Positioning in the presence of passive distributed elements

Description

BACKGROUND I. Field

[0001] The present disclosure relates generally to wireless communications and more specifically to transmitting reference signals to one or more devices.II. Background

[0002] Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power,...). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), etc., and can use one or more protocols, such as high-speed uplink packet access (HSUPA), single carrier HSUPA (SC-HSUPA), dual carrier HSUPA (DC-HSUPA), etc.

[0003] Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more access points (e.g., base stations, femtocells, picocells, relay nodes, and / or the like) via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from access points to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to access points. Further, communications between mobile devices and access points may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and / or access points with other access points) in peer-to-peer wireless network configurations. WO 2004 / 080105 A2 discloses a method and apparatus to perform position determination in a wireless (e.g., cellular) communication network with repeaters. A signal received by a terminal is initially identified as being from a repeater. A position and a position uncertainty for the identified repeater are obtained (e.g., from a repeater database) and provided as the position estimate and position uncertainty for the terminal if (1) a more accurate position estimate for the terminal cannot be obtained, (2) the terminal is deemed to be in an indoor environment, or (3) the terminal is located sufficiently close to the identified repeater.; If information for additional delays associated with the identified repeater is available, then the position estimate for the terminal may be derived based on a "compensated" time measurement for the identified repeater (i.e., with the additional delays removed) and time measurements for at least two other transmitters received by the terminal. WO 2006 / 076600 A1 discloses a method and system that determines mobile station position information based upon base station identification and a repeater discriminant. A position location database includes base station identifications and repeater discriminant combinations, and unique position information associated with each combination. A repeater implements a discriminant to a transmitted signal in either the forward link, reverse link, or both. The position location database is accessed to determine mobile station position information based upon a base station identification and repeater discriminant. WO 2004 / 095733 A2 describes method and apparatus for determining whether a received signal is transmitted via a repeater. A source signal to be conveyed via a particular repeater may include, or be modified to include, a variety of signal characteristics having a predictable relationship that remains relatively constant, which may be taken together as a signature of the repeater. The signature may reflect a composite of distinct signals. A database of repeater signature references may be developed, and an adequate match between characteristics of an unknown received signal and such signature references indicates that at least part of the unknown signal transmitted via a repeater. Useful signal characteristics for repeater signatures may include some representative of signal strength, and time of arrival information, among many other possibilities.SUMMARY

[0004] In accordance with one or more embodiments and corresponding disclosure thereof, various aspects are described in connection with facilitating utilizing different transmission parameters for positioning reference signals (PRS) of passive distributed elements, as compared to those for a related access point. For example, passive distributed elements can refrain from transmitting PRSs such that wireless devices can only measure PRSs from the access point. In this example, wireless devices can be signaled to measure PRSs only in determining positioning to mitigate additionally determining position from common reference signals (CRSs) of the access point transmitted by the passive distributed elements.

[0005] The invention is defined by the appended independent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a block diagram of a system for providing passive distributed elements to increase access point communication range. FIG. 2 is an illustration of an example communications apparatus for use within a wireless communications environment. FIG. 3 illustrates an example wireless communication system for refraining from transmitting PRSs from passive distributed elements. FIG. 4 is a flow diagram of an example methodology that receives an indicator specifying signal types useable for determining a position. FIG. 5 is a flow diagram of an example methodology that indicates one or more signal types useable for determining a position. FIG. 6 is a block diagram of an example apparatus that receives an indicator specifying one or more signal types receivable for determining a position. FIG. 7 is a block diagram of an example apparatus that indicates one or more signal types receivable for determining a position. FIGS. 8-9 are block diagrams of example wireless communication devices that can be utilized to implement various aspects of the functionality described herein. FIG. 10 illustrates an example wireless multiple-access communication system in accordance with various aspects set forth herein. FIG. 11 is a block diagram illustrating an example wireless communication system in which various aspects described herein can function. DETAILED DESCRIPTION

[0007] Various aspects of the claimed subject matter are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more aspects.

[0008] As used in this application, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, an integrated circuit, an object, an executable, a thread of execution, a program, and / or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and / or thread of execution and a component can be localized on one computer and / or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and / or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and / or across a network such as the Internet with other systems by way of the signal).

[0009] Furthermore, various aspects are described herein in connection with a wireless terminal and / or a base station. A wireless terminal can refer to a device providing voice and / or data connectivity to a user. A wireless terminal can be connected to a computing device such as a laptop computer or desktop computer, or it can be a self contained device such as a personal digital assistant (PDA). A wireless terminal can also be called a wireless device, a system, a subscriber unit, a subscriber station, mobile station, mobile, remote station, access point, remote terminal, access terminal, user terminal, user agent, user device, or user equipment (UE). A wireless terminal can be a subscriber station, wireless device, cellular telephone, PCS telephone, cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, or other processing device connected to a wireless modem. A base station (e.g., access point or Evolved Node B (eNB) or other Node B) can refer to a device in an access network that communicates over the air-interface, through one or more sectors, with wireless terminals. The base station can act as a router between the wireless terminal and the rest of the access network, which can include an Internet Protocol (IP) network, by converting received air-interface frames to IP packets. The base station also coordinates management of attributes for the air interface.

[0010] Moreover, various functions described herein can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc (BD), where disks usually reproduce data magnetically and discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0011] Various techniques described herein can be used for various wireless communication systems, such as Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier FDMA (SC-FDMA) systems, and other such systems. The terms "system" and "network" are often used herein interchangeably. A CDMA system can implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and other variants of CDMA. Additionally, CDMA2000 covers the IS-2000, IS-95 and IS-856 standards. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system can implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM ®< , etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is an upcoming release that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). Further, CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2).

[0012] Various aspects will be presented in terms of systems that can include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems can include additional devices, components, modules, etc. and / or that they may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches can also be used.

[0013] Referring now to the drawings, Fig. 1 illustrates an example system 100 that facilitates providing wireless network access to one or more devices using one or more passive distributed elements. System 100 includes an access point 102 that provides a wireless device 104 with access to a core network (not shown). For example, access point 102 can provide wireless network access to wireless device 104 directly and / or through one or more passive distributed elements 106 and / or 108, which can be wired and / or wirelessly attached to access point 102, for example. Access point 102 can be substantially any device that provides access to one or more network components, such as a macrocell access point, femtocell or picocell access point, eNB, mobile base station, relay node, a portion thereof, and / or the like. Wireless device 104 can be substantially any device that receives access to a wireless network, such as a mobile device, UE, modem (or other tethered device), a portion thereof, etc. Passive distributed elements 106 and 108 can be radio frequency (RF) repeaters, remote radio heads (RRH), a portion thereof, or substantially any device that remotely transmits signals from an access point.

[0014] According to an example, passive distributed elements 106 and 108, as described, can transmit signals transmitted by access point 102 to improve hearability thereof. Thus, for example, where access point 102 transmits a PRS, CRS, etc., passive distributed elements 106 and 108 can transmit substantially the same PRS, CRS, etc. Where wireless device 104 is attempting to determine its position, PRS, CRS, etc. received from passive distributed elements 106 and 108 can cause incorrect position determining since wireless device 104 associates the received PRS, CRS, etc. with the location of access point 102. Access point 102, for example, can control transmissions at the passive distributed elements 106 and 108 such that access point 102 can cause passive distributed elements 106 and 108 to transmit different signals during different time periods. In this regard, for example, passive distributed elements 106 and 108 can transmit PRS, CRS, etc. differently from access point 102 to mitigate confusion at wireless device 104.

[0015] In an example, passive distributed elements 106 and 108 refrain from transmitting PRSs to mitigate confusion in determining positioning. Passive distributed elements 106 and 108, however, can still transmit CRSs for various purposes (e.g., to facilitate channel estimation, etc.). Wireless device 104, in this example, can utilize CRSs in addition or alternatively to PRSs to determine positioning, which can lead to incorrect results as described previously. Thus, where passive distributed elements 106 and 108 are not to be used for positioning, access point 102 can provision an indicator to wireless device 104 to only measure PRSs to determine location. In this regard, wireless device 104 can ignore CRSs transmitted from passive distributed elements 106 and 108 (and access point 102) when determining positioning. In this example, wireless device 104 measures only the PRS transmitted from access point 102 (and / or PRSs from other access points) to determine positioning.

[0016] Referring next to Fig. 2, a communications apparatus 200 that can participate in a wireless communications network is illustrated. The communications apparatus 200 can be a wireless terminal, mobile device, a portion thereof, or substantially any device that can receive reference signals (RSs) in a wireless network. The communications apparatus 200 can include an assistance data receiving component 202 that obtains assistance data related to RSs transmitted in a wireless network, an RS receiving component 204 that can obtain one or more RSs from an access point and / or related passive distributed elements (not shown), and an RS utilizing component 206 that can process at least one of the one or more obtained RSs.

[0017] According to an example, assistance data receiving component 202 can obtain assistance data from an access point related to utilizing RSs transmitted by the access point and / or one or more related passive distributed elements. For example, assistance data receiving component 202 can obtain data related to location of the passive distributed elements, data related to identifying features of RSs transmitted by the passive distributed elements (e.g., resources utilized, RS sequences utilized, identifiers present in the RSs, etc.), indicators of types of RSs that can be utilized for performing computations at communications apparatus 200, and / or the like. In addition, RS receiving component 204 can obtain RSs from the access point and / or the one or more passive distributed elements. RS utilizing component 206 can process and utilize the RSs according to the assistance data, for example.

[0018] In an example, where the assistance data includes indications specifying types of RSs that can be utilized for certain computations, RS utilizing component 206 can ignore other RSs. Thus, in an example, an access point can transmit PRSs without allowing passive distributed elements to transmit the same, as described above. Thus, the assistance data can specify to only measure PRSs for determining positioning. This can be a one bit indicator, in one example, where the other bit value indicates substantially any RS can be utilized for positioning. As described, when the assistance data indicates only measuring PRS for positioning, RS utilizing component 206 can ignore CRSs or other RSs received from the passive distributed elements and / or access point. Thus, in this example as well, positioning can be determined without confusion caused from passive distributed elements transmitting RSs related to the access point. When the assistance data indicates that substantially any RS can be utilized, on the other hand, RS utilizing component 206 can process substantially any RS from the related access point (and / or potential passive distributed elements) to determine positioning. In one example, however, this indicator can be specified where the access point does not leverage passive distributed elements.

[0019] Turning to Fig. 3, illustrated is a wireless communications system 400 that facilitates processing RSs from access points that utilize passive distributed elements. System 400 includes an access point 102 that provides one or more wireless devices, such as wireless device 104, with access to a core network (not shown). Moreover, access point 102 can be a macrocell access point, femtocell access point, picocell access point, mobile base station, a portion thereof, and / or substantially any device that provides wireless network access. In addition, for example, wireless device 104 can be a UE, modem (or other tethered device), a portion thereof, and / or substantially any device that receives access to a wireless network. In addition, access point 102 can utilize one or more passive distributed elements, such as passive distributed element 106 to increase signal power. Passive distributed element 106 can be an RF repeater, RRH, and / or the like, as described.

[0020] Access point 102 can comprise an assistance data providing component 402 that generates and transmits assistance data related to RSs of an access point and / or one or more passive distributed elements employed by the access point, a transmitting component 308 that transmits RSs and / or other data to a wireless device, and a remote transmitting component 310 that causes one or more passive distributed elements to transmit an RS or other data to a wireless device. Passive distributed element 106 can include a receiving component 312 that obtains signals from an access point 102 (e.g., dedicated or broadcast over a wired or wireless connection) and a transmitting component 314 that transmits the signals received from the access point 102. Wireless device 104 comprises an assistance data receiving component 404 that obtains assistance data related to one or more access points and corresponding passive distributed elements, an RS receiving component 318 that obtains an RS from the one or more access points or corresponding passive distributed elements, and a position determining component 406 that computes a position of the wireless device 104 based at least in part on the received RS.

[0021] According to an example, access point 102 can transmit PRSs without causing passive distributed element 106 to transmit the same. Access point 102, however, can cause passive distributed element 106 to transmit CRSs to allow devices receiving from passive distributed element 106 to communicate with the passive distributed element 106 (e.g., perform channel estimation for signals received therefrom, etc.). In this example, access point 102 can notify wireless device 104 to not consider CRSs in determining position (e.g., since the CRS received from passive distributed element 106 relates to access point 102, and passive distributed element 106 is remotely located, as described). Thus, in this example, assistance data providing component 306 can transmit assistance data to wireless device 104 that indicates only PRSs are to be used in determining positioning. Assistance data receiving component 404 can obtain this indication for utilization in measuring PRSs for positioning.

[0022] In this regard, for example, transmitting component 308 can transmit a PRS related to access point 102, and remote transmitting component 310 can refrain from forwarding the PRS to passive distributed element 106 for transmitting. RS receiving component 318 can obtain the PRS. Position determining component 406, for example, can determine the PRS is, in fact, a PRS (and not a CRS or other RS) and can determine a position of the wireless device 104 based at least in part on the PRS. In addition, transmitting component 308 can transmit a CRS, and remote transmitting component 310 can cause passive distributed element 106 to transmit the CRS. Receiving component 312 can receive the CRS, and transmitting component 314 can transmit the CRS. RS receiving component 318 can receive the CRS from access point 102 and / or passive distributed element 106. Position determining component 322, however, can ignore the CRS for the purposes of determining position of the wireless device 104 based at least in part on the indicator in the assistance data, for example.

[0023] In another example, assistance data providing component 402 can set the indicator to a different value. For example, the indicator can be a 1-bit indicator for which one value indicates to only utilize PRSs in determining position while the other value indicates not to only utilize PRSs in determining position. Thus, when assistance data providing component 402 communicates the indicator set to the latter value, RS receiving component 318 can obtain the PRS and CRS(s) described above, and position determining component 406 can discern a position of wireless device 104 based at least in part on the PRS and / or CRS(s). It is to be appreciated, in this example, that assistance data providing component 402 can additionally include location information related to access point 102 in the assistance data. Moreover, this indicator value can be utilized, for example, where passive distributed element 106 is not present such that all RSs in the cell are generated by access point 102 (and thus there is no confusion from passive distributed elements in determining location from RSs, as described).

[0024] Referring now to Figs. 4-7, methodologies that can be performed in accordance with various aspects set forth herein are illustrated. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts can, in accordance with one or more aspects, occur in different orders and / or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with one or more aspects.

[0025] Referring to Fig. 4, an example methodology 700 that facilitates determining signals that can be utilized for computing a position is illustrated. At 702, an indicator can be received specifying one or more signal types receivable from one or more access points or passive distributed elements for determining a position. In an example, passive distributed elements can transmit CRSs related to corresponding access points. Thus, specifying not to use CRSs for positioning (and instead to use only PRSs) can mitigate any resulting confusion. Where an access point does not have passive distributed elements, however, it can indicate that substantially any RS can be utilized to determine positioning. As described, in an example, this can be a 1-bit indicator in assistance data. In any case, at 704, signals of the one or more signal types can be measured to determine positioning data.

[0026] Referring to Fig. 5, an example methodology 900 that facilitates indicating one or more signal types that can be utilized to determine a position is illustrated. At 902, an indication can be transmitted to one or more wireless devices related to one or more signal types receivable for computing positioning data. As described, the indication can be received in assistance data. The indication, for example, can be a 1-bit indicator that specifies whether or not only PRSs should be used for determining a position. At 904, a signal of the one or more signal types can be transmitted to the one or more wireless devices. Thus, the wireless devices can utilize at least the signal for determining a position (e.g., and other signals of the one or more types from other access points or passive distributed elements).

[0027] It will be appreciated that, in accordance with one or more aspects described herein, inferences can be made regarding determining resources for transmitting a PRS at an access point, generating symbol sequences for the same, and / or the like. As used herein, the term to "infer" or "inference" refers generally to the process of reasoning about or inferring states of the system, environment, and / or user from a set of observations as captured via events and / or data. Inference can be employed to identify a specific context or action, or can generate a probability distribution over states, for example. The inference can be probabilistic-that is, the computation of a probability distribution over states of interest based on a consideration of data and events. Inference can also refer to techniques employed for composing higher-level events from a set of events and / or data. Such inference results in the construction of new events or actions from a set of observed events and / or stored event data, whether or not the events are correlated in close temporal proximity, and whether the events and data come from one or several event and data sources.

[0028] Now referring to Fig. 6, illustrated is a system 1100 that facilitates determining one or more signal types to utilize for determining positioning. For example, system 1100 can reside at least partially within a base station, mobile device, or another device that provides access to a wireless network. It is to be appreciated that system 1100 is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor using instructions and / or data retrieved from a computer readable storage medium. System 1100 includes a logical grouping 1102 of electrical components that can act in conjunction. For instance, logical grouping 1102 can include an electrical component for receiving an indicator specifying one or more signal types receivable from one or more access points or passive distributed elements for determining a position 1104.

[0029] As described, the indicator can specify whether or not to use only PRSs in determining a position, and thus can be a 1-bit indicator in one example. For example, for access points that utilize passive distributed elements, specifying to only measure PRSs allows the passive distributed elements to not transmit PRSs but still transmit CRS and other RSs without allowing measuring thereof for determining positioning. Further, logical grouping 1102 can comprise an electrical component for measuring signals of the one or more signal types to determine positioning data 1106. Additionally, system 1100 can include a memory 1108 that retains instructions and / or data for executing functions associated with electrical components 1104 and 1106. While shown as being external to memory 1108, it is to be understood that one or more of electrical components 1104 and 1106 can exist within memory 1108.

[0030] Now referring to Fig. 7, illustrated is a system 1300 that facilitates indicating one or more signal types useable for determining a position. For example, system 1300 can reside at least partially within a base station, mobile device, or another device that provides access to a wireless network. It is to be appreciated that system 1300 is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor using instructions and / or data retrieved from a computer readable storage medium. System 1300 includes a logical grouping 1302 of electrical components that can act in conjunction. For instance, logical grouping 1302 can include an electrical component for transmitting an indication to one or more wireless devices related to one or more signal types receivable for computing positioning data 1304.

[0031] As described, the indicator can specify whether or not to use only PRSs in determining a position, and thus can be a 1-bit indicator in one example. For example, where system 1300 utilizes passive distributed elements, specifying to only measure PRSs allows the passive distributed elements to not transmit PRSs but still transmit CRS and other RSs without allowing measuring thereof for determining positioning to mitigate confusion resulting from the remotely located passive distributed element transmitting RSs of system 1300. Further, logical grouping 1302 can comprise an electrical component for transmitting a signal of the one or more signal types to the one or more wireless devices 1306. Additionally, system 1300 can include a memory 1308 that retains instructions and / or data for executing functions associated with electrical components 1304 and 1306. While shown as being external to memory 1308, it is to be understood that one or more of electrical components 1304 and 1306 can exist within memory 1308.

[0032] Fig. 8 is a block diagram of a system 1400 that can be utilized to implement various aspects of the functionality described herein. In one example, system 1400 includes a base station or Node B 1402. As illustrated, Node B 1402 can receive signal(s) from one or more UEs 1404 via one or more receive (Rx) antennas 1406 and transmit to the one or more UEs 1404 via one or more transmit (Tx) antennas 1408. Additionally, Node B 1402 can comprise a receiver 1410 that receives information from receive antenna(s) 1406. In one example, the receiver 1410 can be operatively associated with a demodulator (Demod) 1412 that demodulates received information. Demodulated symbols can then be analyzed by a processor 1414. Processor 1414 can be coupled to memory 1416, which can store information related to code clusters, access terminal assignments, lookup tables related thereto, unique scrambling sequences, and / or other suitable types of information. In one example, Node B 1402 can employ processor 1414 to perform methodologies 700, 900, and / or other similar and appropriate methodologies. Node B 1402 can also include a modulator 1418 that can multiplex a signal for transmission by a transmitter 1420 through transmit antenna(s) 1408.

[0033] Fig. 9 is a block diagram of another system 1500 that can be utilized to implement various aspects of the functionality described herein. In one example, system 1500 includes a mobile terminal 1502. As illustrated, mobile terminal 1502 can receive signal(s) from one or more base stations 1504 and transmit to the one or more base stations 1504 via one or more antennas 1508. Additionally, mobile terminal 1502 can comprise a receiver 1510 that receives information from antenna(s) 1508. In one example, receiver 1510 can be operatively associated with a demodulator (Demod) 1512 that demodulates received information. Demodulated symbols can then be analyzed by a processor 1514. Processor 1514 can be coupled to memory 1516, which can store data and / or program codes related to mobile terminal 1502. Additionally, mobile terminal 1502 can employ processor 1514 to perform methodologies 700, 900, and / or other similar and appropriate methodologies. Mobile terminal 1502 can also employ one or more components described in previous figures to effectuate the described functionality; in one example, the components can be implemented by the processor 1514. Mobile terminal 1502 can also include a modulator 1518 that can multiplex a signal for transmission by a transmitter 1520 through antenna(s) 1508.

[0034] Referring now to Fig. 10, an illustration of a wireless multiple-access communication system is provided in accordance with various aspects. In one example, an access point 1600 (AP) includes multiple antenna groups. As illustrated in Fig. 10, one antenna group can include antennas 1604 and 1606, another can include antennas 1608 and 1610, and another can include antennas 1612 and 1614. While only two antennas are shown in Fig. 10 for each antenna group, it should be appreciated that more or fewer antennas may be utilized for each antenna group. In another example, an access terminal 1616 can be in communication with antennas 1612 and 1614, where antennas 1612 and 1614 transmit information to access terminal 1616 over forward link 1620 and receive information from access terminal 1616 over reverse link 1618. Additionally and / or alternatively, access terminal 1622 can be in communication with antennas 1606 and 1608, where antennas 1606 and 1608 transmit information to access terminal 1622 over forward link 1626 and receive information from access terminal 1622 over reverse link 1624. In a frequency division duplex system, communication links 1618, 1620, 1624 and 1626 can use different frequency for communication. For example, forward link 1620 may use a different frequency then that used by reverse link 1618.

[0035] Each group of antennas and / or the area in which they are designed to communicate can be referred to as a sector of the access point. In accordance with one aspect, antenna groups can be designed to communicate to access terminals in a sector of areas covered by access point 1600. In communication over forward links 1620 and 1626, the transmitting antennas of access point 1600 can utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals 1616 and 1622. Also, an access point using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access point transmitting through a single antenna to all its access terminals.

[0036] An access point, e.g., access point 1600, can be a fixed station used for communicating with terminals and can also be referred to as a base station, a Node B, an access network, and / or other suitable terminology. In addition, an access terminal, e.g., an access terminal 1616 or 1622, can also be referred to as a mobile terminal, user equipment, a wireless communication device, a terminal, a wireless terminal, and / or other appropriate terminology.

[0037] Referring now to Fig. 11, a block diagram illustrating an example wireless communication system 1700 in which various aspects described herein can function is provided. In one example, system 1700 is a multiple-input multiple-output (MIMO) system that includes a transmitter system 1710 and a receiver system 1750. It should be appreciated, however, that transmitter system 1710 and / or receiver system 1750 could also be applied to a multi-input single-output system wherein, for example, multiple transmit antennas (e.g., on a base station), can transmit one or more symbol streams to a single antenna device (e.g., a mobile station). Additionally, it should be appreciated that aspects of transmitter system 1710 and / or receiver system 1750 described herein could be utilized in connection with a single output to single input antenna system.

[0038] In accordance with one aspect, traffic data for a number of data streams are provided at transmitter system 1710 from a data source 1712 to a transmit (TX) data processor 1714. In one example, each data stream can then be transmitted via a respective transmit antenna 1724. Additionally, TX data processor 1714 can format, encode, and interleave traffic data for each data stream based on a particular coding scheme selected for each respective data stream in order to provide coded data. In one example, the coded data for each data stream can then be multiplexed with pilot data using OFDM techniques. The pilot data can be, for example, a known data pattern that is processed in a known manner. Further, the pilot data can be used at receiver system 1750 to estimate channel response. Back at transmitter system 1710, the multiplexed pilot and coded data for each data stream can be modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for each respective data stream in order to provide modulation symbols. In one example, data rate, coding, and modulation for each data stream can be determined by instructions performed on and / or provided by processor 1730.

[0039] Next, modulation symbols for all data streams can be provided to a TX MIMO processor 1720, which can further process the modulation symbols (e.g., for OFDM). TX MIMO processor 1720 can then provides NT modulation symbol streams to NT transceivers 1722a through 1722t. In one example, each transceiver 1722 can receive and process a respective symbol stream to provide one or more analog signals. Each transceiver 1722 can then further condition (e.g., amplify, filter, and up-convert) the analog signals to provide a modulated signal suitable for transmission over a MIMO channel. Accordingly, NT modulated signals from transceivers 1722a through 1722t can then be transmitted from NT antennas 1724a through 1724t, respectively.

[0040] In accordance with another aspect, the transmitted modulated signals can be received at receiver system 1750 by NR antennas 1752a through 1752r. The received signal from each antenna 1752 can then be provided to respective transceivers 1754. In one example, each transceiver 1754 can condition (e.g., filter, amplify, and down-convert) a respective received signal, digitize the conditioned signal to provide samples, and then processes the samples to provide a corresponding "received" symbol stream. An RX MIMO / data processor 1760 can then receive and process the NR received symbol streams from NR transceivers 1754 based on a particular receiver processing technique to provide NT "detected" symbol streams. In one example, each detected symbol stream can include symbols that are estimates of the modulation symbols transmitted for the corresponding data stream. RX MIMO / data processor 1760 can then process each symbol stream at least in part by demodulating, deinterleaving, and decoding each detected symbol stream to recover traffic data for a corresponding data stream. Thus, the processing by RX MIMO / data processor 1760 can be complementary to that performed by TX MIMO processor 1720 and TX data processor 1718 at transmitter system 1710. RX MIMO / data processor 1760 can additionally provide processed symbol streams to a data sink 1764.

[0041] In accordance with one aspect, the channel response estimate generated by RX MIMO / data processor 1760 can be used to perform space / time processing at the receiver, adjust power levels, change modulation rates or schemes, and / or other appropriate actions. Additionally, RX MIMO / data processor 1760 can further estimate channel characteristics such as, for example, signal-to-noise-and-interference ratios (SNRs) of the detected symbol streams. RX MIMO / data processor 1760 can then provide estimated channel characteristics to a processor 1770. In one example, RX MIMO / data processor 1760 and / or processor 1770 can further derive an estimate of the "operating" SNR for the system. Processor 1770 can then provide channel state information (CSI), which can comprise information regarding the communication link and / or the received data stream. This information can include, for example, the operating SNR. The CSI can then be processed by a TX data processor 1718, modulated by a modulator 1780, conditioned by transceivers 1754a through 1754r, and transmitted back to transmitter system 1710. In addition, a data source 1716 at receiver system 1750 can provide additional data to be processed by TX data processor 1718.

[0042] Back at transmitter system 1710, the modulated signals from receiver system 1750 can then be received by antennas 1724, conditioned by transceivers 1722, demodulated by a demodulator 1740, and processed by a RX data processor 1742 to recover the CSI reported by receiver system 1750. In one example, the reported CSI can then be provided to processor 1730 and used to determine data rates as well as coding and modulation schemes to be used for one or more data streams. The determined coding and modulation schemes can then be provided to transceivers 1722 for quantization and / or use in later transmissions to receiver system 1750. Additionally and / or alternatively, the reported CSI can be used by processor 1730 to generate various controls for TX data processor 1714 and TX MIMO processor 1720. In another example, CSI and / or other information processed by RX data processor 1742 can be provided to a data sink 1744.

[0043] In one example, processor 1730 at transmitter system 1710 and processor 1770 at receiver system 1750 direct operation at their respective systems. Additionally, memory 1732 at transmitter system 1710 and memory 1772 at receiver system 1750 can provide storage for program codes and data used by processors 1730 and 1770, respectively. Further, at receiver system 1750, various processing techniques can be used to process the NR received signals to detect the NT transmitted symbol streams. These receiver processing techniques can include spatial and space-time receiver processing techniques, which can also be referred to as equalization techniques, and / or "successive nulling / equalization and interference cancellation" receiver processing techniques, which can also be referred to as "successive interference cancellation" or "successive cancellation" receiver processing techniques.

[0044] It is to be understood that the aspects described herein can be implemented by hardware, software, firmware, middleware, microcode, or any combination thereof. When the systems and / or methods are implemented in software, firmware, middleware or microcode, program code or code segments, they can be stored in a machine-readable medium, such as a storage component. A code segment can represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment can be coupled to another code segment or a hardware circuit by passing and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. can be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, etc.

[0045] For a software implementation, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes can be stored in memory units and executed by processors. The memory unit can be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

Claims

1. A method (700) of wireless communication performed by a wireless device (104; 200), comprising: receiving (702) an indicator that specifies whether only positioning reference signals, PRS, or any reference signal, RS receivable from one or more access points (102) that provide access to a core network and / or passive distributed elements (106, 108) that remotely transmit signals from the one or more access points (102) can be utilized for determining a position of the wireless device (104; 200); receiving reference signals from an access point (102) and / or one or more passive distributed elements (106, 108); and determining (704) positioning data only based on PRS included in the received RS when the indicator specifies that only PRS can be utilized for determining a position, or determining positioning data based on any of the received RS when the indicator specifies that any RS can be utilized for determining a position.

2. The method (700) of claim 1, wherein when the indicator specifies that only PRS can be utilized for determining a position, determining (704) positioning data is based on PRS transmitted only from the access point (102) and from other access points.

3. An apparatus comprising means adapted to execute the steps of the method of any one of claims 1 or 2.

4. A computer program comprising program instructions which are computer-executable to cause the apparatus of claim 3 to execute the steps of the method of claim 1 or 2.

5. A method (900) of wireless communication, performed by an access point (102), comprising: transmitting (902) an indicator that specifies whether only positioning reference signals, PRS, or any reference signal, RS receivable from one or more access points (102) that provide access to a core network and / or passive distributed elements (106, 108) that remotely transmit signals from the one or more access points (102) can be utilized for determining a position of a wireless device (104; 200), wherein when the access point utilizes passive distributed elements, the indicator specifies that only PRS can be utilized for determining a position, and the method further comprises causing the passive distributed elements to refrain from transmitting PRS; and transmitting (904) reference signals including PRS to the one or more wireless devices (104; 200).

6. The method of claim 5, wherein when the access point does not utilize passive distributed elements, the indicator specifies that any RS can be utilized for determining a position.

7. An apparatus comprising means adapted to execute the steps of the method of any one of claims 5 or 6.

8. A computer program comprising program instructions which are computer-executable to cause the apparatus of claim 7 to execute the steps of the method of one of claims 5 or 6 .