CLIAMS:CLAIMS
We claim:

1. A method of reducing power consumption in a User Equipment (UE) in an LTE network, the method comprises of:
detecting, by the User Equipment (UE), a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call;
receiving, by an IP multimedia Sub-System (IMS), a message indicating suspension of data transfer and an Radio Transmission Link (RTP) buffer size from the UE;
initiating, by the IMS, writing of recent data in the RTP buffer;
checking, by the IMS, if the RTP buffer is full or not;
terminating a Digital Signal Processor (DSP) and initiating a DSP timer (T1 timer) if the RTP buffer is full;
checking if the DSP timer is expired or not after a pre-set time; and
activating the DSP if the DSP timer is expired.

2. The method of claim 1, further comprising:
Checking, by the IMS, if a resume data indication is received before the timer expiry;
sending the recent data to the network; and
continuing the VoLTE call.

3. The method of claim 1, further comprising:
detecting, by the User Equipment (UE) in a first Radio Access Terminal (RAT), a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call;
transmitting by the UE, a message to the IMS indicating suspension of data transfer along with the RTP buffer size;
initiating, by the IMS, writing of recent data in the RTP buffer;
checking, by the IMS, if the RTP buffer is full or not;
terminating a Digital Signal Processor and initiating a DSP timer if the RTP buffer is full;
checking if the DSP timer is expired or not after a pre-set time;
activating the DSP if the DSP timer (T1 timer) is expired;
checking if the data resume indication is received from a second RAT;
transmitting the recent data to the second RAT if the data resume indication is received from the second RAT and VoLTE call is allowed in the second RAT.

4. The method of claim 3, further comprising:
Discarding, by the IMS, the recent data if the VoLTE call is not allowed in the second RAT; and
terminating the VoLTE call.

5. A user equipment (UE), adapted to reduce power consumption during a Voice over LTE (VoLTE) call, the UE comprising at least one component adapted for:
detecting a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call;
transmitting a message to an IP multimedia Sub-System (IMS) indicating suspension of data transfer and a Radio Transmission Link Protocol (RTP) buffer size;
initiating writing of recent data in the RTP buffer;
checking if the RTP buffer is full or not;
terminating a Digital Signal Processor (DSP) and initiate a DSP timer (T1 timer) if the RTP buffer is full;
checking if the DSP timer is expired or not after a pre-set time; and
activating the DSP if the DSP timer is expired.

Dated this the 29th day of June 2015

Signature

KEERTHI J S
Patent agent
Agent for the applicant

,TagSPECI:
FORM 2
THE PATENTS ACT, 1970
[39 of 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10; Rule 13)

METHOD FOR REDUCING POWER CONSUMPTION IN COMMUNICATION DEVICES DURING VOICE OVER LTE (VoLTE) CALL

SAMSUNG R&D INSTITUTE INDIA – BANGALORE Pvt. Ltd.
# 2870, ORION Building, Bagmane Constellation Business Park,
Outer Ring Road, Doddanakundi Circle,
Marathahalli Post,
Bangalore -560037, Karnataka, India
Indian Company

The following Specification particularly describes the invention and the method it is being performed

FIELD OF THE INVENTION
The present invention generally relates to mobile communication systems and particularly relates to a method and apparatus for reducing power consumption in wireless communication devices during Voice over LTE (VoLTE) call.

BACKGROUND OF THE INVENTION
Mobile communication systems have been developed to provide voice services while ensuring the user's activity. However, the mobile communication systems have gradually expanded their respective services from voice services to include data services such as Internet and multimedia content. While many existing wireless communication technologies utilize separate communication channels for voice and data communications, there is currently movement among many providers of wireless communication services towards wireless communication technologies which utilize packet-switched communication channels for all types of communications.

However, providing good connection quality for both voice services and data services via a shared packet-switched communications link may be challenging, particularly in poor Radio Link Failure (RLF) conditions. This may potentially reduce the throughput of the communication link available for voice communications. Accordingly, improvements in wireless communications would be desirable.

Consider a scenario, where while an active volte call is ongoing, a Radio link failure occurs and the UE could not recover the service until expiry of the Real-time Transport Protocol (RTP) timer. Due to RLF, the user equipment (UE) will keep on generating the RTP packets until the RTP timer expires. These generated packets will be discarded on Mobile originating (MO) side due to Data Radio Bearer (DRB) release and on Mobile Terminating (MT) side due to volte call end.

Consider another scenario, where during an active volte call is ongoing, RLF happens and the UE recovers the services after few seconds. During temporary out of service (OOS) time, the UE generates RTP and RTCP packets. In this case, only few old packets will be sent by the UE and new packets which are buffered will be discarded due to less grants allocation for volte call from network and when the packet data control protocol (PDCP) discard timer expires.

In another scenario, when an active volte call is ongoing, the UE moves to other Radio Access Technology (RAT) which is evolved High Rate Packet Data (eHRPD). The volte call ends when UE moves to eHRPD, because the volte call is not supported there as per the operator requirement. During Long-Term Evolution (LTE) to eHRPD transition period, UE generates RTP and RTCP packets and these packets are transmitted with less data rate in eHRPD thereby causing delay in sending BYE message for end to end call signaling.

In view of the foregoing, there exists a need to provide an improved method for reducing power consumption during VoLTE call.

The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.

SUMMARY OF THE INVENTION

Embodiments of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method for reducing power consumption in User Equipments (UE) in an LTE network.

The various embodiments of the present invention disclose a method for reducing power consumption in wireless communication devices during VoLTE call. According to the present invention, the method comprises the steps of detecting by a User Equipment (UE), a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call, transmitting by the UE, a message to an IP Multimedia Subsystem (IMS) indicating suspension of data transfer and an RTP buffer size, initiating, by an IMS, writing of recent data in the RTP buffer, checking, by the IMS, if the RTP buffer is full or not, terminate a Digital Signal Processor (DSP) and initiate a DSP timer (T1 timer) if the RTP buffer is full, checking if DSP timer (T1 timer) is expired or not after a pre-set time, and activating the DSP if the DSP timer (T1 timer) is expired.

According to an embodiment herein, the method further comprises of checking by the IP multimedia subsystem (IMS) if the resume data indication is received before the timer expiry or not, sending the recent data to the network if the resume data indication is received before the timer expiry and continuing the VoLTE call.

According to an embodiment herein, the method further comprises of detecting, by the User Equipment (UE) in a first Radio Access Terminal (RAT), a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call, transmitting by the UE, a message to an IMS indicating suspension of data transfer and an RTP buffer size, initiating, by the IMS, writing of recent data in the RTP buffer, checking, by the IMS, if the RTP buffer is full or not, terminate a Digital Signal Processor and initiate a DSP timer (T1 timer) if the RTP buffer is full, checking if DSP timer (T1 timer) is expired or not after a pre-set time, activating the DSP if the DSP timer (T1 timer) is expired, checking if the data resume indication is received from a second RAT, transmitting the recent data to the second RAT if the data resume indication is received from the second RAT and VoLTE call is allowed in second RAT.

According to an embodiment herein, the method further comprises of discarding the recent data if the VoLTE call is not allowed in the second RAT and terminating the VoLTE call.

Embodiments herein further disclose a user equipment (UE) adapted to reduce power consumption during a Voice over LTE (VoLTE) call. The UE comprises at least one component adapted for detecting a Radio Link Failure (RLF) during a Voice over LTE (VoLTE) call, transmitting a message to an IMS indicating suspension of data transfer and an RTP buffer size, initiating writing of recent data in the RTP buffer, checking if the RTP buffer is full or not, terminating a Digital Signal Processor (DSP) and initiate a DSP timer (T1 timer) if the RTP buffer is full, checking if DSP timer (T1 timer) is expired or not after a pre-set time and activating the DSP if the DSP timer (T1 timer) is expired.

The foregoing has outlined, in general, the various aspects of the invention and is to serve as an aid to better understanding the more complete detailed description which is to follow. In reference to such, there is to be a clear understanding that the present invention is not limited to the method or application of use described and illustrated herein. It is intended that any other advantages and objects of the present invention that become apparent or obvious from the detailed description or illustrations contained herein are within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

Figure 1 is a flow diagram illustrating a scenario where the UE does not recover to normal call services until timer expiry, according to an embodiment of the present invention.

Figure 2 is a flow diagram illustrating a scenario where UE recovers to normal services after a Radio Link Failure (RLF), according to an embodiment of the present invention.

Figure 3 is a flow diagram illustrating a scenario in which UE has moved to another RAT (eHRPD) where volte is not allowed, according to an embodiment of the present invention.

Figure 4 is a graphical representation of a timeline illustrating a DRX Cycle for DSP when data is suspended, according to an embodiment of the present invention.

Figure 5 is a flow chart illustrating a method for reducing power consumption in UE during volte call, according to an embodiment of the present invention.

Although specific features of the present invention are shown in some drawings and not in others, this is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The various embodiments of the present invention disclose a method of reducing power consumption in UE in an LTE network during VoLTE call. In the following detailed description of the embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

The specification may refer to “an”, “one” or “some” embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and/or “comprising” when used in this specification, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations and arrangements of one or more of the associated listed items.

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 this disclosure pertains. 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 the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Figure 1 is a flow diagram illustrating a scenario where the UE fails to recover to normal services until timer expiry, according to an embodiment of the present invention. According to the present invention, a User Equipment (UE) 102 has established a connection with the LTE network 110 for a voice call. The UE starts an RTP timer on reception of each RTP Rx packet, and restarts on receipt of a next RTP Rx packet. When the UE 102 detects a Radio Link Failure (RLF) at step 112, there will be no RTP Rx packets and the RTP timer will continue running. When the UE 102 detects a Radio Link Failure (RLF) at step 112, the Radio Resource Controller (RRC) calculates a buffer size from a PDCP discard timer and a maximum bit rate (MBR) rate using the formula:
Audio Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000
Video Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000.

Accordingly, at step 114, the RRC 108 transmits a data suspend indication along with the calculated buffer size to an IP multimedia subsystem (IMS) 106. Upon receiving the indication, at step 116, the IMS allocates a buffer of the buffer size indicated in the message and starts buffering the RTP data. At step 118, when the buffer gets full, the Digital Signal Processor (DSP) is stopped. At step 120, once the DSP is stopped, the DSP is released for a preset time period T1 to save the power. Here the time period T1 is a configurable timer value based on implementation. At step 122, if IMS does not receive the data resume indication before the expiry of T1 period, then upon the expiry of T1 period, at step 124, the IMS 106 acquires the DSP/Vocoder 104. Further, at step 126, the IMS 106 overwrites the buffer with recent RTP data and repeats the steps 118 to 126 until the RTP timer expiry.

Figure 2 is a flow diagram illustrating a scenario where UE recovers the normal services after few seconds of RLF, according to an embodiment of the present invention. According to an embodiment of the present invention, at step 212, when the UE 202 detects an RLF, the UE 202 calculates buffer size from a PDCP discard timer and an MBR rate using the formula:
Audio Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000
Video Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000.

Accordingly, at step 214, the RRC 208 sends a data suspend and buffer size indication to the IMS 206. At step 216, upon receiving the indication, the IMS allocates a buffer of the indicated size and starts buffering the RTP data. At step 218, when the buffer gets full the DSP is stopped. Further at step 220, release the DSP for T1 period to save power. Here T1 is a configurable timer value based on implementation. When the UE finds a cell and overcomes RLF, the service is resumed before the expiry of T1 period at step 222. At step 224, after the UE overcomes RLF, the IMS 206 receives data resume indication from RRC 208. Upon receiving the data resume indication, at step 226, the IMS 206 acquires the DSP/Vocoder 204. At step 228, the IMS 206 sends the buffered data which is the recent RTP data to the RRC 208. This enables the UE 202 in sending most recently generated RTP packets to the other party which is useful.

Figure 3 is a flow diagram illustrating a scenario in which UE has moved to other RAT (eHRPD) where volte is not allowed. According to an embodiment of the present invention, when the UE detects a RLF, there will be no RTP Rx packet so RTP timer will continue running, and RRC calculates buffer size from PDCP discard timer and MBR rate at step 310 using the formula:
Audio Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000
Video Buffer Size (bytes) = PDCP Discard duration (ms) * MBR rate (kbps) / 8000.

Accordingly, at step 312, the first RAT 306 onto which the UE is currently registered sends a data suspend and a buffer size indication to the IMS 304. At step 314, upon receiving the indication, IMS 304 allocates a buffer of the indicated size and starts buffering the RTP data. At step 316, the IMS 304 checks if the buffer is full or not and if the buffer is full, then stop the DSP. At step 318, once the DSP is stopped, release the DSP for a time period T1 to save the power. Here T1 is a configurable timer value based on implementation. At step 320, if data resume indication is not received before the expiry of T1, then at step 322, the IMS 304 acquires the DSP/Vocoder 302 upon the expiry of T1 period. After acquiring the DSP/Vocoder 302, at step 324, the IMS 304 starts overwriting the buffer with recent RTP data and repeats the steps 316 to 324 until the RTP timer expiry.

Further, at step 326, when the UE overcomes the RLF by registering onto the second RAT 308, the IMS 304 receives a data resume indication from the second RAT 308. The volte call ends upon moving to the second RAT 308 which is the eHRPD, as the volte call is not supported there according to the operator requirement. Unlike the previous embodiment, the RTP data buffering is limited to reduce the delay in sending the buffered data to the second RAT 308. Upon receiving the data resume indication, at step 328, the IMS 304 discards the buffered data or the limited buffered data is sent thereby causing less a delay in sending BYE message for end to end call signaling. The End to end signaling time is thus reduced when UE is moving to a new RAT where volte call is not allowed.

Figure 4 is a graphical representation timeline illustrating a DRX Cycle for DSP when data is suspended, according to an embodiment of the present invention. When the data transfer is suspended due to the RLF, the DSP is switched ON and OFF repeatedly to save power until the timer expiry. The DSP timer (T1 timer) is configured accordingly. If the DSP is ON, the data is buffered and if the DSP is OFF, the IMS goes to sleep until the DSP timer (T1 timer) expiry. Next time when the DSP is acquired i.e. on the expiry of the DSP timer, the IMS overwrites the buffer with the recent RTP data. And, when the DSP is in sleep mode, if the IMS receives the data resume indication, the sleep is interrupted and the IMS sends the recently buffered data to the other party.

Figure 5 is a flow chart illustrating a method for reducing power consumption in UEs during volte call, according to an embodiment of the present invention. UE starts RTP timer on every RTP Rx packet, and restart on receipt of next RTP Rx packet. At step 502, the UE detects an RLF while on a volte. Now there will not be any RTP Rx packet so RTP timer will continue to run. At step 504, the UE transmits a message to an IMS indicating suspension of data transfer along with a buffer size. Upon receiving the indication, at step 506, the IMS initiates writing of recent data in the RTP buffer. Further at step 508, the IMS checks if the RTP buffer is full. If the RTP buffer is not full, at step 510, check if the RTP timer has expired. If the RTP timer is not expired, then continue writing of recent data in the RTP buffer. If the RTP timer is expired, then at step 512, clear the buffer and end the call.

If the RTP buffer is full, then at step 514, terminate the DSP and initiate a DSP timer (T1 timer). At step 516, check if the data resume indication is received. If yes, then at step 518, check if the volte call is possible, if yes, at step 520, transmit the buffered data and the call is resumed. If the volte call is not possible, then at step 522, clear the buffer and the call ends. If the data resume indication is not received, at step 524, check if the RTP timer is expired. If it is expired, clear the buffer and the call ends. If the RTP timer is not expired, then at step 526, check if the DSP timer (T1 timer) is expired after a pre-set time. If the DSP timer (T1 timer) is not expired, then repeat the steps from the step 516. If the DSP timer (T1 timer) is expired, then at step 528, activate the DSP and repeat the steps from the step 506.

The present embodiments have been described with reference to specific example embodiments; it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. Furthermore, the various devices, modules, and the like described herein may be enabled and operated using hardware circuitry, for example, complementary metal oxide semiconductor based logic circuitry, firmware, software and/or any combination of hardware, firmware, and/or software embodied in a machine readable medium. For example, the various electrical structure and methods may be embodied using transistors, logic gates, and electrical circuits, such as application specific integrated circuit.

Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.