DE102015205852B4 - Cell measurements in unlicensed frequency bands - Google Patents

Abstract

A method for a wireless user equipment (UE) device to perform cell measurements, the method comprising:
through the UE device:
Defining a reference symbol vector for a cell, each corresponding element of the reference symbol vector having a corresponding subcarrier of the cell transmitting a corresponding reference symbol;
Performing a channel estimation on each corresponding element of the reference symbol vector;
Estimating a cell strength of the cell in a first manner by cross correlating the channel estimates of different elements of the reference symbol vector.

Description

priority claim

The present application claims the priority of the provisional US Application No. 61 / 975,116 entitled "Cell Measurements in Unlicensed Frequency Bands" and filed on Apr. 4, 2014, the entire application of which is incorporated herein by reference in its entirety and in entirety is fully explained.

area

The present application relates to wireless communication systems comprising an apparatus, a system, and a method for performing cell measurements in channels in which interference may be present.

Description of the Related Art

The use of wireless communication systems is rapidly increasing. In addition, there are many different technologies and standards of wireless communication. Some examples of wireless communication standards include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (eg, 1xRTT, 1xEV-DO, HRPD, eHRPD ) IEEE 802.11 (Wi-Fi or Wi-Fi), IEEE 802.16 (WiMAX), Bluetooth and others.

In some wireless communication systems, such as certain cellular communication networks, wireless communication is performed on frequency bands that have been licensed (e.g., by a provider of the cellular network). Additionally, in some wireless communication systems, such as Wi-Fi and Bluetooth wireless communication systems, wireless communication is performed on unlicensed frequency bands, such as the 2.4 GHz ISM frequency band.

document DE 10 2013 112 546 A1 discloses a method and a mobile device for common cell identity detection and cell measurement for an LTE system.

document EP 1128 592 A2 discloses a multicarrier CDMA and channel estimation.

document US 2014/0024388 A1 discloses mobile-based interference management on the downlink.

document US 2008/0285433 A1 discloses a reference sequence construction for rapid cell search.

Presented herein are embodiments of apparatus, systems and methods for performing cell measurements in unlicensed frequency bands and / or channels where significant interference is possible and devices configured to implement the methods.

While cellular networks controlled by cellular networks (e.g., licensed bands) may be subject to relatively little external interference, unlicensed bands may be subject to interference from other wireless communication technologies under various possible sources. For example, Bluetooth, Wi-Fi, and / or any of various other wireless communication technologies may be used in industrial, scientific, medical (ISM) frequency bands, for example at 2.4 GHz or 5 GHz.

One possible way to measure the cell strength of a cell in a cellular communication network may include autocorrelating cell reference symbol subcarriers. However, this technique can overestimate the strength of the cell when there is interference, since it can not distinguish between (at least part of) the interference strength and the signal strength.

Accordingly, as an alternative technique for measuring the cell strength of a cell in a cellular communication network, it may be possible to cross-correlate reference symbol subcarriers of the cell to resolve the interference propagation time. For example, a wireless device may construct a vector of reference symbol subcarriers of a cell. The wireless device may have a channel estimate relative to each element of the vector and can then cross-correlate these channel estimates with each other to produce an estimate of the signal strength.

Such an estimate of the signal strength may be provided back to the serving cell of the wireless device to provide a more accurate estimate of the signal strength of the cell, which in turn may improve the cell selection and re-selection procedures for the mobile device. A signal strength estimate calculated in this manner may be provided on a standalone basis in some embodiments (e.g., as a substitute for any alternative signal strength measurement technique). Alternatively, this may be provided in combination with an estimate of signal strength generated in some other way, for example by autocorrelating the reference symbol subcarriers of the cell. This may be helpful in some cases as a technique for estimating the interference power present in a cell, since the difference between the estimates calculated using such techniques may be representative of the interference power present in the cell.

The techniques described herein may be implemented in and / or used with a number of different types of devices, including, but not limited to, cellular base stations, cell phones, tablet computers, portable computing devices, portable media players, and anyone from various other computer devices.

This summary is intended to provide a brief overview of some of the subject matter described herein. Accordingly, it should be understood that the features described above are examples rather than intended to limit the scope of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, the following figures, and the following claims.

list of figures

• 1 ein beispielhaftes (und vereinfachtes) System drahtloser Kommunikation gemäß einiger Ausführungsformen veranschaulicht;
• 2 eine Basisstation (BS) in Kommunikation mit einer Benutzer-Ausrüstungs-(„user equipment“, UE) -Vorrichtung gemäß einiger Ausführungsformen veranschaulicht;
• 3 ein beispielhaftes Blockdiagramm einer UE gemäß einiger Ausführungsformen veranschaulicht;
• 4 ein beispielhaftes Blockdiagramm einer BS gemäß einiger Ausführungsformen veranschaulicht;
• 5 ein Flussdiagramm ist, das ein beispielhaftes Verfahren zum Ausführen von Zell-Messungen in nicht-lizenzierten Frequenzbändern gemäß einiger Ausführungsformen veranschaulicht;
• 6 ein Blockdiagramm ist, das beispielhafte RSRP-Mess-Komponenten gemäß einer RSRP-Mess-Technik gemäß einiger Ausführungsformen veranschaulicht;
• 7 ein Blockdiagramm ist, das beispielhafte mögliche RF-Mess-Blöcke in einem Front-End drahtloser Vorrichtung gemäß einiger Ausführungsformen veranschaulicht; und
• 8 konzeptuelle Komponenten verschiedener Zell-Messungen der physikalischen Schicht gemäß einiger Ausführungsformen veranschaulicht.

A better understanding of the present subject matter can be obtained when the following detailed description of the embodiments is considered in conjunction with the following drawings in which:

• 1 illustrates an exemplary (and simplified) wireless communication system according to some embodiments;
• 2 illustrates a base station (BS) in communication with a user equipment (UE) device according to some embodiments;
• 3 illustrates an exemplary block diagram of a UE according to some embodiments;
• 4 an exemplary block diagram of a BS illustrated in accordance with some embodiments;
• 5 FIG. 10 is a flowchart illustrating an exemplary method of performing cell measurements in unlicensed frequency bands, in accordance with some embodiments; FIG.
• 6 FIG. 10 is a block diagram illustrating exemplary RSRP measurement components according to an RSRP measurement technique, according to some embodiments; FIG.
• 7 FIG. 10 is a block diagram illustrating exemplary possible RF measurement blocks in a front-end wireless device according to some embodiments; FIG. and
• 8th illustrates conceptual components of various physical layer cell measurements according to some embodiments.

While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are illustrated by way of example in the drawings and described in detail herein. It should be understood, however, that the drawings and detailed description thereof are not intended to be limited to any particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the subject matter is defined by the appended claims.

Detailed description

terms

• Speicher-Medium („memory medium“) - Jeder der verschiedenen Typen von nicht-flüchtigen Speichervorrichtungen oder Speichervorrichtungen. Es ist beabsichtigt, mit dem Begriff „Speicher-Medium“ ein Installations-Medium zu umfassen, z.B. eine CD-ROM, Floppy-Disks oder eine Band-Vorrichtung; einen Computersystem-Speicher oder
• einen Arbeitsspeicher („random access memory“) wie zum Beispiel einen DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, usw.; einen nicht-flüchtigen Speicher wie zum Beispiel einen Flash, ein magnetisches Medium, zum Beispiel eine Festplatte oder
• einen optischen Speicher; Register oder andere ähnliche Typen von Speicherelementen usw. Das Speichermedium kann andere Typen nicht-flüchtigen Speichers, sowie Kombinationen dieser umfassen. Zusätzlich kann das Speichermedium in einem ersten Computersystem angeordnet sein, in dem die Programme ausgeführt werden, oder in einem zweiten verschiedenen Computersystem angeordnet sein, das sich mit dem ersten Computersystem über ein Netzwerk wie zum Beispiel das Internet verbindet. Im letzten Fall kann das zweite Computersystem Programm-Instruktionen an den ersten Computer zum Ausführen bereitstellen. Der Begriff „Speicher-Medium“ kann zwei oder mehr Speicher-Medien umfassen, die in verschiedenen Orten untergebracht sein können, z.B. in verschiedenen Computer-Systemen, die über ein Netzwerk verbunden sind. Das Speicher-Medium kann Programm-Instruktionen (z.B. als Computer-Programme ausgestaltet) speichern, die durch einen oder mehr Prozessoren ausgeführt werden können.

The following is a glossary of terms used in this disclosure:

• Memory medium - Any of various types of non-volatile memory devices or memory devices. It is intended to include the term "storage medium" an installation medium, eg, a CD-ROM, floppy disks, or a tape device; a computer system memory or
• a random access memory such as a DRAM, DDR RAM, SRAM, EDO RAM, RAM RAM, etc .; a non-volatile memory such as a flash, a magnetic medium, for example a hard disk or
• an optical memory; Registers or other similar types of storage elements, etc. The storage medium may include other types of non-volatile memory, as well as combinations thereof. Additionally, the storage medium may be located in a first computer system in which the programs are executed, or may be located in a second, different computer system that connects to the first computer system via a network, such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "storage medium" may include two or more storage media that may be located in different locations, eg, in different computer systems connected via a network. The storage medium may store program instructions (eg, configured as computer programs) that may be executed by one or more processors.

Carrier medium - a storage medium as described above, and a physical transfer medium, such as a bus, network and / or other physical transfer medium, such that signals such as electrical, transmitted electromagnetic or digital signals.

Programmable Hardware Element - includes various hardware devices having multiple programmable functional blocks connected via a programmable link. Examples include field programmable gate arrays (FPGAs), programmable logic devices (PLDs), field programmable object arrays (FPOAs), and complex PLDs (CPLDs). The programmable function blocks can range from fine grained blocks (combinatorial logic or look-up tables) to coarse grained blocks (arithmetic logic units or processor cores). A programmable hardware element may also be referred to as a "reconfigurable logic".

Computer system - each of the various computing or processing systems, include a personal computer system (PC), mainframe system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing System or other device or combinations of devices. In general, the term "computer system" may be broadly defined to encompass any device (or combination of devices) having at least one processor executing instructions from a storage medium.

User equipment (UE) (or "UE device") - any of the various types of computer system devices that are mobile or portable and that perform wireless communications. Examples of UE devices include mobile phones or smartphones (eg, iPhone ™, Android ™ -based phones), portable gaming devices (eg, Nintendo DS ™, PlayStation Portable ™, Gameboy Advance ™, iPhone ™), portable devices (eg, Smart Watch, Smart Glasses), laptops, PDAs, portable internet devices, music players, data storage devices or other handheld devices, etc. In general, the term "UE" or "UE device" may be broadly defined to encompass any electronic, computing and / or or telecommunications device (or combination of devices) that is easily transportable by a user and capable of communicating wirelessly.

Base Station - The term "base station" has the full breadth of its ordinary meaning and includes at least one station of wireless communication installed in a fixed location and used to communicate as part of a wireless telephone system or radio system.

Processing element - refers to different elements or combinations of elements. Processing elements include, for example, circuits such as a Application Specific Integrated Circuit (ASIC), parts or circuits of individual processor cores, entire processor cores, individual processors, programmable hardware devices such as a Field Programmable Gate Array (FPGA), and / or larger parts of systems that include multiple processors.

Channel - a medium used to transmit information from a transmitter to a receiver. It should be noted that because the characteristics of the term "channel" may vary according to different wireless protocols, the term "channel" as used herein may be considered to be used in a manner consistent with the standard of the type of device is in relation to which the term is used. In some standards, channel widths may be variable (e.g., depending on the capabilities of the device, band conditions, etc.). For example, LTE can support scalable channel bandwidths from 1.4 MHz to 20 MHz. In contrast, WLAN channels can be 22 MHz wide, while Bluetooth channels can be 1 MHz wide. Other protocols and standards may include different definitions of channels. In addition, some standards may define and use several types of channels, e.g. different channels for the uplink or the downlink and / or different channels for different uses, such as data, control information, etc.

Band - The term "band" encompasses the full breadth of its usual meaning and encompasses at least a portion of the spectrum (e.g., radio frequency spectrum) in which channels are used or discarded for the same purpose.

Automatic - refers to an action or operation performed by a computer system (eg, software executed by the computer system) or device (eg, circuit, programmable hardware elements, ASICs, etc.) without a user input identifying the action or Operation specified or executed directly. Thus, the term "automatic" is in contrast to an operation that is performed manually or specified by the user, with the user providing an input to perform the operation directly. An automatic procedure may be initiated by an input provided by the user, but the subsequent actions that are performed "automatically" will not be specified by the user, i. are not executed "manually", with the user specifying each action to be performed. For example, a user who fills in an electronic form by selecting each field and providing an input specifying information (eg by tapping the information, by selecting check boxes, by radio selection, etc.) fills that Manually form even if the computer system needs to update the form in response to the user actions. The form may be automatically filled by the computer system, the computer system (e.g., software running on the computer system) analyzing the fields of the form and filling out the form without any user input specifying the responses for the fields. As indicated above, the user can invoke the form automatically fill in, but is not involved in actually filling out the form (e.g., the user does not manually specify the responses for the fields, rather they are automatically filled in). The present invention provides various examples of operations that are performed automatically in response to the actions the user has taken.

Figures 1 and 2 - communication system

1 illustrates an exemplary (and simplified) wireless communication system according to some embodiments. It should be noted that the system of 1 rather, it is an example of a possible system and embodiments may be implemented as desired in any of the various systems.

As shown, the exemplary wireless communication system includes a base station 102A transmitted via a transmission medium with one or more user devices 106A . 106B , etc. until 106N communicated. Each of the user devices may be referred to herein as a "user equipment" (UE). This will become the user devices 106 referred to as UEs or UE devices.

The base station 102A may be a base transceiver station (BTS) or a radio cell and may include hardware that facilitates wireless communication with the UEs 106A to 106N allows. The base station 102A can also be configured with a network 100 (eg a core network of a provider of cellular services ("cellular service provider"), a telecommunications network such as a Public Switched Telephone Network (PSTN) and / or the Internet in many different ways) to communicate. This allows the base station 102A Communication between the user devices and / or between the user devices and the network 100 support.

The communication area (or coverage area) of the base station may be referred to as a "cell." The base station 102A and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication or telecommunication standard technologies, for example GSM, UMTS (WCDMA) , TD-SCDMA), LTE, LTE-Advanced (LTE-A), 3GPP2 CDMA2000 (eg 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, WiMAX etc.

In addition, one or more access points (for example access point 104 ) with the network 100 be communicatively coupled. These may include Wi-Fi access points configured to support cellular network offloading and / or other wireless communication services as part of the wireless communication system, as described in U.S. Patent Nos. 4,783,866 1 to provide.

base station 102A and other similar base stations (for example, base stations 102B ... 102N) and / or access points (for example access point 104 ) operating in accordance with the same or another standard of wireless communication may thus be provided as a network of cells providing a continuous or near-continuous overlapping service to the UEs 106A N and similar devices can provide over a wide geographic area by means of one or more standards of wireless communication.

While the base station 102A as a "serving cell" for UEs 106A-N can act as in 1 illustrates, every UE 106 thus to be able to receive signals from (and possibly within the communication range of) one or more other cells (those through the base stations 102B-N and / or may be provided by any other stations) and / or wireless local area networks (WLANs) referred to as "neighboring cells" or "adjacent WLANs" (eg, as appropriate) and / or generally referred to as "neighbors." can be. Such neighbors may also be able to communicate between user devices and / or between user devices and the network 100 to support. Such neighbors may include "macro" cells, "micro" cells, "pico" cells, "femto" cells, WLANs, and / or cells that provide any of the various granularities of the size of the area to be served. For example, in 1 illustrated base stations 102A-B Provide macro-cells, the base station 102N can provide a micro-cell, and the access point 104 can be a Wi-Fi AP providing Wi-Fi. Other configurations are also possible.

It should be noted that a UE 106 may be able to communicate using multiple standards of wireless communication. For example, a UE 106 be configured to communicate using two or more of the following: GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A, WLAN, Bluetooth, one or more global navigation satellite systems (GNSS). eg GPS or GLONASS), one and / or more mobile television broadcasting standards (eg ATSC-M / H or DVB-H), etc. Other combinations of wireless communication standards (comprising more than two Standards of wireless communication) are also possible.

2 illustrates a user equipment 106 (eg one of the devices 106A to 106N) according to some embodiments, with a base station 102 (eg one of the base stations 102A to 102N) communicated. The UE 106 may be a device with cellular communication capability, for example, a mobile phone, a handheld device, a computer or a tablet, or almost any type of wireless device.

The UE 106 may include a processor configured to execute program instructions stored in memory. The UE 106 Any of the method embodiments described herein may execute by executing such stored instructions. Alternatively or additionally, the UE 106 comprise a programmable hardware element, such as a field-pregadable gate array (FPGA) configured to execute any of the method embodiments described herein or any portion of the method embodiments described herein.

In some embodiments, the UE 106 be configured to communicate using any of the multiple radio access technologies / protocols of wireless communication. For example, the UE 106 be configured to communicate using two or more of GSM, UMTS, CDMA2000, LTE, LTE-A, WLAN / Wi-Fi or GNSS. Other combinations of wireless communication technologies may also be possible.

The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In one embodiment, the UE 106 be configured to communicate using one of the following: CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE using a single shared radio and / or GSM or LTE using the common radio. The common radio may be coupled to a single antenna or may be coupled to multiple antennas (eg for MIMO) to perform wireless communications. In general, a radio may comprise any combination of a baseband processor, an analog RF signal processing circuit (eg, including filters, mixers, oscillators, amplifiers, etc.) or digital processing circuitry (eg, for digital modulation and other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 share one or more parts of a receive and transmit chain between multiple wireless communication technologies, as discussed above.

In some embodiments, the UE 106 separate transmit and / or receive chains (eg comprising separate RF and / or digital radio components) for each wireless communication protocol with which it is configured to communicate. As another possibility, the UE 106 include one or more radios shared between multiple wireless communication protocols and one or more wireless devices used exclusively by a single wireless communication protocol. For example, the UE 106 comprise a common radio for communicating with LTE or 1xRTT (or LTE or GSM) and individual radios for communicating using both the Wi-Fi and the Bluetooth. Other configurations are also possible.

FIG. 3 shows an example block diagram of a UE

3 illustrates an exemplary block diagram of a UE 106 according to some embodiments. As shown, the UE 106 a system-on-chip (SOC) 300 which may include parts for various purposes. As shown, the SOC 300 for example, a processor or processors 302 , the program instructions for the UE 106 can run, and a display circuit 304 which can perform graphics processing and display signals to the display 360 can provide. The processor or processors 302 can also be sent to the memory management unit (MMU) 340 be coupled, which may be configured addresses from the processor or from the processors 302 to receive and store these addresses in places in memory (eg memory 306 , Read only memory (ROM) 350 , NAND flash memory 310 ) and / or other circuitry or devices, such as the display circuitry 304 , the circuit 330 wireless communication, the connector I / F 320 and / or the ad 360 , The MMU 340 may be configured to perform memory protection and page table translation or construction. In some embodiments, the MMU 340 as part of the processor or processors 302 be included.

As shown, the SOC 300 to various other circuits of the UE 106 be coupled. For example, the UE 106 different types of memory (eg including NAND-Flash 310 ), a connector interface 320 (eg for coupling to a computer system, a dock, a charging station, etc.), the display 360 and a circuit of wireless communication (eg radio) 330 (eg for LTE, Wi-Fi, GPS etc.).

The UE device 106 may include at least one antenna and, in some embodiments, multiple antennas to perform wireless communication with base stations and / or other devices. For example, the UE device may 106 Antenna (s) 335 use to run the wireless communication. As indicated above, the UE 106 in some embodiments, to wirelessly communicate using multiple standards of wireless communication.

As described hereinafter, the UE 106 Hardware and software components include to implement part or all of the methods described herein. The processor 302 the UE device 106 may be configured to implement some or all of the methods described herein, eg, by executing program instructions stored on a storage medium (eg, a non-transitory computer-readable storage medium). In other embodiments, the processor 302 be configured as a programmable hardware element, for example, a FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Alternatively (or additionally), the processor 302 the UE device 106 in conjunction with one or more of the others components 300 . 304 . 306 . 310 . 320 . 330 . 335 . 340 . 350 . 360 be configured to implement part or all of the features described herein.

Figure 4 - Exemplary block diagram of a base station

4 illustrates an exemplary block diagram of a base station 102 according to some embodiments. It should be noted that the base station of the 4 is just one example of a possible base station. As shown, the base station 102 a processor or processors 404 include the program instructions for the base station 102 can execute. The processor or processors 404 can also be sent to a memory management unit (MMU) 440 be coupled, which may be configured addresses from the processor or from the processors 404 to receive and store these addresses in places in memory (eg memory 460 and read-only memory (ROM) 450 ) or to other circuits or devices.

The base station 102 can have at least one network interface ("network port") 470 include. The network interface 470 may be configured to couple to a telephone network and a variety of devices such as UE devices 106 Provide access to the telephone network, as in above 1 and 2 described.

The network interface 470 (or an additional network interface) may also or alternatively be configured to couple to a cellular network, eg a core network of a provider of cellular services. The core network may include mobility-related services and / or other services of a variety of devices, such as UE devices 106 provide. In some cases, the network interface 470 via the core network to a telephone network and / or the core network may provide a telephone network (eg, among UE devices serviced by the provider cellular services).

The base station 102 can at least one antenna 434 and possibly include multiple antennas. The antenna (s) 434 may be configured to function as a wireless transceiver and may further be configured with UE devices via radio 430 to communicate. The antenna (s) 434 communicate / communicate with the circuit 430 wireless communication via a communication chain 432 , The communication chain 432 may be a receive chain, a transmission chain, or both. The radio 430 may be configured to communicate over various standards of wireless communication, including but not limited to LTE, LTE-A, UMTS, CDMA2000, Wi-Fi, etc.

The BS 102 can be configured to communicate wirelessly using multiple standards of wireless communication. In some examples, the base station 102 Several wireless facilities include the base station 102 allow to communicate according to several wireless communication technologies. As a possibility, the base station 102 For example, include an LTE radio for performing a communication according to LTE, as well as for performing a communication according to Wi-Fi. In such a case, the base station 102 to be able to function as an LTE base station and / or as a Wi-Fi access point. As another possibility, the base station 102 a multi-mode radio capable of carrying out communications according to any one of the multiple wireless communication technologies (eg, LTE and Wi-Fi).

The BS 102 may include hardware and software components for implementing part or all of the methods described herein. The processor 404 the base station 102 may be configured to implement some or all of the methods described herein, eg, by executing program instructions stored on a storage medium (eg, a non-volatile, computer-readable storage medium). Alternatively, the processor 404 be configured as a programmable hardware element, for example as an FPGA (Field Programmable Gate Array) or as an ASIC (Application Specific Integrated Cricuit) or as a combination of these. Alternatively (or additionally), the processor 404 the BS 102 in conjunction with one or more of the other components 430 . 432 . 434 . 440 . 450 . 460 . 470 be configured to implement part or all of the features described herein.

Figure 5 flow chart

5 FIG. 10 is a flow chart illustrating a method of performing cell measurements according to some embodiments. FIG. The method can suppress the inaccuracy that may otherwise be introduced by the interference and that can cause the cell strength to be overestimated. Accordingly, the method may be particularly suitable for use in channels in which interference can be practically expected, for example channels in unlicensed frequency bands, at least in some examples. If desired, the method may also be used in other applications (eg, in licensed frequency bands where interference can be much more tightly controlled, and thus limited, at least in some examples). Aspects of the procedure of 5 may be implemented as desired by a user equipment (UE) device or, more generally, in conjunction with any of the computer systems or any of the devices described in the above figures, among other devices.

In 502 a reference symbol vector for a cell can be defined. Each corresponding element of the reference symbol vector may represent a corresponding subcarrier of the cell, which transmits a corresponding reference symbol (eg, a cell-specific reference symbol). In some examples, the cell may be on a channel in an unlicensed frequency band.

If desired, the elements of the reference symbol vector may comprise subcarriers of several different OFDM symbols. For example, in an exemplary LTE system, reference symbols on the subcarriers o and 6 of the first OFDM symbol (symbol 0 ) of each slot and subcarriers 3 and 9 of the fifth OFDM symbol (Smbol 4 ) being found. In this case, the potential effect of the frequency selectivity can be reduced by inserting the reference symbol transmitting subcarrier of the two OFDM symbols 0 and 4 , for example, compared with a scenario in which only the subcarriers 0 and 6 from the OFDM symbol 1 be used in the reference symbol vector.

In 504 For example, a channel estimation may be performed on each corresponding element of the reference symbol vector. This may be for each corresponding element multiplying a signal received at the respective subcarrier of the element by a conjugate of the corresponding reference symbol transmitted by the corresponding subcarrier.

In 506 For example, the cell strength for the cell can be calculated in a first way. As a particular example, the cell strength calculation may be a calculation of the received power of a reference signal received power (RSRP) in an LTE communication system. Alternative calculations of cell strength are also possible.

The first mode of cell strength calculation may include cross-correlating channel estimates of different elements of the reference symbol vector. Such a cross correlation can significantly reduce (eliminate) the effect of interference and noise in the cell-strength calculation. If applicable and desired, the cell strength subcomputations may be performed on a per path basis (eg, based on the number of transmit and receive antennas) and combined (in a weighted or linear fashion as desired) to a median Generate cell strength estimate. If desired, additionally or alternatively, a long term averaging can also be carried out in the time domain. An exponential or linear window can be used in many different ways in such a case. For example, in at least some examples, an exponential window may at least partially smooth out the potential burst property of Wi-Fi interference.

In some examples, the calculated cell strength (s) may be reported to a base station (eg, among various other possible cell measurements). For example, a UE may occasionally transmit a cell measurement report (eg, periodically or upon request) to a serving base station of the UE, which includes cell measurements generated by the method of 5 were obtained. The cell measurements may be used for any of a variety of purposes, such as for connection adaptation, re-selection, handover, etc.

In some embodiments, the UE may also calculate the cell strength of the cell in a second manner. For example, according to the second mode of cell strength calculation, the reference symbol subcarriers of the cell may be autocorrelated. In the absence of interference, this calculation can provide a similar result as the first way of cell strength calculation; in the presence of interference, the result may give a higher estimate of cell strength than the first way of cell-strength calculation, which difference may represent the presence of interference in the cell.

In such embodiments, the UE may also report the cell strength as calculated to the base station in the second way. The two calculated cell-strength values can be provided in any of several ways. For example, as one possibility, each calculated cell strength value may may be provided as an absolute value (ie, without reference to each other) or, alternatively, a calculated cell-strength value may be provided and a difference between the calculated cell-strength values may be used as an indication of the other calculated cell-strength Value are provided.

It should be noted that some or all of the proceedings of the 5 can be repeated as desired. For example, a UE may perform the method of 5 for each of the multiple cells in a measurement set repeat (or execute concurrently) with respect to which the UE performs the task of performing the cell measurements at a particular time. As another (alternative or additional) possibility, an UE may perform the method of 5 repeat on an occasional (eg, periodic) temporary basis, for example, to maintain a current or recent cell-strength estimate for a particular cell on an ongoing basis. Further, in at least some examples, such prior cell strength estimates may be used for each cell as part of a time domain averaging technique, such as described above.

Figures 6 - 8 - Additional information

6-8 and the information as below with the 6-8 are provided by way of example from various considerations and details relating to possible systems in which the method of the 5 and / or other aspects of this disclosure, and are not intended to be limiting as to the disclosure as a whole. Numerous variations and alternatives are possible in the details provided herein and should be considered within the scope of the disclosure.

In 3GPP cellular networks, it may be difficult to address traffic growth with the licensed spectrum that is currently available in many urban markets for LTE systems. 5 GHz and other license-free bands represent a possible additional spectrum to expand their service offerings. At least in some instances, a non-licensed spectrum may not match the qualities of a licensed spectrum. Solutions that allow efficient use of unlicensed spectrum, for example, as a supplement to a licensed deployment, can be valuable. As an option, the LTE RAT can be used in unlicensed deployments: 5GHz and other license-free tapes can be used to add LTE as carrier aggregation additions to the licensed band communication or as a stand-alone LTE To provide deployments.

wobei RSSI der Indikator der Stärke des empfangenen Signals ist und N die Anzahl von Ressourcen-Blöcken ist, über die die Messung ausgeführt wurde.One aspect of LTE communication is the use of LTE measurements. The LTE measurements can provide cell-specific signal strength metrics. According to some embodiments, these measurements may be used to classify different LTE candidate cells according to their signal strengths, for example, for handover and cell re-selection decisions. As one example, the RSRP may be used to measure the average received power over the resource elements that transmit cell-specific reference signals within a particular frequency bandwidth. As another example, a reference signal received quality (RSRQ) may be a carrier-to-interference (C / I) type of measurement that determines the quality of the signal displayed reference signal. The RSRQ measurement may be used in at least some embodiments to provide additional information when the RSRP is insufficient to make a reliable handover or reliable cell reselection decision. RSRQ can be defined by (at least some versions of) the 3GPP specification as: $$RSRQ=N\frac{RSRP}{RSSI}\left[\text{dB}\right].$$

where RSSI is the indicator of the strength of the received signal and N is the number of resource blocks over which the measurement was made.

6 is a block diagram exemplifying RSRP measurement components according to a possible RSRP measurement technique. As shown, phase (I) and quadrature (Q) signals received in the time domain may be provided to a Fast Fourier Transform (FFT) block. The pilot tones (sub-carriers transmitting reference symbols) may be used for each reference symbol in conjunction with the appropriate reference symbol for each pilot tone to perform a least squares (LS) channel estimation in the frequency domain , A Finite Impulse Response (FIR) filter can then be applied and the results averaged to produce an RSRP measurement.

7 FIG. 10 is a block diagram illustrating exemplary possible RF measurement blocks in a front end of a wireless device according to some embodiments. As shown, signals may be received by each antenna of the wireless device and provided to a corresponding RF front-end block. From there, the signals can be provided to the symbol demodulators, with take-offs for the RSRP / RSRQ measurements and the frequency tracking loop (FTL) and the reference symbol (RS) estimate. Signal to interference plus noise ratio (SINR). The signals may be provided by the symbol demodulators to the decoders, with a take-off for a post-detected SINR estimate. Decoded data may then be provided to higher layers for further processing.

As previously noted, LTE deployments in unlicensed frequency bands ("LTE-U") may be a useful option for carriers to improve their service offerings. As one possible implementation of such a system, a network may configure a primary carrier (PCell) in a licensed band and a secondary carrier (SCell) in an unlicensed band. The primary bearer may be used to schedule communications and communicate data while the secondary bearer may be used to communicate data (eg, scheduling that communicates via the primary bearer) has been). In such a case, the secondary carrier may coexist with the WLAN and / or other communications over which the network can not control.

If LTE-U and Wi-Fi work in the same frequency range, different techniques may be possible to allow effective coexistence between the technologies. However, if an LTE-U device performs inter-frequency measurements at other (adjacent) frequencies, the device may not be able to determine whether or not these frequencies are interference-free. In such conditions, measurements that do not take into account the possibility of significant interference may result in unpredictable mobility behavior in the LTE-U space.

Accordingly, an improved RSRP measurement algorithm can be provided for scenarios in which the interference may be present, for example, in unlicensed deployments. The method can not use the channel estimate in the same way as the alternative RSRP measurement techniques (eg, the FIR filter used in 6 can be bypassed). This can improve the accuracy in case of interference.

To overcome any degradation from the frequency selectivity of the fading channels, the received reference symbols (RSs) may be symbols 0 and symbols 4 be combined in a vector. In such a case, the computation may include an RS of 3 subcarriers each (eg, rather than 6 subcarriers each), which may reduce the effect of frequency selectivity.

In the case of interference and high noise (e.g., as in a channel of an unlicensed band in which Wi-Fi may be present), this method can improve rejection of noise + interference by 6dB or more, e.g. for at least some previously used RSRP measurement techniques.

In addition, long term averaging can be used in the time domain (e.g., 100-200MS or any other length of time), for example, to reduce the time domain variations. Furthermore, an exponential time window may be used, e.g. to smooth out the potential burst property of WiFi interference.

The following is provided as a more detailed example of a possible improved RSRP measurement technique. It should be noted that variations and alternatives to the example provided below are possible.

As a first step, the channel may be at the subcarrier k and from the transmitting antenna m and the receiving antenna 1 where Y is the received signal, R is the reference symbol at subcarrier k, are estimated as: $$H_{LS}^{l.m}\left(k\right)-Y_{im}\left(k\right)R_l^i\left(k\right)*$$

$$P_l\left(i\right)=P_{l0}\left(i\right)+P_{l1}\left(i\right)$$

$$RSRP\left(i\right)=Abs\left\{combiner\left(P_0\left(i\right)+P_1\left(i\right)\right)\right\}$$

The RSRP can then be calculated as (where n is the index of the OFDM symbol and i is the cell ID): $$P_{lm}\left(i\right)=\frac{1}{K-1}\frac{1}{N}{\displaystyle {\Sigma }_{n=0}^N}{\displaystyle \underset{k=0}{\overset{K-2}{\Sigma }}{H}_{LS}^{l.m}\left(k+\mathrm{1,}n\right)*\times H_{LS}^{l.m}\left(k.n\right).i=1.2....\text{Mc}}$$

$$P_l\left(i\right)=P_{l0}\left(i\right)+P_{l1}\left(i\right)$$

$$RSRP\left(i\right)=Abs\left\{cOmbiner\left(P_0\left(i\right)+P_1\left(i\right)\right)\right\}$$

Thus, the channel estimates at the pilot tones that form the reference symbol vector may be crossed with each other, which may serve to cancel the Wi-Fi (or other) interference at each reference symbol that can not be canceled, if instead an autocorrelation of each reference symbol is executed (eg as can be done in some RSRP calculations). It should be noted that the combiner function may be either weighted averaging (e.g., based on signal strength per path / antenna) or simple linear averaging.

Further, in some examples, it may be desirable to calculate the RSRP in a number of ways and report the difference between the results to the network. For example, the difference between the RSRP, as calculated in the above example, and the RSRP, as calculated by correlating each reference symbol to itself, may be reported as a bias in a measurement report. Since the difference between the RSRP, as calculated according to the various algorithms, can essentially represent the amount of interference present in the cell, this can be a useful metric for networks to improve the LTE-U provisions. Alternatively, the RSRP may simply be calculated in the manner described above and reported to the network without reference to alternative methods of calculating an RSRP.

8th Figure 12 illustrates conceptual components of various physical layer cell measurements according to some embodiments, such as RSRP and RSRQ when executed in a non-licensed band. As shown, P _s 810 may represent the power of the reference symbol provided by the serving cell (or more generally by the cell being measured). P _D 820 may represent the performance of the data symbols provided by the serving cell (or more generally, the cell being measured). P _I 830 may represent interference from neighboring cells (eg, other LTE U cells and / or Wi-Fi networks).

While correlating a reference symbol with itself can cancel out the interference caused by orthogonal transfers, such as may be performed by other LTE cells, Wi-Fi signals can not be suppressed by such calculations. Thus, computing an RSRP in such a manner may result in inaccurately high RSRP (and RSRQ) value, since the un-suppressed interference can be measured as part of P _s 810. This can also be expressed as follows, where alpha represents the proportion of interference that is not suppressed in the RSRP measurements, but using self correlation rather than the cross correlation to calculate RSRP: $$\frac{1}{RSRQ}=\frac{RSSI}{N\cdot RSRP}=2\frac{P_S+P_D+P_I}{P_S}>2\frac{P_S+P_D+P_I}{P_S+\mathrm{<figure-callout\; id="1"\; label="\alpha \; P"\; filenames="DE102015205852B4\_0011.png,DE102015205852B4\_0013.png"\; state="\{\{state\}\}">\alpha \; </figure-callout>}{P}_{}{}_1}=\frac{1}{RSR{Q}_{inaccurate}}$$

Hereinafter, further exemplary embodiments are provided.

A set of embodiments may include a method of performing cell measurements: defining a reference symbol vector for a cell, each corresponding element of the reference symbol vector having a corresponding subcarrier of the cell transmitting a corresponding reference symbol; estimating the channel at each corresponding element of the reference symbol vector; and calculating a cell strength of the cell by cross-correlating channel estimates of different elements of the reference symbol vector.

According to some embodiments, estimating the channel on a corresponding element of the reference symbol vector comprises multiplying a signal received at the corresponding subcarrier of the element by a conjugate of the corresponding reference symbol transmitted by the corresponding subcarrier.

In some embodiments, the reference symbol vector includes elements corresponding to the subcarriers comprised of a plurality of OFDM symbols of a subframe of the cell.

According to some embodiments, the cell is on a channel in an unlicensed frequency band.

An additional exemplary embodiment may include a wireless user equipment (UE) device, comprising: a radio; and a processing element operably coupled to the radio; wherein the UE is configured to implement any or all parts of one of the methods of the above examples.

Another exemplary set of embodiments may include a non-transitory computer-accessible storage medium comprising program instructions that, when executed on a device, cause the device to implement any or all portions of any of the methods of the preceding examples.

Yet another exemplary set of embodiments may include a computer program having instructions for performing any or all portions of the methods of the preceding examples.

Yet another exemplary set of embodiments may include an apparatus having means for performing any or all of the elements of the method of any of the foregoing examples.

The embodiments of the present disclosure may be implemented in any of various forms. For example, some embodiments may be implemented as a computer implemented method, a computer readable storage medium, or a computer system. Other embodiments may be implemented using one or more custom hardware devices such as ASICs. Still other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

In some embodiments, a non-transitory computer-readable storage medium may be configured to store program instructions and / or data, the program instructions, when executed by a computer system, causing the computer system to perform a method , eg any of the embodiments of the method described herein or any combination of the embodiments of the method described herein, or any subset of any embodiments of the method described herein, or any combination of such subsets.

In some embodiments, a device (eg, a UE 106 ) to configure a processor (or a set of processors) and a storage medium, the storage medium storing program instructions, the processor being configured to read and execute the program instructions from the storage medium wherein the program instructions are executable to implement any of the various embodiments of the method described herein (or any combination of the embodiments of the method described herein, or any subset of any embodiments of the method described herein, or any combination of such subsets) , The device can be realized in any of various forms.

Although the embodiments have been described in great detail above, numerous variations and modifications will become apparent to those skilled in the art once the foregoing disclosure has been fully acquired. It is intended that the following claims be interpreted to include all such variations and modifications.

Claims (14)

A method for a wireless user equipment (UE) device to perform cell measurements, the method comprising: by the UE device: defining a reference symbol vector for a cell, each corresponding element of the reference symbol vector having a corresponding one Subcarrier of the cell, which transmits a corresponding reference symbol; Performing a channel estimation on each corresponding element of the reference symbol vector; Estimating a cell strength of the cell in a first manner by cross correlating the channel estimates of different elements of the reference symbol vector. Method according to Claim 1 wherein performing the channel estimation on a corresponding element of the reference symbol vector comprises multiplying a signal received at the corresponding subcarrier of the element by a conjugate of the corresponding reference symbol transmitted by the corresponding subcarrier. The method of any one of the preceding claims, wherein the reference symbol vector comprises elements corresponding to the subcarriers comprised of a plurality of OFDM symbols of a subframe of the cell. The method of any one of the preceding claims, wherein the cell is on a channel in an unlicensed band. The method of any one of the preceding claims, further comprising: Estimating the cell strength of each of a plurality of cells in the first manner by cross correlating channel estimates of different elements of corresponding reference symbol vectors for each of the plurality of cells. The method of any one of the preceding claims, further comprising: Estimating cell cell strength in a second manner by autocorrelating channel estimates of subcarriers of the cell transmitting reference symbols. Method according to Claim 6 method further comprising: reporting a difference between the cell strength of the cell estimated in the first manner and the cell strength of the cell estimated to be the second meadow to a serving cell of the UE device. The method of any preceding claim, wherein the cell functions according to LTE, wherein the cell strength estimate is an estimate of an RSRP of the cell. The method of any one of the preceding claims, wherein cross-correlating channel estimates of different elements of the reference symbol vector is configured to reduce the interference and / or noise effects of cell strength estimated in the first manner. Computer program that provides instructions for performing one of the procedures Claims 1 to 9 having. Wireless User Equipment (UE) device comprising: a radio; and a processing element operably coupled to the radio; wherein the radio and the processing element are configured to: Defining a reference symbol vector for the first cell, each corresponding element of the reference symbol vector having a corresponding subcarrier of the cell transmitting a corresponding reference symbol; Calculating a cell strength of a first cell, wherein the cell strength of the first cell is at least partially calculated by cross correlating channel estimates of different reference symbol subcarriers of the first cell, wherein cross-correlating channel estimates of different reference symbol subcarriers the first cell has a cross-correlation of channel estimates of elements of the reference symbol vector with each other; and Providing an indication of the calculated cell strength of the first cell to a serving cell of the UE device. UE device according to Claim 11 wherein, to calculate the cell strength of the first cell, the radio and the processing element are further configured to: perform cell-power sub-calculations on a per-path basis based on a number of transmit and receive antennas the first cell and the UE; and averaging the per-path cell strength subcomputations to produce an averaged cell strength estimate. UE device according to Claim 12 wherein the per-path cell strength sub-computations are averaged in a linear manner or in a weighted manner. UE device according to one of Claims 11 to 13 wherein the radio and the processing element are further configured to: perform a time domain averaging of the cell strength subcomputations performed at different times to calculate the cell strength of the first cell, wherein the time Domain averaging using an exponential time window.

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