WO2013060016A1

WO2013060016A1 - Methods and apparatuses for provision of an effective pathloss offset calculation mechanism for a communication system

Info

Publication number: WO2013060016A1
Application number: PCT/CN2011/081483
Authority: WO
Inventors: Wei Bai; Na WEI; Haiming Wang; Pengfei Sun; Jing HAN; Wei Hong
Original assignee: Renesas Mobile Corporation
Priority date: 2011-10-28
Filing date: 2011-10-28
Publication date: 2013-05-02

Abstract

A method, apparatus and computer program product are provided enabling provision of an efficient manner of determining a pathloss offset in a communication system. A method and apparatus may receive a message from a base station. The message may indicate a pathloss model of a current wireless environment, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. The method and apparatus may also determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. The method and apparatus may also determine an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

Description

METHODS AND APPARATUSES FOR PROVISION OF AN EFFECTIVE PATHLOSS OFFSET CALCULATION MECHANISM FOR A COMMUNICATION SYSTEM

TECHNOLOGICAL FIELD Embodiments of the present invention relate generally to wireless communication technology and, more particularly, to a method, apparatus and computer program product for providing an effective pathloss offset calculation mechanism for a communication system.

BACKGROUND Mobile terminals routinely communicate within a licensed spectrum via networks supervised by various cellular operators. The licensed spectrum, however, has a finite capacity and may become somewhat scarce as the number of mobile terminals that are configured to communicate within the licensed spectrum increases at fairly dramatic rates. As the demands placed upon the licensed spectrum by the various mobile terminals begin to saturate the licensed spectrum, the mobile terminals may experience increasing levels of interference or limited resources with the licensed spectrum potentially eventually becoming a bottleneck for such communications. Accordingly, it may be necessary to enable cellular operations on license exempt bands as well as in suitable instances to help offload the traffic, improve the peak data rate and improve the spectrum efficiency.

An increasing number of other network topologies are being integrated with cellular networks. However, there may already be some other network system or other cellular operations operating on an unlicensed band. These other network topologies include, for example, wireless fidelity (WiFi) networks, ad hoc networks and various other local area networks. The terminals, either mobile or fixed, supported by these other network topologies may communicate with one another in an unlicensed spectrum, such as a licensed-exempt industrial scientific medical (ISM) radio band. The ISM radio band supports other non-celiular systems, such as WiFi systems operating in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, ZigBee systems operating in accordance with the IEEE 802.15 standard, Bluetooth systems and universal serial bus (USB) wireless systems. In this regard, the ISM radio band may include the 2.4 GHz ISM band in which WiFi 802.11 b and 802.11g systems operate and the 5 GHz ISM band in which WiFi 802.11a systems operate. Though cellular

technologies have not generally been deployed in the ISM band, such deployment could be considered for local-area Long Term Evolution (LTE) cellular networks as long as they meet the regulatory requirements in country-specific ISM bands, e.g., Federal

Communications Commission (FCC) in the United States. Another example of a license exempt band is TV White Space (TVWS), which has been investigated widely in the recent years due to the large available bandwidths at suitable frequencies (e.g., TV spectrum in the 54 - 698 MHz range in the U.S.) for different radio applications. In the United States, the FCC has regulated licensed or license-exempt TV bands for the secondary-system applications, e.g., cellular, WiFi, WiMax, etc., on TV Band Devices (TVBD). At present, in a wireless communication system, uplink (UL) power control is typically widely used to ensure the power from different mobile terminals communicating with a base station is almost at same level, and the base station may also set the transmission power at the minimum level which the base station may be capable of detecting. In an LTE system, there are typically two types of power control, such as an open-loop power control and a close-loop power control. In open-loop power control, a relevant input factor to decide the UL transmission power may be the pathloss (PL).

Currently, in a LTE system, mobile terminals may use the measured downlink (DL) pathloss as the UL pathloss and may then calculate open-loop power control. In a Time Division Duplex (TDD) LTE system, this may be acceptable because the UL and DL transmission may be using the same frequency and may have the same channel properties. For a Frequency Division Duplex (FDD) LTE system, the UL and DL may be on different carrier, however, the UL and DL carrier may be on same frequency band so there may not be a big difference between the DL pathloss and UL pathloss.

On the other hand, for an unlicensed band of an LTE system there may be pathloss reference challenges such as, for example, a big pathloss difference between uplink and downlink carriers. For instance, in a lower frequency band, the pathloss difference between uplink and downlink carriers may be very large. Such a large pathloss difference may not be reliable for a mobile terminal to utilize to calculate the downlink pathioss as a reference to determine the UL transmission power. Additionally, in unlicensed band of an LTE system, the LTE system may operate in a variable ON/OFF state in order to allow another communication system to utilize the spectrum/medium of the unlicensed band. For instance, during a turned off period, the LTE system may typically shut off all transmissions to allow transmissions via a medium for another system since any signal may cause another system(s) to misinterpret that the medium is busy. When the LTE system turns on, the LTE system may utilize the medium of the unlicensed band. The variable ON/OFF state of the LTE system may break a downlink-uplink linkage which may create challenges to calculate the pathloss reference to determine the UL transmission power. For example, in an instance in which a downlink carrier taken as the pathloss reference for an uplink carrier is turned off, a mobile terminal may lose the pathloss reference and may not be able to measure the pathloss. As such, the mobile terminal may be unable to utilize the pathloss reference to calculate the UL transmission power.

In view of the foregoing drawbacks, it may be beneficial to provide a more efficient and reliable mechanism is in which to calculate a pathloss offset for a communication system.

BRIEF SUMMARY OF EXAMPLE EMBODIMENTS

A method, apparatus and computer program product are therefore provided in accordance with an example embodiment to provide an efficient and reliable manner in which to determine pathloss offset for a communication system. In an example embodiment, a base station(s) such as, for example, an evolved node B(s) (eNBs) may provide a pathfoss model(s) to User Equipment(s) (UEs) and may enable the UE(s) to determine a pathloss offset between a measured downlink carrier and a target uplink carrier. The UE(s) may utilize this determined pathloss offset in part to determine uplink pathloss for an open loop power control.

In this regard, some example embodiments may enable provision of a pathloss reference for a UE(s) to determine an uplink pathloss with acceptable accuracy even in an instance in which a downlink carrier and uplink carrier may be far away in a frequency domain. In some example embodiments, a UE(s) may flexibly select a pathloss reference for an uplink carrier and as such may increase the power control accuracy. By providing a pathloss model(s) to a UE{s), the example embodiments may minimize signaling overhead between an eNB(s) and a UE(s) since the UE(s) may utilize the provided pathloss model in part to determine the pathloss offset between different downlink carriers and uplink carriers. In one example embodiment, a method is provided that includes receiving a message, from a base station, indicating a pathloss model of a current wireless environment, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. The method may further include determining a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. The method may further include determining an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss. In another example embodiment, an apparatus is provided that includes at least one processor and at least one memory including computer program code with the at least one memory and the computer program code being configured to, with the processor, cause the apparatus at least to receive a message, from a base station, indicating a pathloss model of a current wireless environment, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. The at least one memory and the computer program code are also configured to, with the at least one processor, cause the apparatus to determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. The at least one memory and the computer program code are also configured to, with the at least one processor, cause the apparatus to determine an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

In yet another example embodiment, a method is provided that includes determining a pathloss model of a current wireless environment. The method may further include generating a message indicating the pathloss model, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. The method may further include enabling provision of the generated message to at least one device, to enable the device to determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. The message provided to the device may also enable the device to determine an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss. In yet another example embodiment, an apparatus is provided that includes at least one processor and at least one memory including computer program code with the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus at least to determine a pathloss model of a current wireless environment. The at least one memory and the computer program code are also configured to, with the at least one processor, cause the apparatus to generate a message indicating the pathloss model, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. The at least one memory and the computer program code are also configured to, with the at least one processor, cause the apparatus to enable provision of the generated message to at least one device, to enable the device to determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. The provided message may also enable the device to determine an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: FIG. 1 is one example of a communications system according to an example embodiment of the invention;

FIG. 2 is a diagram of a table of supported Evolved Universal Mobile

Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) operating frequency bands in an LTE system according to an example embodiment of the invention; FIG. 3 is a diagram illustrating the regulatory requirement for TVWS according to an example embodiment of the invention;

FIG. 4 is a diagram of a system according to an example embodiment of the invention;

FIG. 5 is a schematic block diagram of an apparatus from the perspective of a base station in accordance with an example embodiment of the invention;

FIG. 6 is a block diagram of an apparatus from the perspective of a terminal in accordance with an example embodiment of the invention;

FIG. 7 is a diagram illustrating an example of signaling a pathloss model, an indicated exponent of frequency, and an indication of component carriers provided to User Equipment according to an example embodiment of the invention; FIG. 8 illustrates a flowchart for enabling provision of an efficient and reliable manner in which to determine pathloss offset for a communications system from the perspective of a terminal according to an example embodiment of the invention; and

FIG. 9 illustrates a flowchart for enabling provision of an efficient and reliable manner in which to determine pathloss offset for a communications system from the perspective of a base station according to an example embodiment of the invention.

DETAILED DESCRIPTION

Some embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown, indeed, various embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout.

As used in this application, the term 'circuitry' refers to all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of

processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device. As defined herein a "computer-readable storage medium," which refers to a non- transitory, physical or tangible storage medium (e.g., volatile or non-volatile memory device), may be differentiated from a "computer-readable transmission medium," which refers to an electromagnetic signal. As referred to herein, a pathloss model may, but need not, relate to a

mathematical model equation which depicts the relationship between a radio signal attenuation and frequency, distance or the like.

Referring now to FIG. 1 , in accordance with an example embodiment of the invention, a communication system is provided in which a network entity, such as an access point, a base station, an evolved node B (eNB) or the like, may utilize carrier aggregation and in this regard may communicate with a licensed band carrier(s) as well as an unlicensed band carrier(s).

Referring now to FIG. 2, a table illustrating supported frequency bands in an LTE system is provided. In an instance in which downlink and uplink carriers are chosen which have the biggest frequency gap (e.g., 21 10 MHz - 17 0 MHz, 2155 MHz - 1755 MHz) such as, for example, operating band 4 and the free space as a channel mode is utilized may yield the following result of the pathloss difference between an uplink and a downlink carrier in which the pathloss model in a free space channel condition is given by

As such, the PL difference between a downlink and uplink carrier may be denoted by

APL = PL_D - PL_U = ft* -1.8dfl

For UL transmission, the PL difference between the downlink and uplink carrier may be accepted because an eNB may also use the Transmit Power Control (TPC) command to adjust the transmission power as desired.

In an instance in which an FDD-LTE system is deployed on an unlicensed band, and the irregular ON/OFF for the LTE system is invoked, there may be different pathloss scenarios which may cause problems. The first problem may involve the irregular ON/OFF of an LTE carrier which may break the linkage between the DL carrier and UL carrier. In an instance in which the DL carrier may be taken as the pathloss reference for an UL carrier is turned off, a mobile terminal such as for example, User Equipment (UE) may lose the PL reference and may not measure the PL and hence may be unable to determine the UL transmission power. Another problem may involve TVWS, in which there may be some channels that may only be used for DL or only be used for UL, and the pathloss performance on such carriers may be very different. As such, for a given UL carrier, there may be no DL carrier having a similar pathloss performance and as such it may be difficult for a UE to determine the UL transmission power according to the downlink pathloss.

Referring now to FIG. 3, a diagram illustrating an example of a regulatory requirement for TV White Space is provided. In the example embodiment of FIG. 3, channel #1 to #20 of the TVWS may only be allowed to be used for DL transmission (e.g., a fixed device only) and some channels may only be allowed to be used for UL transmission (e.g., channels which are adjacent to a TV channel). For these carriers of the TVWS, FDD may be the only viable option for facilitating communications.

Consider an instance in which channel 2 (e.g., 54 MHz) is configured as the DL carrier and channel 38 (e.g., 614 MHz) is configured as the UL carrier and the configured DL carrier is used as PL reference. In this regard, the PL difference between the UL carrier and DL carrier in free space may be calculated as follows:

APL = PL_D - PL_V = 10 * loglO » 21άΒ

From the above result, it may be determined that in the lower frequency band, the PL difference between UL and DL carriers may be very big, e.g., around 100 times. As such, it may not be reliable for a UE to use the DL PL as the reference to determine the UL transmission power.

In addition, in a different channel model, the relationship between the pathloss and the exponent of the frequency (also referred to herein as exponent of carrier frequency) may be different. For example, in a free space model, a value of the exponent of frequency may be two while a value of the exponent of frequency may be zero in a two-Ray channel model. The bigger the exponent of frequency, the bigger the PL difference may be which may make it difficult to determine the DL PL as a reference for determining UL transmission power.

In this regard, some example embodiments of the invention may alleviate the challenges associated with the pathloss acquisition based in part on the problems corresponding to the variable UL-DL linkage and the big difference of the PL performance on UL and DL carriers. As such, some example embodiments may enable provision of an effective pathloss offset calculation mechanism for a communication system such as, for example, an FDD-LTE system.

Referring now to FIG. 4, a schematic block diagram of a communications system according to an example embodiment is provided. In the example embodiment of FIG. 4, the base station an eNB 12 (also referred to herein as a base station 12) or the like, may communicate with a plurality of terminals in the licensed spectrum and may optionally communicate in a license exempt band 18 (also referred to herein as unlicensed band 18), such as within the ISM band or the TVWS band. While a communications system that provides coordination of communication using carrier aggregation in a licensed band and an unlicensed band may be configured in various different manners, FIG. 4 illustrates a generic system diagram in which a terminal, such as a mobile terminal, may

communicate in a licensed spectrum, as well as in license exempt band 18, with the network 10, such as by the exchange of cellular signals as shown in the solid lightening bolts in FIG. 4. In addition, the mobile terminal may communicate in a license exempt band 18, such as, but not limited to, the ISM band and/or TVWS, and in the license exempt band there may be other terminals/networks communicating with each other as shown in the dashed lightening bolts. As shown in FIG. 4, an embodiment of a system 7 in accordance with an example embodiment of the invention may include a set of first terminals 14 and a set of second terminals 16. The first terminals 14 may each be capable of communication, such as cellular communication, in the licensed band, as well as in the license exempt band, with a network 10 (e.g., a cellular network). Some terminals 6 may form another network, which may be a cellular system(s) or non-cellular system(s). The first terminals 14 may be configured to communicate (e.g., directly) with one or more of the second terminals 16 as well as at least one access point (AP) 3 (e.g., a WiFi AP, a wireless local area network (WLAN) AP) in a license exempt band 18, The first terminals 14 may be configured to listen to signaling on the license exempt band 8. While each set of the first and second terminals is shown to include multiple terminals, either set or both sets may include a single terminal in other embodiments. While the cellular network may be configured in accordance with Long Term Evolution (LTE), the network may employ other mobile access mechanisms such as wideband code division multiple access (W-CDMA), CDMA2000, global system for mobile communications (GSM), general packet radio service (GPRS), LTE-Advanced (LTE-A) and/or the like. The non-cellular network may be configured in IEEE 802.11 systems or other shared band technologies (e.g., TVWS). The network 10 may include a collection of various different nodes, devices or functions that may be in communication with each other via corresponding wired and/or wireless interfaces. As such, the illustration of FIG. 4 should be understood to be an example of a broad view of certain elements of the system and not an all-inclusive or detailed view of the system or the network. One or more communication terminals such as the first terminals 14 and second terminals 16 may be in communication with each other or other devices via the licensed band of the network 10 and/or the unlicensed band 18. In some cases, each of the communication terminals may include an antenna or antennas for transmitting signals to and for receiving signals from an access point (e.g., AP 3), base station, node B, eNB (e.g., eNB 12) or the like. Although one eNB 12 and one AP 3 is shown as part of the system of FIG. 4, it should be pointed out that any suitable number of eNBs 12 and APs 3 may be part of the system of FIG. 4 without departing from the spirit and scope of the invention. The eNB may be, for example, part of one or more cellular or mobile networks or public land mobile networks (PLMNs). In turn, other devices such as processing devices (e.g., persona! computers, server computers or the like) may be coupled to the terminals via the network. In some example embodiments, the first terminals 14 may be one or more mobile communication devices (e.g., user equipment (UE)) such as, for example, a mobile telephone, portable digital assistant (PDA), pager, laptop computer, or any of numerous other hand held or portable communication devices, computation devices, content generation devices, content consumption devices, or combinations thereof. Alternatively, the first terminals may be fixed communication devices that are not configured to be mobile or portable. In either instance, the terminals may include one or more processors that may define processing circuitry either alone or in combination with one or more memories. The processing circuitry may utilize instructions stored in the memory to cause the terminals to operate in a particular way or execute specific functionality when the instructions are executed by the one or more processors. The first terminals may also include communication circuitry and corresponding hardware/software to enable communication with other devices.

The second terminals 16 may be communication devices such as, for example, a WiFi station, a WLAN station (according to a WLAN technique such as, for example, IEEE 802.11 techniques), a Bluetooth station or the like(s)). The second terminals may be configured to communicate with the AP 3 (e.g., a WiFi AP, a WLAN AP) as well as the first terminals 4.

Referring now to FIG. 5, a schematic block diagram of an apparatus according to an example embodiment is provided. In the example embodiment of FIG. 5, the eNB 12 may be embodied as or otherwise include an apparatus 20 as generically represented by the block diagram of FIG. 5. In this regard, the apparatus may be configured to communicate with the sets of first and second terminals 14, 16. While one embodiment of the apparatus is illustrated and described below, it should be noted that the components, devices or elements described below may not be mandatory and thus some may be omitted in certain embodiments. Additionally, some embodiments may include further or different components, devices or elements beyond those shown and described herein.

As shown in FIG. 5, the apparatus 20 may include or otherwise be in

communication with processing circuitry 22 that is configurable to perform actions in accordance with example embodiments described herein. The processing circuitry may be configured to perform data processing, application execution and/or other processing and management services according to an example embodiment of the invention. In some example embodiments, the apparatus or the processing circuitry may be embodied as a chip or chip set. In other words, the apparatus or the processing circuitry may comprise one or more physical packages (e.g., chips) including materials, components and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interaction for component circuitry included thereon. The apparatus or the processing circuitry may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single "system on a chip." As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

In an example embodiment, the processing circuitry 22 may include a processor 24 and memory 26 that may be in communication with or otherwise control a device interface 28. As such, the processing circuitry may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein in relation to the eNB 12.

The device interface 28 may include one or more interface mechanisms for enabling communication with other devices, such as the sets of first and second terminals 14, 16. In some cases, the device interface may be any means such as a device or circuitry embodied in either hardware, or a combination of hardware and software that is configured to receive and/or transmit data from/to a network and/or any other device or module in communication with the processing circuitry 22. In this regard, the device interface may include, for example, an antenna (or multiple antennas) and supporting hardware and/or software for enabling communications with a wireless communication network and/or a communication modem, such as a cellular modem 21 (e.g., an LTE modem), and/or an optional non-cellular modem 23 (e.g., a WiFi modem, WLAN modem, etc.) for enabling communications with the sets of first and second terminals. In an example embodiment the cellular modem 21 may be configured to facilitate

communications via a primary cell (PCell) on a licensed band (for example, of network 10) and the non-cellular modem 23 may be able to facilitate communications via a secondary cell (SCell) on the unlicensed band 18.

In an example embodiment, the memory 26 may include one or more non- transitory memory devices such as, for example, volatile and/or non-volatile memory that may be either fixed or removable. The memory may be configured to store information, data, applications, instructions or the like for enabling the apparatus 20 to carry out various functions in accordance with example embodiments of the present invention. For example, the memory could be configured to buffer input data for processing by the processor 24. Additionally or alternatively, the memory could be configured to store instructions for execution by the processor. As yet another alternative, the memory may include one of a plurality of databases that may store a variety of files, contents or data sets. Among the contents of the memory, applications may be stored for execution by the processor in order to carry out the functionality associated with each respective

application. In some cases, the memory may be in communication with the processor via a bus for passing information among components of the apparatus.

The processor 24 may be embodied in a number of different ways. For example, the processor may be embodied as various processing means such as one or more of a microprocessor or other processing element, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or the like. In an example embodiment, the processor may be configured to execute instructions stored in the memory 26 or otherwise accessible to the processor. As such, whether configured by hardware or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry - in the form of processing circuitry 22) capable of performing operations according to embodiments of the present invention while configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software

instructions, the instructions may specifically configure the processor to perform the operations described herein. In one embodiment, the first terminals 14 (also referred to herein as user equipment (UE) 14) may be embodied as or otherwise include an apparatus 30 as generically represented by the block diagram of FIG. 6. In this regard, the apparatus may be configured to provide for communications in the licensed spectrum, such as cellular communications, with the eNB 12 or another terminal and communications in the license exempt band, such as non-cellular communications, with another terminal (e.g., second terminal 16). While the apparatus may be employed, for example, by a mobile terminal, it should be noted that the components, devices or elements described below may not be mandatory and thus some may be omitted in certain embodiments. Additionally, some embodiments may include further or different components, devices or elements beyond those shown and described herein.

As shown in FIG. 6, the apparatus 30 may include or otherwise be in

communication with processing circuitry 32 that is configurable to perform actions in accordance with example embodiments described herein. The processing circuitry may be configured to perform data processing, application execution and/or other processing and management services according to an example embodiment of the present invention. In some embodiments, the apparatus or the processing circuitry may be embodied as a chip or chip set. In other words, the apparatus or the processing circuitry may comprise one or more physical packages (e.g., chips) including materials, components and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interaction for component circuitry included thereon. The apparatus or the processing circuitry may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single "system on a chip." As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

In an example embodiment, the processing circuitry 32 may include a processor 34 and memory 36 that may be in communication with or otherwise control a device interface 38 and, in some cases, a user interface 44. As such, the processing circuitry may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein. However, in some embodiments taken in the context of the mobile terminal, the processing circuitry may be embodied as a portion of a mobile computing device or other mobile terminal. The optional user interface 44 may be in communication with the processing circuitry 32 to receive an indication of a user input at the user interface and/or to provide an audible, visual, mechanical or other output to the user. As such, the user interface in the context of a mobile terminal may include, for example, a keyboard, a mouse, a joystick, a display, a touch screen, a microphone, a speaker, and/or other input/output mechanisms.

The device interface 38 may include one or more interface mechanisms for enabling communication with other devices and/or networks. In some cases, the device interface may be any means such as a device or circuitry embodied in either hardware, or a combination of hardware and software that is configured to receive and/or transmit data from/to a network and/or any other device or module in communication with the processing circuitry 32. In this regard, the device interface may include, for example, an antenna (or multiple antennas) and supporting hardware and/or software for enabling communications with a wireless communication network and/or a communication modem or other hardware/software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB), Ethernet or other methods. In the illustrated embodiment, for example, the device interface includes a cellular modem 40 (e.g., an LTE modem) for supporting communications in the licensed spectrum, such as communications with the eNB 12, and an optional non-cellular modem 42 (e.g., a WiFi modem, WLAN modem, Bluetooth (BT) modem, etc.) for supporting communications in the license exempt band 18, such as non-cellular communications, e.g., communications in the ISM band and/or the TVWS band, with other terminals (e.g., second terminals 16 (e.g., a WiFi station(s), a WLAN station(s)), etc.).

In an example embodiment, the memory 36 may include one or more non- transitory memory devices such as, for example, volatile and/or non-volatile memory that may be either fixed or removable. The memory may be configured to store information, data, applications, instructions or the like for enabling the apparatus 30 to carry out various functions in accordance with example embodiments of the present invention. For example, the memory could be configured to buffer input data for processing by the processor 34. Additionally or alternatively, the memory could be configured to store instructions for execution by the processor. As yet another alternative, the memory may include one of a plurality of databases that may store a variety of files, contents or data sets. Among the contents of the memory, applications may be stored for execution by the processor in order to carry out the functionality associated with each respective application. In some cases, the memory may be in communication with the processor via a bus for passing information among components of the apparatus. The processor 34 may be embodied in a number of different ways. For example, the processor may be embodied as various processing means such as one or more of a microprocessor or other processing element, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC, an FPGA or the like. In an example embodiment, the processor may be configured to execute instructions stored in the memory 36 or otherwise accessible to the processor. As such, whether configured by hardware or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry - in the form of processing circuitry 32) capable of performing operations according to embodiments of the present invention while configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software

instructions, the instructions may specifically configure the processor to perform the operations described herein.

To overcome the problems that may be associated with the variable ON/OFF pattern of a LTE system in an unlicensed band which may cause uplink/downlink linkage failure and the potential large frequency gap between a downlink carrier (e.g., a channel) and an uplink carrier (e.g., another channel) which may result in unreliably determining uplink transmission power, the example embodiments may enable a UE 14 to derive the uplink pathloss, as described more fully below.

In this regard, the example embodiments may enable a UE 14 to derive uplink pathloss according to the determined downlink pathloss with an acceptable accuracy and may enable a UE 14 to easily and efficiently change a pathloss reference in an instance in which a downlink carrier is turned off. The example embodiments may also minimize the signalling overhead between an eNB 12 and a UE 14 for determining the uplink transmission power based in part on enabling the UE 14 to determine the pathloss offset, as described more fully below.

In some example embodiments, the pathloss performance may depend on several factors, including but not limited to, the propagation distance between a transmitter and a receiver of an eNB and UE, the central frequency of a carrier(s), other parameters that may be fixed values and any other suitable factors. In an example embodiment, an eNB (e.g., eNB 12) may provide a pathloss model to a UE (e.g., UE 14) to enable the UE to utilize the provided pathloss model in part to determine the uplink pathloss for open loop power control, as described more fully below. The pathioss model(s) provided by the eNB to the UE may include, but are not limited to, the following example pathioss models.

Free space

PL = 10 * log ia( °j ₂

\^naj) _{| wnere a} value of the exponent of carrier

frequency is 2,

and in which f denotes the carrier frequency d denotes the distance between the

transmitter and receiver.

Two-Ray channel

PL =

d² , where a value of the exponent of carrier frequency is 0, and G_t denotes the total gain of the transmitter and receiver, h_t denotes the height of the transmitter and h_r denotes the height of the receiver.

Hata model

Pl(dB) - 69.55 + 26.16log 10 (f_c) - 12.82logX0 h_t) - a(h_r)

+ (44.9 - 6.SUogl0{_h )logl0id) where a value of the exponent of carrier frequency is 2.6, and f_c denotes the

carrier frequency, h_t denotes the height of the transmitter and h_r denotes the height of the

receiver.

Okumura Hata COST231 model

PL(dff) = 46.3 + 33.9io0lO( _c) - 13.82^0^10 (7i_t) - a h_r) + (44.9 - 6.55loglQ(h_t)) loglO(.d

+ CM

where a value of the exponent of carrier frequency is 3.39, and CM is one

additional factor which is used to adjust the pathioss {e.g., which may, but need not, be 0

dB for a typical city and 3 dB for metropolitan area of a city).

The pathioss models provided above are exemplary for purposes of illustration

and not of limitation and in this regard, the eNB may provide any other suitable pathioss

models to a UE without departing from the spirit and scope of the invention.

In some example embodiments, the UE may determine that the difference

between an uplink pathioss and a downlink pathioss may depend on a propagation model

(e.g., an exponent of the carrier frequency), for example, in an instance in which a

transmitter and receiver at the eNB (e.g., eNB 12) are at the same place. For a UE (e.g., UE 12) which may have not moved (e.g., the distance between the eNB and UE is not changed, the height of the transmitter and receiver are not changed), the UE may determine the uplink pathloss based in part on the downlink pathloss since the UE knows the pathloss model utilized and provided by an eNB that the UE is communicating with, regardless of whether the downlink carrier and the uplink carrier are at the same frequency band.

As described above, an eNB (e.g., eNB 12) may indicate or determine a pathloss model that the eNB utilizes and may provide the determined pathloss model to a UE (e.g., UE 14) that the eNB is communicating with. In one example embodiment, the eNB may be designated (e.g., previously assigned) to utilize a predefined pathloss model. In an alternative embodiment, the processor (e.g., processor 24) of the eNB may perform one or more tests in a practical environment in which the eNB operates and based in part on the results of the tests, the processor of the eNB may choose or select a pathloss model. The pathloss model may be tested and/or determined during network deployment. The eNB may also provide the exponent of carrier frequency corresponding to the determined pathloss model to the UE as well as one or more component carriers (e.g., a set of component carriers) in which the UE may select for downlink transmissions. The processor (e.g., processor 34) of the UE may utilize the received pathloss model and the corresponding exponent of carrier frequency in part to calculate the pathloss offset between a measured downlink carrier (e.g., a channel) and a target uplink carrier (e.g., a channel).

In an example embodiment, the eNB (e.g., eNB 12) may provide the pathloss model, the exponent of carrier frequency corresponding to the pathloss model and indications of the one or more carrier components to the UE in a signalling broadcast (also referred to herein as broadcasted signal or broadcasted message). The one or more component carriers (e.g., downlink carriers) provided by the eNB to the UE may be operated by the same downlink transmitter as a current carrier in which the UE is receiving the broadcasted signal. In one example embodiment, the eNB may, but need not, indicate a proposal of a DL carrier as a pathloss reference for an uplink carrier, that the UE may consider utilizing, in the broadcasted signal. In this regard, the proposed pathloss reference may correspond to a proposed downlink carrier in which the UE may consider utilizing in part to determine uplink pathloss for the open loop power control even in an instance in which the downlink carrier and an uplink carrier may be far away in a frequency domain. In one example embodiment, the information indicating the pathloss model, the corresponding exponent of carrier frequency and the one or more component carriers may be provided by the eNB to the UE via dedicated signalling during a configuration of a secondary cell (SCell) (e.g., unlicensed band 18) of a system (e.g., an LTE system (e.g., system 7)).

In some example embodiments, an eNB (e.g., eNB 12) may not necessarily provide a downlink carrier as a pathloss reference for an uplink carrier to a UE (e.g., UE 14). For example, the eNB may allow the UE to decide which DL carrier may be used as the pathloss reference. In an example embodiment, the UE may change the pathloss reference to correspond to a different downlink carrier in response to determining that the downlink carrier is turned off.

For instance, consider an example in which a set of component carriers (CCs) provided by the eNB to the UE may indicate a downlink component carrier 1 (DL CC1), a downlink component carrier 2 (DL CC2), a downlink component carrier 3 (DL CC3) as well as uplink component carriers 1 , 2, 3 (UL CC1 , UL CC2, UL CC3). Presume further that the eNB provided the indicated pathloss model and the corresponding exponent of the carrier frequency associated with the uplink and downlink carriers, utilized by the eNB, to the UE. In this regard, the UE may calculate the pathloss based in part on selecting one of the downlink carriers as a pathloss reference. In this example embodiment, presume that the processor of the UE chose the downlink CC2 as the pathloss reference and based on calculations the UE may determine that the pathloss offset corresponding to downlink CC2 and the uplink CC1 is 2 decibels (dB). As such, the processor (e.g., processor 34) of the UE may then utilize the determined PL offset to calculate the uplink transmission power for uplink CC1 by adding the pathloss value of 2 dB to a determined downlink pathloss of the downlink CC2. In this regard, the processor of the UE may calculate the pathloss offset between any of the downlink and uplink carrier pairs such as, for example, any combination of one uplink carrier and one downlink carrier. In an instance in which the UE determines the pathloss corresponding to a downlink carrier (e.g., a single downlink carrier), the UE may determine the pathloss for each of the uplink carriers by adding the corresponding pathloss offset to the determined pathloss.

In an example embodiment, in response to receiving the broadcast data (e.g., the broadcast signal) indicating the pathloss model utilized by the eNB, the processor (e.g., processor 34) of the UE may choose/select a downlink carrier (e.g., a downlink channel) from the broadcasted component carriers (e.g., a set of component carriers) having a reliable downlink channel condition (e.g., a DL carrier which the UE determines has a reliable pathloss estimation). In this regard, the processor of the UE may calculate the pathloss offset according to the indicated exponent of carrier frequency corresponding to the pathloss model, as described more fully below.

Consider an example in which an eNB (e.g., eNB 12) broadcasts or sends (e.g., via a message) a pathloss model, a corresponding exponent of the carrier frequency and indications of one or more component carriers to a UE. In an example embodiment, the eNB may send the pathloss model and the corresponding exponent of the carrier frequency utilized by the eNB as well as one or more component carriers to the UE via dedicated signaling or one or more messages. The signaling/message(s) generated by the processor (e.g., processor 24) of the eNB (e.g., eNB 12) may, but need not, relate to a Radio Resource Control (RRC) signal(s)/RRC message(s). As shown in FIG. 7, the dedicated message 3 (also referred to herein as a dedicated signal(s) (e.g., an RRC message, an RRC signal)) generated by the eNB and sent to the UE may include data indicating a pathloss model, a corresponding exponent of the carrier frequency and indications of one or more carriers (e.g., carriers by the same transmitter).

In response to receiving the RRC signal(s) or the RRC message(s), the processor (e.g., processor 34) of the UE may analyze the identified component carriers (e.g., a set of component carriers (e.g., channels)) and may select a downlink carrier (e.g., a channel) from the component carriers provided by the eNB. In an example embodiment, the processor of the UE may select a downlink carrier from the provided component carriers based in part on the processor of the UE determining that the downlink carrier has a robust downlink quality, in this regard, the eNB may allow the UE to decide which downlink carrier is used as the pathloss reference. For purposes of illustration and not of limitation, the UE may select a downlink carrier with a good/reliable channel quality, or the UE may choose a primary cell (PCell) (e.g., network 10) as the downlink carrier, or may choose any other suitable carrier. The processor of the UE may utilize the selected downlink carrier in part to calculate the pathloss offset.

Additionally, in response to the UE (e.g., UE 14) receiving the RRC signals/RRC messages from eNB, the processor of the UE may analyze the data and may utilize the indication of the exponent of the frequency (e.g., a value of 3.39 of an exponent of carrier frequency) along with the identified pathloss model (e.g., the Okumura Hata COST231 pathloss model) to calculate the pathloss offset between a downlink carrier and an uplink carrier.

For instance, in an example embodiment, the processor of the UE may determine that the message (e.g., message 3) includes data indicating an exponent of frequency is 3.39 corresponding to the the Okumura Hata COST231 pathloss model. As such, the processor (e.g., processor 34) of the UE may calculate the pathloss (PL) offset as follows:

PL_Qnsn dB-) - 10 * 3.39 * loglO (f_a/f_u) where ^denotes the selected downlink carrier and f_u denotes a target uplink carrier.

In response to calculating the pathloss offset, the processor of the UE may calculate the downlink pathloss and may add the calculated pathloss offset to the downlink pathloss to obtain the uplink pathloss for open loop power control. The uplink pathloss may be utilized by the UE as an input in determining the uplink transmission power.

Referring now to FIG. 8, a flowchart of an example embodiment of enabling provision of efficient and reliable manner in which to determine a pathloss offset in a communication system is provided according to an example embodiment. At operation 800, an apparatus (e.g., UE 14) may receive a message (e.g., message 3), from a base station (e.g., eNB 12), indicating a pathloss model of a current wireless environment, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers. At operation 805, an apparatus (e.g., UE 14) may determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. At operation 810, an apparatus (e.g., UE 14) may determine an uplink pathloss (e.g., for an open loop power control) based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

Referring now to FIG. 9, a flowchart of an example embodiment of enabling provision of efficient and reliable manner in which to determine a pathloss offset in a communication system is provided according to another example embodiment. At operation 900, an apparatus (e.g., eNB 12) may determine a pathloss model of a current wireless environment. At operation 905, an apparatus (e.g., eNB 12) may generate a message (e.g., message 3) indicating the pathloss model, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers.

At operation 910, an apparatus (e.g., eNB 12) may provide the generated message to at least one device (e.g., UE 4). The apparatus may provide the generated message to the device (e.g., UE 14) to enable the device to determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency. In this regard, the generated message provided by the apparatus to the device may also enable the device to determine an uplink pathloss (e.g., for an open loop power control) based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

It should be pointed out that FIGS. 8 and 9 are flowcharts of a system, method and computer program product according to an example embodiment of the invention. It will be understood that each block of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by various means, such as hardware, firmware, and/or a computer program product including one or more computer program instructions. For example, one or more of the procedures described above may be embodied by computer program instructions. In this regard, in an example embodiment, the computer program instructions which embody the procedures described above are stored by a memory device (e.g., memory 26, memory 36) and executed by a processor (e.g., processor 24, processor 34). As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (e.g., hardware) to produce a machine, such that the instructions which execute on the computer or other

programmable apparatus cause the functions specified in the flowcharts blocks to be implemented. In one embodiment, the computer program instructions are stored in a computer-readable memory that can direct a computer or other programmable apparatus to function in a particular manner, such that the instructions stored in the computer- readable memory produce an article of manufacture including instructions which implement the function specified in the flowcharts blocks. The computer program instructions may also be loaded onto a computer or other programmable apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus implement the functions specified in the flowcharts blocks. Accordingly, blocks of the flowcharts support combinations of means for performing the specified functions. It will also be understood that one or more blocks of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware and computer instructions. In an example embodiment, an apparatus for performing the methods of FIGS. 8 and 9 above may comprise a processor (e.g., the processor 24, the processor 34) configured to perform some or each of the operations (800 - 810, 900 - 910) described above. The processor may, for example, be configured to perform the operations (800 - 810, 900 - 910) by performing hardware implemented logical functions, executing stored instructions, or executing algorithms for performing each of the operations. Alternatively, the apparatus may comprise means for performing each of the operations described above. In this regard, according to an example embodiment, examples of means for performing operations (800 - 810, 900 - 910) may comprise, for example, the processor 24 (e.g., as means for performing any of the operations described above), the processor 34 and/or a device or circuit for executing instructions or executing an algorithm for processing information as described above.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitiy described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. A method comprising:

receiving a message, from a base station, indicating a pathloss model of a current wireless environment, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers;

determining a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency; and

determining an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

2. The method of claim 1, wherein prior to determining the pathloss offset, the method further comprises:

selecting the downlink carrier, among the component carriers, identified by the base station.

3. The method of claim 1, wherein receiving further comprises receiving the message via an unlicensed band of a secondary cell of a Long Term Evolution system.

4. The method of claim 2, wherein selecting further comprises selecting the downlink carrier in response to determining that the downlink carrier comprises a reliable downlink channel condition.

5. The method of claim 1 , further comprising:

receiving a proposal in the message of a pathloss reference, from the base station, the pathloss reference corresponding to a proposed downlink carrier in which to utilize in part to determine the uplink pathloss.

6. The method of claim 1 , further comprising:

determining a downlink carrier component, among a plurality of downlink carriers of the carrier components, to utilize as a pathloss reference for the uplink carrier in order to determine, in part, the uplink pathloss.

7. The method of claim 6, further comprising: changing the pathloss reference to correspond to a different downlink carrier in response to determining that the downlink carrier component is turned off,

wherein the downlink carrier corresponds to the downlink carrier component.

8. An apparatus comprising:

at least one processor; and

at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least perform:

9. The apparatus of claim 8, wherein prior to determining the pathloss offset, the memory and the computer program code are configured to, with the processor, cause the apparatus to:

select the downlink carrier, among the component carriers, identified by the base station.

10. The apparatus of claim 8, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

receive the message by receiving the message via an unlicensed band of a secondary cell of a Long Term Evolution system.

1 1. The apparatus of claim 9, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

select the downlink carrier by selecting the downlink carrier in response to determining that the downlink carrier comprises a reliable downlink channel condition.

12. The apparatus of claim 8, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

receive a proposal in the message of a path!oss reference, from the base station, the pathloss reference corresponding to a proposed downlink carrier in which to utilize to determine, in part, the uplink pathloss.

13. The apparatus of claim 8, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

determine a downlink carrier component, among a plurality of downlink carriers of the carrier components, to utilize as a pathloss reference for the target uplink carrier in order to determine, in part, the uplink pathloss.

14. The apparatus of claim 13, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

change the pathloss reference to correspond to a different downlink carrier in response to determining that the downlink component carrier is turned off,

wherein the downlink carrier corresponds to the downlink component carrier.

15. A method comprising:

determining a pathloss model of a current wireless environment;

generating a message indicating the pathloss model, a value of an exponent of carrier frequency corresponding to the pathloss model and an indication of one or more component carriers; and

enabling provision of the generated message to at least one device, to enable the device to determine a pathloss offset between a downlink carrier and a target uplink carrier based in part on utilizing data indicating the pathloss model and the value of the exponent of carrier frequency and determine an uplink pathloss based in part on adding a value of the determined pathloss offset to a value of a determined downlink pathloss.

16. The method of claim 15, wherein determining the pathloss model comprises identifying a pathloss model previously assigned to a base station.

17. The method of claim 15, wherein determining the pathloss model comprises selection of the pathloss model based in part on one or more results of tests performed in an environment of a base station.

18. The method of claim 15, further comprising: including an indication of a determined proposal of a pathloss reference in the message, the proposed pathloss reference corresponding to a proposed downlink carrier for consideration by the device to enable the device to utilize the proposed downlink carrier to determine, in part, the uplink pathloss.

19. An apparatus comprising:

at least one processor; and

determining a pathloss model of a current wireless environment;

20. The apparatus of claim 19, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

determine the pathloss model by identifying a pathloss model previously assigned to the apparatus.

21. The apparatus of claim 19, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

determine the pathloss model by selection of the pathloss model based in part on one or more results of tests performed in an environment of the apparatus.

22. The apparatus of claim 9, wherein the memory and the computer program code are configured to, with the processor, cause the apparatus to:

include an indication of a determined proposal of a pathloss reference in the message, the proposed pathloss reference corresponding to a proposed downlink carrier for consideration by the device to enable the device to utilize the proposed downlink carrier to determine, in part, the uplink pathloss.

23. The apparatus of claim 9, wherein the apparatus comprises a base station and the device comprises a mobile terminal.