WO2015113596A1

WO2015113596A1 - Method, apparatus and computer program

Info

Publication number: WO2015113596A1
Application number: PCT/EP2014/051746
Authority: WO
Inventors: Maciej JANUSZEWSKI; Alexey TRUSHANIN; Roman Maslennikov; Mikhail SHASHANOV; Mikhail SHKERIN
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2014-01-30
Filing date: 2014-01-30
Publication date: 2015-08-06

Abstract

A method comprising receiving, in a user equipment, initial first gain information to be used by said user equipment, receiving, in the user equipment, second gain information gain to be used by said user equipment for a data rate selection procedure and causing data to be transmitted from said user equipment using a power defined by said initial first gain information independently of said second gain information.

Description

Title

Method, apparatus and computer program

This disclosure relates to methods and apparatus and, in particular but not exclusively, to method and apparatus for controlling data transmissions in a communication network.

A communication system can be seen as a facility that enables communication sessions between two or more nodes such as fixed or mobile devices, machine-type terminals, access nodes such as base stations, servers and so on. A communication system and compatible communicating entities typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. For example, the standards, specifications and related protocols can define the manner how devices shall communicate, how various aspects of communications shall be implemented and how devices for use in the system shall be configured.

A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE) or terminal. A communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties. Typically a device such as a user equipment is used for enabling receiving and transmission of communications such as speech and content data.

Communications can be carried on wireless carriers. Examples of wireless systems include public land mobile networks (PLMN) such as cellular networks, satellite based communica- tion systems and different wireless local networks, for example wireless local area networks (WLAN). In wireless systems a communication device provides a transceiver station that can communicate with another communication device such as e.g. a base station of an access network and/or another user equipment. The two directions of communications between a base station and communication devices of users have been conventionally referred to as downlink and uplink. Downlink (DL) can be understood as the direction from the base station to the communication device and uplink (UL) the direction from the communication device to the base station. According to an aspect, there is provided a method comprising receiving, in a user equipment, initial first gain information to be used by said user equipment, receiving, in the user equipment, second gain information to be used by said user equipment for a data rate selec- tion procedure and causing data to be transmitted from said user equipment using a power defined by said initial first gain information independently of said second gain information.

The first and second gain information may relate to a first and second respective gain factor. The method may comprise receiving the first gain information from a radio network controller.

The method may comprise receiving the first gain information via a high-speed shared control channel.

The method may comprise using absolute and relative grant command channels for the data rate selection.

The method may comprise defining the first gain factor as zero if the absolute grant com- mand is zero.

The method may comprise defining the first gain factor using the initial first gain information if the absolute grant command is non-zero. The first gain information may relate to the gain for a dedicated physical data channel.

The method may comprise using the second gain information for a data rate selection procedure for a dedicated physical data channel. The method may comprise performing the method in a first mode of operation of the user equipment.

The first gain information may depend on at least one of the average system load and the target inference over thermal noise ratio. The method may comprise receiving modified first gain information; and causing data to be transmitted from said user equipment using a power defined by said modified first gain information independently of said second gain information. The method may be performed by a user equipment

According to another aspect, there is provided a method comprising sending initial first gain information to be used by a user equipment, sending second gain information to be used by a user equipment in a data rate selection procedure and receiving data using a power de- fined by said initial first gain information.

According to another aspect there is provided an apparatus, said apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to receive initial first gain information to be used by said apparatus, receive second gain information to be used by said apparatus for a data rate selection procedure and transmit data using a power defined by said initial first gain information independently of said second gain information. The first and second gain information may relate to a first and second respective gain factor.

The at least one processor and at least one memory may be configured to receive the first gain information from a radio network controller. The at least one processor and at least one memory may be configured to receive the first gain information via a high-speed shared control channel.

The at least one processor and at least one memory may be configured to use absolute and relative grant command channels for the data rate selection.

The at least one processor and at least one memory may be configured to define the first gain factor as zero if the absolute grant command is zero.

The at least one processor and at least one memory may be configured to define the first gain factor using the initial first gain information if the absolute grant command is non-zero.

The first gain information may relate to the gain for a dedicated physical data channel. The at least one processor and at least one memory may be configured to use the second gain information for a data rate selection procedure for a dedicated physical data channel. The first gain information may depend on at least one of the average system load and the target inference over thermal noise ratio.

The at least one processor and at least one memory may be configured to receive modified first gain information, and cause data to be transmitted from said user equipment using a power defined by said modified first gain information independently of said second gain information.

According to another aspect there is provided an apparatus, said apparatus comprising means for receiving initial first gain information to be used by said apparatus, means for re- ceiving second gain information to be used by said apparatus for a data rate selection procedure and means for transmitting data using a power defined by said initial first gain information independently of said second gain information.

A computer program comprising program code means adapted to perform the method(s) may also be provided. The computer program may be stored and/or otherwise embodied by means of a carrier medium.

Reference is now made by way of example only to the accompanying drawings in which: Figure 1 shows a schematic diagram of a communication system comprising a base station and a plurality of communication devices;

Figure 2 shows a schematic diagram of a mobile communication device according to some embodiments;

Figure 3 shows a schematic diagram of a control apparatus according to some embodiments;

Figure 4 shows a method of sending gain information to a UE;

Figure 5 shows a schematic diagram of a communication system comprising a communication device and a radio resource controller. In the following certain exemplifying embodiments are explained with reference to a wireless or mobile communication system serving mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communica- tion system and mobile communication devices are briefly explained with reference to Figures 1 to 2 to assist in understanding the technology underlying the described examples.

In a wireless communication system 100 mobile communication devices or user equipment (UE) 102, 103, 105 are provided wireless access via at least one base station or similar wire- less transmitting and/or receiving node or point.

In an HSPA system, base stations are typically controlled by at least one appropriate controller apparatus, so as to enable operation thereof and management of mobile communication devices in communication with the base stations. The controller apparatus may be part of the base station. In Figure 1 control apparatus 108 and 109 are shown to control the respective macro base stations 106 and 107. The control apparatus of a base station can be interconnected with other control entities. In Figure 1 base stations 106 and 107 are shown as connected to a wider communications network 1 13 via gateway 1 12. A further gateway function may be provided to connect to another network. The smaller base stations 1 16, 1 18 and 120 may also be connected to the network 1 13, for example by a separate gateway function and/or via the controllers of the macro stations. In the example, stations 1 16 and 1 18 are connected via a gateway 1 1 1 whilst station 120 connects via the controller apparatus 108. In some embodiments, the smaller stations may not be provided. It will be appreciated that embodiments may also be applicable to a UMTS network. In a UMTS network user equipment 101 ', 102', 103' and 104' may be in communication with NodeBs 105' and 106'. The Node Bs 105' and 106' may themselves be controlled by an RNC 1 12'. In a UMTS system the control apparatus may be provided in a radio network controller. A possible mobile communication device will now be described in more detail with reference to Figure 2 showing a schematic, partially sectioned view of a communication device 200. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mo- bile device such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided nu- merous services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content include downloads, television and radio programs, videos, advertisements, various alerts and other information.

The mobile device 200 may receive signals over an air or radio interface 207 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 2 transceiver apparatus is designated schematically by block 206. The transceiver apparatus 206 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

A mobile device is typically provided with at least one data processing entity 201 , at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204. The user may control the op- eration of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 208, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

The communication devices 102, 103, 105 may access the communication system based on various access techniques, such as code division multiple access (CDMA), or wideband CDMA (WCDMA). Other non-limiting examples comprise time division multiple access (TDMA), frequency division multiple access (FDMA) and various schemes thereof such as the interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA) and so on. An example of wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). The various development stages of the 3GPP specifications are referred to as releases. In a UMTS network user equipment 102', 103', and 105' may be in communication with NodeBs 106' and 107'. The Node Bs 106' and 107' may themselves be controlled by an RNC 1 12' Other examples of radio access system include those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access).

Figure 3 shows an example of a control apparatus for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a base station. In some embodiments, base stations comprise a separate control apparatus. In other embodiments, the control apparatus can be another network element such as a radio network controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller.

The control apparatus 109 can be arranged to provide control on communications in the service area of the system. The control apparatus 109 comprises at least one memory 301 , at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. For example the control apparatus 109 can be configured to execute an appropriate software code to provide the control functions which allow communication between the base stations. Both the data rate and the total UE Transmitter (TX) power or gain for the data channel (E- DPDCH) may be jointly defined via the power control (Inner Loop Power Control (ILPC)) and scheduler power grant mechanisms, which are determined and sent by a base station. The ILPC controls the total power of all channels associated with a UE proportionally and the scheduler grant controls the E-DPDCH-to-DPCCH (Dedicated Physical Data Channel- Dedicated Physical Control Channel) power ratio. Therefore, the E-DPDCH power is defined by both ILPC and the grant. Powers of all other channels are defined only by ILPC, i.e. are already decoupled from the rate adaptation procedure (grant mechanism). Decoupling of the data channel (E-DPDCH) power control and rate adaptation procedures to provide independent power control driven by receiver (RX) power conditions and rate adaptation driven by the data reception reliability may improve rate adaptation. This may result in an improvement of the data rate and RX power control stability of the system. One possible modification consists of changing the scheduler and power control algorithms at the Node B side without changing the control signalling and the UE behaviour. One possible Node B algorithm modification involves driving the ILPC by the RX power condition and driving the rate adaptation procedure by the data (E-DPDCH) reception reliability. The exist- ing grant signalling mechanisms (absolute and relative grants) are used primarily for the rate adaptation (E-TFC (Transport Format Combination) selection) purposes.

In this proposal, UE procedures keep the remaining tie of data rate and power control. Hence, changing the E-TFC used for the data transmission (via absolute and relative grant mechanisms) still leads to the power grant level change (the rise of the E-DPDCH power over the DPCCH power). Consequently, E-TFC variations (always present in non-stationary channels) lead to additional variations of the E-DPDCH power and, thus, the total TX and RX powers. These variations can be tracked by the ILPC loop. However, some time is needed for ILPC to re-adjust the total power to the required level. Thus, this proposal does not pro- vide a complete decoupling between power control and rate adaptation. Adverse power variations may lead to lower stability of operation of system control procedures and to lower data throughputs.

A rate adaptation solution called "SINR (Signal-to-lnterference and Noise Ratio)-based scheduling" reduces the adverse impact of the power variations. The SINR-based scheduling modifies the rate adaptation and power control mechanisms as follows. The ILPC is driven by the RX power condition similarly to the above example where control signalling and UE behaviour are not changed. The serving grant power level is assigned semi-statically (e.g. in the beginning of the data transmission via a single E-AGCH (Absolute Grant Chan- nel) command) within the existing absolute grant scheduling mechanism by setting the E- DPDCH channel power over the DPCCH channel so that to guarantee the required DPCCH reception reliability and is fixed during the data transmission. The OLPC (Outer Loop Power control) is disabled and a separate loop driven by the measured E-DPDCH SINR and/or the E-DPDCH BLER (Block Error Rate) is used to control the data rate (E-TFC to be used for the data transmission) independently of the E-DPDCH power (assigned by the serving grant). For this reason, a feedback control channel is introduced. The UE behaviour is changed to make possible an independent setting of the power via the legacy grant signalling (absolute and relative grants) and the rate using the E-TFC via a new control channel. This method addresses adverse E-DPDCH TX power variation by introducing a separate channel for the E-TFC and changing the E-TFC selection procedure performed at the UE side. The flow chart in figure 4 shows a method of rate adaption which does not require the introduction of an additional control channel. The function of the blocks shown in figure 4 may be implemented in the UE. This method makes use of a UE operation mode in which the E-DPDCH gain factor is fixed a non-zero value for any received serving grant except for the grant of zero when the E- DPDCH is not transmitted. In this mode, the absolute and relative grant commands are used only for E-TFC selection but do not impact the E-DPDCH gain factor. The same E-TFC selection procedure as in the legacy standard may then be used by using the signalled grant value with no modifications. According to this mechanism, different gain factors are defined for different E-TFCs. In the proposed method, these gain factors now play a part of virtual gains factors used for the E-TFC selection only. An E-TFC with the maximal virtual gain factor fitting the received virtual serving grant level can be selected. An E-TFC corresponding to a lower transport block size (data rate) can be also scheduled depending on the data buffer status and the available TX power budget. The signalled grant (E-DPDCH gain factor) may then be ignored for the UE TX power settings. The pre-defined gain factor is to be signalled instead semi-statically via RNC signalling, HS-SCCH (High Speed Shared Control Channel) orders, or other applicable mechanism. This approach may solve the problem of adverse E-DPDCH TX power variations, but does not require introduction of an additional control channel as in SINR-based scheduling. As shown in figure 5, the legacy E-AGCH and E-RGCH (Relative Grant Channel) channels are used for the E-TFC selection and a semi-static signalling (including but not limited to RNC signalling and/or HS-SCCH orders) are used for the gain factor selection.

The E-DPDCH gain factor may have a relatively low impact on the system performance. Thus, this parameter can be signalled for each UE when it enters the network depending on the average system load (number of active UEs), system settings such as target RoT, and others. The E-DPDCH gain factor is then kept unchanged during the UE operation or can be corrected using the same signalling mechanisms as for the initial setting.

The pre-defined gain factor signalled as described above is to be taken for any non-zero serving grant instead of the factor defined during the E-TFC selection procedure. The zero gain factor (no data transmission) is to be taken for the zero serving grant.

The required data processing apparatus and functions of a user equipment, base station apparatus, a communication device, and any other appropriate apparatus may be provided by means of one or more data processors. The described functions may be provided by one or more processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non-limiting examples. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof.

Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The software may be stored on such physical media as memory chips, or memory blocks imple- mented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more of any of the other embodiments previously discussed.

Claims

Claims:

1. A method comprising

receiving, in a user equipment, initial first gain information to be used by said user equipment;

receiving, in the user equipment, second gain information gain to be used by said user equipment for a data rate selection procedure; and

causing data to be transmitted from said user equipment using a power defined by said initial first gain information independently of said second gain information.

2. A method according to claim 1 , wherein the first and second gain information relates to a first and second respective gain factor.

3. A method according to claim 1 or claim 2, comprising receiving the first gain informa- tion from a radio network controller.

4. A method according to claim 1 or claim 2, comprising receiving the first gain information via a high-speed shared control channel.

5. A method according to any one of the preceding claims, comprising using absolute and relative grant command channels for the data rate selection.

6. A method according to any one of the preceding claims, comprising defining the first gain factor as zero if the absolute grant command is zero.

7. A method according to any one of the preceding claims, comprising defining the first gain factor using the initial first gain information if the absolute grant command is non-zero.

8. A method according to any one of the preceding claims, wherein the first gain information relates to the gain for a dedicated physical data channel.

9. A method according to any one of the preceding claims comprising using the second gain information for a data rate selection procedure for a dedicated physical data channel.

10. A method according to any of the preceding claims, comprising performing the method in a first mode of operation of the user equipment.

1 1 . A method according to any of the preceding claims, wherein the first gain information depends on at least one of the average system load and the target inference over thermal noise ratio.

12. A method according to any of the preceding claims, comprising:

receiving modified first gain information; and

causing data to be transmitted from said user equipment using a power defined by said modified first gain information independently of said second gain information.

13. A method comprising

sending initial first gain information to be used by a user equipment;

sending second gain information to be used by a user equipment in a data rate selection procedure; and

receiving data using a power defined by said initial first gain information.

14. An apparatus, said apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to:

receive initial first gain information to be used by said apparatus;

receive second gain information to be used by said apparatus for a data rate selection procedure; and

transmit data using a power defined by said initial first gain information independently of said second gain information.

15. An apparatus according to claim 14, wherein the first and second gain information relates to a first and second respective gain factor.

16. An apparatus according to claim 14, wherein the at least one memory and the computer code are configured to receive the first gain information from a radio network controller.

17. An apparatus according to claim 14 wherein the at least one memory and the computer code are configured to receive the first gain information via a high-speed shared control channel.

18. An apparatus according to claim 14 wherein the at least one memory and the computer code are configured to use absolute and relative grant command channels for the data rate selection.

19. An apparatus according to claim 15 wherein the at least one memory and the computer code are configured to define the first gain factor as zero if the absolute grant command is zero.

20. An apparatus according to claim 15, wherein the at least one memory and the computer code are configured to define the first gain factor using the initial first gain information if the absolute grant command is non-zero.

21 . An apparatus according to any one of claims 14 to 20, wherein the first gain information relates to the gain for a dedicated physical data channel.

22. An apparatus according to any one of claims 14 to 21 wherein the at least one memory and the computer code are configured to use the second gain information for a data rate selection procedure for a dedicated physical data channel.

23. An apparatus according to any of claims 14 to 22, wherein the first gain information depends on at least one of the average system load and the target inference over thermal noise ratio.

24. An apparatus according to any of claims 14 to 23, wherein the at least one memory and the computer code are configured to receive modified first gain information; and cause data to be transmitted from said user equipment using a power defined by said modified first gain information independently of said second gain information.

25. A computer program comprising computer executable instructions which when run are configured to perform the method of any one of claims 1 to 12.