DESC:RELATED APPLICATION

Benefit is claimed to Indian Provisional Application No. 4143/CHE/2013 titled “ENERGY AWARE PACKET ENCODING/DECODING AND SCHEDULING REQUESTS IN LTE FOR POWER SAVING DURING VOLTE" filed on 17 September 2013, which is herein incorporated in its entirety by reference for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to a field of wireless communication, and more particularly relates to method and system for reducing power consumption in a user device during wireless communication.

BACKGROUND OF THE INVENTION

Packet traffic during Voice over Long-Term Evolution (VOLTE) call is predictable as packet generation happens at a regular interval of 20ms/40ms and so on. Connected DRX feature of Long-Term Evolution (LTE) as given in specifications can be helpful in saving power of a user equipment (UE), since DRX parameters can be easily adjusted by a network so that UE can sleep during inter-packet arrival time. However connected DRX feature has limitation that if uplink packet is available in Radio Link Control/ Medium Access Control (RLC/MAC) of the LTE, sleep pattern has to be broken and packet must be transmitted to the network in uplink. So some synchronization mechanism for packet encoding/decoding and Uplink/Downlink (UL/DL) transmission should be invented, so that the UE can sleep for more time during inter-packet arrival times. Voice packet encoding/decoding if not synchronized with uplink/downlink radio activity, leads the user device/ user equipment (UE) to be awake most of the time and power saving is almost impossible.

Therefore, there is a need of method and system for reducing power consumption in a user device during a wireless communication.

SUMMARY
An objective of the present invention is to provide method and system for reducing power consumption in a user device during a wireless communication.
An embodiment of the present invention describes a method of reducing power consumption in a user device during wireless communication. The method comprises receiving one or more data packets during a first DRX cycle at the user device, determining time period in a second DRX cycle for decoding the received data packets in order to increase time duration of sleeping mode of the user device, and decoding the received data packets during the determined time period at the user device.

Another embodiment of the present invention describes a system for reducing power consumption in a user device during wireless communication. The system comprises means for receiving one or more data packets during a first DRX cycle at the user device, means for determining time period in a second DRX cycle for decoding the received data packets in order to increase time duration of sleeping mode of the user device, and means for decoding the received data packets during the determined time period at the user device.

In one embodiment, a requisite time duration is determined for decoding the received one or more data packets. Time duration available in the second DRX cycle is determined during which the user device performs radio activities such as serving cell measurement, PDCCH decoding, SR transmission, and HARQ Ack Transmission. The one or more data packets are decoded during the determined time duration available in the second DRX cycle so as to increase time duration of sleeping mode of the user device. Here, the first DRX cycle is a cycle in which the data packet is received and the second DRX cycle is a cycle which comes next to the first DRX cycle.

In another embodiment, one or more data packets are encoded in a second DRX cycle during transmission of previously encoded one or more data packets. Time duration of transmission of one or more data packets is synchronized with time duration of reception of one or more data packets in order to increase the time duration of sleeping mode of the user device.
In yet another embodiment, time duration of transmission of one or more data packets is synchronized with time duration of reception of one or more data packets. A response time duration to a scheduling request for transmission of one or more data packets is estimated. Time duration is determined for sending the scheduling request in order to finish the transmission of the one or more data packets during the time duration of reception of one or more data packets.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 illustrates a diagrammatic representation depicting a typical voice traffic pattern.

Figure 2 illustrates a schematic representation depicting a connected DRX feature in a LTE.

Figure 3 illustrates an effective Ton during DL VOIP packet reception.

Figure 4 illustrates a UL Voice packet processing during a connected mode DRX.

Figure 5 illustrates a system for reducing power consumption in a user device during wireless communication according to an embodiment of the present invention.

Figure 6 illustrates downlink (DL) Voice packet processing during connected mode DRX according to an embodiment of the present invention.

Figure 7 illustrates uplink (UL) Voice packet processing during connected mode DRX according to another embodiment of the present invention.

Figure 8 illustrates a method of reducing power consumption in a user device during wireless communication according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments. The present invention can be modified in various forms. Thus, the embodiments of the present invention are only provided to explain more clearly the present invention to the ordinarily skilled in the art of the present invention. In the accompanying drawings, like reference numerals are used to indicate like components.
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.
The present invention describes method and system for performing decoding and encoding of Voice over Internet Protocol (VoIP) packets during an On-duration of a connected Discontinuous Reception (DRX) as much as possible such that an Off-duration can be maximized thereby resulting in a high power saving during a Voice over LTE call. The present invention also describes a method of buffering and decoding each received packet data, during next wakeup duration of next DRX cycle for a downlink, so that the UE can sleep for more time. Further, each received packet data is decoded if timing between the received packets and going to sleep is sufficient. In an uplink, each uplink packet data, uplink packet is encoded during transmission of previously ready packet. Further, each uplink packet data, uplink packet is encoded just before the transmission of packet if modem is on before. In an uplink SR, transmission is synchronized to downlink (DL) Physical Downlink Control Channel (PDCCH) decoding occurs when the connected DRX is applied in LTE.

Figure 1 illustrates a diagrammatic representation of a typical voice traffic pattern. Generally, Voice over Internet Protocol (VoIP) traffic generates packets at every 20ms cycle. Speech packet is generated every 20ms in both uplink (UL) and downlink (DL) when a user is continuously speaking. When the user doesn’t speak, silence is detected and then at every 160 ms, only Silence Insertion Descriptor (SID) frames are exchanged in the silent period. Subsequently, when the user starts speaking, the VOIP packets are exchanged every 20ms. In every 20ms, a LTE phone typically takes 7ms to wake up, decode data and send Hybrid automatic repeat request (HARQ) response. Then in the remaining rest 13ms, the UE can sleep.

Figure 2 illustrates a schematic representation depicting a connected DRX feature in the LTE. The connected DRX feature in the LTE is a generic feature which can be used in any traffic pattern. However, it becomes easy for a network to configure the connected DRX for VOIP traffic as traffic is quite predictable. As a simple setting, the network sets DRX cycle as 20ms or 40ms. Then in the downlink, the UE decodes Physical Downlink Control Channel (PDCCH) once in every 20ms or 40ms. Once the packet is decoded successfully, the packet is provided to the UE’s vocoder for further decoding to extract Adaptive Multi-Rate (AMR) packet to be played out at the UE’s speaker.

During every On-duration in the connected DRX (Ton), the following operations occur.

1. Serving/Neighboring Cell measurement
2. PDCCH decoding
3. SR Transmission
4. HARQ ACK Transmission for DL
5. VOIP packet encoding (per packet 5 ms time)
6. VOIP packet decoding (per packet 5 ms time)

Figure 3 illustrates an effective on duration (Ton) of the user device during down-link (DL) VOIP packet reception. A wakeup time varies in a range of 2-3ms in logs for the VOIP packet reception. A protocol processing of incoming VOIP packet takes 2-3ms and further decoding of the VOIP packet takes 5ms. As shown in the figure 3, the UE remains on due to protocol for 7ms. Thereafter, the UE takes around 5ms for the VOIP packet decoding, because of which Ton becomes 11ms. If the VOIP packet decoding can happen in energy away way then the UE’s Ton can be reduced by 45% providing significant power savings.

Figure 4 illustrates an up-link (UL) Voice packet processing during a connected mode DRX. The VOIP packet encoding starts X unit of time before scheduled wakeup. During a 20ms packet generation cycle, the UE approximately takes 11ms from wake up to actual packet sent, when Semi-Persistent Scheduling (SPS) feature not being enabled. Hence Ton=11ms if SPS not enabled. If the SPS feature is enabled, then Ton is approximately 6ms. Henceforth, a minimum Ton of 6-11 ms is always required during any uplink using the SPS feature. During UL VOIP, random X ms are added to the Ton. Hence it is desirable to synchronize UL packet encoding during Ton, so that UE sleep can be maximized.

Figure 5 illustrates a system for reducing power consumption in a user device during wireless communication according to an embodiment. The system comprises means for receiving one or more data packets during a first DRX cycle at the user device, means for determining time period in a second DRX cycle for decoding the received data packets in order to increase time duration of sleeping mode of the user device, and means for decoding the received data packets during the determined time period at the user device. Further, the system comprises means for synchronizing time duration of transmission of one or more data packets with time duration of reception of one or more data packets in order to increase the time duration of sleeping mode of the user device and means for encoding one or more data packets in a second DRX cycle during transmission of previously encoded one or more data packets.

In one embodiment, the means for receiving one or more data packets includes a receiving module 501, the means for determining time period includes a processing module 502, the means for decoding the received data packets includes decoding module 503, and the means for synchronizing time duration of transmission of one or more data packets with time duration of reception of one or more data packets includes a synchronizing module 504, means for encoding one or more data packets in a second DRX cycle includes encoding module 505.
In order to increase the time duration (Toff) of sleeping mode of the user device during the connected mode DRX, the system is configured with three embodiments as described below:

1. For DL VOIP packets, the user device receives the packet during Ton (7ms) but decoding happens during next Ton. Packet decoding generally takes 4-5ms. So the user device reduces the Ton effectively significantly by 45 %.
2. For UL VOIP packet, if un-encoded packet is ready, while the user device radio frequency (RF) is in sleep, encoding of packet is differed. Encoding a new packet happens, during the UL transmission of previously ready packet. There will be a delay of 10-20ms, however this is insignificant as VOIP is tolerant for a 200ms delay. Since gains in terms of power saving are huge, the user device can tolerate a delay of 10-20ms.
3. UL should be synchronized to DL connected DRX pattern. Ton for DL 7ms. Typically Ton is 6-11ms. If the UL is synchronized to DL then the total Ton of 7-11ms is possible. Otherwise if the UL and the DL are not synchronized then the total Ton can become 16-18ms, thereby implying no possible sleep.

Figure 6 illustrates Down-link (DL) Voice packet processing during connected mode DRX according to one embodiment of the present invention. In this embodiment, one or more data packets (DL VOIP packet) are received during a first DRX cycle at the user device. So, time period in a second DRX cycle is determined for decoding the received data packets (DL VOIP packet) in order to increase time duration of sleeping mode of the user device. Time duration available in the second DRX cycle is determined during which the user device performs radio activities such as serving cell measurement, PDCCH decoding, SR transmission, and HARQ Ack Transmission. The one or more data packets (DL VOIP packet) are decoded during the determined time duration available in the second DRX cycle so as to increase time duration of sleeping mode of the user device. Thus, it is apparent that the DL VOIP packet decoding is deferred till next Ton (Wakeup). In one exemplary embodiment, Toff increases from 9ms to 13ms thereby providing significant power saving.

Here, the first DRX cycle is a cycle in which the data packet is received and the second DRX cycle is a cycle which comes next to the first DRX cycle.

Figure 7 illustrates Up-link (UL) Voice packet processing during connected mode DRX according to another embodiment of the present invention. In this embodiment, one or more data packets (UL VOIP packet) are encoded in a second DRX cycle during transmission of previously encoded one or more data packets (UL VOIP packet). Time duration of transmission of one or more data packets (UL VOIP packet) is synchronized with time duration of reception of one or more data packets (DL VOIP packet) in order to increase the time duration of sleeping mode of the user device.
In one embodiment, an Uplink (UL) SR is synchronization to downlink (DL) PDCCH decoding, wherein if the UL is synchronized to the DL then total Ton of 7-11ms is possible. Else if the UL and the DL are not synchronized then the total Ton can become 16-18ms, thereby implying no possible sleep during 20ms DRX cycle. Therefore in order to reduce Ton, the user device estimates a typical response time to scheduling request and choose the timing of sending SR accordingly such that UL transmission finishes in downlink On-period.

This embodiment provides huge power saving possible with energy aware UL/DL encoding/Decoding as On-duration can be reduced by 45%. The present invention can be applicable even with SPS enabled. Also the proposed invention is according to 3rd Generation Partnership Project (3GPP) specifications.

Figure 8 illustrates a flow diagram of a method of reducing power consumption in a user device during wireless communication according to one embodiment of the present invention. One or more data packets are received during a first DRX cycle at the user device at step 801. Time period in a second DRX cycle is determined for decoding the received data packets in order to increase time duration of sleeping mode of the user device at step 802. The received data packets are decoded during the determined time period at the user device at step 803.
Although the invention of the method and system has been described in connection with the embodiments of the present invention illustrated in the accompanying drawings, it is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and changes may be made thereto without departing from the scope and spirit of the invention.
,CLAIMS:
1. A method of reducing power consumption in a user device during wireless communication, the method comprising:
receiving one or more data packets during a first DRX cycle at the user device;
determining time period in a second DRX cycle for decoding the received data packets in order to increase time duration of sleeping mode of the user device; and
decoding the received data packets during the determined time period at the user device.

2. The method as claimed in claim 1, wherein the determining time period in the second DRX cycle for decoding the received data packets comprises:
determining a requisite time duration for decoding the received one or more data packets;
determining time duration available in the second DRX cycle during which the user device performs radio activities, said radio activities comprises serving cell measurement, PDCCH decoding, SR transmission, and HARQ Ack Transmission; and
decoding the one or more data packets during the determined time duration available in the second DRX cycle so as to increase time duration of sleeping mode of the user device.

3. The method as claimed in claim 1, wherein the first DRX cycle is a cycle in which the data packet is received and the second DRX cycle is a cycle which comes next to the first DRX cycle.

4. The method as claimed in claim 1 further comprising encoding one or more data packets in a second DRX cycle during transmission of previously encoded one or more data packets.

5. The method as claimed in claim 1 further comprising synchronizing time duration of transmission of one or more data packets with time duration of reception of one or more data packets in order to increase the time duration of sleeping mode of the user device.

6. The method as claimed in claim 5, wherein the synchronizing time duration of transmission of one or more data packets with time duration of reception of one or more data packets comprises:
estimating a response time duration to a scheduling request for transmission of one or more data packets; and
determining time duration for sending the scheduling request in order to finish the transmission of the one or more data packets during the time duration of reception of one or more data packets.

7. A system for reducing power consumption in a user device during wireless communication, the system comprising:
means for receiving one or more data packets during a first DRX cycle at the user device;
means for determining time period in a second DRX cycle for decoding the received data packets in order to increase time duration of sleeping mode of the user device; and
means for decoding the received data packets during the determined time period at the user device.

8. The system as claimed in claim 7 further comprising encoding one or more data packets in a second DRX cycle during transmission of previously encoded one or more data packets.

9. The system as claimed in claim 7 further comprising means for synchronizing time duration of transmission of one or more data packets with time duration of reception of one or more data packets in order to increase the time duration of sleeping mode of the user device.