GB2500895A

GB2500895A - A User Equipment obtaining a duty cycle command and using a Long Duty Cycle if certain conditions are met

Info

Publication number: GB2500895A
Application number: GB1205962.2A
Authority: GB
Inventors: Petteri Kalle Kela; Henri Jani Llari Virta
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2012-04-03
Filing date: 2012-04-03
Publication date: 2013-10-09
Also published as: GB201205962D0

Abstract

The UE obtains a duty cycle command 301 from the RAN and uses the long duty cycle 304 if both of the following conditions are true: a) the short duty cycle is configured and an inactivity timer has expired 302 and b) the short duty cycle is configured and a short duty cycle counter has expired 303. If condition a) is false or condition b) is false, the UE uses the short duty cycle 305. In one aspect, a long duty cycle is used 304 when possible because it reduces a UE's power consumption. If, however, the UE has been active within an on period, use of the short duty cycle may be advisable to avoid latencies in the transmission. The UE performs a method of transmission or reception when either a long duty cycle is configured or a short duty cycle is configured. The duty cycle command may be a Discontinuous Reception (DRX) Command MAC Control element. Embodiments of the invention include a method of removing data from a buffer that is located in a UE.

Description

METHODS AND APPARATUS FOR TRANSMISSION OR RECEPTION

Technical Field

The present invention relates to a method and apparatus for transmission or S reception. The present application relates generally radio access networks (RAN5), Radio Resource Control (RRC), and Discontinuous Transmission and Reception (DTX/DRX).

Background

Universal Mobile Telecommunication System (UMTS), Universal Terrestrial Radio Access Network (UTRAN), a Long Term Evolution (LTE) network called Evolved IJTRAN (E-UTRAN), and an LTE advanced network are some examples of RANs. A base station, or an evolved Node B (eNB) in 3rd Generation Partnership Project (3GPP) LTE, assigns radio resources to a user equipment (DIE) and signa's this information to the DIE on a control channel. The UE may be a mobile terminal or another type of device capable of communication in a RAN. Transmissions are divided in an LTE network into lms time periods called subframes. The radio resources, which are assigned to the DIE, are available in subframes on a certain data channel of the RAN. Transmitted packets may be lost. When a retransmission of a packet is needed, the retransmission is performed using Hybrid Adaptive Repeat and Request (HARQ).

The Discontinuous Transmission and Reception (DTX1DRX) function provides transmission and reception possibilities in the downlink direction or in the uplink direction. Control channels are intended for requesting and informing radio resources of shared channels and the shared channels are intended for transmitting data. The following describes use of the channels in the LTE network. When there is a need fbr a downlink transmission, the RAN sends a downlink (DL) assignment on Physical Downlink Control Channel (PDCCH). The DL assignment discloses one or more subframes on Physical Downlink Shared Channel (PDSCH). Then the DIE monitors the PDSCH according to the DL assignment and receives data.

Alternatively, when there is a need for an uplink transmission, the UE sends a scheduling request (SR) on Physical Uplink Contr& Chann& (PUCCH) and the RAN normally replies to the SR with an uplink (UL) grant on Physical Downlink Control Channel (PDCCH). The UL grant discloses one or more subframes on Physical S Uplink Control Channel (PUSCH). Then the UE can send data on the PUSCH according to the UL grant.

The DRX function can be utilised to reduce power consumption at the UE. A duty cycle includes an on period and an off period. The UE may be allowed to sleep during the off period. In the LTE network, the duty cycle is termed "DRX Cycle", the on period is "On Duration", and the off period is "Opportunity for DRX". In addition, it is possible to use a DRX Inactivity Timer to lengthen the On Duration and shorten the Opportunity fbr DRX. The DRX Inactivity Timer is started if the UE is involved in transmission or reception. When the DRX Inactivity Timer is running the UE continues monitoring the PDCCH until the DRX Inactivity Timer expires. The expiration of the DRX Inactivity Timer does not necessarily mean that the UE can sleep to the next on period. The UE must stay in the active state if its scheduling request is pending or it has data in a UL HARQ buffer.

Figure 1 illustrates the DRX function and certain DRX terms. The LTE terms corresponding to these DRX terms are mentioned in parenthesis. A long duty cycle 101 (DRX Cycle) specifies the periodic repetition of an on period 102 (On Duration) followed by a possible off period 103 (Opportunity for DRX). An on period timer (onDurationTitner) is started at beginning of the on period 102 and it expires when the on period ends. At the beginning of the on period 102, the on period timer contains a number of time periods (subframes) of the on period and its value turns to zero when the on period ends. Thus, the on period timer measures the on period in time units (subframes). Correspondingly, an inactivity timer measures the duration of a certain time period 104 in time units (subframes). The inactivity timer is started in response to a resource allocation 105 that is either a DL assignment or an lit grant. If the UE receives another resource allocation before the expiration of the inactivity timer, the inactivity timer is restarted. Thus, it is possible that the DIE misses the off period because of the resource aHocations. In the LTE network, the UE monitors the PDCCH for possible resource allocations. A short duty cycle 106 (DRX Short Cycle) specifies a periodic repetition of the on period 102. The short duty cycle is an S alternative for the long duty cycle 101. The off period 107 of the short duty cycle 106 is shorter than the off period 103 of the long duty cycle 101. The on periods 102 have the same length in the both cycles. The long duty cycle 101, the on duration 102, the time period 104 set in the inactivity timer, and the short duty cycle 106 are parameters which affect the operation of the DRX frmnction. The parameter values can be set in many ways. There are at least two subject matters to consider. One is the power consumption of the UE and the other is latency in the transmission or reception.

The eNB schedules transmission resources, i.e. subframes, for UEs located in its area. In more detail, the eNB schedules the resources allocations to the DIEs taking into account the on periods of the UEs. The eNB knows when a single UE has an on period. The short duty cycle reduces the latency in the transmission or reception, because the off periods are shorter in the short duty cycle than in the long duty cycle.

For example, when browsing Web pages users expect short latencies. On the other hand, a long duty cycle with a long off period is beneficial for reducing the UE's power consumption.

Hereafter the most relevant 3GPP specifications are referenced with "TS" and numbers and section (or page), for example, TS 36.32 1, section 5.7. The referenced TS 36.213 is version V10.4.0, the referenced TS 36.321 is version V10.4.0, and the referenced TS 36.331 is version V10.5.0. In addition to the LTE terms, certain general telecommunication terms are used in the present specification. One of these terms is a duty cycle which is utilised in various systems. A resource allocation contains radio resources allocated to the liE for sending or receiving data. The resources are subframes in the LTE network and time slots in a Global System for Mobile Communications (GSM) network. The discontinuous reception and transmission may or may not be based on the LTE DRX function (TS 36.321, section 5.7 and TS 36.33 1, page 172). The LTE DRX ifinction specifies a logic which the UE must follow. The logic includes the following rules A), B), and C): A) if a DRX Command MAC control clement is received: -stop onDurationTiiner; -stop drx-JnactivityTiiner.

B) if dr'c-JnactivitvTi,ner expires or a DRX Command MAC control clement is received in this subframe: -ifthe Short DRX cycle is configured: -start or restart drxS/iortCycleTitner; -usc the Short DRX Cycic.

-else: -usc the Long DRX cycle.

C) if drxShortCycleTiiner expires in this subframe: -use the Long DRX cycle.

In the above logic, a DRX command is termed in the LTE network a "DRX Command MAC control clement", the on period is measured by an onDuraflonTirner, the inactivity timer is termed a drx-InactivityTimer, and the number of short duty cycles is measured with a a'rxShortCycleTimer. The number of short duty cycles is some integer from I to 16. In the above logic, "the Short DRX cycle is configured" means that the UE has received DRX parameters sent from the RAN and has taken them into use. The liE uses by default the Long DRX Cycle. In the above logic, "use the Short DRX Cycle" means that the UE either continues the use of the Short DRX cycle or the UE stops the use of the Long DRX Cycle and starts the use of the Short DRX cycle.

The logic has involved a problem that when the short DRX Cycle is configured at the liE and the liE receives the DRX command, the TilE must take the short DRX into use, even though there has not been any activity within the on period.

S This consumes the battety of the liE uselessly. The activity includes detecting such resource allocation on the PDCCH that is addressed to the UE.

The prior art DRX function has also involved another problem that relates to uplink transmissions. When the TiE has data to send to the RAN, it must first send a scheduling request on the PUCCH to the eNB, after which the eNB informs on the PDCCH the liE about resources allocations. Then the liE sends the data on the PUSCH according to the resource allocations. The problem is that the UE does not know whether the data is handled successfully in the RAN or not. Thus, the liE must retain the data in its buffer and monitor the PDCCH due to possible retransmission requests. Because the liE must stay in the active state, its off period (Opportunity for DRX) is shortened.

Summary

According to a first aspect of the present invention, there is provided a method of transmission or reception at a user equipment when either a long duty cycle is configured or a short duty cycle is configured, the method comprising the following performed at the user equipment: receiving a duty cycle command from a radio access network, using the long duty cycle when both of the following conditions are true: the short duty cycle is configured and an inactivity timer has expired and the short duty cycle is configured and a short duty cycle counter has expired.

In one embodiment of the method: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period, and the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.

S In one embodiment of the method, the method comprises the following: determining an action on the basis of at least one of the following grounds: the receiving of the duty cycle command, detecting a certain type of the duty cycle command, and detecting certain information includcd in the duty cycle command.

In one embodiment of the method, the method comprises at least one of the following performed according to the action: stopping the short duty cycle, and starting the long duty cycle.

In one embodiment of the method, the method comprises at least one of the following performed according to the action: stopping the long duty cycle, and starting the short duty cycle.

In one embodiment of the method, the method comprises the following performed according to the action: removing data from a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.

In one embodiment of the method, a Discontinuous Reception (DRX) Command MAC Control Element is utilised as the duty cycle command.

In one embodiment of the method, a downlink control message is utilised as the duty cycle command.

In one embodiment of thc mcthod, the downlink control message is formulated using the format ofDownlink Control Information (DCI).

In one embodiment of the method the downlink control message includes a S Resource Indication Value (MV).

According to a second aspect of the present invention, there is provided a method of removing data from a buffer that is located in auscr equipment, the method comprising thc following pcrformcd in a radio access nctwork: dctcrmining that a message sent from a user equipment is successfully handled in the radio access network, wherein the message carries the data; and triggering the user equipment to remove the data from a buffer that is located in the user equipment.

In one embodiment of the method, the buffer is used in a hybrid adaptive repeat and request (HARQ) procedure.

In one embodiment of the method, the triggering empties all uplink (IJL) HARQ buffers at the user equipment.

In one embodiment of the method, the triggering is based on one of the following techniques: utilising a DRX Command MAC Control Element, utilising a downlink control message.

In one embodiment of the method, the determining is based on at least one of the following grounds: a certain time period is passed without a retransmission request of the message, the message is acknowledged to be received, the message is the last one in a transmission,

S

the message has minor importance.

According to a third aspect of the present invention, there is provided apparatus, compnsrng: S a processing system constructed and arranged to cause the apparatus to perform at a user equipment at least the following: receiving a duty cycle command from a radio access network, using a long duty cycle when both of the following conditions are true at the uscr equipment: a short duty cycle is configured and an inactivity timer has expired and the short duty cycle is configured and a short duty cycle counter has expired.

In one embodiment of the apparatus: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period, and the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.

In one embodiment of the apparatus, the apparatus is arranged to perform: determining an action on the basis of at least one of the following grounds: the receiving of the duty cycle command, detecting a certain type of the duty cycle command, and detecting certain information included in the duty cycle command.

In one embodiment of the apparatus, the apparatus is arranged to perform at least one of the following: stopping the short duty cycle, and starting the long duty cycle.

hi one embodiment of the apparatus, the apparatus is arranged to perform at least one of the following: stopping the long duty cycle, and starting the short duty cycle.

In one embodiment of the apparatus, the apparatus is arranged to perfornt removing data am a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.

According to a fourth aspect of the present invention, there is provided apparatus, comprising: a processing system constructed and arranged to cause the apparatus to perform in a radio access network at least the following: forming a duty cycle command so that it triggers a user equipment to usc of the long duty cycle when both of the fOllowing conditions are true at the user equipment: a short duty cycle is configured and an inactivity timer has expired and the short duty cycle is configured and a short duty cycle counter has expired.

In one embodiment of the apparatus, the duty cycle command is such that: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period, and wherein the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.

In one embodiment of the apparatus, the apparatus is arranged to perform: including an action into the duty cycle command.

In one embodiment of the apparatus, the action causes at least one of the following: triggering the user equipment to stop the short duty cycle, and triggering the user equipment to start the long duty cycle.

S

In one embodiment of the apparatus, the action causes at least one of the following: triggering the user equipment to stop the long duty cycle, and triggering the user equipment to start the short duty cycle.

In one embodiment of the apparatus, the action causes: triggering the user equipment to remove data from a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.

In one embodiment of the apparatus, the triggering is based on one of the following techniques: utilising a DRX Command MAC Control Element, and utilising a downlink control message.

According to a fifth aspect of the present invention, there is provided apparatus, compnsing: a processing system constructed and arranged to cause the apparatus to perform in a radio access network at least the following: determining that a message sent from a user equipment is successfully handled in the radio access network, wherein the message carries the data; and triggering the user equipment to remove the data from a buffer that is located in the user equipment.

The processing systems described above may comprise at least one processor, and at least one memory including computer program code, the at least one memory and the computer program code being arranged to, with the at least one processor, cause the apparatus to perform as described above.

There may also be provided a computer program comprising instructions such S that when the computer program is executed on a computing device, the computing device is arranged to carry out a method as described above. There may also be provided a non-transitory computer-readable storage medium comprising a set of computer-readable instructions stored thereon, which, when executed by a processing systcm, causc the processing systcm to carry out a method as described abovc.

One aspect of the present invention is that a long duty cycle is used when possible, because it reduces the liE's power consumption. 1f however, the liE has been active within the on period, use of the short duty cycle may be advisable to avoid latencics in the transmission. Embodiments of the present invention aim to solve the problem related to the DRX command. In other words, when the short duty cycle is configured at the liE and the liE receives a duty cycle command, the liE will usc the long duty cycle, if there has not been any activity within the on period and thus there is no reason to use the short duty cycle.

In anther aspect, the present invention aims to solve the problem related to the uplink transmissions. Generally spcaking, the solution is to inform the UE to flush its Ut buffer, or the all Ut buffers, when there is no reason to expect that any retransmission is needed.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 shows schematically an example of the DRX function; Figure 2 shows schematically an example of a method of removing data from a buffer; Figure 3 shows schematically an example of a method of transmission or S reception; Figure 4 shows schematically an example of an apparatus placed in a user equipment; and Figurc 5 shows schematically an example of an apparatus locating in a radio access network;

Detailed Description

The present specification principally describes two methods: a method of removing data from a buffer and a method of transmission or reception. The first method is intended for flushing one or more buffers. As mentioned in the above, in the case of an LTE network, the UE must monitor the PDCCH to detect possible retransmission requests if the liE's UI. HARQ buffer is not empty. The flushing of this buffer increases a probability that the liE's active time ends (TS 36.321, section 5.7) and the UE is allowed to move into the inactivity state. The second method is intended for selecting an appropriate duty cycle, i.e. the long duty cycle or the short duty cycle.

Figure 2 shows schematically an example of the method of removing data.

The method affects one or more buffers located in the liE. A buffer is, for example, a IJL HARQ buffer. The method comprises the following to be performed in a base station, or somewhere else in the RAN. The RAN determines 201 that a message sent from the user equipment is successfUlly handled in the RAN. This message carries the data stored in the buffer. When the message is deemed to be successfully handled, the RAN triggers 202 the user equipment to remove data from the buffer. In more detail, the RAN triggers by a buffer command the liE to remove the data.

The buffer command may disclose that a) all buffers are flushed, b) a certain buffer or buffers are flushed, or c) a certain buffer is partly flushed, i.e. the buffer is not empty after removing the data. The tiE obeys the buffer command. After S performing the buffer command, the UE may detect that at least one buffer has emptied. Then the UE determines whether sleeping is allowed or not. The method can be utilised especially in the HARQ procedure, but also in other RAN procedures.

The determining in step 201 is based on at least one of the following grounds.

The first ground is that a certain time period is passed without a retransmission request of the message. Such a retransmission is originated, for example, from a recipient of the message. The recipient is, for example, another liE. Alternatively, the retransmission may be originated from some network element of the RAN. The second ground is that the message is acknowledged to be received. This acknowledgement may be from the recipient of the message or some network element of the RAN. The third ground is that the message is the last one in a transmission.

This is a communication protocol-specific ground. If the communication protocol does not disclose that the message is the last one, the UE may indicate the subject matter in one way or other. The fourth ground is that the message has a minor importance. The liE may communicate with the recipient by sending a set of messages at a time, wherein the set includes at least one message. If the recipient does not obtain the whole set, the recipient requests the UE to resend it. Then the UE generates the data and transmits it in the set of messages to the recipient.

The triggering in step 202 is performed with the buffer command. For example, a DRX command can be used as the buffer command. Because there are different actions, different buffer commands are needed, too. Correspondingly, in the method of transmission or reception, different duty cycle commands are usditi to disclose which action the UE should perform. The following description concems a formulation of commands. Those commands may be the buffer commands or the duty cycle commands.

A Resource Indication Value (RIV) specifies a resource allocation, i.e. which resource blocks (RB) are allocated to the liE. The RAN signals the RIV on the PDCCH and the UE obtains the MV with Downlink Control information (DCI).

S When utilising the RIV in either of the methods, the RAN signals to the UE such RIV value that is an invalid value according to present (March 2012) specifications. TS 36.213, section 7.1.6 specifies a calculation of the REV for downlink transmissions and section 8.2 specifies the calculation for uplink transmissions. There exist a number of invalid values. An invalid value can be uscd in either of the methods to carry a certain command to thc liE.

The DCI format can be utilised in a corresponding way for creating different commands. TS 36.213, section 9.2 specifies valid bitmasks for the DCI format. In addition to these valid bitmasks, there exists invalid bitmasks. An invalid bitmask can be utilised as a command by which the RAN triggers the TilE to perform a certain action.

In one embodiment of the invention, the method of transmission is utilised afler the rule B) and before the rule C) described in the above. The terms used in the method correspond to LTE terms in the following way: -a long duty cycle is DRX Cycle -a short duty cycle is Short DRX Cycle -a short duty cycle counter is drxshortçvcicTitner -a duty cycle command is, for example, a DRX Command MAC Control Element.

The DRX command is specified in TS 36.321, section 6.1.3.3. The eNB uses the DRX command to inform the UE to stop the onDurationTirner and the DRX Inactivity Timer. Stopping these timers, however, has no effect on possible UL HARQ retransmission allocations. In more detail, there may be a need for a retransmission of lost data and due to this need the eNB allocates to the UB uplink resources for retransmitting the lost data. Thus, the UE must keep the data in its UL HARQ buffer and monitor the PDCCH to detect the possible UL HARQ retransmission allocations.

S Figure 3 shows schematically an example of the method of transmission or reception. The UE performs the method when either a long duty cycle is configured or a short duty cycle is configured. The TIE receives or obtains 301 a duty cycle command from the RAN and uses 304 the long duty cycle if both of the following conditions are true: a) the short duty cycle is configured and an inactivity timer has expired 302 and b) the short duty cycle is configured and a short duty cycle counter has expired 303. If condition 302 is false or condition 303 is false, the UE uses 305 the short duty cycle.

In condition 302, the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period. The RAN sets the certain time period.

In condition 303, the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer. The RAN sets the certain integer, for example, an integer between 1 and 16.

In one embodiment of the invention, the UE performs an action in response to obtaining 301 the duty cycle command. The UE determines the action on the basis of at least one of the following grounds. The first ground is obtaining of the duty cycle command. In other words, there exists just one type of duty cycle command. The second ground is detecting the type of the duty cycle command. At present, the type of the duty cycle is quite difficult to inform to the UE. When the duty cycle has a certain type, the UE performs a certain action that is mapped to that type of duty cycle command. The third ground is detecting certain information included in the duty cycle command. In other words, the FE reads the information and determines the action on the basis ofthc information.

In one embodiment of the invention, the action is switching the cycle. Then S the UE stops the short duty cycle and starts the long duty cycle, or vice versa, i.e. the liE stops the long duty cycle and starts the short duty cycle.

In one embodiment of the invention, the action is removing data from the FE's buffer. The UE has included this data in its transmission and the data is handled in the RAN. In more detail, the data is conveyed in thc RAN and it may have reached, or may have not reached, one or more recipients. The RAN is, however, capable of determining whether there is any need for retransmission of the data.

When this need is missing, the RAN triggers the liE to remove the data from the buffer.

The duty cycle command in step 301 is, for example, a DRX Command MAC Control Element. The DRX Command MAC Control Element can be used according the above-mentioned first ground as the duty cycle command. Thus, the duty cycle command triggers the UE to perform an action. The action may be a process including multiple tasks.

Alternatively, the duty cycle command in step 301 is carried in a data structure which is made for the duty cycle command. This means basically that "value 1" in the data structure triggers the UE to perform "action 1" and "value 2" in the data structure triggers the liE to perform "action 2", etc. In other words, the value (1, 2, etc.) discloses, according to the above-mentioned second ground, the type of the duty cycle command. At the present, this kind of data structure is missing, but it may be available in the fUture.

Alternatively, if the DRX Command MAC Control Element can be modified so that the modification does not cause any harm in the RAN or at liEs, the modification is used as thc duty cycle command in stcp 301. Then a basic DRX Command MAC Control Element discloses (more or less according to the second ground) one type of the duty cycle command and the modification discloses another type of the duty cycle command.

S

Alternatively, the duty cycle command in step 301 is, for example, a downlink control message that includes certain information. In the LTE network, the eNB signals the downlink control messagc on thc PDCCH to the UE. Thc ccrtain information includcd in thc downlink control mcssagc is uscd according thc above-mcntioncd third ground to triggcr thc DE to pcrform a ccrtain action. In thc LTE network a suitable format for the downlink control message is the format which is used in the prior art for a Semi-Persistent Scheduling (SPS) assignment. In more detail, this format is used to carry a certain duty cycle command to the UE. The LTE RAN places in the downlink control message such bitmask which is invalid according to the present DCI format (March 2012). In addition, or alternatively, The LTE RAN places in the down link control message such bitmask which is presently (March 2012) an invalid RTV.

It should be noticed that, in the method of removing data (FIG. 2), the buffer command can be formulated using the same principles as described with regard to the duty cycle command. Therefore, the buffer command in step 202 is, for example, a DRX Command MAC Control Element.

Alternatively, the duty cycle command in step 301 is carried in a data structure which is made for this purpose. Then, for example, "value 1" in the data structure would trigger the UE to perform "buffer action 1" and "value 2" would trigger the liE to perform "buffer action 2", etc. This kind of data structure may be available in the future.

Alternatively, if the DRX Command MAC Control Element can be modified so that the modification does not cause any harm in the RAN or at liEs, the modification is uscd as thc buffer command in stcp 202. Then a basic DRX Command MAC Control Element discloses one type of buffer command and the modification discloses another type of buffer command.

S Alternatively, the buffer command in step 202 is, for example, a downlink control message that includes certain information. The certain information can be included the message using such bitmask that is invalid according the present DCI format, or using such bitmask that is an invalid RIV.

Figure 4 shows schematically an example of the apparatus 401 placed in a user equipment 405. The apparatus 401 comprises at least one processor 402 and at least one memory 403 including computer program code 404. The apparatus 401 obtains a duty cycle command 406 from the RAN. In more detail, the duty cycle command 406 is obtained through the user apparatus 405 and through a radio interface 407. The apparatus 401 obeys the duty cycle command and uses the long duty cycle when both of the following conditions are true at the user equipment: a) the short duty cycle is configured and an inactivity timer has expired and b) the short duty cycle is configured and a short duty cycle counter has expired. The above-mentioned inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period. The above-mentioned short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.

The apparatus 401 is further caused to pcrfbrm the method of transmission or reception. Therefore, the apparatus 401 is able to determine an action on the basis of at least one of the following grounds: a) the receiving or obtaining of the duty cycle command, b) detecting a certain type of the duty cycle command, or e) detecting certain information included in the duty cycle command. The apparatus is able to stop the short duty cycle and/or start the long duty cycle, and it is able to stop the long duty cycle and/or start the short duty cycle. The apparatus 401 can also remove data from a buffer 408. This data is included in the transmission or reception and is handled in the radio access network.

Figure 5 shows schematically an example of the apparatus 501 located in the RAN. The apparatus 501 comprises at least one processor 502 and at least one memory 503 including computer program code 504. The apparatus 501 forms a duty cycle command 505 so that the duty cycle command 505 triggers a user equipment to use the long duty cycle when both of the following conditions are true at the user equipment: a) the short duty cycle is configured and thc inactivity timer has expired and b) the short duty cycle is configured and the short duty cycle counter has cxpircd.

The RAN transmits the duty cycle command 505 through a radio interface 506 to a user equipment 507.

The apparatus 501 is able to include an action into the duty cycle command 505. This action causes at least one of the following: triggering the user equipment 507 to stop the short duty cycle, and!or triggering the user equipment 507 to start the long duty cycle. Alternatively, the action causes at least one of the following: triggering the user equipment to stop the long duty cycle, and/or triggering the user equipment to start the short duty cycle. Alternatively, the action causes at least one of the following: triggering the user equipment to remove data from a buffer, wherein the data is included in the transmission or reception and is handled in the radio access network. This triggering is based on one of the following techniques: 1) utilising a DRX Command MAC Control Element or 2) utilising a downlink control message.

The LTE network can efficiently be deployed in both the paired and unpaired spectrums. The basic principle of TDD is to use the same frequency band for transmission and reception. This is a fundamental difference compared to Frequency Division Duplex (FDD) where different frequencies arc used for continuous liE reception and transmission. LTE TDD and FDD modes have been greatly harmonised in the sense that both modes share the same underlying framework, including radio access schemes Orthogonal Frequency Division Multiplexing Access (OFDMA) in downlink and Single Carrier Frequency Division Multiplexing Access (SC-FDMA) in uplink direction, and a concept of a subframc. The TDD mode is inchjdcd together with the FDD mode in many specifications, including also physical layer specifications. The LTE harmonisation has resulted in that in terms of architecture, S the TDD mode and the FDD mode are very similar. Another key feature of the LTE TDD mode is the commonality with Time Division Synchronous Code Division Multiple Access (TD-SCDMA). TD-SCDMA is an air interface found in IJIIVITS mobile telecommunications networks in China as an alternative to Wideband Carrier Frequency Division Multiplexing Access (W-CDMA). Together with TD-CDMA, it is also known as UMTS-TDD or IMT 2000 Timc-Division (IMT-TD). Thcrc is a global trend to reserve significant unpaired spectrum allocations and deploy those allocations in the LTE TDD mode.

As mentioned in the above, the uplink and downlink resources of the RAN which are used in transmissions or receptions are scheduled according to a time-division to the UEs. This time division may or may not be TDD. The time division means that a transmission, either in uplink direction or in downlink direction, is divided in time periods. The present invention can be utilised in LTE networks and in other types of RANs.

The exemplary cmbodimcnts dcscribcd in the above may includc, for example, any suitable network devices, base stations, eNodeBs, RAN devices, laptop computers, Internet appliances, handheld devices, cellular telephones, smart phones, wireless devices, and the like, capable of performing the processes of the exemplary embodiments. The devices and subsystems of the exemplary embodiments can communicate with each other using any suitable protocol and they may be implemented using one or more programmed computer systems or devices.

The present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The application logic, software or instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable medium may S comprise a computer-readable storage medium that may be any media or means that contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

The exemplary embodiments can store information relating to various processes described herein. This information can be stored in one or more memories, such as a hard disk, optical disk, magneto-optical disk, RAM, and the like All or a portion of the exemplary embodiments can be conveniently implemented using one or more general purpose processors, microprocessors, digital signal processors, micro-controllers, and the like, programmed according to the teachings of the exemplary embodiments of the present invention, as will be appreciated by those skilled in the computer and/or software art(s). Appropriate software can be readily prepared by programmers of ordinary skill based on the teachings of the exemplary embodiments, as will be appreciated by those skilled in the software art. In addition, the exemplary embodiments can be implemented by the preparation of application-specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be appreciated by those skilled in the electrical art(s). Thus, the exemplary embodiments are not limited to any specific combination of hardware andlor software.

Stored on any one or on a combination of computer readable media, the exemplary embodiments of the present invention can include software for controlling the components of the exemplary embodiments, for driving the components of the exemplary embodiments, for enabling the components of the exemplary embodiments to interact with a human user, and the like. Such software can include, but is not limited to, device drivers, firmware, operating systems, development tools, applications software, and the like. Such computer readable media ifirther can include the computer program of an embodiment of the present invention for performing afl or a portion (if processing is distributed) of the processing performed in implementing the present invention. Computer code devices of the exemplary embodiments of the S present invention can include any suitable interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs), Java classes and applets, complete executable programs, Common Object Request Brolcer Architecture (CORBA) objects, and the 111cc.

While the prcsent invention has been dcscribed in conncction with a numbcr of exemplary embodiments, and implementations, the present invention is not so limited, but rather covers various modifications, and equivalent arrangements, which fall within the purview of prospective claims.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

CLAIMS1. A method of transmission or reception at a user equipment when either a long duty cycle is configured or a short duty cycle is configured, the method comprising S the following performed at the user equipment: receiving a duty cycle command from a radio access network, using the long duty cycle when both of the following conditions are true: the short duty cycle is configured and an inactivity timer has expired and the short duty cycle is configured and a short duty cycle counter has expired.
2. A method according to claim 1, wherein: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period, and wherein: the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.
3. A method according to claim 1 or claim 2, wherein the method comprises: determining an action on the basis ofat least one of the following grounds: the receiving of the duty cycle command, detecting a certain type of the duty cycle command, and detecting certain information included in the duty cycle command.
4. A method according to claim 3, wherein the method comprises at least one of the following performed according to the action: stopping the short duty cycle, and starting the long duty cycle.
5. A method according to claim 3, wherein the method comprises at least one of the following performed according to the action: stopping the long duty cycle, and starting the short duty cycle.
6. A method according to any of claims 3 to 5, wherein the method comprises the S following performed according to the action: removing data from a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.
7. A method according to any of claims I to 6, wherein a Discontinuous Reception (DRX) Command MAC Control Element is utilised as the duty cycle command.
8. A method according to any of claims I to 6, wherein a downlink control message is utihscd as the duty cycle command.
9. A method according to claim 8, wherein the downlink control message is formulated using the format of Downlink Control Information (DCI).
10. A method according to claim 8, wherein the downlink control message includes a Resource Indication Value (RIV).
11. A method of removing data from a buffer that is located in a user equipment, the method comprising the following performed in a radio access network: determining that a message sent from a user equipment is successfully handled in the radio access network, wherein the message carrics the data; and triggering the user equipment to remove the data from a buffer that is located in the user equipment.
12. A method according to claim 11, wherein the buffer is used in a hybrid adaptive repeat and request (HARQ) procedure.
13. A method according to claim 12, wherein the triggering empties all uplink (UL) HARQ buffers at the user equipment.
14. A method according to any of claims 11 to 13, wherein the triggering is based on one of the following techniques: utilising a Discontinuous Reception (DRX) Command MAC Control Element, utilising a downlink control message.
15. A method according to any of claims 11 to 14, whcrcin the determining is based on at least one of the fbllowing grounds: a certain time period is passed without a retransmission request of the message, the message is acknowledged to be received, themessageisthelastoneinatransnilssion, the message has minor importance.
16. Apparatus comprising: a processing system constructed and arranged to cause the apparatus to perform at a user equipment at least the following: receiving a duty cyclc command from a radio access nctwork, using a long duty cycle when both of the following conditions are true at the user equipment: a short duty cycle is configured and an inactivity timer has expired and the short duty cycle is configured and a short duty cycle counter has expired.
17. Apparatus according to claim 16, wherein: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expires after a certain time period, and wherein the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.
18. Apparatus according to claim 16 or claim 17, wherein the apparatus is arranged to perform: determining an action on the basis of at least one of the following grounds: the receiving of the duty cycle command, detecting a certain type of thc duty cyclc command, and detecting certain information includcd in thc duty cycle command.
19. Apparatus according to claim 18, wherein the apparatus is arranged to perform at least one of the following: stopping the short duty cycle, and starting the long duty cycle.
20. Apparatus according to claim 18, wherein the apparatus is arranged to perform at least one of the following: stopping the long duty cycle, and starting the short duty cycle.
21. Apparatus according to any of claims 18 to 20, wherein the apparatus is arranged to perform: removing data from a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.
22. Apparatus, comprising: a processing system constructed and arranged to cause the apparatus to perform in a radio access network at least the following: fbrming a duty cycle command so that it triggers a user equipment to use of the long duty cycle when both of the following conditions are true at the user equipment: a short duty cycle is configured and an inactivity timer has expired and S the short duty cycle is configured and a short duty cycle counter has expired.
23. Apparatus according to claim 22, wherein the duty cycle command is such that: the inactivity timer has either started or restarted after each resource allocation detected by the user equipment and the inactivity timer expircs aftcr a certain time period, and wherein the short duty cycle counter has started in response to an expiration of the inactivity timer and the short duty cycle counter expires when reaching a certain integer.
24. Apparatus according to claim 22 or claim 23, wherein the apparatus is arranged to perform: including an action into the duty cycle command.
25. Apparatus according to claim 24, wherein the action causes at least one of the following: triggering the user equipment to stop the short duty cycle, and triggering the user equipment to start the long duty cycle.
26. Apparatus according to claim 24, wherein the action causes at least one of the following: triggering the user equipment to stop the long duty cycle, and triggering the user equipment to start the short duty cycle.
27. Apparatus according to any of claims 24 to 26, wherein the action causes: triggering the user equipment to remove data from a buffer, wherein data is included in the transmission or reception and is handled in the radio access network.
28. Apparatus according to claim 27, wherein the triggering is based on one of the S following techniques: utilising a Discontinuous Reception (DRX) Command MAC Control Element, and utilising a downlink control message.
29. Apparatus, comprising: a processing system constructed and arranged to cause the apparatus to perform in a radio access network at least the following: determining that a message sent from a user equipment is successffilly handled in the radio access network, wherein the message carries the data; and triggering the user equipment to remove the data from a buffer that is located in the user equipment.
30. A computer program comprising instructions such that when the computer program is executed on a computing device, the computing device is arranged to carry out a method according to any of claims Ito 15.
31. A method of transmission or reception, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.
32. Apparatus for transmission or reception, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.