Patent Publication Number: US-9894706-B2

Title: Toggling discontinuous reception in wireless communications

Description:
TECHNICAL FIELD 
     The present disclosure is directed to communications systems and, more particularly, methods, network nodes, user equipment nodes, and systems for discontinuous reception in wireless communications systems. 
     BACKGROUND 
     In a 3GPP Long Term Evolution (LTE) network architecture, handover of a User Equipment node (UE) takes place between Evolved NodeBs (eNBs). A eNB where a User Equipment (UE) is currently located is called a Source eNB (S-eNB). A eNB to which the UE is handed over is called a Target eNB (T-eNB). Handover is a process of handing over the UE from a cell controlled by the S-eNB to a cell controlled by the T-eNB. 
       FIG. 1  illustrates operations and sequences of messages performed by components of a telecommunications system for handover. Referring to  FIG. 1 , as a user equipment node (UE) moves into the coverage area of a cell in the T-eNB, it sends a Measurement Report. The Measurement Report triggers a sequence of handover related events by the T-eNB, the S-eNB, and the core network and eventually further involves the UE for handover. 
     In order to transmit a measurement report over an uplink shared (UL-SCH) channel, the UE must have Physical Uplink Shared Channel (PUSCH) resources. For that purpose the UE reports its buffer status by a buffer status report (BSR). The UE begins by first sending a Scheduling Request. 
       FIG. 2  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates when a drx-InactivityTimer is started and restarted. The sequence of events in  FIG. 2  includes the UE sending a dedicated scheduling request (D-SR) on a Physical Uplink Control Channel (PUCCH). The UE then remains discontinuous reception (DRX) Active, i.e. continuously receiving, while the SR is pending, i.e. until the UE receives a grant on PUSCH or, whichever occurs first, until the UE exhausts a maximum number of attempts (not shown). The UE receives the UL grant and starts a drx-InactivityTimer to further prolong the DRX Active Time. The UE uses the UL grant in accordance with standardized priorities and logical channel prioritization. The BSR describes the size of each buffer in the UE and has highest priority. The radio access network acknowledges the data received on UL-SCH and grants in accordance with the BSR. Once again; the drx-InactivityTimer is started (or restarted). The size of the grant is now large enough for the UE to include the Measurement Report. The sequence ends as orchestrated by the L1/L2 layers of the network, with the UE acknowledging data received and passing the data onwards to its RRC layers. The UE starts (or restarts) the drx-InactivityTimer each time the Physical Downlink Control Channel (PDCCH) indicates a new transmission (DL or UL). 
     As used herein, the term “Active Time” can be the time related to DRX operation, such as defined in subclause 5.7 of 3GPP TS 36.321, during which the MAC entity monitors the PDCCH. The term “DRX Cycle” can be the periodic repetition of the On Duration followed by a possible period of inactivity. The term “drx-InactivityTimer” can be the number of consecutive PDCCH-subframe(s) after the subframe in which a PDCCH indicates an initial UL, DL or SL user data transmission for this MAC entity. 
     There is also a case when PUCCH has not been provisioned, where instead the UE must first use the random access procedure to resynchronize by sending a Random Access SR (RA-SR). 
       FIG. 3  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates starting of a drx-InactivityTimer. The illustrated sequence of events is similar to that of D-SR. In both cases, the Active Time is limited by the drx-InactivityTimer. This timer has been pre-configured by RRC using the current values.  FIG. 4  illustrates an example DRX-configuration data structure according to 3GPP TS 36.331 E-UTRA RRC. 
     A goal of DRX is to conserve battery energy in the UE, including by providing the briefest possible phases of receive Active time when a UE is configured to receive from an eNB. Handover is essential for retainability in a mobile communication network. Handover is usually performed at radio coverage borders and requires as good communication path as possible so that the Handover procedures can be performed quickly and reliably. For this purpose, handover procedures need longer phases of continuous receive Active time than are optimal from a battery saving point of view. 
       FIG. 5  illustrates two events at times t 1  and t 2  during the handover phase which can be essential to have good communication between the S-eNB and the UE, and to retain the UE. The timer must be sufficiently long so that the Active time does not end ahead of time t 2 , which would otherwise result in the UE moving back to DRX sleep which ceases its ability to receive and, thus, cannot be reached by the S-eNB until next a time the UE is awake and ready to receive.  FIG. 6  illustrates two events at times t 1  and t 2  during the handover phase. In the example of  FIG. 6 , the timer expires before a RRCConnectionReconfiguration message is received at time t 2  from the S-eNB resulting in handover failure. 
     A current approach to attempt to avoid this problem is to use larger timer values (or alternatively to use short repetition cycles), which results in larger handover success rate and better Key Performance Indicator (KPI) retainability but is an unfavorable compromise for DRX with regards to the communication overhead required from the end points providing data services. 
     Table 1 lists some example compromise DRX schemes. Larger timer values and/or shorter cycles are used for situations where greater robustness for handover is needed. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Service 
                 Load 
                 Timer 
                 Cycle 
               
               
                   
                   
               
             
            
               
                   
                 Mixed MBB 
                 Low 
                 psf100 
                 sf320 
               
               
                   
                 Mixed MBB 
                 High 
                 psf200 
                 sf320 
               
               
                   
                 VoLTE 
                 Low 
                 psf1 
                 sf40 
               
               
                   
                 VoLTE 
                 High 
                 psf5 
                 sf20 
               
               
                   
                   
               
            
           
         
       
     
     In Table 1 the services correspond to service specific DRX biased by handover, the timer values are used to configure the drxInactivityTimer, and the cycle values are used to configure the cycle length associated with the longDRX-CycleStartOffset. The term VoLTE refers to voice over LTE, and the term MBB refers to mobile broadband. 
     There is a continuing problem to address the collision of interests between DRX and handover. The problem is particularly challenging with services that affect VoLTE performance. Service specific DRX increases packet delays and dropped packets, and increases the risk of dropped calls. Moreover, DRX may be tuned in a way that provides insufficient battery lifetime. 
     Mixed MBB is known to be very bursty with just occasional appearance of small amounts of traffic. Larger timer values, such as 100 ms or 200 ms, defeat many of the goals of DRX because the ever-lasting data tails repeatedly restart the timer before 100 ms or 200 ms has passed. 
     The negative consequences can be worse and more accentuated for paced services where smaller inactivity timers and larger cycles would otherwise provide much improved battery-savings without sacrificing service QoE. Table 2 lists three examples when service-specific DRX is not biased by handover needs and is better tuned to the services. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Service 
                 Timer 
                 Cycle 
               
               
                   
                   
               
             
            
               
                   
                 Mixed MBB 
                 psf5 
                 sf80 
               
               
                   
                 Paced MBB 
                 psf2 
                 sf640 
               
               
                   
                 VoLTE 
                 psf1 
                 sf40 
               
               
                   
                   
               
            
           
         
       
     
     In Table 2 the services correspond to service specific DRX biased. The time values are used to configure the drxInactivityTimer, and the cycle values are used to configure the cycle length associated with the longDRX-CycleStartOffset. 
     VoLTE provides managed voice which is a core value for the mobile network operator. Competition to VoLTE from Over the Top (OTT) competition, e.g. from Skype or FaceTime, increases the importance of VoLTE performance. Various approaches for increasing VoLTE performance can involve complex retransmission schemes which are unfavorable to both battery economy and handover performance. 
     It can be harder to find an acceptable compromise for Paced MBB. Paced MBB is important to operators in view of the overwhelming bulk of existing traffic which is handled as Paced MBB. An example of Paced MBB is streaming video such as Youtube or Netflix. Due to user abandonment, it is usually not a good approach to transfer too much content, e.g. a Youtube clip, at once but instead a better approach can be to pace the content. For this purpose efficient DRX schemes are needed which allow a client to quickly fill up a playout buffer and then pace such occasions. Streaming traffic over mobile networks, such as LTE, has been a substantial load on the mobile networks and data volumes are continuing to increase. The current trend suggests that more than half of all traffic over mobile internet will be streaming video. 
     Table 2 suggests that it may be better to select shorter timers instead of any compromise timers, and to use service-specific cycles instead of the timers that better serve handover. For example, with VoLTE the nature of the voice over IP service is well-defined and allows for matching of the regularity of DRX with that of voice packet arrivals. A shorter cycle can be used because although the UE moves back to DRX sleep quite shortly after t 1  it will wake up with shorter regularity. Shorter cycles can be viewed as an opportunity to increase quality of communication, but could negatively affect performance. Shorter cycles, such as 40 ms, increase packet delays and dropped packets. The risk of dropped calls is always higher as a result of discontinued opportunities to communicate. 
     Operators now occasionally use approaches that manually toggle cell configuration and use the more robust values whenever higher load situations are expected to occur, such as from larger venues and user concentrations. These approaches can be cumbersome to implement. The approach may be difficult to tailor for an individual user&#39;s coverage since there is always a tail to the duration required for a procedure. The individual coverage or load situation may grow worse than what is expected in average and might require even more extended Active time for proper communication. 
     The approaches described in the Background section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in the Background section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in the Background section. 
     SUMMARY 
     Some embodiments of the present disclosure are directed to a method by a user equipment node (UE) for discontinuous reception (DRX) of traffic from a source radio access network (S-RAN) node of a telecommunications system. The method includes determining whether a condition has occurred that can trigger initiation of handover to a target RAN (T-RAN) node. Based on determining that the condition has not occurred, a selection is made among a plurality of service-specific DRX configurations based on a service type of the traffic from the S-RAN node, and DRX by the UE of traffic from the S-RAN node is controlled based on the selected service-specific DRX configuration. Based on determining that the condition has occurred, DRX by the UE of traffic from the S-RAN node is controlled based on a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     A potential advantage of this approach is that it can provide coupling between DRX configuration schemes and a required level of connection robustness. When a condition occurs which can trigger initiation of handover to a target RAN, the UE ceases selecting among service-specific DRX configurations and begins using a service-agnostic DRX configuration that can improve UE messaging responsiveness and avoid the UE being dropped by the radio access network. The UE may begin to continuously receive messages from the S-eNB responsive to the service-agnostic DRX configuration, which can improve its operational reliability particularly during conditions of poor signal quality. When the condition no longer occurs, such as due to improved signal quality, the UE can resume selecting among service-specific DRX configurations to extend its battery life. 
     Some other embodiments of the present disclosure are directed to a UE providing DRX of traffic from a S-RAN node of a telecommunications system. The UE includes at least one processor, and at least one memory coupled to the at least one processor. The at least one processor includes computer readable program code embodied in the at least one memory that when executed by the at least one processor causes the at least one processor to perform operations. The operations include determining whether a condition has occurred that can trigger initiation of handover to a T-RAN node. Based on determining that the condition has not occurred, the operations include selecting among a plurality of service-specific DRX configurations based on a service type of the traffic from the S-RAN node, and controlling DRX by the UE of traffic from the S-RAN node based on the selected service-specific DRX configuration. Based on determining that the condition has occurred, the operations include controlling DRX by the UE of traffic from the S-RAN node based on a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     Some other embodiments of the present disclosure are directed to a UE providing DRX of traffic from a S-RAN node of a telecommunications system. The UE includes a determining module, a selecting module, and a controlling module. The determining module is for determining whether a condition has occurred that can trigger initiation of handover to a T-RAN node. The selecting module is for, based on determining that the condition has not occurred, selecting among a plurality of service-specific DRX configurations based on a service type of the traffic from the S-RAN node, and controlling DRX by the UE of traffic from the S-RAN node based on the selected service-specific DRX configuration. The controlling module is for, based on determining that the condition has occurred, controlling DRX by the UE of traffic from the S-RAN node based on a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     Some other embodiments of the present disclosure are directed to a method by a S-RAN node of a telecommunications system for controlling DRX by a UE of traffic from the S-RAN node. The method includes receiving a message from the UE. The method further includes, based on content of the message from the UE, sending a message to the UE containing a request for the UE to suspend control of DRX which uses selections among a plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node, and for the UE to initiate control of DRX that will use a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     Some other embodiments of the present disclosure are directed to a S-RAN node of a telecommunications system for controlling DRX by a UE of traffic from the S-RAN node. The S-RAN node includes at least one processor and at least one memory coupled to the at least one processor and including computer readable program code embodied in the at least one memory that when executed by the at least one processor causes the at least one processor to perform operations. The operations include receiving a message from the UE, and, based on content of the message from the UE, sending a message to the UE containing a request for the UE to suspend control of DRX which uses selections among a plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node, and for the UE to initiate control of DRX that will use a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     Some other embodiments of the present disclosure are directed to a S-RAN node of a telecommunications system for controlling DRX by a UE of traffic from the S-RAN node. The S-RAN node includes a receiving module and a sending module. The receiving module is for receiving a message from the UE. The sending module is for, based on content of the message from the UE, sending a message to the UE containing a request for the UE to suspend control of DRX which uses selections among a plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node, and for the UE to initiate control of DRX that will use a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     Other methods, user equipment, and radio access networks according to embodiments of the invention will be apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional methods, user equipment, and radio access networks be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. Moreover, it is intended that all embodiments disclosed herein can be implemented separately or combined in any way and/or combination. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiment(s) of inventive concepts. In the drawings: 
         FIG. 1  illustrates operations and messaging between a UE, a T-eNB, S-eNB, and core network components of a telecommunications system to prepare for handover; 
         FIG. 2  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates when a drx-InactivityTimer is started and restarted; 
         FIG. 3  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates starting of a drx-InactivityTimer; 
         FIG. 4  illustrates a DRX-configuration data structure according to 3GPP TS 36.331 E-UTRA RRC; 
         FIG. 5  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates when a drx-InactivityTimer is started and restarted; 
         FIG. 6  illustrates operations and messaging between a UE and S-eNB of a radio access network for sending measurement reports in preparation for handover, and illustrates when a drx-InactivityTimer expires before being restarted; 
         FIG. 7  illustrates operations and messaging between a UE and S-eNB of a radio access network for providing explicity control by the S-eNB over UE switching between using service-specific DRX configurations and a service-agnostic DRX configuration which is used to control DRX by the UE of traffic from the S-eNB according to embodiments of a first approach disclosed herein; 
         FIG. 8  illustrates operations and messaging between a UE and S-eNB of a radio access network for providing explicity control by the S-eNB over UE switching between using service-specific DRX configurations and a service-agnostic DRX configuration which is used to control DRX by the UE of traffic from the S-eNB according to embodiments of the second approach disclosed herein; 
         FIG. 9  illustrates content of an example switch message sent from the S-eNB to a UE according to embodiments of the second approach disclosed herein; 
         FIG. 10  illustrates content of another example switch message sent from the S-eNB to a UE according to embodiments of the second approach disclosed herein; 
         FIG. 11  illustrates operations and message flows that can be performed by the S-eNB and the UE for a SWITCH message to be communicated through MAC, such as by inband MAC according to embodiments of the second approach disclosed herein; 
         FIG. 12  illustrates operations and messaging that implicitly trigger a UE to switch from the service-specific DRX configuration to the robust service-agnostic DRX configuration for receiving from a S-eNB according to embodiments of a third approach disclosed herein; 
         FIGS. 13-22  are flowcharts of operations and methods performed by a UE for DRX of traffic from a source radio access network (S-RAN) node of a telecommunications system, according to some embodiments; 
         FIGS. 23-26  are flowcharts of operations and methods performed by a S-RAN node of a telecommunications system for controlling DRX by a UE of traffic from the S-RAN node, according to some embodiments; 
         FIG. 27  is a block diagram of a UE according to some embodiments; 
         FIG. 28  is a block diagram of a RAN node according to some emobidments; 
         FIG. 29  is a block diagram of functional modules that may be implemented within a UE according to some embodiments; and 
         FIG. 30  is a block diagram of functional modules that may be implemented within a RAN node according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which examples of embodiments of inventive concepts are shown. Inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present inventive concepts to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present/used in another embodiment. 
     Various present embodiments disclosed herein may overcome one or more of the potential problems explained above with some previously known approaches. Some embodiments are directed to providing a coupling between DRX configuration schemes and a required level of connection robustness. More specifically, unless a condition occurs which can trigger initiation of handover (e.g., a defined robustness event has not occurred and the connection quality is good), the UE operates in a mode configured to use a first DRX configuration. This mode configuration is service specific and optimized for battery savings with respect to the user services used; e.g. Mixed MBB, VoLTE or Paced MBB. In contrast, as soon as the condition occurs (e.g., when it would be better to keep a tighter connection between the UE and the network), the UE switches to operate in another mode that is configured to start using a second DRX configuration which provides more robust communications. While the other mode configuration provides less optimal battery savings it can be configured to provide a faster and more reliable communication path to the UE. The opposite switch from the other mode configuration back to the service specific configuration is done when the condition ceases to occur and the connection is again good. Operations and messsages associated with three example approaches are explained below. 
     A S-eNB is also referred to herein as a non-limiting example of a S-RAN node. Similarly, a T-eNB is also referred to herein as a non-limiting example of a T-RAN node. 
       FIGS. 13-16  are flowcharts of operations and methods performed by a UE for DRX of traffic from a S-RAN node of a telecommunications system. The operations and methods of  FIGS. 13-16  can apply to all three of the example approaches explained below. 
     Referring to  FIG. 13 , the UE determines (block  1300 ) whether a condition has occurred that can trigger initiation of handover to a T-RAN node. The condition may correspond to mobility events which occurs when the UE starts or ceases to “move out of coverage from the serving cell”. Based on determining (block  1302 ) that the condition has not occurred, the UE selects (block  1304 ) among a plurality of service-specific DRX configurations based on a service type of the traffic from the S-RAN node, and controls DRX by the UE of traffic from the S-RAN node based on the selected service-specific DRX configuration. In contrast, based on determining (block  1302 ) that the condition has occurred, the UE controls (block  1306 ) DRX of traffic from the S-RAN node based on a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. When the UE controls (block  1306 ) DRX based on a service-agnostic DRX configuration, it may suspend DRX to allow continuous receiving (e.g., of any PDCCH assignments from a network node, such as the S-eNB or, after handover, the T-eNB). 
     Referring to  FIG. 14 , when controlling (block  1306 ) DRX, the UE can define (block  1400 ), e.g., initiatize, a drx-inactivity timer value based on the service-agnostic DRX configuration, and control (block  1402 ) duration of continuous reception by the UE based on the drx-inactivity timer value irrespective of whether a service type of the traffic from the S-RAN node changes while using the service-agnostic DRX configuration. 
     Alternatively, when controlling (block  1306 ) DRX, the UE can suspend the selecting (block  1304 ) among the plurality of service-specific DRX configurations irrespective of any changes in a service type of the traffic from the S-RAN node. 
     Referring to  FIG. 15 , based on determining that another condition has occurred that can trigger cessation of handover to the T-RAN node, the UE can cease (block  1500 ) controlling DRX based on the service-agnostic DRX configuration and resume controlling DRX based on one of the plurality of service-specific DRX configurations based on characteristics of traffic from the S-RAN node. 
     Similarly, Referring to  FIG. 16 , based on determining that another condition has occurred based on completing handover to the T-RAN node, the UE can cease (block  1600 ) controlling DRX based on the service-agnostic DRX configuration and resume selecting among a plurality of service-specific DRX configurations based on characteristics of traffic from the T-RAN node to use to control DRX by the UE. 
     Potential advantages of these embodiments may include increasing UE retainability (fewer dropped connections and fewer attempts to re-establish the connection) while also improving DRX for battery savings, which can improve user satisfaction with the UE. The connection provides a more robust communication when that is needed and fewer packets are dropped or delayed beyond their time budget. During times when instead there is no need for such robustness, DRX can use service-specific DRX configurations that are better tuned to providing maximum battery economy. These improvements can be particularly important to network operators who can have difficult to achieve targets for their KPI Key Performance Indicator that monitors dropped calls/connections. 
     Three example approaches are described below for controlling DRX of a UE. The first two approaches are directed to a radio access network explicitly controlling a UE via messaging to suspend the UE&#39;s selections among service-specific DRX configurations. The third approach is directed to the UE being implicitly controlled responsive to the UE determining that a defined condition (event) has occurred that triggers the UE to suspend its selections among service-specific DRX configurations. 
     Approach 1— 
     One approach for controlling a UE&#39;s use of DRX can include using standard procedures to enable a radio access network to start an immediate explicit reconfiguration of DRX with Information Element (IE) DRX-Config.  FIG. 7  illustrates operations and messages by a UE  2700  and a S-eNB  2800  of a radio access network  2750  that explicitly trigger the UE  2700  to suspend use of a service-specific DRX configuration and initiate use of a robust service-agnostic DRX configuration. the UE  2700  responds to a reconfiguration (e.g., RRCConnectionReconfiguration message) from the S-eNB  2800  by suspending use of a service-specific DRX configuration and initiate use of a robust service-agnostic DRX configuration. The IE DRX-Config may be tuned to robust finite values or set to a value release (see Table 3). The UE  2700  is controlled to resume use of a service-specific DRX based on another reconfiguration (e.g., RRCConnectionReconfiguration message) controlled by a T-eNB  2900  after handover of the UE  2700 . 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Service 
                 Timer 
                 Cycle 
               
               
                   
                   
               
             
            
               
                   
                 Service-agnostic 1 
                 &gt;psf2560 
                 Any value 
               
            
           
           
               
               
               
               
            
               
                   
                 Service-agnostic 2 
                 drx release 
               
               
                   
                   
               
            
           
         
       
     
     In Table 3 the services are agnostic to DRX, the time values are used to configure the drxInactivityTimer, and the cycle values are used to configure the cycle length associated with the longDRX-CycleStartOffset. It is noted that the max time value for use in some prior art systems is 2560 ms. 
     This approach may undesirably add substantial signaling to many communication paths, and add redundant signaling to paths that did not need or could not make necessary preparation for handover. Moreover, signaling is needed to restart service-specific DRX, e.g., 100 ms later, when the UE has synchronized to the T-eNB or when the communication path for some other reason no longer needs to be as robust. In the previous case, the required Drx-config can be merged with signaling that is needed for other reasons but in the latter case even more redundant signaling is added. 
     Approach 2— 
     According to another approach, the radio access network maintains direct explicit control over the UE switching from selecting among service-specific DRX configurations and to instead using a robust service-agnostic DRX configuration. This approach may provide more immediate control of the switching and use less extensive messages for control than the first approach.  FIGS. 8-10  illustrate an embodiment of this approach which uses an extension to the Medium Access Control (MAC) protocol to provide improvements over the RRC approach of  FIG. 7 . The radio access network  2750  communicates with the UE using the MAC protocol to control scheduler interaction with DRX. 
       FIG. 8  illustrates operations and messages that explicitly trigger the UE  2700  to suspend its use of the service-specific DRX configuration operation and instead use the robust service-agnostic DRX configuration.  FIG. 9  illustrates an example SWITCH message that can be sent from the S-eNB  2800  of the radio access network  2750  to the UE  2700  to cause the UE  2700  to suspend its use of the service-specific DRX configuration operation. The example SWITCH message has a fixed size of 2 bytes and has the following fields:
         N: The Next field can be one bit. The N field in the example switch message is set to 1 to indicate that the format of the second byte is PMT and PMB;   PFT: The Protocol Feature Type field can be 7 bits. The PFT can be set to the value used in the first byte of INITIAL MESSAGE;   PMT: The Protocol Message Type field size can be 3 bits. The PMT in the SWITCH message can be set to 001; and   PMB: The Protocol Message Body for the switch message on DL-SCH can be as shown in  FIG. 10 .       

     The example format of the SWITCH message of  FIGS. 9 and 10  is provided for completeness and without limitation to other formats of SWITCH messages that can be used herewith. Any SWITCH message format can be used that contains one or more bits configured to explicitly trigger the UE  2700  to suspend its use of the service-specific DRX configuration operation and instead use the robust service-agnostic DRX configuration. 
     Referring to  FIG. 10 , the size of the PMB for the switch message can be 5 bits and have the following fields:
         DC: The DC field can be 4 bits which indicates a DRX configuration; and   PC: The PC field can be a flag with an implication that depends on DC (e.g., not used here).       

       FIG. 11  illustrates operations and message flows that can be performed by the radio access network  2750  and the UE  2700  for a SWITCH message to be communicated through MAC, such as by inband MAC. A trigger condition for sending the SWITCH message can be the reception of a BSR asking for a grant related to DCCH or the reception of a MAC PDU with a DCCH content (see ( 1 ) and ( 2 ) in  FIG. 11 ), or assisted by a quick termination by higher layer (see ( 3 ) in  FIG. 11 ). Sending of the SWITCH message could also be triggered by a request X or Y ( FIG. 11 ) from the UE which is sent in the same PDU as that which contains the BSR (X in  FIG. 11 ) or the Measurement Report (Y in  FIG. 11 ). 
       FIGS. 17-20  are flowcharts of more general operations and methods performed by a UE for DRX of traffic from a S-RAN node of a telecommunications system, according to one or both of the first and second approaches. 
     In the further embodiment of  FIG. 17 , the UE determines (block  1700 ) that the condition has occurred which can trigger initiation of handover to a T-RAN node based on receiving a control message from the S-RAN node, where the control message contains DRX configuration data. The UE uses the DRX configuration data to define (block  1702 ) the service-agnostic DRX configuration which is used to control DRX of traffic from the S-RAN node. 
     The DRX configuration data may contain a flag, index, or pointer to a service-agnostic DRX configuration already stored in memory of the UE, or the DRX configuration data may contain information that defines the service-agnostic DRX configuration for storage in the UE. The UE may control duration of continuous reception by the UE based on a drx-inactivity timer value that is defined based on the DRX configuration data. 
     In the further embodiment of  FIG. 18 , the UE determines (block  1800 ) whether an entering condition has occurred for triggering reporting of measurements to the S-RAN node. Based on determining that the entering condition has occurred, the UE initiates (block  1802 ) reporting of measurements to the S-RAN node, where at least one of the reports contains a request for the S-RAN node to suspend the UE&#39;s use of the service-specific DRX configurations. The UE can then determine that the condition has occurred which can trigger initiation of handover to a T-RAN node based on receiving (block  1804 ) a message from the S-RAN node controlling the UE to suspend the selecting among the plurality of service-specific DRX configurations irrespective of any changes in a service type of the traffic from the S-RAN node. 
     In the further embodiment of  FIG. 19 , the UE determines (block  1900 ) whether a leaving condition has occurred for ceasing the reporting of measurements to the S-RAN node. Based on determining that the leaving condition has occurred, the UE sends (block  1902 ) a control message to the S-RAN node indicating that the leaving condition has occurred and requests the S-RAN node to resume the UE&#39;s use of the service-specific DRX configurations. Based on receiving a message from the S-RAN node requesting resumption of the UE&#39;s use of the service-specific DRX configurations, the UE ceases (block  1904 ) the controlling DRX based on the service-agnostic DRX configuration and resumes controlling DRX based on one of the plurality of service-specific DRX configurations selected based on characteristics of traffic from the S-RAN node. 
     In the further embodiment of  FIG. 20 , the UE receives (block  2000 ) a switch message via a medium access control (MAC) protocol from the S-RAN node. The switch message contains a request to suspend the UE&#39;s use of the service-specific DRX configurations. Based on the request, the UE suspends (block  2002 ) use of the service-specific DRX configurations for controlling DRX and initiates controlling DRX of traffic from the S-RAN node based on the service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
       FIGS. 23-26  are flowcharts of related operations and methods performed by a S-RAN node of a telecommunications system for controlling DRX by a UE of traffic from the S-RAN node, according to one or both of the first and second approaches. 
     In the further embodiment of  FIG. 23 , the S-RAN node receives (block  2300 ) a message from the UE. Based on content of the message from the UE, the S-RAN sends (block  2302 ) a message to the UE containing a request for the UE to suspend control of DRX which uses selections among a plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node, and for the UE to initiate control of DRX that will use a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. 
     In the further embodiment of  FIG. 24 , when sending (block  2302 ) the message to the UE containing the request, the S-RAN node may send (block  2400 ) the message to the UE based on determining that the message received from the UE contains an indication that an entering condition has occurred for triggering reporting of measurements in measurement reports to the S-RAN node. 
     With reference to  FIGS. 23-25 , the S-RAN node determines (block  2500 ) that another message received from the UE contains an indication that a leaving condition has occurred for ceasing the reporting of measurements in measurement reports to the S-RAN node. Based on determining (block  2500 ) that the leaving condition has occurred, the S-RAN node sends (block  2502 ) another message to the UE containing a request for the UE to cease control of DRX which uses the service-agnostic DRX configuration and to resume control of the DRX which uses selections among the plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node. 
     The message received (block  2300 ) from the UE can include a measurement report. The step of sending (block  2400 ) the message to the UE containing the request can include sending the message to the UE based on determining that the measurement report contains a measurement of signals received by the UE that satisfies a condition for initiating handover of the UE to a T-RAN node. 
     The message sent (block  2400 ) to the UE containing the request, can include DRX configuration data that the UE uses to determine the service-agnostic DRX configuration. 
     In the further embodiment of  FIG. 26 , the step of sending (block  2302 ) the message to the UE ( 2700 ) containing the request, can include the S-RAN node determining (block  2600 ) that the message received from the UE contains a request for the S-RAN node to suspend the UE&#39;s use of the service-specific DRX configurations. Based on the request, the S-RAN node sends (block  2602 ) the message to the UE containing the request for the UE to suspend control of DRX which uses selections among the plurality of service-specific DRX configurations, and for the UE to initiate control of DRX that will use the service-agnostic DRX configuration. 
     Approach 3— 
     According to another approach, the UE is configured to determine when a defined condition occurs that can trigger initiation of handover to a T-eNB (or other T-RAN node) without requiring explicit signalling from a radio access network. The defined condition can correspond to one or more defined robustness events which the UE monitors to determine when it will implicitly switch from using the service-specific DRX configuration to using the robust service-agnostic DRX configuration. The robustness events may be one or more of the same mobility events which occur when the UE starts or ceases to “move out of coverage from the serving cell”. In one embodiment, the robust DRX configuration may preferrably be one where DRX is released (suspended until further notice). 
       FIG. 12  illustrates operations and messages that implicity trigger a UE  2700  to switch from the service-specific DRX configuration to the robust service-agnostic DRX configuration for receiving from a S-eNB  2800  (or other S-RAN node).  FIGS. 21 and 22  are flowcharts of operations and methods that may be performed by a UE for DRX of traffic from a S-RAN node (e.g., S-eNB  2800 ) according to some embodiments of this approach. Referring to  FIG. 21 , when determining whether the condition has occurred that can trigger initiation of handover to the T-RAN node (e.g., T-eNB  2900 ), the UE can determine (block  2100 ) whether an entering condition has occurred for triggering reporting of measurements to the S-RAN node. The entering condition is also called an entering condition. The UE can can then control (block  2102 ) DRX of traffic from the S-RAN node using the service-agnostic DRX configuration, based on determining that the entering condition has occurred. 
     Referring to  FIG. 22 , the UE may furthermore determine (block  2200 ) whether a leaving condition has occurred for ceasing the reporting of measurements to the S-RAN node. Based on determining that the leaving condition has occurred, the UE can cease (block  2202 ) controlling DRX using the service-agnostic DRX configuration and resume control of DRX using one of the plurality of service-specific DRX configurations selected based on characteristics of traffic from the S-RAN node. 
     Some of the operations may be performed using some existing protocol specifications, which may thereby add one more action to the list of UE actions performed responsive to detecting events that may trigger handover or, in the context of various of the present approaches, may require a robust communication path. The UE may determine (block  2100  of  FIG. 21 ) whether an entering condition has occurred for triggering reporting of measurements to the S-RAN node based on 3GPP TS 36.331 including, but are not limited to, any one or more of Event A2, Event A3, Event A5, Event A6, Event B1, and Event B2. 
     For Event A2, the UE determines (block  2100 ) if the S-eNB has become worse than a defined threshold. The UE performs measurements on signals received from the S-RAN node (service cell), which may be Reference Signal Received Quality (RSRQ) and/or Reference Signal Received Power (RSRP), and which may be performed without taking into account any offsets. RSRP can be measured as an average of power levels received across all Reference Signal symbols within the considered measurement frequency bandwidth. The UE compares the measurements to a defined threshold value, which may be defined within a reportConfigugEUTRA message, to determine when Event A2 (entering condition for reporting) has occurred. The UE may combine each measurement value (Ms) with a hysteresis parameter (Hys) for this event, and compare the result to a threshold value (Thresh) to determine whether the comparison satisfies Event A2 (entering condition for reporting). The threshold value and the hysteresis value may be defined by a reportConfigugEUTRA message received by the UE from the network for Event A2. 
     For example, the UE can determine that an entering condition for the Event A2 is satisfied (has occurred) when the following condition is satisfied:
 
 Ms+Hys&lt;Thresh.   Inequality A2-1 (Entering condition)
 
     The UE can determine that a leaving condition for the Event A2 is satisfied (has occurred) when the following condition is satisfied
 
 Ms−Hys&gt;Thresh.   Inequality A2-2 (Leaving condition)
 
     For Event A3, the UE determines if a neighbor eNB, e.g., T-eNB, has become an offset amount better than the Primary Cell (PCell), e.g., S-eNB, or Primary Secondary Cell (PSCeII). The UE can determine that an entering condition for the Event A3 is satisfied (has occurred) when the following condition is satisfied:
 
 Mn+Ofn+Ocn−Hys&gt;Mp+Ofp+Ocp+Off.   Inequality A3-1 (Entering condition)
 
     The UE can determine that a leaving condition for the Event A3 is satisfied (has occurred) when the following condition is satisfied
 
 Mn+Ofn+Ocn+Hys&lt;Mp+Ofp+Ocp+Off.   Inequality A3-2 (Leaving condition)
 
     In the conditional equations for Event A3, the terms have the following meanings:
         1) Mn is the measurement result of the neighboring cell, not taking into account any offsets;   2) Ofn is the frequency specific offset of the frequency of the neighboring cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell);   3) Ocn is the cell specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbour cell), and set to zero if not configured for the neighbour cell;   4) Mp is the measurement result of the PCell/PSCeII, not taking into account any offsets;   5) Ofp is the frequency specific offset of the frequency of the PCell/PSCell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the PCell/PSCeII);   6) Ocp is the cell specific offset of the PCell/PSCeII (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the PCell/PSCeII), and is set to zero if not configured for the PCell/PSCeII;   7) Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event); and   8) Off is the offset parameter for this event (i.e. a3-Offset as defined within reportConfigEUTRA for this event).       

     The UE can respond to a comparison satisfying the entering condition by suspending use of the service-specific DRX configurations for controlling DRX of traffic from the S-RAN node and initiate use of the service-agnostic DRX configuration to control DRX. In constrast, the UE can respond to a comparison satisfying the leaving condition by ceasing use of the service-agnostic DRX configuration to control DRX of traffic from the S-RAN node and resume using selections among the service-specific DRX configurations to control DRX. 
     For Event A5, the UE determines if a PCell, e.g., S-eNB, or PSCeII has become worse than a first threshold value (threshold 1 ) and a neighbor eNB has become better than a second threshold value (threshold 2 ). For example, the UE can perform measurements on signals received from the S-RAN node and perform measurements on signals received from the T-RAN node. The UE can determine whether comparison of the measurements on signals satisfies the entering condition for the Event A5 is satisfied (has occurred) when the following two conditions are satisfied:
 
 Mp+Hys&lt;Thresh 1  Inequality A5-1 (Entering condition 1)
 
 Mn+Ofn+Ocn−Hys&gt;Thresh 2  Inequality A5-2 (Entering condition 2)
 
     Thus, for example, the UE can determine whether comparison of the measurements on signals received from the S-RAN node to a first threshold (Thresh 1 ) and comparison of the measurements on signals received from the T-RAN node to a second threshold (Thresh 2 ) satisfy the entering condition. The UE can then respond to the comparisons satisfying the entering condition by controlling DRX of traffic from the S-RAN node using the service-agnostic DRX configuration. 
     The UE can determine that a leaving condition for the Event A5 is satisfied (has occurred) when the following two conditions are satisfied:
 
 Mp−Hys&gt;Thresh 1  Inequality A5-3 (Leaving condition 1)
 
 Mn+Ofn+Ocn+Hys&lt;Thresh 2.  Inequality A5-4 (Leaving condition 2)
 
     In the conditional equations for Event A5, the terms have the following meanings:
         1) Mp is the measurement result of the PCeII or PSCeII, not taking into account any offsets;   2) Mn is the measurement result of the neighboring cell, not taking into account any offsets;   3) Ofn is the frequency specific offset of the frequency of the neighbor cell (i.e. offsetFreq as defined within measObjectEUTRA corresponding to the frequency of the neighbor cell);   4) Ocn is the cell specific offset of the neighbor cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbor cell), and set to zero if not configured for the neighbor cell;   5) Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event);   6) Thresh 1  is the threshold parameter for this event (i.e. a5-Threshold 1  as defined within reportConfigEUTRA for this event); and   7) Thresh 2  is the threshold parameter for this event (i.e. a5-Threshold 2  as defined within reportConfigEUTRA for this event).       

     The UE can respond to the comparisons satisfying the entering conditions (entering conditions 1 and 2) by suspending use of the service-specific DRX configurations for controlling DRX of traffic from the S-RAN node and initiate use of the service-agnostic DRX configuration to control DRX. In constrast, the UE can respond to the comparisons satisfying the leaving conditions (leaving conditions 1 and 2) by ceasing use of the service-agnostic DRX configuration for controlling DRX of traffic from the S-RAN node and resume using selections among the service-specific DRX configurations to control DRX. 
     For Event A6, the UE determines if a neighbor, e.g., T-eNB, has become a defined offset amount better than the SCell. The UE can determine that an entering condition for the Event A6 is satisfied (has occurred) when the following condition is satisfied:
 
 Mn+Ocn−Hys&gt;Ms+Ocs+Off.   Inequality A6-1 (Entering condition)
 
     The UE can determine that a leaving condition for the Event A6 is satisfied (has occurred) when the following condition is satisfied:
 
 Mn+Ocn+Hys&lt;Ms+Ocs+Off.   Inequality A6-2 (Leaving condition)
 
     In the conditional equations for Event A6, the terms have the following meanings:
         1) Mn is the measurement result of the neighboring cell, not taking into account any offsets;   2) Ocn is the cell specific offset of the neighbor cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the frequency of the neighbor cell), and set to zero if not configured for the neighbor cell;   3) Ms is the measurement result of the serving cell, not taking into account any offsets;   4) Ocs is the cell specific offset of the serving cell (i.e. cellIndividualOffset as defined within measObjectEUTRA corresponding to the serving frequency), and is set to zero if not configured for the serving cell;   5) Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigEUTRA for this event); and   6) Off is the offset parameter for this event (i.e. a6-Offset as defined within reportConfigEUTRA for this event).       

     The UE can respond to the comparison satisfying the entering condition by suspending use of the service-specific DRX configurations for controlling DRX of traffic from the S-RAN node and initiate use of the service-agnostic DRX configuration to control DRX. In constrast, the UE can respond to the comparison satisfying the leaving condition by ceasing use of the service-agnostic DRX configuration for controlling DRX of traffic from the S-RAN node and resume using selections among the service-specific DRX configurations to control DRX. 
     For Event B1, the UE determines if an inter Radio Access Technology (RAT) neighbor has become better than a defined offset. The UE can determine that an entering condition for the Event B1 is satisfied (has occurred) when the following condition is satisfied:
 
 Mn+Ofn−Hys&gt;Thresh.   Inequality B1-1 (Entering condition)
 
     The UE can determine that a leaving condition for the Event B1 is satisfied (has occurred) when the following condition is satisfied:
 
 Mn+Ofn+Hys&lt;Thresh.   Inequality B1-2 (Leaving condition)
 
     In the conditional equations for Event B1, the terms have the following meanings:
         1) Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets. For CDMA 2000 measurement result, pilotStrength is divided by −2;   2) Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the neighbour inter-RAT cell);   3) Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfiglnterRAT for this event); and   4) Thresh is the threshold parameter for this event (i.e. b1-Threshold as defined within reportConfiglnterRAT for this event). For CDMA2000, b1-Threshold is divided by −2.       

     The UE can respond to the comparison satisfying the entering condition by suspending use of the service-specific DRX configurations for controlling DRX of traffic from the S-RAN node and initiate use of the service-agnostic DRX configuration to control DRX. In constrast, the UE can respond to the comparison satisfying the leaving condition by ceasing use of the service-agnostic DRX configuration for controlling DRX of traffic from the S-RAN node and resume using selections among the service-specific DRX configurations to control DRX. 
     For Event B2, the UE determines if a PCeII has become worse than a first threshold (threshold 1 ) and an inter RAT neighbor has become better than a second threshold (threshold 2 ). The UE can determine that an entering condition for the Event B2 is satisfied (has occurred) when the following two conditions are satisfied:
 
 Mp+Hys&lt;Thresh 1  Inequality B2-1 (Entering condition 1)
 
 Mn+Ofn−Hys&gt;Thresh 2.  Inequality B2-2 (Entering condition 2)
 
     The UE can determine that a leaving condition for the Event B2 is satisfied (has occurred) when the following two conditions are satisfied:
 
 Mp−Hys&gt;Thresh 1  Inequality B2-3 (Leaving condition 1)
 
 Mn+Ofn+Hys&lt;Thresh 2.  Inequality B2-4 (Leaving condition 2)
 
     In the conditional equations for Event B2, the terms have the following meanings:
         1) Mp is the measurement result of the PCeII, not taking into account any offsets;   2) Mn is the measurement result of the inter-RAT neighbor cell, not taking into account any offsets. For CDMA2000 measurement result, pilotStrength is divided by −2;   3) Ofn is the frequency specific offset of the frequency of the inter-RAT neighbor cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the inter-RAT neighbor cell);   4) Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfiglnterRAT for this event);   5) Thresh 1  is the threshold parameter for this event (i.e. b2-Threshold 1  as defined within reportConfiglnterRAT for this event); and   6) Thresh 2  is the threshold parameter for this event (i.e. b2-Threshold 2  as defined within reportConfigInterRAT for this event). For CDMA2000, b2-Threshold 2  is divided by −2.       

     The UE can respond to the comparison satisfying the entering condition by suspending use of the service-specific DRX configurations for controlling DRX of traffic from the S-RAN node and initiate use of the service-agnostic DRX configuration to control DRX. In contrast, the UE can respond to the comparison satisfying the leaving condition by ceasing use of the service-agnostic DRX configuration for controlling DRX of traffic from the S-RAN node and resume using selections among the service-specific DRX configurations to control DRX. 
     Further General Operations— 
     In accordance with one or more of the embodiments disclosed herein, a UE can monitor and report entering and leaving conditions for events that may trigger handover. When detecting and reporting the entering condition for such an event, the UE may operate to: 1) suspend DRX when sending that report to the mobile communication network; or 2) piggy-backing a control message to that report which requests its peer in the mobile communication network to suspend DRX, and then wait for the network to send a message to concur and activate such a suspension. 
     When detecting and reporting the leaving condition for such an event, the UE may operate to: 1) resume DRX when sending that report to the radio access network; 2) piggy-back a control message to that report which requests its peer in the radio access network to resume DRX, and then wait for the radio access network to send a message to concur and activate such resumption; or 3) wait for the network to send a message to deactivate the suspension. 
     After having either suspended handover and completed handover, the UE may operate to wait for the radio access network to to send a message to deactivate the suspension of DRX. 
     The radio access network may operate to control the entering and leaving conditions for events monitored by the UE which may trigger handover, and monitor reporting of these events from the UE. The radio access network responds to receipt of a report of the entering condition for one of the events by: 1) suspending DRX; or 2) receiving a control message with that report where the UE requests to suspend DRX, and responding thereto by sending a message to the UE requesting the UE to activate the suspension. 
     The radio access network may respond to receiving a report on the leaving condition for such an event, by: 1) resuming DRX; responding to receipt of a control message with that report where the UE requests to resume DRX, by sending a message to the UE requesting resumption of DRX; or 3) sending a message to the UE to deactivate the suspension of DRX. 
     The radio access network may respond to having suspended handover and completed handover, by sending a message to the UE to deactivate the suspension of DRX. 
     Example UE and RAN 
     Non-limiting example user equipment nodes (UEs) can include, but are not limited to, tablet computers, mobile terminals, smart phones, desktop computers, laptop embedded equipped (LEE), laptop mounted equipment (LME), etc. 
       FIG. 27  is a block diagram of a UE  2700  that is configured to perform operations according to one or more embodiments disclosed herein. The UE  2700  includes at least one transceiver  2710 , at least one processor  2702 , and at least one memory  2720  containing program code  2722 . The UE  2700  may further include a display  2730 , a user input interface  2732 , and a speaker  2734 . 
     The transceiver  2710  is configured to communicate with a RAN node through a wireless air interface using one or more of the radio access technologies disclosed herein. The processor  2702  may include one or more data processing circuits, such as a general purpose and/or special purpose processor, e.g., microprocessor and/or digital signal processor. The processor  2702  is configured to execute computer program instructions of the program code  2722  stored in the memory  2720  to perform at least some of the operations described herein as being performed by a UE. 
       FIG. 28  is a block diagram of a RAN node  2800  that is configured according to one or more embodiments disclosed herein for a source RAN node (e.g., S-eNB), a target RAN node (e.g., T-eNB), and/or another RAN node. The RAN node  2800  can include at least one transceiver  2010 , at least one network interface  2828 , at least one processor  2802 , and at least one memory  2820  containing program code  2822 . 
     The transceiver  2810  is configured to communicate with the UE  2700  using one or more of the radio access technologies disclosed herein. The processor  2802  may include one or more data processing circuits, such as a general purpose and/or special purpose processor, e.g., microprocessor and/or digital signal processor, that may be collocated or distributed across one or more networks. The processor  2802  is configured to execute computer program instructions of the program code  2822  stored in the memory  2820  to perform at least some of the operations described herein as being performed by a RAN node. The network interface  2828  communicates with other RAN nodes and/or a core network. 
       FIG. 29  illustrates modules residing in the UE  2700  that perform operations as disclosed herein according to some embodiments. The UE  2700  includes a determining module  2900 , a selecting module  2902 , and a controlling module  2904 . The determining module  2900  for determining whether a condition has occurred that can trigger initiation of handover to a T-RAN node. The selecting module  2902  is for, based on determining that the condition has not occurred, selecting among a plurality of service-specific DRX configurations based on a service type of the traffic from the S-RAN node, and controlling DRX by the UE of traffic from the S-RAN node based on the selected service-specific DRX configuration. The controlling module  2904  is for, based on determining that the condition has occurred, controlling DRX by the UE  2700  of traffic from the S-RAN node based on a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. The modules  2900 ,  2902 , and  2904  may perform other operations disclosed herein with regard to  FIGS. 14-22 . 
       FIG. 30  illustrates modules residing in the RAN node  2800  that perform operations as disclosed herein according to some embodiments. The RAN  2800  includes a receiving module  3000  for receiving a message from the UE  2700 , and a sending module  3002  for, based on content of the message from the UE  2700 , sending a message to the UE  2700  containing a request for the UE  2700  to suspend control of DRX which uses selections among a plurality of service-specific DRX configurations based on a service type of traffic from the S-RAN node, and for the UE  2700  to initiate control of DRX that will use a service-agnostic DRX configuration that is agnostic to the service type of the traffic from the S-RAN node. The modules  3000  and  3002  may perform other operations disclosed herein with regard to  FIGS. 24-26 . 
     ABBREVIATIONS 
     BSR Buffer Status Report (a MAC control element) 
     CBRA Contention Based Random Access 
     CFRA Contention Free Random Access 
     DC DRX configuration (index to such) 
     DL Downlink 
     DRX Discontinuous Reception 
     D-SR Dedicated SR 
     eNB evolution NodeB 
     F3 PUCCH Format 3 
     HO Handover 
     IE Information Element 
     KPI Key Performance Indicator 
     MAC Medium Access Control 
     NAS Non Access Stratum 
     OTT Over the Top 
     PC PUCCH Configuration (release that) 
     PDCCH Physical Downlink Control Channel 
     PFT Protocol Feature Testing 
     PMB Protocol Message Body 
     PMT Protocol Message Type 
     PUCCH Physical Uplink Control Channel 
     PUSCH Physical Uplink Shared Channel 
     RA-SR Random Access SR 
     RRC Radio Resource Control 
     S-eNB Source eNB 
     SL Side Link 
     SN Sequence Number 
     SR Scheduling Request 
     T-eNB Target eNB 
     TTI Transmission Time Interval 
     UE User Equipment node 
     UL-SCH Uplink Shared (a Transport Channel) 
     VoLTE Voice over LTE 
     FURTHER DEFINITIONS AND EMBODIMENTS 
     In the above-description of various embodiments of present inventive concepts, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of present inventive concepts. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which present inventive concepts belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense expressly so defined herein. 
     When an element is referred to as being “connected”, “coupled”, “responsive”, or variants thereof to another element, it can be directly connected, coupled, or responsive to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected”, “directly coupled”, “directly responsive”, or variants thereof to another element, there are no intervening elements present. Like numbers refer to like elements throughout. Furthermore, “coupled”, “connected”, “responsive”, or variants thereof as used herein may include wirelessly coupled, connected, or responsive. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Well-known functions or constructions may not be described in detail for brevity and/or clarity. The term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements/operations, these elements/operations should not be limited by these terms. These terms are only used to distinguish one element/operation from another element/operation. Thus a first element/operation in some embodiments could be termed a second element/operation in other embodiments without departing from the teachings of present inventive concepts. The same reference numerals or the same reference designators denote the same or similar elements throughout the specification. 
     As used herein, the terms “comprise”, “comprising”, “comprises”, “include”, “including”, “includes”, “have”, “has”, “having”, or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation “e.g.”, which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. The common abbreviation “i.e.”, which derives from the Latin phrase “id est,” may be used to specify a particular item from a more general recitation. 
     Example embodiments are described herein with reference to block diagrams and/or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices) and/or computer program products. It is understood that a block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions that are performed by one or more computer circuits. These computer program instructions may be provided to a processor circuit of a general purpose computer circuit, special purpose computer circuit, and/or other programmable data processing circuit to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuitry to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby create means (functionality) and/or structure for implementing the functions/acts specified in the block diagrams and/or flowchart block(s). 
     These computer program instructions may also be stored in a tangible computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the functions/acts specified in the block diagrams and/or flowchart block or blocks. Accordingly, embodiments of present inventive concepts may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.) that runs on a processor such as a digital signal processor, which may collectively be referred to as “circuitry,” “a module” or variants thereof. 
     It should also be noted that in some alternate implementations, the functions/acts noted in the blocks may occur out of the order noted in the flowcharts. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Moreover, the functionality of a given block of the flowcharts and/or block diagrams may be separated into multiple blocks and/or the functionality of two or more blocks of the flowcharts and/or block diagrams may be at least partially integrated. Finally, other blocks may be added/inserted between the blocks that are illustrated, and/or blocks/operations may be omitted without departing from the scope of inventive concepts. Moreover, although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows. 
     Many variations and modifications can be made to the embodiments without substantially departing from the principles of the present inventive concepts. All such variations and modifications are intended to be included herein within the scope of present inventive concepts. Accordingly, the above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended examples of embodiments are intended to cover all such modifications, enhancements, and other embodiments, which fall within the spirit and scope of present inventive concepts. Thus, to the maximum extent allowed by law, the scope of present inventive concepts are to be determined by the broadest permissible interpretation of the present disclosure including the following examples of embodiments and their equivalents, and shall not be restricted or limited by the foregoing detailed description.