Patent Description:
The present disclosure relates generally to communication systems, and more particularly, to techniques for use in synchronization in wireless networks.

Examples of such multiple-access technologies include code division multiple access (CDMA) systems, wideband CDMA (W-CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, wide band single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

For example, <NUM> NR (new radio) communications technology is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, <NUM> communications technology includes enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with requirements, especially in terms of latency and reliability; and massive machine type communications for a very large number of connected devices, and typically transmitting a relatively low volume of non-delay-sensitive information. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in <NUM> communications technology and beyond.

In licensed spectrum, a base station (or a cell, node, etc.) can listen to other base stations, obtain timing, and perform network listen based synchronization. For example, a small cell base station may listen to one or more macro cell base stations and synchronize its timing to the timing received from one or more macro cell base stations. In unlicensed or shared spectrum, better coexistence and spectrum sharing can be achieved if different nodes have common timing, as described for instance in documents <CIT> or 3GPP R1-<NUM>. However, in the absence of global positioning system (GPS) connected anchor base stations (e.g., macro cell base stations) that may provide time for synchronization in the unlicensed or shared spectrum, timing lag may accumulate across hops in a network listen based synchronization and may affect network performance.

Therefore, there is a desire for a method and an apparatus for synchronization or time alignment in the unlicensed/shared spectrum.

Embodiments and aspects that do not fall within the scope of the claims are merely examples used for explanation of the invention.

The present disclosure provides an example method and an apparatus for reverse time alignment in a wireless network. The example method includes a UE obtaining timing values from a serving node and one or more non-serving nodes. The received timing values may be different from one another as time lag may accumulate across hops in network listen based synchronization. The UE then computes one or more time differences based on the timing value received from the serving node and the non-serving nodes and reports the time differences to the serving node. In one implementation, the serving node may update the timing value at the serving node based on the time differences sent from the UE. In another implementation, the UE may receive the updated timing values and synchronize the timing value at the UE to the updated timing value received from the serving node.

<FIG> illustrates an example schematic diagram of a wireless communications system <NUM> including a user equipment having an aspect of a reverse time alignment function for reverse time alignment in a wireless network. Referring to <FIG>, in an aspect, a wireless communication system <NUM> includes an user equipment (UE) <NUM>, one or more processors <NUM>, and/or a reverse time alignment function <NUM> running on processor <NUM> (or processors <NUM> in a distributed computing environment) for reverse time alignment in a wireless network. In an aspect, the UE <NUM> and/or reverse time alignment function <NUM> includes a receiving function <NUM> to obtain (e.g., receive or estimate) a first timing value from a serving node and one or more second timing values from one or more non-serving nodes, a computing function <NUM> to compute one or more timing differences between the first timing value and each of one or more second timing values, a reporting function <NUM> to report the one or more timing differences to the serving node. In an additional or optional aspect, the UE <NUM> and/or reverse time alignment function <NUM> may further include a synchronizing function <NUM> to synchronize timing at UE <NUM> to a third timing value obtained from the serving node. The UE <NUM> may include a RF transceiver <NUM> and/or a memory <NUM> for reverse time alignment.

As illustrated in <FIG>, UE <NUM> may communicate with one or more nodes. The nodes may be one serving node, e.g., serving node <NUM>, and one or more non-serving nodes, e.g., non-serving nodes <NUM> and <NUM>. Serving node <NUM> and non-serving nodes <NUM>, <NUM> may be neighbor nodes. In an aspect, UE <NUM> may communicate with serving node <NUM> via one or more over-the-air links, e.g., uplink (UL) <NUM> and/or downlink (DL) <NUM>. In an aspect, UL <NUM> is generally used for communication from UE <NUM> to serving node <NUM> and the DL <NUM> is generally used for communication from serving node <NUM> to UE <NUM>. Additionally, UE <NUM> may communicate with non-serving node <NUM> via one or more over-the-air links, e.g., UL <NUM>/DL <NUM> and/or uplink (UL) or non-serving node <NUM> via one or more over-the-air links <NUM>/<NUM>.

UE <NUM> may be a mobile apparatus and may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology.

Serving node <NUM> and/or non-serving nodes <NUM> and/or <NUM> may be a base station (BS) or Node B or eNodeB, a macro cell, a small cell (e.g., a femtocell, or a pico cell), a relay, a peer-to-peer device, etc. In an example aspect, the nodes may operate according to wireless local area network (WLAN) specification as defined in IEEE <NUM> and/or may operate according to Wideband Code Division Multiple Access (W-CDMA), Code Division Multiple Access (CDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), Global System for Mobile Communications (GSM), <NUM> (NR) standard as defined in 3GPP Specifications.

<FIG> illustrates an example methodology <NUM> for reverse time alignment in a wireless network.

In an aspect, at block <NUM>, methodology <NUM> may include obtaining, at a user equipment (UE), a first timing value from a serving node and a second timing value from each of one or more non-serving nodes of the UE. For example, in an aspect, UE <NUM> and/or reverse time alignment function <NUM> may include a receiving function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to obtain at UE <NUM> a first timing value, e.g., TS, from serving node <NUM> (or a node UE <NUM> is camped on or associated with) and a second timing value from each of one or more non-serving nodes of the UE, e.g., TNS1 and TNS2 from non-serving nodes <NUM> and <NUM>, respectively. TS may be defined as a timing value obtained from serving node <NUM>, TNS1 may be defined as a timing value obtained from a non-serving node <NUM>, and/or TNS2 may be defined as a timing value obtained another non-serving node <NUM>.

UE <NUM> may obtain the timing values (e.g., Ts, TNS1, and/or TNS2) from a serving node (e.g., serving node <NUM>) and/or one or more non-serving nodes (e.g., non-serving nodes <NUM> and/or <NUM>) via synchronization signals that may be broadcasted from the nodes. For instance, in LTE, the synchronization signals may be primary or secondary synchronization signals. In an additional aspect, UE <NUM> may obtain the timing values from system information blocks (SIBs) that are broadcasted from the nodes. In one implementation, a SIB may include a coordinated universal time (UTC). In an additional aspect, UE <NUM> may estimate the timing values (e.g., TS, TNS1, and/or TNS2) from signal waveforms transmitted by the serving and/or the non-serving nodes. The signal waveforms, which allow a UE to distinguish between nodes, may be synchronization or pilot signals transmitted by serving and non-serving nodes and the estimating may be performed using signal processing techniques implemented at a receiver of the UE.

At block <NUM>, methodology <NUM> may include computing, at the UE, one or more timing differences between the first timing value and each of the one or more second timing values. For example, in an aspect, UE <NUM> and/or reverse time alignment function <NUM> may include a computing function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to compute one or more timing differences (e.g., timing deltas (TD)) between the first timing value (e.g., Ts) and each of one or more second timing values (e.g., TNS1, TNS2, etc.). For example, UE <NUM> and/or reverse time alignment function <NUM> may compute timing differences between the serving node <NUM> and non-serving node <NUM> (e.g., TD1) and/or the serving node <NUM> and the non-serving node <NUM> (e.g., TD2) as shown below: <MAT> <MAT>.

At block <NUM>, methodology <NUM> includes reporting the one or more timing differences to the serving node. For example, in an aspect, UE <NUM> and/or reverse time alignment function <NUM> may include a reporting function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to report the one or more timing differences, e.g., TD1 and/or TD2 to serving node <NUM>.

UE <NUM> may report the one or more timing differences, which can also be referred to as "timing deltas," to the serving node so that the serving node may adjust timing of the serving node. That is, serving node <NUM> may configure the timing at serving node <NUM> based on timing deltas obtained from UE <NUM>. In one aspect, the timing differences may be reported via a message from UE <NUM> to serving node <NUM>. The message may be a control channel or a data channel message. In another aspect, the message may be a "timing alignment command" or "TA command. " In an additional aspect, UE <NUM> may report timing differences of non-serving nodes <NUM>, <NUM> UE <NUM> observes only if the timing differences of the non-serving nodes <NUM>, <NUM> are within a certain range, as defined, for example, by a network operator.

Additionally, UE <NUM> may combine the timing differences obtained from multiple non-serving nodes, e.g., nodes <NUM> and <NUM>, into one (or more) messages for reporting to the serving node <NUM>. For example, serving node <NUM> may obtain timing differences, via individual or combined messages, from multiple UEs <NUM> served by serving node <NUM>. Once serving node <NUM> obtains the timing differences, serving node <NUM> decides whether to adjust the timing of the serving node <NUM>. In one implementation, determining whether to adjust the timing at serving node <NUM> may be defined by a network operator by configuring at a node level, a cluster level, or a network level.

In addition to reporting the timing differences to serving node <NUM>, UE <NUM> also reports additional information to assist serving node <NUM> in determining propagation delays (e.g., DS, DNS1, DNS2, etc.) from serving node <NUM> and/or non-serving nodes <NUM> and <NUM>. For example, UE <NUM> may report additional information, e.g., path loss, received signal strength indicator (RSSI), or other metrics related to distance to serving node <NUM>. Serving node <NUM>, upon receiving the additional information (e.g., one or more of path loss, RSSI, other metrics, etc.) estimates the propagation delays associated with serving node <NUM> and/or non-serving nodes <NUM>, <NUM>, and adjusts the timing differences. For instance, timing adjustments, e.g., TD1(ADJ) and TD2(ADJ), may be adjusted based on the propagation delays (e.g., propagation delay estimates) of the serving and the non-serving nodes as shown below: <MAT> <MAT>.

In another implementation, UE <NUM> may estimate the propagation delays associated with serving node <NUM> and/or non-serving nodes <NUM>, <NUM>, and may apply them to the timing differences prior to reporting to serving node <NUM>. In other words, UE <NUM> may determine the timing adjustments, e.g., TD1(ADJ) or TD2(ADJ), and report them to serving node <NUM> and/or non-serving nodes <NUM>, <NUM>.

UE <NUM> may report the timing differences to serving node <NUM> when UE <NUM> is in a connected mode or an idle mode. In one implementation, when UE <NUM> is in the connected mode, UE <NUM> may report the timing differences to the serving node <NUM> using uplink (UL) control or data channels. For example, the timing differences may be reported via a physical uplink control channel (PUCCH) or as media access control (MAC) control elements via a physical uplink shared channel (PUSCH). In another implementation, when UE <NUM> is in an idle mode, UE <NUM> may wake up (e.g., from sleep mode), transition to connected mode, and/or report the timing differences to the serving node <NUM> as described above.

Optionally, at block <NUM>, methodology <NUM> may include receiving a third timing value from the serving node. For example, in an aspect, UE <NUM> and/or reverse time alignment function <NUM> may include a receiving function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to obtain a third timing value from serving node <NUM>. The third timing value may be a revised or updated timing from serving node <NUM> which may be determined by serving node <NUM> based on the timing differences reported by UE <NUM> to serving node <NUM>.

Optionally, at block <NUM>, methodology <NUM> may include synchronizing timing at the UE to the third timing value obtained from the serving node. For example, in an aspect, UE <NUM> and/or reverse time alignment function <NUM> may optionally include synchronizing function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to synchronize timing at the UE, e.g., UE <NUM>, to the third timing value obtained from serving node <NUM>. The mechanism described above synchronizes the nodes and improves the performance.

<FIG> illustrates an example CoMP transmission system <NUM> with two nodes (or transmission points/TPs), e.g., nodes <NUM> and <NUM>, with each of the nodes serving multiple UEs simultaneously, e.g., UEs <NUM> and <NUM>. In such a CoMP transmission system, different UEs may recommend different timing alignments for the nodes. <FIG> also includes a central unit <NUM> which may perform the functions of a centralized network manager, e.g., operations, administration, and management.

For example, in CoMP transmission system <NUM>, UE <NUM> may obtain timing (or timing information) from nodes <NUM> and <NUM>, simultaneously. As UE <NUM> is farther (e.g., from a distance perspective) from node <NUM> compared to node <NUM>, UE <NUM> may experience time lag with regards to communications with node <NUM>. The time lag experienced at UE <NUM> may be due to higher propagation delay between UE <NUM> and node <NUM> vs propagation delay between UE <NUM> and node <NUM>. Similarly, as UE <NUM> is farther (e.g., from a distance perspective) from node <NUM> as compared to node <NUM>, UE <NUM> may experience time lag with regards to communications with node <NUM>. The time lag experienced at UE <NUM> may be due to higher propagation delay between UE <NUM> and node <NUM> vs propagation delay between UE <NUM> and node <NUM>. Therefore, the multipath delay experienced by a UE in a CoMP transmission system may be larger due to transmissions from multiple nodes/TPs which may not be a problem if the cyclic prefix (CP) is large enough. However, the configuration of CP values is generally limited as higher values may affect network performance.

For instance, the UEs may compute timing differences, for example, as described above in reference to <FIG> and <FIG>, and report the timing differences to the nodes. For example, UE <NUM> may compute the timing differences (e.g., differences in the propagation delays) between nodes <NUM> and <NUM> and report the timing differences to nodes <NUM> and <NUM>. Similarly, UE <NUM> may compute the timing differences between nodes <NUM> and <NUM> and report the timing differences to nodes <NUM> and <NUM>. In one implementation, nodes <NUM> and/or <NUM>, upon receiving the timing differences from UEs <NUM> and/or <NUM>, may maintain (e.g., store, manage, etc.) timing specific to a UE. That is, node <NUM> may maintain one timing for communications with UE <NUM> and another timing for communications with UE <NUM>. Similarly, node <NUM> may maintain one timing for communications with UE <NUM> and another timing for communications with UE <NUM>.

In an aspect, each node, e.g., node <NUM> or <NUM>, may maintain separate timing for different UEs. For instance, node <NUM> may maintain separate timings for UE <NUM> and <NUM> and may use the separate timings for communications with the specific UE. For example, node <NUM> may maintain timings, T<NUM> and T<NUM> at node <NUM> and may use T<NUM> for communications with UE <NUM> and/or may use T<NUM> for communications with UE <NUM>. Similarly, node <NUM> may maintain timings, T<NUM>' and T<NUM>' at node <NUM> and may use T<NUM>' for communications with UE <NUM> and/or may use T<NUM>' for communications with UE <NUM>. The use of separate timings reduces multipath delays in CoMP transmission networks and/or may improve network performance.

Referring to <FIG>, in an aspect, a CoMP transmission system <NUM> includes node <NUM>, one or more processors <NUM>, and/or a time alignment function <NUM> running on processor <NUM> (or processors <NUM> in a distributed computing environment) for time alignment. In an aspect, node <NUM> and/or time alignment function <NUM> may further include a receiving function <NUM> to obtain timing information from a plurality of user equipments (UEs) and/or a storing function <NUM> to store, at node <NUM>, separate timings for each of the plurality of UEs for communicating with node <NUM>. In an additional or optional aspect, node <NUM> and/or time alignment function <NUM> may further include a communicating function <NUM> to communicate with the plurality of user equipments using the separate timings stored for each of the plurality of UEs. Further, node <NUM> may include a RF transceiver <NUM> and/or a memory <NUM> for time alignment in CoMP transmission networks.

As illustrated in <FIG>, node <NUM> may communicate with one or more UEs <NUM>, <NUM>. In an aspect, node <NUM> may communicate with UE <NUM> via one or more over-the-air links, e.g., uplink (UL) <NUM> and/or downlink (DL) <NUM>. In an aspect, UL <NUM> is generally used for communication from UE <NUM> to node <NUM> and/or DL <NUM> is generally used for communication from node <NUM> to UE <NUM>. Additionally, node <NUM> may also communicate with UE <NUM> via one or more over-the-air links, e.g., UL <NUM>/DL <NUM>. Similarly, node <NUM> may communicate with one or more UEs. In an aspect, node <NUM> may communicate with UE <NUM> via one or more over-the-air links, e.g., uplink (UL) <NUM> and/or downlink (DL) <NUM>. In an aspect, UL <NUM> is generally used for communication from UE <NUM> to node <NUM> and/or DL <NUM> is generally used for communication from node <NUM> to UE <NUM>. Additionally, node <NUM> may also communicate with UE <NUM> via one or more over-the-air links, e.g., UL <NUM>/DL <NUM>.

<FIG> illustrates an example methodology <NUM> for time alignment in a consolidated multi-point (CoMP) transmission network.

In an aspect, at block <NUM>, methodology <NUM> may include obtaining, at a first node of a plurality of nodes of the CoMP transmission network, timing information from a plurality of user equipments (UEs), wherein the timing information for each UE of the plurality of UEs indicates a difference in timing between a first timing value received at the UE from the first node and a second timing value received at the UE from a second node of the plurality of nodes of the CoMP transmission network. For example, in an aspect, node <NUM> and/or time alignment function <NUM> may include a receiving function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to obtain, at node <NUM>, timing information from a plurality of user equipments (UEs), e.g., UEs <NUM> and <NUM>, wherein the timing information for each UE of the plurality of UEs indicates a difference in timing between a first timing value received at the UE from the first node and a second timing value received at the UE from a second node of the CoMP transmission network. The difference in timing received at node <NUM> from UE <NUM> may be defined as TDUE202 (TNode260-TNode210). Similarly, the difference in timing received at node <NUM> from UE <NUM> may be defined as TDUE204 (TNode210-TNode260).

At block <NUM>, methodology <NUM> may include storing, at the first node, the timing information for each of the plurality of UEs for communicating with the first node. For example, in an aspect, node <NUM> and/or time alignment function <NUM> may include a storing function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to store, at node <NUM>, the timing information for each of the plurality of UEs for communicating with the first node, e.g., node <NUM>. For example, node <NUM> may store the following timings, e.g., TDUE202 (TNode260-TNode210) and TDUE204 (TNode210-TNode260).

Optionally, at block <NUM>, methodology <NUM> may include communicating, by the first node, with the plurality of user equipments using the separate timings stored for each of the plurality of UEs. For example, in an aspect, node <NUM> and/or time alignment function <NUM> may optionally include communicating function <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to communicate, by the first node, e.g., node <NUM>, with the plurality of user equipments, UEs <NUM> and <NUM>, using the separate timings, stored for each of the plurality of UEs, e.g., e.g., TDUE202 (TNode260-TNode210) and TDUE204 (TNode210-TNode260). Accordingly, time alignment in CoMP transmission networks may be achieved.

Referring to <FIG>, one example of an implementation of a UE <NUM> may include a variety of components, some of which have already been described above, including components such as one or more processors <NUM>, memory <NUM>, and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with the modem <NUM> and reverse time alignment function <NUM> to achieve reverse time alignments at UE <NUM>. Further, the one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM>, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies.

In an aspect, the one or more processors <NUM> can include a modem <NUM> that uses one or more modem processors. The various functions related to reverse time alignment function <NUM> may be included in modem <NUM> and/or processors <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with the transceiver <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or modem <NUM> associated with reverse time alignment function <NUM> may be performed by the transceiver <NUM>.

Also, the memory <NUM> may be configured to store data used herein and/or local versions of applications <NUM> or reverse time alignment function <NUM> and/or one or more of its subcomponents being executed by at least one processor <NUM>. The memory <NUM> can include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, the memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining reverse time alignment function <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when the UE <NUM> is operating at least one processor <NUM> to execute the reverse time alignment function <NUM> and/or one or more of its subcomponents.

The transceiver <NUM> may include at least one receiver <NUM> and at least one transmitter <NUM>. The receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The receiver <NUM> may be, for example, a radio frequency (RF) receiver. In an aspect, the receiver <NUM> may receive signals transmitted by at least one node <NUM>. Additionally, the receiver <NUM> may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. The transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of the transmitter <NUM> may include, but is not limited to, a RF transmitter.

Moreover, in an aspect, the UE <NUM> may include a RF front end <NUM>, which may operate in communication with one or more antennas <NUM> and transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station <NUM> or wireless transmissions transmitted by the UE <NUM>. The RF front end <NUM> may be communicatively coupled with one or more antennas <NUM> and can include one or more low-noise amplifiers (LNAs) <NUM>, one or more switches <NUM>, one or more power amplifiers (PAs) <NUM>, and one or more filters <NUM> for transmitting and receiving RF signals.

In an aspect, the LNA <NUM> can amplify a received signal at a desired output level. In an aspect, the RF front end <NUM> may use one or more switches <NUM> to select a particular LNA <NUM> and its specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA(s) <NUM> may be used by the RF front end <NUM> to amplify a signal for an RF output at a desired output power level. In an aspect, the RF front end <NUM> may use one or more switches <NUM> to select a particular PA <NUM> and its specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters <NUM> can be used by the RF front end <NUM> to filter a received signal to obtain an input RF signal. In an aspect, the RF front end <NUM> can use one or more switches <NUM> to select a transmit or receive path using a specified filter <NUM>, LNA <NUM>, and/or PA <NUM>, based on a configuration as specified by the transceiver <NUM> and/or processor <NUM>.

As such, the transceiver <NUM> may be configured to transmit and receive wireless signals through one or more antennas <NUM> via RF front end <NUM>. In an aspect, the transceiver <NUM> may be tuned to operate at specified frequencies such that UE <NUM> can communicate with, for example, one or more cells associated with one or more base stations <NUM>, <NUM>, <NUM>. In an aspect, for example, the modem <NUM> can configure the transceiver <NUM> to operate at a specified frequency and power level based on the configuration of the UE <NUM> and communication protocol used by the modem <NUM>.

In an aspect, the modem <NUM> can be a multiband-multimode modem, which can process digital data and communicate with the transceiver <NUM> such that the digital data is sent and received using the transceiver <NUM>. In an aspect, the modem <NUM> can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem <NUM> can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem <NUM> can control one or more components of UE <NUM> (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In another aspect, the modem configuration can be based on base station information associated with the UE <NUM> as provided by the network during cell selection and/or cell reselection.

Referring to <FIG>, one example of an implementation of a node <NUM> may include a variety of components, some of which have already been described above, including components such as one or more processors <NUM>, memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with modem <NUM> and time alignment function <NUM> to align time in a CoMP transmission network. Further, the one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM>, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies.

In an aspect, the one or more processors <NUM> can include a modem <NUM> that uses one or more modem processors. The various functions related to communications component <NUM> may be included in modem <NUM> and/or processors <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with the transceiver <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or modem <NUM> associated with the time alignment function <NUM> may be performed by the transceiver <NUM>.

Also, the memory <NUM> may be configured to store data used herein and/or local versions of applications <NUM> or time alignment function <NUM> and/or one or more of its subcomponents being executed by at least one processor <NUM>. The memory <NUM> can include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, the memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining time alignment function <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when node <NUM> is operating at least one processor <NUM> to execute the time alignment function <NUM> and/or one or more of its subcomponents.

The transceiver <NUM> may include at least one receiver <NUM> and at least one transmitter <NUM>. The receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The receiver <NUM> may be, for example, a radio frequency (RF) receiver. In an aspect, the receiver <NUM> may receive signals transmitted by at least one UE (e.g., UEs, <NUM>, <NUM>). Additionally, the receiver <NUM> may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. The transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of the transmitter <NUM> may include, but is not limited to, a RF transmitter.

Moreover, in an aspect, node <NUM> may include a RF front end <NUM>, which may operate in communication with one or more antennas <NUM> and transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one UE <NUM> or <NUM> or wireless transmissions transmitted by the node <NUM>. The RF front end <NUM> may be communicatively coupled with one or more antennas <NUM> and can include one or more low-noise amplifiers (LNAs) <NUM>, one or more switches <NUM>, one or more power amplifiers (PAs) <NUM>, and one or more filters <NUM> for transmitting and receiving RF signals.

As such, the transceiver <NUM> may be configured to transmit and receive wireless signals through one or more antennas <NUM> via RF front end <NUM>. In an aspect, the transceiver <NUM> may be tuned to operate at specified frequencies such that node <NUM> can communicate with, for example, one or more UEs, e.g., UEs <NUM> and <NUM>. In an aspect, for example, the modem <NUM> can configure the transceiver <NUM> to operate at a specified frequency and power level based on the configuration of node <NUM> and communication protocol used by the modem <NUM>.

In an aspect, the modem <NUM> can be a multiband-multimode modem, which can process digital data and communicate with the transceiver <NUM> such that the digital data is sent and received using the transceiver <NUM>. In an aspect, the modem <NUM> can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem <NUM> can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem <NUM> can control one or more components of the node <NUM> (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In another aspect, the modem configuration can be based on base station information associated with the node <NUM> as provided by the network during cell selection and/or cell reselection.

As used in this application, the terms "function," "process," "system" and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a module may be, but is not limited to being, a process running on a processor, a processor, 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 process. One or more modules can reside within a module and/or thread of execution and a module may be localized on one computer and/or distributed between two or more computers. In addition, these modules can execute from various computer readable media having various data structures stored thereon. The processes may communicate by way of local and/or remote modules such as in accordance with a signal having one or more data packets, such as data from one module interacting with another module in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal.

Furthermore, various aspects are described herein in connection with a terminal, which can be a wired terminal or a wireless terminal. A terminal can also be called a system, device, subscriber unit, subscriber station, mobile station, mobile, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, communication device, user agent, user device, or user equipment (UE). A wireless terminal may be a cellular telephone, a satellite phone, a 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, a computing device, or other processing devices connected to a wireless modem. Moreover, various aspects are described herein in connection with a base station. A base station may be utilized for communicating with wireless terminal(s) and may also be referred to as an access point, a Node B, or some other terminology.

Several aspects of improved measurement event reporting message associated with a tune away have been presented with reference to a W-CDMA system.

By way of example, various aspects described herein related to RACH preamble transmission may be extended to other UMTS and/or LTE and/or other systems where UE has bursty data to transmit which is not suitable for establishing a dedicated channel (e.g., during a forward access channel (CELL_FACH) state)). For example, such UMTS systems may include TD-SCDMA, High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+) and TD-CDMA. Also, such LTE and/or other systems may include Long Term Evolution (LTE) (in FDD, TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems.

In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a "processing system" that includes one or more processors. The software may reside on a computer-readable medium. The computer-readable medium may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disk (CD), digital versatile disk (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may be resident in the processing system, external to the processing system, or distributed across multiple entities including the processing system. The computer-readable medium may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

Claim 1:
A method (<NUM>) for use in providing reverse time alignment in a consolidated multi-point, CoMP, transmission network, comprising:
obtaining (<NUM>), at a user equipment, UE (<NUM>), a first timing value from a serving node (<NUM>) and a second timing value from a non-serving node (<NUM>, <NUM>) of the UE (<NUM>), wherein the non-serving node (<NUM>, <NUM>) operates in an unlicensed or shared spectrum;
computing (<NUM>), at the UE (<NUM>), a difference in timing between the first timing value and the second timing value;
reporting (<NUM>), by the UE (<NUM>), the difference in timing to the serving node (<NUM>);
reporting, by the UE (<NUM>), additional information to the serving node (<NUM>) to assist the serving node (<NUM>) in estimating propagation delays of the serving node (<NUM>) and/or the non-serving node (<NUM>, <NUM>);
obtaining (<NUM>), at the UE (<NUM>), an adjusted difference in timing from the serving node (<NUM>), wherein the adjusted difference in timing is based on the estimated propagation delays associated with the serving node (<NUM>) and the non-serving node (<NUM>, <NUM>); and
synchronizing (<NUM>) timing at the UE (<NUM>) to the adjusted difference in timing received from the serving node (<NUM>).