may process various radio control functions that enable communication with one or more radio networks via the RF circuitry 206. The radio control functions may include, but are not limited to: signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, the modulation/demodulation circuitry of the baseband circuitry 204 may include FFT, precoding, and/or constellation mapping/demapping functionality. In some embodiments, the encoding/decoding circuitry of baseband circuitry 204 may include convolution, tail-biting convolution, turbo, Viterbi (Viterbi), and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functions are not limited to these examples, and other suitable functions may be included in other embodiments.

In some embodiments, the baseband circuitry 204 may include elements of a protocol stack, e.g., elements of an evolved utran (eutran) protocol, including, for example, Physical (PHY) elements, Medium Access Control (MAC) elements, Radio Link Control (RLC) elements, Packet Data Convergence Protocol (PDCP) elements, Radio Resource Control (RRC) elements, and/or non-access stratum (NAS) elements. A Central Processing Unit (CPU)204e of the baseband circuitry 204 may be configured to run elements of a protocol stack for signaling of the PHY, MAC, RLC, PDCP, and/or RRC layers, and/or NAS. In some embodiments, the baseband circuitry may include audio digital signal processor(s) (DSP)204 f. The audio DSP(s) 204f may be or include elements for compression/decompression and echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, components of the baseband circuitry may be combined in a single chip or a single chipset, or arranged on the same circuit board, as appropriate. In some embodiments, some or all of the constituent components of the baseband circuitry 204 and the application circuitry 202 may be implemented together, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 204 may provide communications compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 204 may support communication with EUTRAN and/or other Wireless Metropolitan Area Networks (WMANs), Wireless Local Area Networks (WLANs), Wireless Personal Area Networks (WPANs). Embodiments in which the baseband circuitry 204 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. In some embodiments, the device may be configured to operate in accordance with communication standards or other protocols or standards including Institute of Electrical and Electronics Engineers (IEEE)802.16 wireless technology (WiMax), IEEE 802.11 wireless technology (WiFi), including IEEE 802.11ad operating in the 60GHz millimeter wave spectrum, or various other wireless technologies such as global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE Radio Access Network (GERAN), Universal Mobile Telecommunications System (UMTS), UMTS Terrestrial Radio Access Network (UTRAN), or other 2G, 3G, 4G, 5G, etc. technologies that have been or will be developed.

The RF circuitry 206 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, RF circuitry 206 may include switches, filters, amplifiers, and the like to facilitate communication with a wireless network. RF circuitry 206 may include a receive signal path that may include circuitry to down-convert RF signals received from FEM circuitry 208 and provide baseband signals to baseband circuitry 204. RF circuitry 206 may also include a transmit signal path that may include circuitry to up-convert baseband signals provided by baseband circuitry 204 and provide RF output signals to FEM circuitry 208 for transmission.

In some embodiments, RF circuitry 206 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 206 may include a mixer circuit 206a, an amplifier circuit 206b, and a filter circuit 206 c. The transmit signal path of the RF circuitry 206 may include filter circuitry 206c and mixer circuitry 206 a. RF circuitry 206 may also include synthesizer circuitry 206d, which synthesizer circuitry 206d is used to synthesize frequencies for use by mixer circuitry 206a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 206a of the receive signal path may be configured to down-convert the RF signal received from the FEM circuitry 208 based on the synthesized frequency provided by the synthesizer circuitry 206 d. The amplifier circuit 206b may be configured to amplify the downconverted signal, and the filter circuit 206c may be a Low Pass Filter (LPF) or a Band Pass Filter (BPF) configured to remove unwanted signals from the downconverted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuitry 204 for further processing. In some embodiments, the output baseband signal may be a zero frequency baseband signal, but this is not a requirement. In some embodiments, mixer circuit 206a of the receive signal path may comprise a passive mixer, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 206a of the transmit signal path may be configured to upconvert the input baseband signal based on a synthesis frequency provided by the synthesizer circuitry 206d to generate an RF output signal for the FEM circuitry 208. The baseband signal may be provided by the baseband circuitry 204 and may be filtered by the filter circuitry 206 c. The filter circuit 206c may include a Low Pass Filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may comprise two or more mixers and may be arranged for quadrature down-conversion and/or quadrature up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley (Hartley) image rejection). In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may be configured for superheterodyne operation.

In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, RF circuitry 206 may include analog-to-digital converter (ADC) circuitry and digital-to-analog converter (DAC) circuitry, and baseband circuitry 204 may include a digital baseband interface to communicate with RF circuitry 206.

In some dual-mode embodiments, separate radio IC circuitry may be provided to process signals for each spectrum, although the scope of the embodiments is not limited in this respect.

In some embodiments, synthesizer circuit 206d may be a fractional-N synthesizer or a fractional-N/N +1 synthesizer, although the scope of embodiments is not limited in this respect as other types of frequency synthesizers may be appropriate. For example, synthesizer circuit 206d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase locked loop with a frequency divider.

The synthesizer circuit 206d may be configured to synthesize an output frequency based on the frequency input and the divider control input for use by the mixer circuit 206a of the RF circuit 206. In some embodiments, synthesizer circuit 206d may be a fractional-N/N +1 synthesizer.

In some embodiments, the frequency input may be provided by a Voltage Controlled Oscillator (VCO), but this is not required. The divider control input may be provided by the baseband circuitry 204 or the application processor 202 according to a desired output frequency. In some embodiments, the divider control input (e.g., N) may be determined from a look-up table based on the channel indicated by the application processor 202.

Synthesizer circuit 206d of RF circuit 206 may include a frequency divider, a Delay Locked Loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the divider may be a dual-mode divider (DMD) and the phase accumulator may be a Digital Phase Accumulator (DPA). In some embodiments, the DMD may be configured to divide an input signal by N or N +1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, a DLL may include a set of cascaded tunable delay elements, a phase detector, a charge pump, and a D-type flip-flop. In these embodiments, the delay elements may be configured to decompose the VCO period into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this manner, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuit 206d may be configured to generate a carrier frequency as the output frequency, while in other embodiments the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with a quadrature generator and divider circuit to generate multiple signals at the carrier frequency having multiple phases that are different from each other. In some embodiments, the output frequency may be the LO frequency (f)_LO). In some embodiments, the RF circuitry 206 may include an IQ/polarity converter.

FEM circuitry 208 may include a receive signal path that may include circuitry configured to operate on received RF signals from one or more antennas 210, amplify the received signals, and provide an amplified version of the received signals to RF circuitry 206 for further processing. FEM circuitry 208 may also include a transmit signal path, which may include circuitry configured to amplify signals provided by RF circuitry 206 for transmission by one or more of one or more antennas 210.

In some embodiments, FEM circuitry 208 may include TX/RX switches to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a Low Noise Amplifier (LNA) to amplify the received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuitry 206). The transmit signal path of FEM circuitry 208 may include a Power Amplifier (PA) to amplify an input RF signal (e.g., provided by RF circuitry 206), and may include one or more filters to generate an RF signal for subsequent transmission (e.g., by one or more of one or more antennas 210).

In some embodiments, the communication device 200 may include additional elements, such as memory/storage, a display, a camera, sensors, and/or input/output (I/O) interfaces, as described in more detail below. In some embodiments, the communication device 200 described herein may be part of a portable wireless communication device, such as a Personal Digital Assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or another device that may receive and/or transmit information wirelessly. In some embodiments, the communication device 200 may include one or more user interfaces designed to enable a user to interact with the system, and/or peripheral component interfaces designed to enable peripheral components to interact with the system. For example, the communication device 200 may include one or more of a keyboard, keypad, touch pad, display, sensor, non-volatile memory port, Universal Serial Bus (USB) port, audio jack, power interface, one or more antennas, graphics processor, application processor, speaker, microphone, and other I/O components. The display may be an LCD or LED screen including a touch screen. The sensors may include a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may communicate with components of a positioning network, such as Global Positioning System (GPS) satellites.

Antenna 210 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, antennas 210 may be effectively separated to take advantage of different channel characteristics and spatial diversity that may result.

Although communication device 200 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including Digital Signal Processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Radio Frequency Integrated Circuits (RFICs), and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements.

Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

Fig. 3 is a block diagram of a communication device according to some embodiments. The device may be a UE (e.g., the UE shown in fig. 1). Physical layer circuitry 302 may perform various encoding and decoding functions, which may include forming a baseband signal for transmission and decoding a received signal. Communication device 300 may also include a medium access control layer (MAC) circuit 304 to control access to the wireless medium. The communication device 300 may also include processing circuitry 306 (e.g., one or more single-core or multi-core processors) and memory 308, the processing circuitry 306 and memory 308 arranged to perform the operations described herein. The physical layer circuitry 302, MAC circuitry 304, and processing circuitry 306 may handle various radio control functions that enable communication with one or more radio networks compatible with one or more radio technologies. The radio control functions may include signal modulation, encoding, decoding, radio frequency shifting, and the like. For example, similar to the device shown in fig. 2, in some embodiments, communication may be accomplished using one or more of WMAN, WLAN, and WPAN. In some embodiments, the communication device 300 may be configured to operate in accordance with 3GPP standards or other protocols or standards, including WiMax, WiFi, WiGig, GSM, EDGE, GERAN, UMTS, UTRAN, or other 2G, 3G, 4G, 5G, etc. technologies that have been or will be developed. The communication device 300 may include a transceiver circuit 312 for enabling wireless communication with other external devices and an interface 314 for enabling wired communication with other external devices. As another example, transceiver circuitry 312 may perform various transmit and receive functions, such as conversion of signals between a baseband range and a Radio Frequency (RF) range.

Antenna 301 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some MIMO embodiments, antennas 301 may be effectively separated to take advantage of different channel characteristics and spatial diversity that may result.

Although communication device 300 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements (e.g., processing elements including DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, FPGAs, ASICs, RFICs, and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements. Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein.

Fig. 4 illustrates another block diagram of a communication device in accordance with some embodiments. In alternative embodiments, communication device 400 may operate as a standalone device or may be connected (e.g., networked) to other communication devices. In a networked deployment, the communication device 400 may operate in the server-client network environment with the identity of a server communication device, a client communication device, or both. In an example, the communications device 400 can operate as a peer to peer communications device in a peer to peer (P2P) (or other distributed) network environment. The communication device 400 may be a UE, eNB, PC, tablet PC, STB, PDA, mobile phone, smartphone, web appliance, network router, switch or bridge, or any communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by the communication device. Further, while only a single communication device is shown, the term "communication device" should also be taken to include any collection of communication devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methods discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

Examples as described herein may include, or may operate on, logic or multiple components, modules, or mechanisms. A module is a tangible entity (e.g., hardware) capable of performing specified operations and may be configured or arranged in a particular manner. In an example, the circuitry may be arranged as a module in a specified manner (e.g., internally or with respect to an external entity such as other circuitry). In an example, all or portions of one or more computer systems (e.g., a stand-alone client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application portions, or applications) to operate to perform modules of specified operations. In an example, the software may reside on a communication device readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

Thus, the term "module" is understood to encompass a tangible entity, i.e., an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., temporarily) configured (e.g., programmed) to operate in a specific manner or to perform some or all of any of the operations described herein. Considering the example where modules are temporarily configured, not every module need be instantiated at any given time. For example, where the modules include a general purpose hardware processor configured using software, the general purpose hardware processor may be configured at different times as respective different modules. The software may thus configure the hardware processor to, for example, constitute a particular module at a certain instance in time and to constitute a different module at a different instance in time.

A communication device (e.g., computer system) 400 may include a hardware processor 402 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a hardware processor core, or any combination thereof), a main memory 404, and a static memory 406, some or all of which may communicate with each other via an interlink (e.g., bus) 408. The communication device 400 may also include a display unit 410, an alphanumeric input device 412 (e.g., a keyboard), and a User Interface (UI) navigation device 414 (e.g., a mouse). In an example, the display unit 410, the input device 412, and the UI navigation device 414 may be a touch screen display. The communication device 400 may also include a storage device (e.g., drive unit) 416, a signal generation device 418 (e.g., a speaker), a network interface device 420, and one or more sensors 421, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or other sensor. The communication device 400 may include an output controller 428, e.g., a serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., Infrared (IR), Near Field Communication (NFC), etc.) connection for communicating with or controlling one or more peripheral devices (e.g., printer, card reader, etc.).

The storage device 416 may include a communication device-readable medium 422 having stored thereon one or more sets of data structures or instructions 424 (e.g., software), the one or more sets of data structures or instructions 424 embodying or being used by any one or more of the techniques or functions described herein. The instructions 424 may also reside, completely or at least partially, within the main memory 404, within static memory 406, or within the hardware processor 402 during execution thereof by the communication device 400. In an example, one or any combination of the hardware processor 402, the main memory 404, the static memory 406, or the storage device 416 may constitute communication device readable media.

While the communication device-readable medium 422 is shown to be a single medium, the term "communication device-readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 424.

The term "communication device-readable medium" can include any medium that can store, encode, or carry instructions for execution by communication device 400 and that cause communication device 400 to perform any one or more of the techniques of this disclosure, or that can store, encode, or carry data structures used by or associated with such instructions. Non-limiting examples of communication device readable media may include solid-state memory, and optical and magnetic media. Specific examples of the communication device readable medium may include: non-volatile memories, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, e.g., internal hard disks and removable disks; a magneto-optical disk; random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, the communication device readable medium may include a non-transitory communication device readable medium. In some examples, the communication device readable medium may include a communication device readable medium that is not a transitory propagating signal.

The transmission medium may also be used to send or receive instructions 424 over a communication network 426 via the network interface device 420 utilizing any one of a number of transmission protocols (e.g., frame relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), hypertext transfer protocol (HTTP), etc.). An example communication network may include: local Area Networks (LANs), Wide Area Networks (WANs), packet data networks (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., referred to as

Is known as the IEEE 802.11 family of standards

IEEE 802.16 family of standards), IEEE 802.15.4 family of standards, LTE family of standards, UMTS family of standards, peer-to-peer (P2P) networks, and so forth. In an example, the network interface device 420 may include one or more physical jacks (e.g., ethernet, coaxial, or telephone jacks) or one or more antennas to connect to the communication network 426. In an example, the network interface device 420 may include multiple antennas to wirelessly communicate using at least one of: single Input Multiple Output (SIMO), MIMO, or Multiple Input Single Output (MISO) techniques. In some examples, the network interface device 420 may communicate wirelessly using multi-user MIMO techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 400, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

As described above, release 12 of the 3GPP specifications introduced DRS (TS 36.211v12.4.0, section 6.11). The DRS may support synchronization and RRM measurements for large and small cells, as well as measurements of channel conditions. The DRS may be periodically transmitted from the eNB through the unlicensed band. The DRS may include CRS and/or CSI-RS (as well as primary and/or secondary synchronization signals). In one definition, a small cell may transmit low power (e.g., up to about 30dBm and encompassing a small area (e.g., 100m or less)) signals, such that only a few users (e.g., tens of users) may be served. Small cells may operate in an "on (or active)" state or an "off (or dormant)" state. This may allow small cells to become dormant when not in use, thereby reducing interference generated by small cells in neighbouring active small cells.

As the number and types of devices increase, the use of the LTE frequency band for data signals and control signals may be overly restricted. In particular, rather than or in addition to using RRM and CSI measurements in the LTE spectrum, the eNB and UE may perform RRM and CSI measurements in the LAA spectrum. The UE may measure the DRS to generate a DRS measurement report (also referred to herein as a DRS report, which is a RRM report when the RRM measurement is transmitted and a CSI report when the CSI measurement is transmitted) and transmit the DRS report to the eNB. However, using DRSs for channel estimation and handover in LAA spectrum may encounter problems not present in LTE spectrum. In particular, the inherent nature of contention-based access systems may not allow DRS signals to be transmitted and measured at regular intervals, but rather used at "burst" intervals. However, the eNB may expect the UE to periodically perform DRS measurements based on a consistent reference power between measurements. If the period of DRS transmission is too sparse, this may result in inconsistent measurement accuracy due to lack of received signal samples.

In addition, unlike LTE transmissions from an eNB whose transmissions are constrained to a predetermined bandwidth, the bandwidth of LAA transmissions from an eNB may vary significantly due to significant variations in the use of other non-LTE devices. Accordingly, the bandwidth of LAA DRS transmission may vary accordingly. Although the available LAA bandwidth may vary, the transmission power of the eNB may only be able to vary within certain limits due to FCC or other government transmission requirements. For example, rather than remaining constant in the LAA band, the transmission power of DRS may change as the amount of LAA spectrum available for eNB transmission changes.

Thus, the power level of DRS transmissions in the LAA spectrum from the eNB may vary significantly. This may add additional complications to the UE measurements, as the RSRP or RSRQ may vary not only due to channel conditions, but also due to transmission power variations, for example. This is problematic because in 3GPP, the UE may assume that the transmission power of CRS and/or CSI-RS in DRS is constant regardless of the subframe in which the DRS is transmitted within the Discovery Measurement Timing Configuration (DMTC). That is, while it is assumed that the measurements at the UE are consistent to maintain the radio link to the serving cell, the power level may vary. However, for RRM measurements, if the power level changes significantly, the network may unnecessarily affect the handover of the UE to another cell. Although emphasis is placed here, handover is only one of the functions for RRM measurements. This may cause a large amount of unnecessary control overhead in the EPC (and within the UE) and result in a significant reduction in connection strength. CSI measurement variations may also be problematic, but may be relatively small, as switching channels may use less control overhead due to communications with the same eNB being maintained, as well as causing channel usage that is only slightly inferior to the best channel. However, in either case, when the source of DRS measurement fluctuation for RRM measurements is power based rather than channel based, it would be desirable for the eNB to use the LAA spectrum to provide DRSs for the UE to determine and adjust the DRSs. This is in addition to CSI measurements that vary due to transmission power rather than based on the effects of the channel. The eNB indicates subframes for CSI measurement. In CRS-TM, LAA UEs may measure CSI using CRS in subframes indicated by the eNB. In DMRS-TM, LAA UEs may measure CSI using CSI-RS in subframes indicated by the eNB.

Fig. 5 illustrates reference signal fluctuations in the LAA spectrum, according to some embodiments. The reference signals may be, for example, DRSs (CRS and CSI-RS) transmitted by the eNB and measured at the UE. The eNB and UE may be any of the devices described herein. For example, the UE may be a user-based device, such as a smartphone, tablet, or wearable device, or may be an MTC device or other non-user-based device, such as a sensor.

DRS (i) as described above_rs) May be transmitted in different transmission opportunities (TXOPs) or in any subframe within different DMTCs. Due to the Listen Before Talk (LBT) nature of transmissions on the LAA spectrum, DRSs are transmitted for extended periods based on the overall LAA spectrum used by other devices. Thus, rather than periodically transmitting DRSs in a particular subframe, DRSs may be transmitted semi-periodically or randomly in the LAA spectrum (e.g., DRSs are transmitted at different subframes within different frames). As shown, some frames may not have any subframes containing DRSs. DRS and, in general, LAA transmissions may be bursty. As used herein, DRS is used synonymously with DRS transmission.

Each DRS transmission may vary significantly in power from one transmission to the next. As shown, the variation may be 50-100% of the minimum transmission level, although this range is not exclusive. Significant changes may result in undesirable changes in the channel or handover to another eNB, i.e., changes that would not occur if there were no power change. DRS may be received and fluctuations may be measured by the UE.

When DRS is transmitted using the LAA spectrum, the UE may determine that DRS transmission power for RRM measurements in the DMTC may not be constant under certain LAA channel or network deployment conditions, unlike LTE DRS transmissions that may be transmitted in the PDSCH. In some embodiments, the UE may compare the DRS measurement to other most recent DRS measurements on the same channel, since the UE may not know the bandwidth used by the eNB to transmit the DRS signal.

For example, the UE may apply averaging across DRS transmissions to determine whether a particular DRS measurement should be reported and/or corrected to the eNB. In some embodiments, the UE may not apply averaging across burst transmissions if the UE determines that the transmission power for the DRS is consistent, otherwise the averaging is applied. For example, the UE may make DRS measurements for the previous 3-5 DRS transmissions (stored in the UE memory, the number of DRS transmissions may be greater if needed) and determine the mean and standard deviation of the DRS measurements. If the current DRS measurement is outside a predetermined range (e.g., 1, 1.5, or 2 standard deviations from the average DRS measurement), the UE may take corrective action. Corrective measures may include, for example, the UE adjusting the measurement results before reporting the adjusted measurement results to the eNB, not reporting the measurement results, or reporting the measured measurement results but indicating that the measurement results may be abnormal.

The UE may adjust the measurement results, e.g., using the most recent DRS measurement value and/or the average DRS value. For example, the UE may report an average of the current DRS value and one or both of the most recent DRS measurement and/or the average DRS value. If the UE reports raw DRS measurements, unused bits in the uplink transmission may be used to indicate the adjustment to the eNB. The UE may also discard only the current abnormal measurement results.

The eNB may store the change in DRS measurements. Thus, regardless of the DRS value reported by the UE to the eNB, the eNB can still determine whether the reported DRS value may have changed due to a power change caused by a LAA bandwidth change. The eNB may be able to compensate slightly for the reported DRS value. For example, the eNB may compare the currently reported value with a previously reported value, and change the currently reported value by a change in LAA DRS transmission power. The eNB may determine RRM and/or CSI.

Thus, the UE may assume that the transmission power for CRS and CSI-RS in DRS under predetermined conditions is constant for RRM measurements. These conditions may include transmitting the DRS without any data loading, or the eNB indicating in a non-transparent manner in the network that the nominal power DRS power level is used. In some embodiments, the eNB may signal the power level change through explicit signaling. The signaling may occur simultaneously with the DRS or may be transmitted in the next subframe or DMTS after the DRS is transmitted. The signaling may be a single bit to indicate that the DRS power level has been adjusted or that it is not the nominal DRS power level. In some embodiments, the signaling may include more than one bit and indicate the amount of change from the nominal power level. The signaling may be broadcast in a System Information Broadcast (SIB) or other control signal addressing the UEs in the cell.

In other embodiments, the eNB may not provide such an indication to the UE. Alternatively, the UE may be able to infer from other characteristics of the DRS transmission that the power level has changed. For example, if the DRS signal is received substantially periodically (which may indicate that very few other devices are using the LAA spectrum, and therefore the eNB is broadcasting DRSs over a large number of LAA channels), the UE may infer that the DRS power level is consistent. On the other hand, if DRS transmissions are received randomly (sparsely), the UE may infer that a large number of other devices are occupying/using the LAA bandwidth and that DRSs are being transmitted on a small set of LAA frequencies. In the latter case, the UE may infer that the eNB may have increased the power of the DRS.

If the UE determines that the DRS power level changes significantly, rather than the channel changing alone, in some embodiments, the UE may only selectively report measurements for the DRS. The reported measurement results may be of constant workThose at rate levels. If the measurement function is f (g) and the input to the function is at time i_rsObserved Reference Signal (RS), then:

m(i_rs)＝f(RS(i_rs))

where m () is the measured value. If the UE reports only the measurement results of the reference signals having the uniform power, the final report m can be made through the instantaneous measurement_report：

Where P is a set of indicators for constant reference power subframes, and m (i)_rs0) is always assumed to be reported.

Alternatively, the report sent by the UE may be obtained by averaging all measurements. In other embodiments, the reporting sent by the UE may be done by averaging or weighting the filtered observations of P. The average or weighting may be given by a function E ():

m_report＝E(m(i_rs) If i) if i_rs∈P

Applying an averaging filter may make the UE measurements less fluctuating and more accurate. Averaging may be performed for a predetermined number of DRS measurements or may be variable, e.g., depending on the variation in DRS measurements of the last DRS measurement. The weighting of each previous DRS measurement may depend on the amount of change in the previous DRS measurements relative to the average.

Fig. 6 illustrates a flow diagram of reference signal reporting, according to some embodiments. The reference signal reporting may be performed by any of the UEs shown in fig. 1-4 described herein. It is apparent that a transmission (e.g., a DRS transmission) can be encoded for transmission at a transmission source and decoded at a receiver of the transmission.

At operation 602, the UE may receive a DRS from a serving eNB and decode the DRS. The DRS may be received on one or more LAA channels, and may contain CRS and/or CSI-RS. DRSs may be sent in periodically occurring DMTC occasions having a duration of 6ms and a configurable period of 40, 80, or 160 ms. DRS transmission on the LAA band is also affected by LBT. A DL transmission burst containing DRS without PDSCH may follow a single idle observation interval of at least 25 μ s, however, DRS may not be transmitted as frequently as scheduled due to LBT. In some embodiments, the DRS may have further flexibility and may be transmitted by the network once in any subframe within the DMTC timeframe. The UE may be configured by higher layers with one or more CSI processes on a per serving cell basis. Each CSI process may be associated with a CSI-RS resource and a CSI interference measurement (CSI-IM) resource. Each CSI process may be configured by higher layer signaling with or without PMI/RI reporting, and CSI reporting may be periodic or aperiodic. In some embodiments, the eNB may change the DRS sequence (e.g., Zadoff-Chu sequence) according to the DRS power level.

At operation 604, the UE may determine whether the DRS is a normal DRS, i.e., a DRS transmitted by the eNB using a nominal power level. In some embodiments, the UE may wait to report the DRS before a sufficient amount of time to receive an indication from the eNB indicating that the DRS is transmitted at an excessively high power level. In some embodiments, the UE may determine that the DRS level is inherently anomalous through characteristics of the DRS, e.g., DRS measurements are received randomly or significantly different from previous DRSs. The UE may store one or more previous DRS measurements to make such a determination. For example, the UE may determine whether the current measurement is outside of one or two standard deviations from the previous measurement. In some embodiments, this may be combined with knowledge of the UE mobility state (the speed at which the UE is moving) to determine whether such a change may have occurred under normal operating conditions or whether artifacts may be caused by a change in power level.

At operation 606, if the UE determines that the DRS has been transmitted at a normal power level (or otherwise after adjustment as described below), the UE may transmit DRS measurements to the eNB. The measurement results may be used by the eNB for handover (RRM) and channel condition (CSI/CSI-RS) determination. In some embodiments, DRS measurements may include RSRP and/or RSRQ. The UE may send measurement reports using the LAA band at a fixed subframe offset or relative subframe offset from the measurement instance or within the measurement window. The eNB may determine from the measurement results whether handover to another eNB (e.g., PCell or SCell, either of which may be a macro eNB or a micro eNB) is appropriate. The eNB may also determine whether to switch the UE to another channel.

At operation 608, if the UE determines that the DRS has been transmitted at the abnormal power level, the UE may determine whether to filter the DRS measurements. That is, the UE may determine whether the DRS measurement should be reported to the eNB.

At operation 610, the DRS measurement may be discarded by the UE instead of being transmitted to the eNB. Alternatively, the UE may transmit a predetermined value (e.g., 0) outside of the normal range to indicate that the measurement report may have an abnormal DRS.

At operation 612, the UE may adjust the DRS measurements instead of discarding the DRS measurements. In particular, the UE may average the DRS measurements with a predetermined number of DRS measurements before reporting the DRS measurements at operation 606. In some embodiments, the averaging may occur for RRM measurements rather than for CSI/CSI-RS measurements.

Examples of the invention

Example 1 is an apparatus of a User Equipment (UE), the apparatus comprising: an interface; and processing circuitry in communication with the interface and configured to: decoding a Discovery Reference Signal (DRS) transmission from an evolved node B (eNB) in an unlicensed frequency band; determining whether a power level of a DRS transmission has changed relative to a nominal power level used to transmit a plurality of previously received DRS transmissions; in response to determining that the power level of the DRS transmission is the nominal power level, generating a report for transmission to the eNB via the interface, the report including DRS measurements for handover and channel state determination; and in response to determining that the power level of DRS transmissions has changed relative to a nominal power level, performing an adjustment of at least one of reporting or transmissions reported to the eNB.

In example 2, the subject matter of example 1 optionally includes, wherein: adjusting the transmission of the report includes discarding the DRS measurements and avoiding transmission of the report.

In example 3, the subject matter of example 2 optionally includes, wherein the processing circuitry is further configured to: generating a report for transmission to an eNB in an unlicensed frequency band, the report including DRS measurements for DRS transmissions whose power transmission is at a nominal power level in a different Discovery Measurement Timing Configuration (DMTC); and avoid generating reports for DRS transmissions whose power transmission changes relative to a nominal power level.

In example 4, the subject matter of example 3 optionally includes, wherein: the report includes Radio Resource Management (RRM) measurements of the UE on other enbs, and the processing circuitry is further configured to generate a Channel State Information (CSI) report including CSI measurements of channel state information reference signal (CSI-RS) transmissions, wherein the CSI report is independent of a power level of a related DRS transmission in the unlicensed frequency band.

In example 5, the subject matter of any one or more of examples 1-4 optionally includes, wherein: the adjustment to the report includes changing the DRS measurements to create changed DRS measurements before transmitting the DRS measurements to the eNB, the report including the changed DRS measurements.

In example 6, the subject matter of example 5 optionally includes, wherein: altering the DRS measurement comprises determining an average of the DRS measurement and a predetermined number of previous DRS measurements.

In example 7, the subject matter of example 6 optionally includes, wherein the processing circuitry is further configured to: the method further includes determining whether the DRS measurements are outside of a predetermined number of standard deviations from an average of previous DRS measurements, and averaging the DRS measurements in response to determining that the DRS measurements are outside of the predetermined number of standard deviations from the average of immediately previous DRS measurements.

In example 8, the subject matter of any one or more of examples 1-7 optionally includes, wherein the processing circuitry is further configured to: in response to receiving an indication of a power level change from the eNB, determining that a power level of DRS transmissions in the unlicensed frequency band has changed relative to a nominal power level.

In example 9, the subject matter of any one or more of examples 1-8 optionally includes, wherein the processing circuitry is further configured to: determining that a power level of the DRS transmission has changed relative to a nominal power level in response to an inference from characteristics of the DRS transmission in the unlicensed frequency band.

In example 10, the subject matter of any one or more of examples 1-9 optionally includes, wherein: the processing circuitry includes a baseband processor, and the apparatus further includes: a transceiver configured to communicate with the eNB via an interface.

Example 11 is an apparatus of an evolved node b (enb), the apparatus comprising: an interface; and processing circuitry in communication with the interface and arranged to: determining whether to adjust a power level of a Discovery Reference Signal (DRS) transmission; encoding a DRS transmission for transmission to a User Equipment (UE) after determining whether to adjust a power level of the DRS transmission; and in response to determining to adjust a power level of the DRS transmission and after transmitting the DRS transmission in the unlicensed frequency band, decode one of a first DRS report from the UE that includes the adjusted DRS measurements or a second DRS report from the UE that lacks Radio Resource Management (RRM) measurements of DRS-based transmissions.

In example 12, the subject matter of example 11 optionally includes, wherein: the second DRS report includes a Channel State Information (CSI) report including CSI measurements of a channel state information reference signal (CSI-RS) transmission, the CSI report being decoded independently of a power level of the DRS transmission.

In example 13, the subject matter of any one or more of examples 11-12 optionally includes, wherein: the adjusted DRS measurements include an average of the DRS measurements and a predetermined number of immediately preceding DRS measurements in the unlicensed band.

In example 14, the subject matter of example 13 optionally includes, wherein: the adjusted DRS measurements are decoded when DRS measurements of DRS transmissions in the unlicensed frequency band are outside of a predetermined number of standard deviations from the mean of the immediately preceding DRS measurements.

In example 15, the subject matter of any one or more of embodiments 11-14 can optionally include, wherein the processing circuitry is further configured to: an indication of a change in power level for a DRS transmission in an unlicensed frequency band is generated for transmission to a UE.

In example 16, the subject matter of example 15 optionally includes, wherein: the indication comprises a single bit.

In example 17, the subject matter of any one or more of examples 11-16 optionally includes, wherein the processing circuitry is further configured to: the DRS sequence of DRS transmission is changed according to whether the power level of DRS transmission is adjusted.

In example 18, the subject matter of any one or more of examples 11-17 optionally includes, wherein: the adjusted DRS measurement includes a predetermined value that is outside of a normal range of values for the DRS measurement.

Example 19 is a computer-readable storage medium storing instructions for execution by one or more processors to: decoding a Discovery Reference Signal (DRS) transmission from an evolved node B (eNB) in an unlicensed frequency band; performing DRS measurements of DRS transmissions; and depending on the power level of the DRS transmission and the DRS measurement, performing one of the following: generating a first report for transmission to the eNB in the unlicensed frequency band, the first report including the adjusted DRS measurements, or refraining from generating the first report and refraining from generating a second report for transmission to the eNB in the unlicensed frequency band, the second report including the DRS measurements.

In example 20, the subject matter of example 19 optionally includes, wherein: the DRS measurements include Radio Resource Management (RRM) measurements used to determine handover of the UE to other enbs, and the instructions further configure the one or more processors to generate Channel State Information (CSI) reports including CSI measurements of channel state information reference signal (CSI-RS) transmissions.

In example 21, the subject matter of any one or more of examples 19-20 optionally includes, wherein: the adjusted DRS measurements include an average of the DRS measurements and a predetermined number of immediately preceding DRS measurements.

In example 22, the subject matter of example 21 optionally includes, wherein the instructions further configure the one or more processors to: averaging the DRS measurements in response to determining that the DRS measurements are outside of a predetermined number of standard deviations from an average of the immediately preceding DRS measurements.

In example 23, the subject matter of any one or more of examples 19-22 optionally includes that the instructions further configure the one or more processors to: in response to receiving an indication of a power level change from the eNB, determining that a power level of DRS transmission has changed.

In example 24, the subject matter of any one or more of examples 19-23 optionally includes, wherein the instructions further configure the one or more processors to: determining that a power level of the DRS transmission has changed in response to an inference from characteristics of the DRS transmission.

Example 25 is a method of reporting a reference signal, the method comprising: decoding a Discovery Reference Signal (DRS) transmission from an evolved node B (eNB) in an unlicensed frequency band; performing DRS measurements of DRS transmissions; and depending on the power level of the DRS transmission and the DRS measurement, performing one of the following: generating a first report for transmission to the eNB in the unlicensed frequency band, the first report including the adjusted DRS measurements, or refraining from generating the first report and refraining from generating a second report for transmission to the eNB in the unlicensed frequency band, the second report including the DRS measurements.

In example 26, the subject matter of example 25 optionally includes, wherein: the DRS measurements include Radio Resource Management (RRM) measurements and generate Channel State Information (CSI) reports that include CSI measurements of channel state information reference signal (CSI-RS) transmissions.

In example 27, the subject matter of any one or more of examples 25-26 optionally includes, wherein: the adjusted DRS measurements include an average of the DRS measurements and a predetermined number of immediately preceding DRS measurements.

In example 28, the subject matter of example 27 can optionally include, further comprising: the DRS measurements are averaged in response to determining that the DRS measurements are outside of a predetermined number of standard deviations from an average of immediately preceding DRS measurements.

In example 29, the subject matter of any one or more of examples 25-28 optionally includes, further comprising: in response to receiving an indication of a power level change from the eNB, determining that a power level of DRS transmission has changed.

In example 30, the subject matter of any one or more of examples 25-29 optionally includes, further comprising: determining that a power level of the DRS transmission has changed in response to an inference from characteristics of the DRS transmission.

Example 31 is an apparatus of a User Equipment (UE), the apparatus comprising: means for decoding a Discovery Reference Signal (DRS) transmission from an evolved node B (eNB) in an unlicensed frequency band; means for performing DRS measurements on DRS transmissions; and depending on the power level of the DRS transmission and the DRS measurement, one of the following: means for generating a first report for transmission to the eNB in the unlicensed frequency band, the first report including the adjusted DRS measurements, or means for refraining from generating the first report and means for refraining from generating a second report for transmission to the eNB in the unlicensed frequency band, the second report including the DRS measurements.

In example 32, the subject matter of example 31 optionally includes, wherein: the DRS measurements include Radio Resource Management (RRM) measurements, and the apparatus further includes means for generating Channel State Information (CSI) reports including CSI measurements of channel state information reference signal (CSI-RS) transmissions.

In example 33, the subject matter of example 32 optionally includes, wherein: the adjusted DRS measurements include an average of the DRS measurements and a predetermined number of immediately preceding DRS measurements.

In example 34, the subject matter of example 33 optionally includes, further comprising: means for averaging DRS measurements in response to determining that the DRS measurements are outside of a predetermined number of standard deviations from an average of the immediately preceding DRS measurements.

In example 35, the subject matter of any one or more of examples 32-34 optionally includes, further comprising: means for determining that a power level of a DRS transmission has changed in response to receiving an indication of a power level change from an eNB.

In example 36, the subject matter of any one or more of examples 32-35 optionally includes, further comprising: means for determining that a power level of the DRS transmission has changed in response to an inference from characteristics of the DRS transmission.

Although embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments shown are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

Such embodiments of the subject matter may be referred to herein, individually and/or collectively, by the term "embodiment" merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept (in the event that more than one is in fact disclosed). Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

In this document, the term "a" or "an" is used to include one or more, independently of any other instances or uses of "at least one" or "one or more," as is common in patent documents. In this document, the term "or" is used to refer to the nonexclusive, or "a or B" includes "a but not B," "B but not a," and "a and B," unless otherwise indicated. In this document, the terms "comprising" and "wherein" are used as the plain-english equivalents of the respective terms "comprising" and "wherein". Furthermore, in the following claims, the terms "comprising" and "including" are open-ended; that is, a system, UE, object, composition, formulation, or process that includes elements in addition to those listed after such term in a claim is still considered to fall within the scope of that claim. Furthermore, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

The abstract of the present disclosure is provided to comply with 37c.f.r. section 1.72(b) requirements for an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. Furthermore, in the foregoing detailed description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims (17)

1. An apparatus of a User Equipment (UE), the apparatus comprising:

an interface; and

a processing circuit in communication with the interface and configured to:

decoding a discovery reference signal, DRS, transmission from an evolved node B, eNB, in an unlicensed frequency band;

determining whether a power level of the DRS transmission has changed relative to a nominal power level used to transmit a plurality of previously received DRS transmissions;

in response to determining that the power level of the DRS transmission is the nominal power level, generating a report for transmission to the eNB via the interface, the report including DRS measurements for handover and channel state determination; and

in response to determining that a power level of the DRS transmission has changed relative to the nominal power level, performing an adjustment of at least one of the report or the transmission of the report to the eNB,

wherein the processing circuit is further configured to:

determining that a power level of the DRS transmission in the unlicensed frequency band has changed relative to the nominal power level in response to receiving an indication of a power level change from the eNB or in response to an inference from characteristics of the DRS transmission in the unlicensed frequency band.

2. The apparatus of claim 1, wherein:

adjusting transmission of the report includes discarding the DRS measurement and avoiding transmission of the report.

3. The apparatus of claim 2, wherein the processing circuitry is further configured to:

generating a report for transmission to the eNB in the unlicensed frequency band, the report including DRS measurements for DRS transmissions in a DMTC whose power transmission is at the nominal power level for different discovery measurement timing configurations; and

refraining from generating a report for DRS transmissions whose power transmission changes relative to the nominal power level.

4. The apparatus of claim 3, wherein:

the report includes radio resource management, RRM, measurements of the other eNBs by the UE, and

the processing circuitry is further configured to generate a channel state information, CSI, report comprising channel state information, CSI, measurements of a channel state information reference signal, CSI-RS, transmission, wherein the CSI report is independent of a power level of a related DRS transmission in the unlicensed frequency band.

5. The apparatus of claim 1, wherein:

adjusting the report includes changing the DRS measurements to create changed DRS measurements prior to transmitting the DRS measurements to the eNB, the report including the changed DRS measurements.

6. The apparatus of claim 5, wherein:

altering the DRS measurement comprises determining an average of the DRS measurement and a predetermined number of previous DRS measurements.

7. The apparatus of claim 6, wherein the processing circuitry is further configured to:

determining whether the DRS measurement is outside a predetermined number of standard deviations from a mean of previous DRS measurements, an

Averaging the DRS measurements in response to determining that the DRS measurements are outside of the predetermined number of standard deviations from an average of immediately preceding DRS measurements.

8. An apparatus of an evolved node B, eNB, the apparatus comprising:

an interface; and

processing circuitry in communication with the interface and arranged to:

determining whether to adjust a power level of a Discovery Reference Signal (DRS) transmission;

encoding the DRS transmission for transmission to a User Equipment (UE) after determining whether to adjust a power level of the DRS transmission; and

in response to determining to adjust a power level of the DRS transmission and after transmitting the DRS transmission in an unlicensed frequency band, decode one of a first DRS report from the UE that includes the adjusted DRS measurements or a second DRS report from the UE that lacks Radio Resource Management (RRM) measurements based on the DRS transmission,

wherein the processing circuit is further configured to:

generating an indication of a change in power level of the DRS transmission in the unlicensed frequency band for transmission to the UE; or

Changing a DRS sequence of the DRS transmission according to whether to adjust a power level of the DRS transmission.

9. The apparatus of claim 8, wherein:

the second DRS report comprises a Channel State Information (CSI) report comprising CSI measurements of a channel state information reference signal (CSI-RS) transmission, the CSI report being decoded independent of a power level of the DRS transmission.

10. The apparatus of claim 8 or 9, wherein:

the adjusted DRS measurements include an average of DRS measurements and a predetermined number of immediately preceding DRS measurements in the unlicensed frequency band.

11. The apparatus of claim 10, wherein:

the adjusted DRS measurements are decoded when DRS measurements of the DRS transmission in the unlicensed frequency band are outside of a predetermined number of standard deviations from an average of the immediately preceding DRS measurements.

12. The apparatus of claim 8, wherein:

the indication comprises a single bit.

13. The apparatus of claim 8 or 9, wherein:

the adjusted DRS measurements include predetermined values that are outside of a normal range of values for DRS measurements.

14. An apparatus of a User Equipment (UE), the apparatus comprising:

means for decoding a discovery reference signal, DRS, transmission from an evolved node B, eNB, in an unlicensed frequency band;

means for performing DRS measurements on the DRS transmissions;

depending on the power level of the DRS transmission and DRS measurements, one of:

means for generating a first report for transmission to the eNB in the unlicensed frequency band, the first report including the adjusted DRS measurements, or

Means for refraining from generating the first report and means for refraining from generating a second report for transmission to the eNB in the unlicensed frequency band, the second report including the DRS measurements, an

Means for determining that a power level of the DRS transmission has changed in response to receiving an indication of a power level change from the eNB or in response to an inference from a characteristic of the DRS transmission.

15. The apparatus of claim 14, wherein:

the DRS measurement comprises a Radio Resource Management (RRM) measurement, and

the apparatus also includes means for generating a channel state information, CSI, report that includes CSI measurements of a channel state information reference signal, CSI-RS, transmission.

16. The apparatus of claim 14, wherein:

the adjusted DRS measurements include an average of the DRS measurements and a predetermined number of immediately preceding DRS measurements.

17. The apparatus of claim 16, further comprising:

means for averaging the DRS measurements in response to determining that the DRS measurements are outside of a predetermined number of standard deviations from an average of the immediately preceding DRS measurements.

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