US20110274063A1

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Publication number: US20110274063A1
Application number: US13/103,612
Authority: US
Inventors: Ming-Che Li
Original assignee: Individual
Current assignee: Innovative Sonic Corp
Priority date: 2010-05-10
Filing date: 2011-05-09
Publication date: 2011-11-10
Also published as: US20110273994A1; TWI502945B; TW201215065A; TW201210294A; US8625558B2

Abstract

A method and apparatus are disclosed for handling SRS and PUCCH in a wireless communication system. In one embodiment, the method comprises using a PDCCH transmission to trigger a dynamic aperiodic SRS transmission. In addition, the method comprises transmitting the triggered dynamic aperiodic SRS transmission in a first subframe. Furthermore, the method comprises transmitting a PUCCH transmission in the same first subframe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application for patent claims the benefit of U.S. Provisional Patent Application Ser. No. 61/332,825, filed on May 10, 2010, entitled “Method and Apparatus of Handling Dynamic Aperiodic SRS in a Wireless Communication System”.

FIELD

This disclosure relates generally to a method and apparatus to handle and process dynamic aperiodic SRS in a wireless communication network.

BACKGROUND

In LTE, Single Carrier Frequency Division Multiple Access (SC-FDMA) transmission was selected for uplink (UL) direction. A wireless transmit/receive unit (WTRU) in the UL will transmit only on a limited, contiguous set of assigned sub-carriers in an FDMA arrangement. The WTRU transmits its their UL data (and in some cases their control information) on the physical uplink shared channel (PUSCH). The transmission of the PUSCH is scheduled and controlled by the eNodeB using the so-called uplink scheduling grant.

An evolved NodeB (eNodeB or eNB) would receive the composite UL signal across the entire transmission bandwidth from one or more WTRUs at the same time, but each WTRU would only transmit into a subset of the available transmission bandwidth. In order to allow for the eNodeB to estimate UL channel quality for UL scheduling, sounding reference signals (SRS) may be transmitted in UL. When an SRS is to be transmitted in a subframe, it occupies the last SC-FDMA symbol of the subframe. If a WTRU is transmitting SRS in a certain subframe, then the last symbol of the subframe is then not used for PUSCH transmission by any WTRU within the cell.

It would be beneficial to provide a method and apparatus to guarantee the triggered dynamic aperiodic SRS transmission could be guaranteed.

SUMMARY

A method and apparatus are disclosed for handling SRS and PUCCH in a wireless communication system. In one embodiment, the method comprises using, a PDCCH transmission to trigger a dynamic aperiodic SRS transmission. In addition, the method comprises transmitting the triggered dynamic aperiodic SRS transmission in a first subframe. Furthermore, the method comprises transmitting a PUCCH transmission in the same first subframe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention.

FIG. 2 is a block diagram of an embodiment of a transmitter system (also known as the access network (AN)) and a receiver system (also known as access terminal (AT) or user equipment (UE)) according to one embodiment of the invention.

FIG. 3 shows an alternative functional block diagram of a communication device according to one embodiment of the invention.

FIG. 4 is a simplified block diagram of the program code shown inFIG. 3 according to one embodiment of the invention.

FIG. 5 is a simplified block diagram of a wireless communication system from an alternative perspective according to one embodiment of the invention.

FIG. 6 outlines an exemplary flow diagram for handling dynamic aperiodic SRS according to one embodiment of the invention.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A (Long Term Evolution Advanced) wireless access, 3GPP2 UMB (Ultra Mobile Broadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including 3GPP TSG RAN WG1 #61 (“Signaling Considerations for Dynamic Aperiodic SRS”—R1-102830). The standards and documents listed above are hereby expressly incorporated herein.

FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention. An access network100 (AN) includes multiple antenna groups, one including104 and106, another including108 and110, and an additional including112 and114. In Figure A1, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal116 (AT) is in communication with

antennas

112 and114, where

antennas

112 and114 transmit information to accessterminal116 overforward link120 and receive information fromaccess terminal116 overreverse link118. Access terminal (AT)122 is in communication with

antennas

106 and108, where

antennas

106 and108 transmit information to access terminal (AT)122 overforward link126 and receive information from access terminal (AT)122 overreverse link124. In a FDD system,

communication links

118,120,124 and126 may use different frequency for communication. For example,forward link120 may use a different frequency than that used byreverse link118.

Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access network. In the embodiment, antenna groups each are designed to communicate to access terminals in a sector of the areas covered byaccess network100.

In communication over

forward links

120 and126, the transmitting antennas ofaccess network100 may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the

different access terminals

116 and122. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage normally causes less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to all its access terminals.

An access network (AN) may be a fixed station or base station used for communicating with the terminals and may also be referred to as an access point, a Node B, a base station, an enhanced base station, an eNodeB, or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmitter system210 (also known as the access network) and a receiver system250 (also known as access terminal (AT) or user equipment (UE)) in aMIMO system200. At thetransmitter system210, traffic data for a number of data streams is provided from adata source212 to a transmit (TX)data processor214.

In one embodiment, each data stream is transmitted over a respective transmit antenna. TXdata processor214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g. BPSK. QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed byprocessor230.

The modulation symbols for all data streams are then provided to aTX MIMO processor220, which may further process the modulation symbols (e.g., for OFDM). TX MIMOprocessor220 then provides N_Tmodulation symbol streams to N_Ttransmitters (TMTR)222athrough222t. In certain embodiments, TX MIMOprocessor220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. N_Tmodulated signals fromtransmitters222athrough222tare then transmitted from N_Tantennas224athrough224t, respectively.

Atreceiver system250, the transmitted modulated signals are received by N_Rantennas252athrough252rand the received signal from each antenna252 is provided to a respective receiver (RCVR)254athrough254r. Each receiver254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

An RXdata processor260 then receives and processes the N_Rreceived symbol streams from N_Rreceivers254 based on a particular receiver processing technique to provide N_T“detected” symbol streams. The RXdata processor260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RXdata processor260 is complementary to that performed by TX MIMOprocessor220 and TXdata processor214 attransmitter system210.

Aprocessor270 periodically determines which pre-coding matrix to use (discussed below).Processor270 formulates a reverse link message comprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by aTX data processor238, which also receives traffic data for a number of data streams from adata source236, modulated by amodulator280, conditioned bytransmitters254athrough254r, and transmitted back totransmitter system210.

Attransmitter system210, the modulated signals fromreceiver system250 are received by antennas224, conditioned by receivers222, demodulated by ademodulator240, and processed by aRX data processor242 to extract the reserve link message transmitted by thereceiver system250.Processor230 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.

Memory

232 may be used to temporarily store some buffered/computational data from240 or242 throughProcessor230, store some buffed data from212, or store some specific program codes. AndMemory272 may be used to temporarily store some buffered/computational data from260 throughProcessor270, store some buffed data from236, or store some specific program codes.

Turning toFIG. 3, this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the invention. As shown inFIG. 3, the communication device300 in a wireless communication system can be utilized for realizing the UEs (or ATs)116 and122 inFIG. 1, and the wireless communications system is preferably the LTE system. The communication device300 may include aninput device302, anoutput device304, acontrol circuit306, a central processing unit (CPU)308, amemory310, aprogram code312, and atransceiver314. Thecontrol circuit306 executes theprogram code312 in thememory310 through theCPU308, thereby controlling an operation of the communications device300. The communications device300 can receive signals input by a user through theinput device302, such as a keyboard or keypad, and can output images and sounds through theoutput device304, such as a monitor or speakers. Thetransceiver314 is used to receive and transmit wireless signals, delivering received signals to thecontrol circuit306, and outputting signals generated by thecontrol circuit306 wirelessly.

FIG. 4 is a simplified block diagram of theprogram code312 shown inFIG. 3 in accordance with one embodiment of the invention. In this embodiment, theprogram code312 includes anapplication layer400, aLayer3

portion

402, and aLayer2

portion

404, and is coupled to aLayer1

portion

406. TheLayer3

portion

402 generally performs radio resource control. TheLayer2

portion

404 generally performs link control. TheLayer1

portion

406 generally performs physical connections.

For LTE or LTE-A system, theLayer2

portion

404 may include a Radio Link Control (RLC) layer and a Medium Access Control (MAC) layer. TheLayer3

portion

402 may include a Radio Resource Control (RRC) layer.

FIG. 5 is a simplified block diagram of a wireless communication system from an alternative perspective. As shown, thesystem500 includes the WTRU (wireless transmit/receive unit)530, theeNB510, and the MME/S-GW (Mobility Management Entity/Serving GateWay)520. TheWTRU530, theeNB510 and the MME/S-GW520 are configured to perform SRS transmission with MIMO and carrier aggregation techniques.

In addition to the components that may be found in a typical WTRU, theWTRU530 includes a processor orCPU532 with anoptional memory534, one or more one transceivers536₁, . . . ,536_N, and anantenna538. TheCPU532 is configured to perform a method of SRS transmission with MIMO and carrier aggregation techniques. The transceivers536₁, . . . ,536_Nare in communication with the CPU orprocessor532 and theantenna538 to facilitate the transmission and reception of wireless communications.

In addition to the components that may be found in a typical eNB, theeNB510 includes a processor orCPU512 with anoptional memory514, one or more transceivers516₁, . . . ,516_M, and anantenna518. TheCPU512 is configured to support SRS functionality with (MIMO) and carrier aggregation techniques. The transceivers516₁, . . . ,516_Mare in communication with theCPU512 and anantennas518 to facilitate the transmission and reception of wireless communications. The CPU is generally configured to: i) determine which WTRUs will be transmitting SRS, ii) determine each WTRU's allocation in frequency and time for SRS transmission, as well as the type of SRS transmission and communicate this information to the WTRUs, iii) receive the SRS measurement information and iv) process the SRS information and inform the scheduler so that the scheduler can make scheduling decisions. TheeNB520 is connected to the MME/S-GW520 which includes aprocessor522 with anoptional memory524.

In the following discussion, the invention will be described mainly in the context of the 3GPP architecture reference model. However, it is understood that with the disclosed information, one skilled in the art could easily adapt for use and implement aspects of the invention in a 3GPP2 network architecture as well as in other network architectures.

In LTE, there is a single transmission of a physical uplink control channel (PUCCH). Physical Uplink Shared Channel (PUSCH), or Sounding Reference Signals (SRSs) with a single antenna and a single carrier. The WTRU does not transmit SRS whenever SRS andPUCCH format 2/a/2b transmission happen to coincide in the same subframe. The WTRU does not transmit SRS whenever SRS and acknowledge/negative acknowledge (ACK/NACK) and/or positive SR transmissions happen to coincide in the same subframe unless the parameter Simultaneous-AN-and-SRS is true. The parameter Simultaneous-AN-and-SRS provided by a higher layer determines if a WTRU is configured to support the transmission of ACK/NACK on PUCCH and SRS in one subframe. If it is configured to support the transmission of ACK/NACK on PUCCH and SRS in one subframe, then in the cell specific SRS subframes WTRU shall transmit ACK/NACK and SR using the shortened PUCCH format, in which the ACK/NACK or the SR transmission on the SC-FDMA symbol corresponding to the SRS is punctured. More specifically, the SC-FDMA is a timing unit, and not a modulation symbol. In addition, when the shortened PUCCH format is used or applied, the PUCCH transmission would be punctured in the last SC-FDMA symbol. Also, since the time is used for possible SRS transmission, no ACK/NACK modulation symbol will be generated to avoid transmission overlapping.

Furthermore, in order for the eNodeB to perform reliable channel estimation for frequency-scheduling for each UL, the transmit power for SRS (and other channels) is controlled.

Additionally, in LTE, Single Carrier Frequency Division Multiple Access (SC-FDMA) transmission was selected for uplink (UL) direction. The specific implementation is based on Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S—OFDM). For the purpose of this application, either term may be used interchangeably. A WTRU in the UL will transmit only on a limited, contiguous set of assigned sub-carriers in an FDMA arrangement. For illustration purposes, if the overall OFDM signal or system bandwidth in the UL is composed of useful sub-carriers numbered 1 to 100, a first given WTRU would be assigned to transmit its own signal on sub-carriers 1-12, a second given WTRU would transmit on sub-carriers 13-24, and so on. An eNodeB (or eNB) would receive the composite UL signal across the entire transmission bandwidth from one or more WTRUs at the same time, but each WTRU would only transmit into a subset of the available transmission bandwidth. DFT-S OFDM in the LTE UL was selected by 3GPP Radio Layer 1 (RAN1) as a form of OFDM transmission with the additional constraint that the time-frequency resource assigned to a WTRU must consist of a set of frequency-consecutive sub-carriers. In the LTE UL, there is no DC sub-carrier (unlike the downlink (DL)). Frequency hopping may be applied in one mode of operation to UL transmissions by a WTRU.

WTRUs transmit their UL data (and in some cases their control information) on the physical uplink shared channel (PUSCH). The transmission of the PUSCH is scheduled and controlled by the eNodeB using the so-called uplink scheduling grant, which is carried on physical downlink control channel (PDCCH) format 0. As part of the uplink scheduling grant, the WTRU receives control information on the modulation and coding scheme (MCS), transmit power control (TPC) command, uplink resources allocation (i.e., the indices of allocated resource blocks), etc. Then, the WTRU will transmit its PUSCH on allocated uplink resources with corresponding MCS at transmit power controlled by the TPC command.

To allow for the eNodeB to estimate UL channel quality for UL scheduling, sounding reference signals (SRS) may be transmitted in UL. In the frequency domain. SRS transmissions may cover the frequency band that is of interest for the frequency domain scheduling. When an SRS is to be transmitted in a subframe, it occupies the last SC-FDMA symbol of the subframe. If a WTRU is transmitting SRS in a certain subframe, then the last symbol of the subframe is then not used for PUSCH transmission by any WTRU within the cell. In order for the eNodeB to perform reliable channel estimation for frequency-scheduling for each UL, the transmit power for SRS (and other channels) is controlled.

In addition, from a UE perspective, there is one transport block (in absence of spatial multiplexing) and one hybrid-ARQ (Hybrid Automatic Repeat Request) entity per scheduled component carrier. Each transport block is mapped to a single component carrier. A UE may be scheduled over multiple component carriers simultaneously. The design principles for downlink control signaling of control region size and uplink and downlink resource assignments can generally be described as following: (1) PDCCH (Physical Downlink Control Channel) on a component carrier assigns PDSCH (Physical Downlink Shared Channel) resources on the same component carrier and PUSCH resources on a single linked UL component carrier. (2) PDCCH on a component carrier can assign PDSCH or PUSCH resources for one of multiple component carriers.

In LTE, UE requires to transmit periodic SRS on the last symbol to help eNB measure the UL channel. Since LTE-A supports UL-MIMO, it is beneficial to trigger dynamic aperiodic SRS from multiple antennas for timely channel information. The SRS resources could be also utilized more efficiently. Base on RAN1 #60bis, the dynamic aperiodic SRS should be triggered at least by a PDCCH UL grant as follows:

In case of aperiodic sounding, triggering is at least by PDCCH UL grants

- FFS how many bits/code points in the DCI message are used (i.e. including whether a PUSCH grant is given at the same time).

Triggering in DL assignment is FFS

Details of what is triggered are FFS

With respect to triggering in DL assignment. 3GPP TSG RAN WG1 #61 states as follows:

PUCCH restriction: for activation in an UL grant the SRS could be time division multiplexed with PUSCH. On the other hand activation in a PDCCH conveying a DL assignment in subframe n would require SRS transmission in subframe n+k (k≧4), similarly to A/N transmission in response to a PDSCH reception or a PDCCH signifying SPS release. Therefore, the UE must always be configured for simultaneous ACK/NACK+SRS to puncture out the last symbol of the ACK/NACK transmission or else the SRS is dropped. Furthermore, if periodic CQI transmission coincides with the aperiodic SRS transmission the SRS is dropped.

In LTE, due to single-carrier constraint, shortened format or dropping is applied when periodic SRS coincides with PUCCH (Physical Uplink Control Channel) as follows:

Periodic SRS andPUCCH 1/1a/1b (SR, A/N):

- If parameter ackNackSRS-SimultaneousTransmission is FALSE, periodic SRS is dropped.
- If parameter ackNackSRS-SimultaneousTransmission is TRUE, periodic SRS is transmitted, and shortened format is applied toPUCCH 1/1a/1b.

Periodic SRS andPUCCH format 2/2a/2b (CQI, A/N):

- Periodic SRS is dropped.

Considering the coincidence of SRS and PUCCH, it would be logical to apply the triggering behavior as described and discussed in 3GPP TSG RAN WG1 #61 for LTE to LTE-A. First, even though dynamic SRS could not be triggered by DL assignment, the coincidence case is also possible for activation by UL grant. Second, since dynamic aperiodic SRS is triggered by eNB, the possible coincidence should be known by eNB, dropping triggered SRS directly seems improper. Also considering the use scenario of UL-MIMO, the channel quality seems quite good in general situation (since uplink transmit diversity is not supported in Rel.10). Transmitting SRS and PUCCH simultaneously on the last symbol seems possible even though some power fall-back is required, and there may be some impact on the SRS measurement on eNB side. Based on this reasons, this PUCCH constraint seems improper to apply to LTE-A directly.

Turning now toFIG. 6, this figure outlines an exemplary flow diagram for handling dynamic aperiodic SRS according to one embodiment of the invention. In step602, a PDCCH is used to trigger a dynamic aperiodic SRS transmission. In one embodiment, the dynamic aperiodic SRS transmission could be triggered by a PDCCH UL grant. In an alternative embodiment, the dynamic aperiodic SRS transmission could be triggered by a PDCCH DL assignment.

Instep604, the triggered dynamic aperiodic SRS is transmitted in a subframe. In an embodiment, the dynamic aperiodic SRS transmits on a cell-specific SRS subframe. Instep606, a PUCCH transmission is performed using the same subframe. In one embodiment, the dynamic aperiodic SRS transmission and the PUCCH transmission are done on a UL. In another embodiment, the PUCCH transmission could be used to effectuate a scheduling request. The PUCCH transmission could also be an acknowledgement for a hybrid automatic repeat request (HARQ). Furthermore, the PUCCH transmission could be used for periodic CQI (Channel Quality Indicator)/PMI (Precoding Matrix Indicator)/RI (Rank Indication) reporting. In an alternative embodiment, the said dynamic aperiodic SRS has higher power priority than the PUCCH. More specifically, if there the power required for transmission exceeds the CC-specific maximum power, power reduction would first apply to the PUCCH transmission. In vet another embodiment, some antennas (or antenna ports) are used to transmit the dynamic aperiodic SRS while other antennas (or antenna ports) are used to transmit the PUCCH. In other words, the dynamic aperiodic SRS is transmitted on the antennas which are not used to transmit the PUCCH.

Instep608, a parameter is used to determine whether a shortened PUCCH format should be used in the PUCCH transmission. In one embodiment, if the parameter is an ackNackSRS-SimultaneousTransmission, the shortened PUCCH format is used in the PUCCH transmission.

In an embodiment, there are two types of SRS transmissions in LIE-A, including: (1) periodic SRS, and (2) dynamic aperiodic SRS. In this embodiment, the dynamic aperiodic SRS transmission would have higher priority than the periodic SRS transmission. Therefore, instep610, if both types of SRS transmission are requested to be transmitted in the same subframe, the periodic SRS transmission would be dropped, and the aperiodic SRS transmission would be transmitted. In particular, the periodic SRS transmission is dropped if the subframe is a UE-specific SRS subframe and the dynamic aperiodic SRS corresponding to the subframe is triggered.

Various aspects of the disclosure have been described above. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. As an example of some of the above concepts, in some aspects concurrent channels may be established based on pulse repetition frequencies. In some aspects concurrent channels may be established based on pulse position or offsets. In some aspects concurrent channels may be established based on time hopping sequences. In some aspects concurrent channels may be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as “software” or a “software module”), or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

In addition, the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (“IC”), an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices. e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a “processor”) such the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Moreover, in some aspects any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects a computer program product may comprise packaging materials.

While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.