Patent Publication Number: US-9433002-B2

Title: Rank indicator transmission during discontinuous reception

Description:
RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. patent application Ser. No. 14/179,227, filed on Feb. 12, 2014, which is a continuation of and claims priority to U.S. patent application Ser. No. 13/467,937, filed on May 9, 2012, which is a continuation of and claims priority to U.S. patent application Ser. No. 12/058,444, filed on Mar. 28, 2008, and issued as U.S. Pat. No. 8,199,725 on Jun. 12, 2012, which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     Easily transportable devices with wireless telecommunications capabilities, such as mobile telephones, personal digital assistants, handheld computers, and similar devices, will be referred to herein as user equipment (UE). The term “user equipment” may refer to a device and its associated Universal Integrated Circuit Card (UICC) that includes a Subscriber Identity Module (SIM) application, a Universal Subscriber Identity Module (USIM) application, or a Removable User Identity Module (R-UIM) application or may refer to the device itself without such a card. A UE might communicate with a second UE, some other element in a telecommunications network, an automated computing device such as a server computer, or some other device. A communications connection between a UE and another component might promote a voice call, a file transfer, or some other type of data exchange, any of which can be referred to as a call or a session. 
     As telecommunications technology has evolved, more advanced network access equipment has been introduced that can provide services that were not possible previously. This advanced network access equipment might include, for example, an enhanced node B (ENB) rather than a base station or other systems and devices that are more highly evolved than the equivalent equipment in a traditional wireless telecommunications system. Such advanced or next generation equipment may be referred to herein as long-term evolution (LTE) equipment. Later generation or future advanced equipment that designates access nodes, for example nodes that provide radio access network (RAN) connectivity to UEs, are also referred to herein by the term ENB. 
     Some UEs have the capability to communicate in a packet switched mode, wherein a data stream representing a portion of a call or session is divided into packets that are given unique identifiers. The packets might then be transmitted from a source to a destination along different paths and might arrive at the destination at different times. Upon reaching the destination, the packets are reassembled into their original sequence based on the identifiers. Voice over Internet Protocol (VoIP) is a well-known system for packet switched-based voice communication over the Internet. The term “VoIP” will refer herein to any packet switched voice call connected via the Internet, regardless of the specific technology that might be used to make the call. 
     For a wireless VoIP call, the signal that carries data between a UE and an ENB can have a specific set of frequency, code, and time parameters and other characteristics that might be specified by the ENB. A connection between a UE and an ENB that has a specific set of such characteristics can be referred to as a resource. An ENB typically establishes a different resource for each UE with which it is communicating at any particular time. 
     New wireless communications systems may employ multiple input multiple output (MIMO) communication techniques. MIMO involves one or both of the UE and the ENB concurrently using multiple antennas for transmitting and/or receiving. Depending upon the radio channel conditions, the multiple antennas may be employed to increase the throughput of the radio link between the UE and the ENB, for example by transmitting independent streams of data on each antenna, or to increase the reliability of the radio link between the UE and the ENB, for example by transmitting redundant streams of data on the multiple antennas. These different communications objectives may be obtained through spatial multiplexing in the first case and through spatial diversity in the second case. Receiving multiple concurrent transmissions from a multi-antenna transmitter by a multi-antenna receiver may involve complicated processing techniques and or algorithms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG. 1  is a block diagram of a telecommunications system according to an embodiment of the disclosure. 
         FIG. 2  is a diagram illustrating on-durations and off-durations for a user equipment according to an embodiment of the disclosure. 
         FIG. 3 a    is an illustration of a periodic rank indicator (RI) reporting resource relative to an on-duration and a retransmission window associated with the on-duration according to an embodiment of the disclosure. 
         FIG. 3 b    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 3 c    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 3 d    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 3 e    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 3 f    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 4 a    is an illustration of a periodic rank indicator reporting resource relative to uplink sub-frames and downlink sub-frames of an enhanced node B according to an embodiment of the disclosure. 
         FIG. 4 b    is an illustration of a periodic rank indicator reporting resource relative to an on-duration and a retransmission window associated with the on-duration, depicting some rank indicator transmissions turned off according to an embodiment of the disclosure. 
         FIG. 5 a    is an illustration of a method of transmitting rank indicator control signals according to an embodiment of the disclosure. 
         FIG. 5 b    is an illustration of another method of transmitting rank indicator control signals according to an embodiment of the disclosure. 
         FIG. 6  is a diagram of a wireless communications system including a user equipment operable for some of the various embodiments of the disclosure. 
         FIG. 7  is a block diagram of a user equipment operable for some of the various embodiments of the disclosure. 
         FIG. 8  is a diagram of a software environment that may be implemented on a user equipment operable for some of the various embodiments of the disclosure. 
         FIG. 9  illustrates an exemplary general-purpose computer system suitable for implementing the several embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It should be understood at the outset that although illustrative implementations of one or more embodiments of the present disclosure are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents. 
     In an embodiment, a user equipment (UE) is disclosed. The UE includes a processor configured to transmit a rank Indicator (RI) using one of an assigned periodic RI reporting resource that precisely aligns with the start of an on-duration of a discontinuous reception (DRX) operation mode of the UE and a first assigned periodic RI reporting resource after the start of the on-duration. 
     In other embodiments, a UE is disclosed that includes a processor configured to transmit a rank indicator (RI) using a first assigned periodic RI reporting resource after the start of a retransmission window. 
     In one embodiment, a method is provided for transmitting a control signal from a user equipment (UE) to an enhanced node B (ENB). The method includes determining when an on-duration of a discontinuous reception (DRX) operation mode of the UE is scheduled, and beginning a periodic transmission of a rank indicator (RI) control signal using one of an assigned periodic RI reporting interval that precisely aligns with the start of an on-duration of a discontinuous reception (DRX) operation mode of the UE and a first assigned periodic RI reporting interval after the start of the on-duration. 
       FIG. 1  illustrates an embodiment of a wireless telecommunications system  100  that includes a UE  10  capable of communicating with an ENB  20  or a similar component. Transmissions of various types of information can take place between the UE  10  and the ENB  20 . For example, the UE  10  might send the ENB  20  various types of application layer data such as VoIP data packets and data packets containing information related to web browsing, emailing, and other user applications, all of which may be referred to as user plane data. Other types of information related to the UE&#39;s application layer will be familiar to one of skill in the art. Any signal containing such information will be referred to herein as a data signal  30 . Information associated with a data signal  30  will be referred to herein as user plane data. 
     The UE  10  might also send the ENB  20  various types of control signaling such as layer  1  scheduling requests, layer  1  control signaling (CQI, PMI, RI, NACK/ACK, etc.), high layer radio resource control (RRC) messages and mobility measurement messages, and other control messages, all of which may be referred to as control plane data, and is familiar to one of skill in the art. The UE  10  typically generates such messages as needed to initiate or maintain a call. Any such signal will be referred to herein as a control signal  40 . Information associated with a control signal  40  will be referred to herein as control plane data. 
     Rank indicator (RI) control signals and/or messages are included among these control signals. An RI control signal may be a message transmitted from the UE  10  to the ENB  20  and may be considered to provide channel state indication (CSI) feedback from the UE  10  to the ENB  20 . In an embodiment, the RI may indicate how many independent data streams may be transmitted by the ENB  20  over the wireless link. The RI may be used by the ENB  20  to adapt communication parameters including modulation parameters, coding rate parameters, and other communication parameters. In an embodiment, the ENB  20  may select a precoding matrix based at least in part on the value of the RI transmitted from the UE  10  to the ENB  20 . 
     In some cases, a dedicated channel might exist between the UE  10  and the ENB  20  via which control plane data may be sent. Requests to send data on the uplink may also use this dedicated channel. This may be called a scheduling request. In other cases, a random access channel (RACH) may be used to initiate a scheduling request. That is, in some cases, a request for resources to send control plane data may be sent via a RACH, and, in other cases, the control plane data itself might be sent via a RACH. 
     When the UE  10  sends a control signal  40  to the ENB  20 , the ENB  20  might return a response signal or other control signal to the UE  10 . For example, if the UE  10  sends a mobility measurement message to the ENB  20 , the ENB  20  might respond by sending an acknowledgement message or some other handover-related control message to the UE  10 . Other types of responses that the ENB  20  might send upon receiving a control signal  40  from the UE  10  will be familiar to one of skill in the art. Any such response by the ENB  20  to a control signal  40  sent by the UE  10  will be referred to herein as a response signal  50 . 
     In order to save battery power, the UE  10  might periodically alternate between a high-power mode and a low-power mode. For example, using techniques known as discontinuous reception (DRX), the UE  10  might periodically enter short periods of relatively high power consumption during which data can be received. Such periods will be referred to herein as on-durations and/or active time. Between the on-durations, the UE  10  might enter longer periods in which power consumption is reduced and data is not received. Such periods will be referred to herein as off-durations. A balance between power savings and performance can be achieved by making the off-durations as long as possible while still keeping the on-durations long enough for the UE  10  to properly receive data. 
     The term “DRX” is used generically to refer to discontinuous reception. To avoid confusion, the terms “on-duration” and “off-duration” may also be used herein to refer to a UE&#39;s capability to receive data. Besides the on-duration, the active time defines the time that the UE is awake, which could be longer than the on-duration due to the possible inactivity timer running which will keep the UE awake for additional time. Additional related discussion is found in 3 rd  Generation Partnership Project (3GPP) Technical Specification (TS) 36.321. 
       FIG. 2  illustrates an idealized view of on-durations and off-durations for the UE  10 . On-durations  210  with higher power usage alternate in time with off-durations  220  with lower power usage. Traditionally, the UE  10  receives data only during the on-durations  210  and does not receive data during the off-durations  220 . As an example, it might be determined that an entire cycle of one on-duration  210  and one off-duration  220  should last 20 milliseconds. Of this cycle, it might be determined that an on-duration  210  of 5 milliseconds is sufficient for the UE  10  to receive data without significant loss of information. The off-duration  220  would then last 15 milliseconds. 
     The determination of the sizes of the on-durations  210  and the off-durations  220  might be based on the quality of service (QoS) parameters of an application. For example, a VoIP call might need a higher level of quality (e.g., less delay) than an email transmission. When a call is being set up, the UE  10  and the ENB  20  enter a service negotiation stage in which a QoS is negotiated based on the maximum allowable delay, the maximum allowable packet loss, and similar considerations. The level of service to which the user of the UE  10  subscribes might also be a factor in the QoS negotiations. When the QoS parameters for a call have been established, the ENB  20  sets the appropriate sizes for the on-durations  210  and the off-durations  220  based on that QoS level. 
     Turning now to  FIG. 3 a   , RI control signal transmissions are discussed. A plurality of assigned periodic RI reporting intervals  250  are shown relative to the on-duration  210  and a retransmission window  230 . In some contexts, the assigned periodic RI reporting intervals  250  may be referred to as assigned periodic RI reporting resources. The RI reporting intervals  250  depicted include a first RI reporting interval  250   a , a second RI reporting interval  250   b , a third RI reporting interval  250   c , a fourth RI reporting interval  250   d , a fifth RI reporting interval  250   e , a sixth RI reporting interval  250   f , a seventh RI reporting interval  250   g , an eighth RI reporting interval  250   h , a ninth RI reporting interval  250   i , a tenth RI reporting interval  250   j , an eleventh RI reporting interval  250   k , and a twelfth RI reporting interval  250   l . It is understood that the assigned periodic RI reporting intervals  250  in a network is an ongoing sequence, and that many RI reporting intervals  250  precede the first RI reporting interval  250   a  and many RI reporting intervals  250  follow the twelfth RI reporting interval  250   l . In an embodiment, the UE  10  may transmit RI control signals during each RI reporting interval  250  using the assigned RI reporting resources, as indicated in  FIG. 3 a    by the solid line arrows. The retransmission window  230  provides an opportunity for the ENB  20  to retransmit data to the UE  10  that the UE  10  was unable to receive properly during the on-duration  210 . Note that the UE  10  may transmit some of the PMI control signals during the on duration  210  and the retransmission window  230 . This may require that the UE  10  have two or more antennas with two different RF chains—a first RF chain associated with a first antenna for receiving and a second RF chain associated with a second antenna for transmitting—so the UE  10  can receive and transmit concurrently. 
     Turning now to  FIG. 3 b   , RI control signal transmissions are discussed further. In an embodiment, it may be inefficient for the UE  10  to transmit RI control signals on every RI reporting interval  250 . Specifically, during some of the RI reporting intervals when the ENB  20  is not transmitting to the UE  10 , there may be no benefit associated with the UE  10  sending RI control signals to the ENB  20 , because the ENB  20  need not adapt communication parameters for communicating with the UE  10  at that time. A wide variety of techniques may be employed to reduce the transmissions of RI control signals. As depicted in  FIG. 3 b    by dashed arrowed line segments, the UE  10  may turn off or stop transmitting RI control signals during the first RI reporting interval  250   a , the second RI reporting interval  250   b  and during the fifth RI reporting interval  250   e  through the twelfth RI reporting interval  250   l , thereby saving the power that otherwise would have been consumed by transmitting the RI control signals during the RI reporting intervals  250   a ,  250   b ,  250   e ,  250   f ,  250   g ,  250   h ,  250   i ,  250   j ,  250   k , and  250   l . The UE  10  analyzes the schedule of the on-duration  210  and determines to transmit on one of the RI reporting intervals  250  during the first RI reporting interval after the start of the on-duration  210  and to continue to transmit the RI control signal during each successive RI reporting interval until the end of the on-duration  210  or the end of the active time. The UE  10  may be instructed by the ENB  20  that it should suspend transmitting RI until the end of the on-duration  210  or the end of the active time. It is understood that each of the RI control signals transmitted by the UE  10  is independent of the other RI control signals transmitted by the UE  10  and may contain new information based on current radio channel conditions. 
     Turning now to  FIG. 3 c   , RI control signal transmissions are discussed further. In an embodiment, the UE  10  may transmit the RI control signal during the RI reporting interval that immediately precedes the on-duration  210  and continues to transmit the RI control signal during each successive RI reporting interval  250  until the end of the on-duration or the end of the active time. By beginning transmitting the RI control signal transmissions before the start of the on-duration  210 , the ENB  20  may be able to receive the RI control signal from the UE  10 , to process the RI information, and to determine how to adapt communication parameters by the start of the on-duration  210 . In some contexts this may be referred to as resuming RI control signal transmissions. 
     Turning now to  FIG. 3 d   , RI control signal transmissions are discussed further. In an embodiment, the UE  10  continues to periodically transmit the RI control signals until the retransmission window  230  has ended, then the UE  10  stops transmitting RI control signals. The UE  10  may begin transmitting the RI control signal either during the first RI reporting interval  250  of the on-duration  210 , for example the third RI reporting interval  250   c  as depicted in  FIG. 3 b   , or during the RI reporting interval  250  that immediately precedes the on-duration, for example the second RI reporting interval  250   b , as depicted in  FIG. 3 c   . As an example, in  FIG. 3 d    the UE  10  is depicted as periodically transmitting RI control signals from the third RI reporting interval  250   c  through the eighth RI reporting interval  250   h . This scenario may also be described as transmitting the RI control signal during a first assigned periodic RI reporting resource after the start of the on-duration  210  and transmitting the RI control signal during each successive assigned periodic RI reporting resource until the end of the retransmission window  230 . 
     Turning now to  FIG. 3 e   , RI control signal transmissions are discussed further. It may be inefficient for the UE  10  to transmit RI control signals after the on-duration  210  has concluded or stopped and before the retransmission window  230  begins. The UE  10  analyzes the schedule of the on-duration  210  and may turn off or stop periodic transmissions of the RI control signal after the on-duration  210  has ended or at the end of the active time. For example, as depicted in  FIG. 3 e   , the UE  10  may turn on periodic transmission of RI control signals during the third RI reporting interval  250   c  through the fourth RI reporting interval  250   d , turn off periodic transmission of RI control signals during the fifth RI reporting interval  250   e  through the seventh RI reporting interval  250   g , turn on or resume periodic transmission of RI control signals for the eighth RI reporting interval  250   h , and then turn off periodic transmission of RI control signals at the ninth RI reporting interval  250   i . In an embodiment, the UE  10  may also transmit the RI control signal during the seventh RI reporting interval  250   g.    
     Turning now to  FIG. 3 f   , RI control signal transmissions are discussed further. In an embodiment, it may be desirable to transmit the RI control signals only during the retransmission window  230 . The UE  10  may begin transmitting the RI control signal with the first RI reporting interval  250  in the retransmission window  230  or with the RI reporting interval  250  that immediately precedes the retransmission window  230  and to transmit RI control signals during each successive RI reporting interval  250  until the end of the retransmission window  230 . 
     One will readily appreciate that the several RI control signal transmission scenarios admit of a variety of related combinations and extensions along the lines of the description above. All of these combinations and extensions are contemplated by the present disclosure. Additional technical details related to discontinuous reception (DRX) operation modes and assigned periodic RI reporting resources may be found in TS 36.300, TS 36.321, and TS 36.213, each of which are hereby incorporated herein by reference for all purposes. 
     Turning now to  FIG. 4 a   , the timing relationship between the RI reporting intervals  250  and a plurality of uplink sub-frames and downlink sub-frames of an ENB is discussed. In a practical wireless network a number of time lags are observed between the UE  10  transmitting the RI control signal and the ENB  20  adapting the communication parameters based on the RI control signals. A propagation delay is introduced by the time it takes for the radio frequency signal emitted by the UE  10  containing the RI control signal to propagate through the radio channel to the ENB  20 . The ENB  20  processing is segmented into uplink sub-frames  260  and downlink sub-frames  270 , for example a first uplink sub-frame  260   a , a second uplink sub-frame  260   b , a third uplink sub-frame  260   c , a first downlink sub-frame  270   a , a second downlink sub-frame  270   b , and a third downlink sub-frame  270   c . The timing of the uplink sub-frame  260  edges and the downlink sub-frame  270  edges may not align due to the propagation delay and/or oscillator drift between the UE  10  and the ENB  20 . As an example, the RI control signal transmitted during the third RI reporting interval  250   c  may be received by the ENB  20  in the first uplink sub-frame  260   a , processed by the ENB  20  to adapt communication parameters in the second uplink sub-frame  260   b , and the newly adapted communication parameters may be employed by the ENB  20  for communicating with the UE  10  during the third downlink sub-frame  270   c . In an embodiment, the best case sub-frame delay is about two sub-frames. In another embodiment, the sub-frame delay may be about three sub-frames or about four sub-frames. 
     Turning now to  FIG. 4 b   , RI control signal transmissions are discussed further. In an embodiment, the UE  10  takes the time lags discussed above with reference to  FIG. 4 a    into account in determining when to begin periodic transmission of the RI control signal before the on-duration  210  and before the retransmission window  230 . As an example, as depicted in  FIG. 4 b   , beginning periodic transmission of the RI control signal with the third RI reporting interval  250   c  may not provide enough lead time for the ENB  20  to receive, process, and adapt communication parameters by the beginning of the on-duration  210 . If the UE  10  began periodic transmission of the RI control signal with the third RI reporting interval, the first downlink sub-frame and also possibly the second downlink sub-frame may not benefit from adaptation based on a fresh RI control signal and less efficient communication operation between the UE  10  and the ENB  20  may result. For example, the ENB  20  may use the previously transmitted RI control signal that does not suit the current radio channel and result in inefficient use of the radio channel. For example, based on an outdated RI, the ENB  20  may use a lower modulation rate and/or a lower coding rate than current channel conditions support. Alternatively, based on an outdated RI, the ENB  20  may use a higher modulation rate and/or a higher coding rate than current channel conditions support, the UE  10  may fail to receive one or more data packets, for example, and the ENB  20  may need to retransmit the data packets using HARQ, possibly decreasing the throughput of the radio channel and increasing the UE  10  power consumption for waking up to listen to the retransmissions. 
     As depicted, the UE  10  begins periodic transmission of RI control signals with the second RI reporting interval  250   b , thereby providing enough time to permit the ENB  20  to receive the RI control signal, process the RI control signal, and adapt communication parameters by the start of the on-duration  210 . Similarly, the UE  10  determines when to start or resume periodic transmission of the RI control signal before the retransmission window  230  taking into account the time needed by the ENB  20  to receive the RI control signal, process the RI control signal, and adapt communication parameters by the start of the retransmission window  230 . The ENB  20  may instruct the UE  10  how to determine when to start or resume periodic transmission of the RI control signal before the retransmission window  230 . 
     Turning now to  FIG. 5 a   , a method  300  of the UE  10  for controlling RI control signal transmissions is discussed. At block  305 , the UE  10  determines when the next on-duration  210  is scheduled. The ENB  20  may instruction the UE  10  to begin this process. At block  310 , the UE  10  determines when the retransmission window  230  associated with the on-duration  210  is scheduled. In block  315 , the UE  10  identifies or selects a RI reporting interval  250  that precedes the start of the on-duration  210 . In an embodiment, the UE  10  may select any RI reporting interval  250  that precedes the start of the on-duration  210 . In another embodiment, the UE  10  may select the RI reporting interval  250  that immediately precedes the start of the on-duration  210 . Another way of describing the behavior of this embodiment is that the UE  10  may select the last RI reporting interval  250  that occurs before the start of the on-duration  210 . In another embodiment, the UE  10  takes into account the time lags of radio frequency signal propagation, timing offsets associated with oscillator drifts, and processing by the ENB  20  to select the RI reporting interval  250  that precedes the on-duration  210 . In an embodiment, the UE  10  may estimate the time lags to consume about a time duration of two sub-frames. In another embodiment, the UE  10  may estimate the time lags to consume about a time duration of three sub-frames or four sub-frames. In some circumstances, depending on timing alignments between the on-duration  210 , the UE  10  may select the last RI reporting interval  250  that occurs before the start of the on-duration  210  or the UE  10  may select the next to the last RI reporting interval  250  that occurs before the start of the on-duration  210 . In another embodiment, however, the UE  10  may select the first RI reporting interval after the start of the on-duration  210 . The UE  10  may select the first RI reporting interval as the precise start of the on-duration  210 , when the RI reporting interval  250  precisely aligns with the start of the on-duration  210 . 
     At block  320 , the UE  10  transmits the RI control signal on the selected RI reporting interval  250 . In an embodiment, the processing of block  320  may include a waiting process or a sleeping process wherein the process  300  only executes block  320  at the appropriate time, for example at the time of the selected RI reporting interval  250 . At block  325 , if the retransmission window  230  associated with the on-duration  210  has not completed, the process  300  returns to block  320 . By looping through blocks  320  and  325 , the UE  10  periodically transmits the RI control signal to the EMS  20 . In an embodiment, it is understood that the UE  10  re-determines the RI values and/or information for each new transmission of the RI control signal. It is also understood that the UE  10  transmits the RI control signal at about the assigned time of the RI reporting interval  250  over assigned RI reporting resources. 
     At block  325 , if the retransmission window  230  associated with the on-duration  210  has completed, the processing returns to block  305 . This can be understood to include stopping periodic transmission of RI control signals until the method  300  returns to block  320 . 
     Turning now to  FIG. 5 b   , a method  350  of the UE  10  for controlling RI control signal transmissions is discussed. At block  355 , the UE  10  determines when the next on-duration  210  is scheduled to begin and to end. At block  360 , the UE  10  determines when the retransmission window  230  associated with the next on-duration  210  is scheduled to begin and end. In block  365 , the UE  10  identifies or selects the RI reporting interval that precedes the next scheduled on-duration  210  to start periodic RI control signal transmissions. As described with respect to block  315  above, the UE  10  may select the RI reporting interval according to several different selection criteria, all of which are also contemplated by the method  350 . 
     At block  370 , the UE  10  transmits the RI control signal on the selected RI reporting interval  250 . In an embodiment, the processing of block  370  may include a waiting process or a sleeping process wherein the process  350  only executes block  370  at the appropriate time, for example at the time of the selected RI reporting interval  250 . At block  375 , if the on-duration  210  has not completed, the method  350  returns to block  370 . By looping through blocks  370  and  375 , the UE  10  periodically transmits the RI control signal to the ENB  20 . In an embodiment it is understood that the UE  10  re-determines the RI values and/or information for each new transmission of the RI control signal. It is also understood that the UE  10  transmits the RI control signal at about the assigned time of the RI reporting interval  250  over assigned RI reporting resources. 
     At block  375 , if the on-duration  210  has completed, the processing proceeds to block  380 . At block  380 , the UE  10  identities or selects the RI reporting interval that precedes the retransmission window  230  to start or resume periodic RI control signal transmissions. As described with respect to block  315  above, the UE  10  may select the RI reporting interval according to several different selection criteria, all of which are also contemplated by method  350 . In another embodiment, however, after on-duration  210  has completed the method  350  may complete and no RI control signals may be transmitted during the retransmission window  230 . In still another embodiment, the method  350  may begin at block  360 , jump from block  360  to block  380 , bypassing blocks  355 ,  365 ,  370 , and  375 . 
     At block  385 , the UE  10  transmits the RI control signal on the selected RI reporting interval  250 . In an embodiment, the processing of block  385  may include a waiting process or a sleeping process wherein the process  350  only executes block  385  at the appropriate time, for example at the time of the selected RI reporting interval  250 . At block  390 , if the retransmission window  230  has not completed, the method  350  returns to block  385 . By looping through blocks  385  and  390 , the UE  10  periodically transmits the RI control signal to the ENB  20 . In an embodiment, it is understood that the UE  10  re-determines the RI values and/or information for each new transmission of the RI control signal. It is also understood that the UE  10  transmits the RI control signal at about the assigned time of the RI reporting interval  250  over assigned RI reporting resources. 
     At block  390 , if the retransmission window  230  has completed, the processing returns to block  355 . This can be understood to include stopping periodic transmission of RI control signals until the method  350  returns to block  370 . 
       FIG. 6  illustrates a wireless communications system including an embodiment of the UE  10 . The UE  10  is operable for implementing aspects of the disclosure, but the disclosure should not be limited to these implementations. Though illustrated as a mobile phone, the UE  10  may take various forms including a wireless handset, a pager, a personal digital assistant (PDA), a portable computer, a tablet computer, or a laptop computer. Many suitable devices combine some or all of these functions. In some embodiments of the disclosure, the UE  10  is not a general purpose computing device like a portable, laptop or tablet computer, but rather is a special-purpose communications device such as a mobile phone, a wireless handset, a pager, a PDA, or a telecommunications device installed in a vehicle. In another embodiment, the UE  10  may be a portable, laptop or other computing device. The UE  10  may support specialized activities such as gaming, inventory control, job control, and/or task management functions, and so on. 
     The UE  10  includes a display  402 . In an embodiment, the UE  10  includes two antennas  403 —a first antenna  403 A and a second antenna  403 B—which may be used for MIMO operations. The two antennas  403  may also permit the UE  10  to transmit the RI control signals during the on-duration  210  and/or during the retransmission window  230  on the first antenna  403 A while concurrently receiving signals sent by the ENB  20  to the UE  10  on the second antenna  403 B. The UE  10  also includes a touch-sensitive surface, a keyboard or other input keys generally referred as  404  for input by a user. The keyboard may be a full or reduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY, and sequential types, or a traditional numeric keypad with alphabet letters associated with a telephone keypad. The input keys may include a trackwheel, an exit or escape key, a trackball, and other navigational or functional keys, which may be inwardly depressed to provide further input function. The UE  10  may present options for the user to select, controls for the user to actuate, and/or cursors or other indicators for the user to direct. 
     The UE  10  may further accept data entry from the user, including numbers to dial or various parameter values for configuring the operation of the UE  10 . The UE  10  may further execute one or more software or firmware applications in response to user commands. These applications may configure the UE  10  to perform various customized functions in response to user interaction. Additionally, the UE  10  may be programmed and/or configured over-the-air, for example from a wireless base station, a wireless access point, or a peer UE  10 . 
     Among the various applications executable by the UE  10  are a web browser, which enables the display  402  to show a web page. The web page may be obtained via wireless communications with a wireless network access node, a cell tower, a peer UE  10 , or any other wireless communication network or system  400 . The network  400  is coupled to a wired network  408 , such as the Internet. Via the wireless link and the wired network, the UE  10  has access to information on various servers, such as a server  410 . The server  410  may provide content that may be shown on the display  402 . Alternately, the UE  10  may access the network  400  through a peer UE  10  acting as an intermediary, in a relay type or hop type of connection. 
       FIG. 7  shows a block diagram of the UE  10 . While a variety of known components of UEs  10  are depicted, in an embodiment a subset of the listed components and/or additional components not listed may be included in the UE  10 . The UE  10  includes a digital signal processor (DSP)  502  and a memory  504 . As shown, the UE  10  may further include a front end unit  506 , a radio frequency (RF) transceiver  508 , an analog baseband processing unit  510 , a microphone  512 , an earpiece speaker  514 , a headset port  516 , an input/output interface  518 , a removable memory card  520 , a universal serial bus (USB) port  522 , a short range wireless communication sub-system  524 , an alert  526 , a keypad  528 , a liquid crystal display (LCD), which may include a touch sensitive surface  530 , an LCD controller  532 , a charge-coupled device (CCD) camera  534 , a camera controller  536 , and a global positioning system (GPS) sensor  538 . In an embodiment, the UE  10  may include another kind of display that does not provide a touch sensitive screen. In an embodiment, the DSP  502  may communicate directly with the memory  504  without passing through the input/output interface  518 . 
     In one embodiment, the front end unit  506  interfaces with the two antennas  403  and may comprise one receive chain and one transmit chain. One antenna  403  is for transmitting and the other antenna  403  is for receiving. This allows the UE  10  to transmit the RI signals at the same time it is receiving control and/or data information from the ENB  20 . 
     The DSP  502  or some other form of controller or central processing unit operates to control the various components of the UE  10  in accordance with embedded software or firmware stored in memory  504  or stored in memory contained within the DSP  502  itself. In addition to the embedded software or firmware, the DSP  502  may execute other applications stored in the memory  504  or made available via information carrier media such as portable data storage media like the removable memory card  520  or via wired or wireless network communications. The application software may comprise a compiled set of machine-readable instructions that configure the DSP  502  to provide the desired functionality, or the application software may be high-level software instructions to be processed by an interpreter or compiler to indirectly configure the DSP  502 . 
     The antenna and front end unit  506  may be provided to convert between wireless signals and electrical signals, enabling the UE  10  to send and receive information from a cellular network or some other available wireless communications network or from a peer UE  10 . In an embodiment the antenna and front end unit  506  may include multiple antennas to support beam forming and/or multiple input multiple output (MIMO) operations. As is known to those skilled in the art, MIMO operations may provide spatial diversity which can be used to overcome difficult channel conditions and/or increase channel throughput. The antenna and front end unit  508  may include antenna tuning and/or impedance matching components, RF power amplifiers, and/or low noise amplifiers. 
     The RF transceiver  508  provides frequency shifting, converting received RF signals to baseband and converting baseband transmit signals to RF. In some descriptions a radio transceiver or RF transceiver may be understood to include other signal processing functionality such as modulation/demodulation, coding/decoding, interleaving/deinterleaving, spreading/despreading, inverse fast Fourier transforming (IFFT)/fast Fourier transforming (FFT), cyclic prefix appending/removal, and other signal processing functions. For the purposes of clarity, the description here separates the description of this signal processing from the RF and/or radio stage and conceptually allocates that signal processing to the analog baseband processing unit  510  and/or the DSP  502  or other central processing unit. In some embodiments, the RF Transceiver  508 , portions of the Antenna and Front End  506 , and the analog baseband processing unit  510  may be combined in one or more processing units and/or application specific integrated circuits (ASICs). 
     The analog baseband processing unit  510  may provide various analog processing of inputs and outputs, for example analog processing of inputs from the microphone  512  and the headset  516  and outputs to the earpiece  514  and the headset  516 . To that end, the analog baseband processing unit  510  may have ports for connecting to the built-in microphone  512  and the earpiece speaker  514  that enable the UE  10  to be used as a cell phone. The analog baseband processing unit  510  may further include a port for connecting to a headset or other hands-free microphone and speaker configuration. The analog baseband processing unit  510  may provide digital-to-analog conversion in one signal direction and analog-to-digital conversion in the opposing signal direction. In some embodiments, at least some of the functionality of the analog baseband processing unit  510  may be provided by digital processing components, for example by the DSP  502  or by other central processing units. 
     The DSP  502  may perform modulation/demodulation, coding/decoding, interleaving/deinterleaving, spreading/despreading, inverse fast Fourier transforming (IFFT)/fast Fourier transforming (FFT), cyclic prefix appending/removal, and other signal processing functions associated with wireless communications. In an embodiment, for example in a code division multiple access (CDMA) technology application, for a transmitter function the DSP  502  may perform modulation, coding, interleaving, and spreading, and for a receiver function the DSP  502  may perform despreading, deinterleaving, decoding, and demodulation. In another embodiment, for example in an orthogonal frequency division multiplex access (OFDMA) technology application, for the transmitter function the DSP  502  may perform modulation, coding, interleaving, inverse fast Fourier transforming, and cyclic prefix appending, and for a receiver function the DSP  502  may perform cyclic prefix removal, fast Fourier transforming, deinterleaving, decoding, and demodulation. In other wireless technology applications, yet other signal processing functions and combinations of signal processing functions may be performed by the DSP  502 . 
     The DSP  502  may communicate with a wireless network via the analog baseband processing unit  510 . In some embodiments, the communication may provide Internet connectivity, enabling a user to gain access to content on the Internet and to send and receive e-mail or text messages. The input/output interface  518  interconnects the DSP  502  and various memories and interfaces. The memory  504  and the removable memory card  520  may provide software and data to configure the operation of the DSP  502 . Among the interfaces may be the USB interface  522  and the short range wireless communication sub-system  524 . The USB interface  522  may be used to charge the UE  10  and may also enable the UE  10  to function as a peripheral device to exchange information with a personal computer or other computer system. The short range wireless communication sub-system  524  may include an infrared port, a Bluetooth interface, an IEEE 802.11 compliant wireless interface, or any other short range wireless communication sub-system, which may enable the UE  10  to communicate wirelessly with other nearby mobile devices and/or wireless base stations. 
     The input/output interface  518  may further connect the DSP  502  to the alert  526  that, when triggered, causes the UE  10  to provide a notice to the user, for example, by ringing, playing a melody, or vibrating. The alert  526  may serve as a mechanism for alerting the user to any of various events such as an incoming call, a new text message, and an appointment reminder by silently vibrating, or by playing a specific pre-assigned melody for a particular caller. 
     The keypad  528  couples to the DSP  502  via the interface  518  to provide one mechanism for the user to make selections, enter information, and otherwise provide input to the UE  10 . The keyboard  528  may be a full or reduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY and sequential types, or a traditional numeric keypad with alphabet letters associated with a telephone keypad. The input keys may include a trackwheel, an exit or escape key, a trackball, and other navigational or functional keys, which may be inwardly depressed to provide further input function. Another input mechanism may be the LCD  530 , which may include touch screen capability and also display text and/or graphics to the user. The LCD controller  532  couples the DSP  502  to the LCD  530 . 
     The CCD camera  534 , if equipped, enables the UE  10  to take digital pictures. The DSP  502  communicates with the CCD camera  534  via the camera controller  536 . In another embodiment, a camera operating according to a technology other than Charge Coupled Device cameras may be employed. The GPS sensor  538  is coupled to the DSP  502  to decode global positioning system signals, thereby enabling the UE  10  to determine its position. Various other peripherals may also be included to provide additional functions, e.g., radio and television reception. 
       FIG. 8  illustrates a software environment  602  that may be implemented by the DSP  502 . The DSP  502  executes operating system drivers  604  that provide a platform from which the rest of the software operates. The operating system drivers  604  provide drivers for the wireless device hardware with standardized interfaces that are accessible to application software. The operating system drivers  604  include application management services (“AMS”)  606  that transfer control between applications running on the UE  10 . Also shown in  FIG. 8  are a web browser application  608 , a media player application  610 , and Java applets  612 . The web browser application  608  configures the UE  10  to operate as a web browser, allowing a user to enter information into forms and select links to retrieve and view web pages. The media player application  610  configures the UE  10  to retrieve and play audio or audiovisual media. The Java applets  612  configure the UE  10  to provide games, utilities, and other functionality. A component  614  might provide functionality related to RI transmission during DRX as described herein. Although the component  614  is shown in  FIG. 8  at an application software level, the component  614  may be implemented at a lower system level than is illustrated in  FIG. 8 . 
     Some aspects of the system  100  described above may be implemented on any general-purpose computer with sufficient processing power, memory resources, and network throughput capability to handle the necessary workload placed upon it.  FIG. 9  illustrates a typical, general-purpose computer system suitable for implementing aspects of one or more embodiments disclosed herein. The computer system  680  includes a processor  682  (which may be referred to as a central processor unit or CPU) that is in communication with memory devices including secondary storage  684 , read only memory (ROM)  686 , random access memory (RAM)  688 , input/output (I/O) devices  690 , and network connectivity devices  692 . The processor  682  may be implemented as one or more CPU chips. 
     The secondary storage  684  is typically comprised of one or more disk drives or tape drives and is used for non-volatile storage of data and as an over-flow data storage device if RAM  688  is not large enough to hold all working data. Secondary storage  684  may be used to store programs which are loaded into RAM  688  when such programs are selected for execution. The ROM  686  is used to store instructions and perhaps data which are read during program execution. ROM  686  is a non-volatile memory device which typically has a small memory capacity relative to the larger memory capacity of secondary storage. The RAM  688  is used to store volatile data and perhaps to store instructions. Access to both ROM  686  and RAM  688  is typically faster than to secondary storage  684 . 
     I/O devices  690  may include printers, video monitors, liquid crystal displays (LCDs), touch screen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, or other well-known input devices. 
     The network connectivity devices  692  may take the form of modems, modem banks, ethernet cards, universal serial bus (USB) interface cards, serial interfaces, token ring cards, fiber distributed data interface (FDDI) cards, wireless focal area network (WLAN) cards, radio transceiver cards such as code division multiple access (CDMA) and/or global system for mobile communications (GSM) radio transceiver cards, and other well-known network devices. These network connectivity devices  692  may enable the processor  682  to communicate with an Internet or one or more intranets. With such a network connection, it is contemplated that the processor  682  might receive information from the network, or might output information to the network in the course of performing the above-described method steps. Such information, which is often represented as a sequence of instructions to be executed using processor  682 , may be received from and outputted to the network, for example, in the form of a computer data signal embodied in a carrier wave. The network connectivity devices  692  may also include one or more transmitter and receivers for wirelessly or otherwise transmitting and receiving signal as are well know to one of ordinary skill in the art. 
     Such information, which may include data or instructions to be executed using processor  682  for example, may be received from and outputted to the network, for example, in the form of a computer data baseband signal or signal embodied in a carrier wave. The baseband signal or signal embodied in the carrier wave generated by the network connectivity devices  692  may propagate in or on the surface of electrical conductors, in coaxial cables, in waveguides, in optical media, for example optical fiber, or in the air or free space. The information contained in the baseband signal or signal embedded in the carder wave may be ordered according to different sequences, as may be desirable for either processing or generating the information or transmitting or receiving the information. The baseband signal or signal embedded in the carrier wave, or other types of signals currently used or hereafter developed, referred to herein as the transmission medium, may be generated according to several methods well known to one skilled in the art. 
     The processor  682  executes instructions, codes, computer programs, scripts which it accesses from hard disk, floppy disk, optical disk (these various disk based systems may all be considered secondary storage  684 ), ROM  686 , RAM  688 , or the network connectivity devices  692 . While only one processor  682  is shown, multiple processors may be present. Thus, while instructions may be discussed as executed by a processor, the instructions may be executed simultaneously, serially, or otherwise executed by one or multiple processors. 
     While several embodiments, have been provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented. 
     Also, techniques, systems, subsystems and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.