WO2014009911A1

WO2014009911A1 - Wireless communication system and method

Info

Publication number: WO2014009911A1
Application number: PCT/IB2013/055703
Authority: WO
Inventors: Manmohan Singh
Original assignee: Renesas Mobile Corporation
Priority date: 2012-07-12
Filing date: 2013-07-11
Publication date: 2014-01-16
Also published as: GB201212389D0; GB2491050A; GB2491050B

Abstract

An apparatus is described which can increase the time before a call is dropped in weak signal areas. The apparatus comprises a processor which is configured determine whether voice and/or video data is in the process of transmission and/or reception; and select the last transmitted Packet Data Unit for polling transmission in response to a polling event if it is determined that that voice and/or video data is in the process of transmission and/or reception. When applied to UMTS and E-UTRA protocols, the last transmitted packet data unit has a sequence number equal to VT(S)-1. It has been found that voice and/or video calls may be dropped in weak signal areas because of a reset triggered for the Acknowledged Mode bearer within the Radio Link Control (RLC). The reset occurs because the same Packet Data Unit was selected for a polling transmission several times and triggered the reset by reaching its maximum transmission count. By selecting the last transmitted packet data unit, the packet data unit selected for polling transmission will change over time, increasing the time before a single packet data unit reaches its maximum transmission count. Although voice and video calls typically do not use AM, AM is used on the control and signalling channel and this has been found to be the cause of the reset.

Description

WIRELESS COMMUNICATION SYSTEM AND METHOD Technical Field

The present invention relates to wireless communication systems, methods and computer programs, and in particular to wireless systems in which data may be transmitted using a mode in which polling events can require selection of a previously transmitted, unacknowledged data packet for retransmission.

Background

In wireless communications systems, such as UMTS and E-UTRA, a User

Equipment (UE) transfers data wirelessly with a base station. The transfer of data is defined by various specifications operating across different layers of the OSI model. In UMTS and E-UTRA, a Radio Link Control (RLC) protocol specification defines standards for a sub-layer within Level 2 of the OSI model.

It has been observed that User Equipment (UE) may drop Voice or Video calls quickly in areas of weak signal strength. For example, in some circumstances, a call may be dropped as soon as two seconds after entering a weak signal area. Investigation of logs from UE experiencing dropped calls in weak signal areas has shown that the call is dropped because of a reset resulting from an unrecoverable error within the RLC.

It would be desirable to increase the time before a voice or video call is dropped in weak signal areas, because it is less disruptive for the user to experience a short reduction in call quality than for the entire call to be dropped.

Embodiments are directed towards increasing the time before a voice or video call is dropped in weak signal areas.

Summary

In accordance with one embodiment, there is provided an apparatus for transmission of data over a wireless network. The apparatus comprises a processing system arranged to, in response to a polling event when there are no Packet Data Units scheduled for transmission or retransmission: determine whether at least one of voice data and video data is in the process of transmission; and

select the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice data and video data is in the process of transmission.

In accordance with another embodiment, there is provided a method of selecting a packet data unit for polling transmission in response to a polling event when there are no Packet Data Units scheduled for transmission or retransmission. The method comprises:

determining whether at least one of voice and video data is in the process of transmission; and

selecting the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice and video data is in the process of transmission.

In another embodiment, there is provided a computer program product comprising computer program code embodied on a computer readable medium, wherein the computer program code, when executed by a processor, causes the processor to perform in response to a polling event and when there are no Packet Data Units (PDUs) scheduled for transmission or retransmission:

The embodiments are generally directed towards ensuring that the last PDU transmitted is selected for a polling transmission in the event that voice or video data is under transmission. The applicant has found that dropped calls in weak signal areas because a single PDU has been selected for polling transmission several times and has reached its maximum retransmission count. When a single PDU reaches its maximum transmission count an RLC reset is triggered. Although voice calls and video calls are unlikely to use a transmission mode which requires polling transmission, the signalling channel will typically use a transmission mode implementing polling. The reset procedure also drops all other connections which are not set up for call reestablishment, even if the data over that connection did not trigger the reset.

Selecting the last PDU transmitted for a polling transmission means that the PDU selected for retransmission will change over time as further PDUs are transmitted, making it less likely that a single PDU will reach its maximum transmission count and trigger a reset. This is particularly advantageous in weak signal areas because new measurement reports result in new PDUs over the signalling channel.

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 a schematic representation of a wireless communication system within which the embodiments operate;

Figure 2 shows a schematic representation of the radio interface protocol architecture for a User Equipment;

Figure 3 is a flow diagram that illustrates the operation of a method, and the result of computer program instructions embodied on a computer readable memory in accordance with one embodiment;

Figure 4 is a flow diagram that illustrates the operation of a method, and the result of computer program instructions embodied on a computer readable memory in accordance with another embodiment;

Figure 5 is a flow diagram that illustrates the operation of a method, and the result of computer program instructions embodied on a computer readable memory in accordance with an embodiment applied to the UMTS protocol;

Figure 6 is a flow diagram that illustrates the operation of a method, and the result of computer program instructions embodied on a computer readable memory in accordance with an embodiment applied to the E-UTRA protocol; Figure 7 is a flow diagram that illustrates the operation of a method, and the result of computer program instructions embodied on a computer readable memory in accordance with another embodiment applied to the E-UTRA protocol;

Figure 8 is a simplified block diagram of a communication network within which embodiments operate; and

Figure 9 is a simplified block diagram of various network devices, which are exemplary electronic devices suitable for use in practicing the exemplary embodiments.

Detailed Description

As used in this specification, a telecommunications device may include but is not limited to the following: (a) wired and wireless telephones, (b) satellite telephones, (c) personal communication devices, (d) electronic devices configured to share content in a local area network (LAN), (e) electronic gaming devices, (f) electronic music devices including, but not limited to, MP3 players and the like, (g) telecommunications network infrastructure equipment, including but not limited to a base station, (h) dual-mode cellular terminals which utilise a cellular network and a non-cellular network, (i) other types of mobile devices or terminals, (j) any machines configured for wireless communications in various applications, including but not limited to, smart homes, smart metering, fleet management, remote healthcare, or access network operation management, or (k) any device used in a device-to-device connection.

"Wireless devices" include in general any device capable of connecting wire- lessly to a network, and includes in particular mobile devices including mobile or cell phones (including so-called "smart phones"), personal digital assistants, pagers, tablet and laptop computers, content-consumption or generation devices (for music and/or video for example), data cards, USB dongles, etc., as well as fixed or more static devices, such as personal computers, game consoles and other generally static enter- tainment devices, various other domestic and non-domestic machines and devices, etc. The term "user equipment" or UE is often used to refer to wireless devices in general, and particularly mobile wireless devices. The terms "transmitter" and "receiver" are also used herein and are to be construed broadly to include the whole of a device that is transmitting/receiving wireless signals as well as only particular components of a device that are concerned with transmitting/receiving wireless signals or causing or leading to the transmission/reception of wireless signals.

Mobile devices include mobile or cell phones (including so-called "smart phones"), personal digital assistants, pagers, tablet and laptop computers, content- consumption or generation devices (for music and/or video for example), data cards, USB dongles, etc.

The term "radio system" is typically used in this specification to refer to one or more of the radio front end, antenna(s), and relevant processing circuitry and software required for transmission/reception in a wireless device. In at least some circumstances, the term "radio system" is used to refer to all of such components.

Figure 1 shows schematically a user equipment or wireless device, in this case in the form of a mobile phone/smartphone 1. The user equipment 1 contains the necessary radio module 2, processor(s) and memory/memories 3, antenna 4, etc. to enable wireless communication with the network. The user equipment 1 in use is in communication with a radio mast 5. As a particular example in the context of UMTS (Universal Mobile Telecommunications System), there may be a network control apparatus 6 (which may be constituted by for example a so-called Radio Network Controller) operating in conjunction with one or more Node Bs (which, in many respects, can be regarded as "base stations"). As another example, LTE (Long Term Evolution) makes use of a so-called evolved Node B (eNB) where the RF transceiver and resource management/control functions are combined into a single entity. The term "base station" is used in this specification to include a "traditional" base station, a Node B, an evolved Node B (eNB), or any other access point to a network, unless the context requires otherwise. The network control apparatus 6 (of whatever type) may have its own processor(s) 7 and memory/memories 8, etc.

Figure 2 shows schematically an example of the radio interface protocol architecture applicable for use with the user equipment and network control apparatus of Figure 1 in, for example, UMTS and E-UTRAN. A similar "layer" architecture is used in other wireless systems. In overview and in general terms, there is a physical layer LI 16, a data link layer L2 18 and a network layer L3 20. The physical layer LI 16 offers information transfer services to MAC and higher layers and defines the relationship between the user equipment and the wireless transmission medium. The data link layer L2 18 is split into following sub layers: Medium Access Control (MAC) 22, Radio Link Control (RLC) 26, Packet Data Convergence Protocol (PDCP) 30 and Broadcast/Multicast Control (BMC) 28. The network layer L3 and the RLC 26 are divided into a Control (C-) plane 34 (which in essence deals with control signals) and a User (U-) plane 36 (which in essence deals with user-generated data traffic). In the C-plane 34, the network layer L3 20 is partitioned into sub layers where the lowest sub layer, denoted as Radio Resource Control (RRC) 32, interfaces with the data link layer L2 18 and ultimately terminates in the radio access network.

The UMTS RLC protocol specification (3 GPP TS 25.322 version 10.1.0 Release 10), incorporated herein by reference, defines different RLC entities for operation of the RLC 26 in three general modes: Transparent Mode (TM), Unacknowledged Mode (UM) and Acknowledged Mode (AM). Which of the modes is used depends on requirements for a particular data traffic type. For example, voice and video data will typically use TM or UM, while signalling data will use AM.

AM sends data in Acknowledged Mode Packet Data Units (AMD PDUs). Each AMD PDU has a sequence number. A state variable VT(S) holds the sequence number of the next AMD PDU to be transmitted for the first time (i.e. excluding retransmitted PDUs) and is incremented after each new AMD PDU is transmitted. During operation in AM under the UMTS RLC protocol specification 25.322, the value of VT(S) is generally maintained within a window defined by a variable Configured Tx Window Size. Configured Tx Window Size is used initially to calculate the maximum allowable sequence number VT(MS).

In AM, both the first apparatus 2 and the second apparatus 4 can operate as a sender or a receiver. When operating as sender, the RLC uses a polling function at certain times to request the peer receiver RLC to send a status report. The polling function can be activated by various triggers including:

o The last Packet Data Unit (PDU) in a transmission buffer

o The last PDU in a retransmission buffer

o Expiration of a Poll timer These are only some examples; other triggers for the polling function may also be used and are described in detail in section 9.7.1 of the UMTS RLC Specification 25.322 (incorporated herein by reference). In response to the polling function a poll bit is set in an Acknowledged Mode Packet Data Unit (AMD PDU), which triggers the receiving RLC to send a status report in response.

If there is an AMD PDU scheduled for transmission or retransmission, the polling bit is set in one of the AMD PDUs scheduled for transmission or retransmission before it is transmitted or retransmitted. However, a poll may be triggered in the sender RLC when no AMD PDU is scheduled for transmission or retransmission. For example, this may happen on poll timer expiry. In that case, providing that there is at least one AMD PDU that has been transmitted, that has not been discarded and that has not yet been acknowledged, the sender RLC selects an AMD PDU that has been transmitted, not been discarded and not yet acknowledged for retransmission with the polling bit set.

The UMTS RLC protocol specification 25.322, section 11.3.2, defines rules for the selection of an AMD PDU for retransmission. Firstly, the AMD PDU with a sequence number equal to VT(S)-1 can be selected. Secondly, when Configured Tx Window Size is less than 2048, any AMD PDU which has not been discarded and has not been acknowledged by the receiving RLC can be selected.

Each AMD PDU has a state variable VT(DAT) which tracks the number of times the AMD PDU has been scheduled to be transmitted. If VT(DAT) reaches a predetermined maximum transmission count, defined by a variable MaxDAT, a reset procedure is triggered.

The triggering of a reset procedure is designed to ensure reliable operation of the AM link but does not consider the operation of any other logical channels which do not use AM and may be more tolerant of short term variations in signal strength encountered in weak signal areas.

Other protocols than the UMTS RLC protocol specification may differ in the way in which a polling event is triggered. For example, The E-UTRA RLC protocol specification 3GPP TS 36.322 version 10.0.0 Release 10, incorporated herein by reference, also defines operation in TM, UM and AM. A polling retransmit in AM can be triggered by a number of events, including: o Expiration of a poll timer.

This is only one example, and other triggers may be used. Triggering a poll is discussed in detail in section 5.2.2 of the E-UTRA RLC protocol specification 36.322, incorporated herein by reference.

The E-UTRA RLC protocol specification 36.322 also differs slightly in the rules to select an AMD PDU for poll transmission when the transmission and retransmission buffer are empty, or if no new RLC data PDU can be transmitted (for example due to window stalling). In the E-UTRA RLC protocol specification 36.322 section 5.2.2.3, either the AMD PDU with a sequence number equal to VT(S)-1 may be considered for retransmission or any AMD PDU which has not been positively acknowledged may be considered for retransmission.

Tracking logs from user equipment with dropped voice and video calls in weak signal areas has revealed that the calls are dropped because of a reset triggered in the RLC. As explained above, the protocol specification allows selection of any AMD PDU which has been transmitted, not discarded and no acknowledged. Therefore, it is possible to select repeatedly the same AMD PDU for a polling transmission. Polling events can be triggered in quick succession and in weak signal areas the link may not be good enough for an acknowledgement to be received. Selection of the same AMD PDU for retransmission therefore quickly increments the transmission count VT(DAT) until it is reaches MaxDAT and a reset is triggered. Voice and video calls typically do not use AM, but AM is used on the control and signalling channel and this has been found to be the cause of the reset.

Figure 3 depicts a logic flow diagram which is followed according to one embodiment of the invention when a polling event occurs and there are no AMD PDUs scheduled for transmission or retransmission. The sender RLC needs to select an AMD PDU for retransmission with the polling bit set. The sender RLC can be in either the user equipment 1 or the network control apparatus 6. Computer program code stored in the memory 3,8 is executed by the processor 2,7 to implement the logic flow of Figure 3. It is first determined in step 38 whether at least one of voice data and video data is being transmitted (for example if a voice call or a video call is established). This determination can be made by the RLC 26 using a library function within the RLC or a call to RRC 32 or a call to the non-access stratum (NAS). In UMTS and E-UTRA, voice data and video data can be carried by a voice service Radio Access Bearer (RAB) or as IP Multimedia Service (IMS) voice data or IMS video data. It is also possible to recognise voice data or video data in UMTS by checking for circuit switched data voice data or circuit switch video data. For voice data this may be present over a voice service RAB. In other embodiments different protocols and services may be used to transmit voice data or video data.

If it is determined in step 38 that voice data and video data is not being transmitted, the execution proceeds to step 42 and the rules for selecting an AMD PDU for retransmission defined in the relevant RLC protocol specification are followed.

If it is determined in step 38 that at least one of voice data and video data is being transmitted, execution proceeds to step 40 and the last transmitted AMD PDU is selected for retransmission. The last transmitted AMD PDU is the most recent AMD PDU transmitted, the timing of any retransmission is not considered. In the UMTS and E-UTRA RLC protocol specifications, the last AMD PDU transmitted can be identified easily by selecting the AMD PDU with a sequence number of VT(S)-1. By selecting the last transmitted AMD PDU for a polling transmission the likelihood of repeatedly selecting the same AMD PDU for a polling transmission is reduced. Typically the Layer 1 protocols will continue to generate new AMD PDUs for the signalling data bearer, for example to transmit measurement reports when the apparatus is in a weak signal field.

A second embodiment is illustrated in the logic flow diagram of Figure 4. This embodiment is specific to the UMTS RLC protocol specification and is implemented when a polling event occurs and there are no AMD PDUs scheduled for transmission or retransmission. The sender RLC needs to select an AMD PDU for retransmission with the polling bit set. Computer program code stored in the memory 3,8 is executed by the processor 2,7 to implement the logic flow of Figure 4. It is first determined in step 44 whether the transmission window size, as given by the variable Configured Tx Window Size, is less than 2048 and whether at least one of voice data and video data is being transmitted. As with step 38 described above in the embodiment of Figure 3, the determination of whether at least one of voice data and video data is being transmitted can be made by the RLC using a library function within the RLC or by a call to the RRC 32 or by a call to the NAS.

If it is determined that the window size is less than 2048 and that both voice data and video data is not being transmitted (in other words neither voice data nor video data is being transmitted), execution proceeds to step 48. In step 48 any unacknowledged AMD PDU is selected for a polling transmission.

If it is determined that the window size is 2048 or greater, or that at least one of voice data and video data is being transmitted, execution proceeds to step 46. In step 46 the last transmitted AMD PDU is selected for a polling transmission by selecting the AMD PDU with a sequence number of VT(S)-1. This reduces the likelihood of selecting the same AMD PDU for retransmission repeatedly. Typically the Layer 1 protocols will continue to generate new AMD PDUs, for example to transmit measurement reports.

A third embodiment is illustrated in the logic flow diagram of Figure 5. This embodiment is specific to the UMTS RLC protocol specification. When a polling event is triggered in a sender RLC, computer program code stored in the memory 3,8 is executed by the processor 2,7 to implement the logic flow of Figure 5. First, at step 50 it is determined whether polling is prohibited. If polling is prohibited execution is stopped at step 52. If polling is not prohibited, execution proceeds to step 54.

At step 54, a check is made whether there is any AMD PDU scheduled for transmission or retransmission. If there is an AMD PDU scheduled for transmission or retransmission, execution proceeds to step 56, where an AMD PDU scheduled for transmission or retransmission is updated to have its polling bit set. If there is no AMD PDU scheduled for transmission or retransmission, execution proceeds to step 58.

At step 58, a check is made whether there is at least one PDU that has been transmitted, that has not been discarded and that has not yet been acknowledged. If there are no such PDUs, execution is stopped at step 60. If there is at least one such PDU execution proceeds to step 62.

At step 62 it is determined whether a voice call or a video call is in progress, for example by checking for transmission of at least one of voice data and video data. For example, this can be achieved by calling a library function within the RLC or by a call to the RRC 32 or by a call to the NAS. Voice data and Video data can be checked in UMTS for looking for any voice service RAB, for example any circuit switched domain voice call or real time video call, or any IMS voice call is present. If a voice or video call is not in progress, execution proceeds to step 64 and the rules for AMD PDU selection given in the UMTS RLC protocol specification are followed. If a voice or video call is in progress, execution proceeds to step 66 and the AMD PDU with sequence number VT(S)-1 is selected for retransmission.

Fourth and fifth embodiments are illustrated in the logic flow diagrams of Figures 6 and 7, respectively. These embodiments are specific to the E-UTRA RLC protocol specification. When a polling event is triggered in a sender RLC, for example by the expiry of a poll timer, computer program code stored in the memory 3,8 is executed by the processor 2,7 to implement the logic flow of Figure 6 or Figure 7.

In the embodiment of Figure 6, it is first determined at step 68 whether both the transmission and retransmission buffers are empty (excluding any transmitted RLC data PDUs which are awaiting an acknowledgement). If they are not, execution proceeds to step 70 and an AMD PDU in the transmission or retransmission buffer is updated to have its polling bit set. If both the buffers are empty execution proceeds to step 72.

At step 72, it is determined whether at least one of voice data and video data is being transmitted. For example, this can be achieved by a call to a library function in the RLC or a call to the RRC 32 or a call to the NAS to determine whether any voice service RAB is present, or any IMS voice and/or IMS video calls are active. If no voice data and video data is being transmitted then execution proceeds to step 74, and the rules for AMD PDU selection set out in the E-UTRA RLC protocol specification are followed. If a voice and/or video call is in progress, execution proceeds to step 76 and the AMD PDU with sequence number VT(S)-1 is selected for retransmission.

In the embodiment of Figure 7, it is first determined at step 78 whether the transmission of new RLC data PDUs is prohibited. For example window stalling may prevent the transmission on new RLC data PDUs. If transmission of new RLC data PDUs is not prohibited, execution proceeds to step 80 and the polling bit is set in a new AMD PDU. If transmission of new RLC data PDUs is prohibited, execution proceeds to step 82. At step 82, it is determined whether at least one of voice data and video data is being transmitted. For example, this can be achieved by a call to a library function in the RLC or a call to the RRC 32 or a call to the NAS to determine whether any voice service RAB is present, or any IMS voice and/or IMS video calls are active. If no voice data and video data is being transmitted then execution proceeds to step 84, and the rules for AMD PDU selection set out in the E-UTRA RLC protocol specification are followed. If a voice and/or video call is in progress, execution proceeds to step 86 and the AMD PDU with sequence number VT(S)-1 is selected for retransmission.

In another embodiment, not illustrated, when a polling event occurs and an AMD PDU is not scheduled for transmission or retransmission, but there is at least one AMD PDU which has been transmitted, not been discarded and not acknowledged, the RLC determines whether voice and/or video data is in the process of transmission and/or reception. If it is, the RLC then determines the AMD PDU with the lowest transmission count. This can be done by examining the state variable VT(DAT) for each AMD PDU.

All the embodiments may be extended to include a check for whether at least one of voice data and video data is being received. Voice data and video data can be received without also being transmitted in the case of media streaming, for example. If at least one of voice data or video data is being received then the last transmitted AMD PDU is selected for a polling transmission. This can be achieved by selecting the AMD PDU with a sequence number of VT(S)-1 in the UMTS and E-UTRA RLC protocols.

In all the embodiments, the time taken to drop a voice or video call in a weak signal field is increased. The user is therefore more likely to move out the weak signal area before an RLC reset is triggered and will experience fewer dropped calls.

A basic system architecture of a communication network where examples of embodiments are practised may comprise a commonly known architecture of one or more communication networks comprising a wired or wireless access network subsystem and a core network. An exemplary communication network will now be described with reference to Figure 8. The communication network 100 may comprise a serving cell 180 that is currently serving a user equipment 150, a neighbouring cell 181 that is a neighbour of the serving cell 180 and a radio network controller (RNC) 130. The serving cell 180 and the neighbouring cell 181 each comprise a base station for serving user equipments within their radio coverage area. The user equipment 150 or another wireless transmit/receive device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a user equipment or attached as a separate element to a user equipment, or the like, is able to communicate with the serving cell 180 or the neighbouring cell 181 via one or more channels for transmitting several types of data.

The communication network 100 may additionally be in communication with various mobility management entities (not shown), which facilitate mobility of user equipments across various carriers, and/or network management entities, which manage resources of the communication network 100.

The general functions and interconnections of the described elements, which also depend on the actual network type, are known to those skilled in the art and described in corresponding specifications, so that a detailed description thereof is omitted herein. However, it is to be noted that several additional network elements and signalling links may be employed for a communication connection to or from user equipments, cells or RNCs, besides those described in detail herein below.

Reference is now made to Figure 9 for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 9 a serving cell 180 or a neighbouring cell 181 is adapted for communication over a wireless link with a user equipment 150, such as a mobile terminal. The serving cell 180 or the neighbouring cell 81 may be a macro Node B, an eNodeB, a remote radio head, relay station, a femto cell or home NodeB, or other type of base station/cellular network access node.

The user equipment 150 may include processing means such as at least one data processor (DP) 150A, storing means such as at least one computer-readable memory (MEM) 150B storing at least one computer program (PROG) 150C, and also communicating means such as a transmitter TX 150D and a receiver RX 150E for bidirectional wireless communications with the serving cell 180 and/or the neighbouring cell 181 via one or more antennas 150F.

The serving cell 180 includes its own processing means such as at least one data processor (DP) 180A, storing means such as at least one computer-readable memory (MEM) 180B storing at least one computer program (PROG) 180C, and communicating means such as a transmitter TX 180D and a receiver RX 180E for bidirectional wireless communications with other devices under its control via one or more antennas 180F. There is a data and/or control path, termed at Figure 9 as a control link which in the 3 GPP cellular system may be implemented as an Iub interface, coupling the serving cell 180 with the RNC 130, and over which the RNC 130 and the serving cell 180 may exchange control messages, such as change notifications. The serving cell 180 also has stored in its local memory at 180B the database which may comprise data indicative of system information transmitted on a BCCH corresponding thereto, as the case may be for the various embodiments detailed above.

Similarly, the neighbouring cell 181 includes its own processing means such as at least one data processor (DP) 181 A, storing means such as at least one computer- readable memory (MEM) 18 IB storing at least one computer program (PROG) 181C, and communicating means such as a transmitter TX 18 ID and a receiver RX 18 IE for bidirectional wireless communications with other devices under its control via one or more antennas 18 IF. There is a data and/or control path, termed at Figure 7 as a control link which in the 3 GPP cellular system may be implemented as an Iub interface, coupling the neighbouring cell 181 with the RNC 130, and over which the RNC 130 and the neighbouring cell 181 may exchange control messages, such as system information update requests and/or change notifications. The neighbouring cell 181 also has stored in its local memory at 18 IB the database which may comprise data indicative of system information transmitted on a BCCH corresponding thereto, as the case may be for the various embodiments detailed above.

The RNC 130 includes processing means such as at least one data processor

(DP) 13 OA, storing means such as at least one computer-readable memory (MEM) 30B storing at least one computer program (PROG) 130C, and communicating means such as a modem 130H for bidirectional communication with the Node B 180 over the control link.

While not particularly illustrated for the user equipment 150, the serving cell

180, the neighbouring cell 181 and the RNC 30, those devices are also assumed to include as part of their wireless communicating means a modem which may be inbuilt on a radio frequency RF front end chip within those devices 150, 180, 181, 130 and which chip also carries the TX 150D/180D/181D/130D and the RX 150E/180E/181E/130E.

Various embodiments of the user equipment 50 can include, but are not limited to: cellular telephones; data cards, USB dongles, laptop computers, personal portable digital devices having wireless communication capabilities including but not limited to laptop/palmtop/tablet computers, digital cameras and music devices, and Internet appliances.

At least one of the PROGs 150C in the user equipment 150 is assumed to include program instructions that, when executed by the associated DP 150A, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above. The serving cell 180, the neighbouring cell 181 and the RNC 130 also have software stored in their respective MEMs to implement certain aspects of these teachings. In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM 150B, 180B, 181B, 130B which is executable by the DP 150A of the user equipment 150, DP 180A of the serving cell 180, DP 181 A of the neighbouring cell 181 and/or DP 130A of the RNC 130, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figure 97, but exemplary embodiments may be implemented by one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC, an application specific integrated circuit ASIC or a digital signal processor DSP.

Various embodiments of the computer readable MEMs 150B, 180B, 18 IB and

130B include any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the DPs 150A, 130A, 181 A and 180A include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

Although at least some aspects of the embodiments described herein with reference to the drawings comprise computer processes performed in processing systems or processors, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of non-transitory source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other non-transitory form suitable for use in the implementation of processes according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a solid-state drive (SSD) or other semiconductor-based RAM; a ROM, for example a CD ROM or a semiconductor ROM; a magnetic recording medium, for example a floppy disk or hard disk; optical memory devices in general; etc.

It will be understood that the processor or processing system or circuitry referred to herein may in practice be provided by a single chip or integrated circuit or plural chips or integrated circuits, optionally provided as a chipset, an application- specific integrated circuit (ASIC), field-programmable gate array (FPGA), digital signal processor (DSP), etc. The chip or chips may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry, which are configurable so as to operate in accordance with the exemplary embodiments. In this regard, the exemplary embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by the processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware).

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, the invention may be applied to any protocol which selects unacknowledged packets for a polling transmission. Although the embodiments have been described with particular reference to the UMTS and E-UTRA protocols, other embodiments may be applied to other protocols. 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

1. An apparatus for transmission of data over a wireless network, the apparatus comprising a processing system arranged to, in response to a polling event when there are no Packet Data Units scheduled for transmission or retransmission:

determine whether at least one of voice data and video data is in the process of transmission; and

2. An apparatus according to claim 1, wherein the Packet Data Units are Acknowledged Mode Packet Data Units.

3. An apparatus according to claim 2, wherein the last transmitted Acknowledged Mode Packet Data Unit has a sequence number equal to VT(S)-1.

4. An apparatus according to any one of the preceding claims, wherein the processing system is further arranged to:

determine whether the transmission window size is less than 2048; and select for transmission any Packet Data Unit available for retransmission if it is determined that the transmission window size is less than 2048 and both voice data and video data are not in the process of transmission, whereby to select the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice data and video data is in the process of transmission.

5. An apparatus according to any one of the preceding claims, further for reception of data over a wireless network, wherein the processing system is further arranged to:

Claims

determine whether at least one of voice data and video data is in the process of reception; and

select the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice data and video data is in the process of reception.

6. An apparatus according to any one of the preceding claims, wherein the voice data is data on a Voice service Radio Access Bearer, IP Multimedia Subsystem Voice data.

7. An apparatus according to claim 6, wherein the voice data is circuit switched data on a Voice service Radio Access Bearer.

8. An apparatus according to any one of the preceding claims, wherein the video data is IP Multimedia system Video data or circuit switched video data.

9. An apparatus according to any one of the preceding claims configured for use in a UMTS or E-UTRA system. 10. A base station comprising an apparatus according to any one of the preceding claims.

11. A mobile device comprising an apparatus according to any one of the preceding claims.

12. A method of selecting a packet data unit for polling transmission in response to a polling event when there are no Packet Data Units scheduled for transmission or retransmission, the method comprising:

determining whether at least one of voice and video data is in the process of transmission; and selecting the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice and video data is in the process of transmission. 13. A method according to claim 12, wherein the Packet Data Units are

Acknowledged Mode Packet Data Units.

14. A method according to claim 13, wherein the last transmitted Acknowledged Mode Packet Data Unit has a sequence number equal to VT(S)-1.

15. A method according to any one of claims 12 to 14, the method further comprising:

determining whether the transmission window size is less than 2048; and selecting for retransmission any Packet Data Unit available for retransmission if it is determined that the transmission window size is less than 2048 and both voice data and video data is not being transmitted, whereby to select the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice data and video data is in the process of transmission.

16. A method according to any one of claims 12 to 15, further comprising: determining whether at least one of voice data and video data is in the process of reception; and

selecting the last transmitted Packet Data Unit for polling transmission in response to the polling event if it is determined that at least one of voice data and video data is in the process of reception.

17. A method according to any one of claims 12 to 16, wherein the voice data is data on a Voice service Radio Access Bearer, IP Multimedia Subsystem Voice data.

18. An method according to claim 17, wherein the voice data is circuit switched data on a Voice service Radio Access Bearer.

19. A method according to any one of claims 12 to 18, wherein the video data is IP Multimedia system Video data or circuit switched video data.

20. A computer program product comprising computer program code embodied on a computer readable medium, wherein the computer program code, when executed by a processor, causes the processor to perform in response to a polling event and when there are no Packet Data Units scheduled for transmission or retransmission: