WO2014079025A1

WO2014079025A1 - Assistant info for new carrier type mobility

Info

Publication number: WO2014079025A1
Application number: PCT/CN2012/085075
Authority: WO
Inventors: Na WEI; Wei Bai; Pengfei Sun; Erlin Zeng; Chunyan Gao; Wei Hong; Lili Zhang; Haiming Wang
Original assignee: Broadcom Corporation
Priority date: 2012-11-22
Filing date: 2012-11-22
Publication date: 2014-05-30
Also published as: CN104813711A; HK1209941A1

Abstract

The present invention addresses a method, apparatus and computer program product for enhanced system information transmissions and/or handover command for new carrier type mobility. The invention comprises determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration; cell-specific reference signal configuration; channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and causing data exchange of the composed assistant information to a network element.

Description

ASSISTANT INFO FOR NEW CARRIER TYPE MOBILITY Field of the invention The present invention generally relates to improvements on handling carrier types in wired or wireless communication systems. More particularly, the present invention addresses apparatuses, methods and computer program product for enhanced system information transmissions and/or handover command for new carrier type mobility.

Background

Standalone new carrier type (SA-NCT) is considered to be one of the main topics for Long Term Evolution LTE in 3GPP Release 12 (Rel-12) enhancement.

The 3GPP Release 11 brings changes to a number of features defined in earlier releases with a non-standalone new carrier type (Rl l NCT). The features, such as enhanced physical download control channel (ePDCCH) replacing physical download control channel PDCCH, where the control channels are no longer fixed to certain time-frequency resources, but more flexibly allocated, and cell-specific (common) reference signals CRS, are at least significantly reduced, if not completely removed. Besides, the system operation on the NCT is now mostly based on channel state information reference signals CSI-RS and demodulation reference signals DM-RS instead of cell-specific reference signals CRS.

With those changes brought by 3GPP Release 11, enabling a new standalone carrier type without CRS and legacy control channels would not require many changes. Such changes mainly include initial access and mobility measurements.

References : [1] Ericsson, "Views on TD-LTE for Rel-12", presentation on CMCC TD-LTE workshop, Apr. 2012

[2] China Mobile, "TD-LTE Evolution and Sharing of TD-LTE Trial"

presentation on CMCC TD-LTE workshop, Apr. 2012

[3] 3GPP RANI #68bis, meeting report

[4] 3GPP RANI #69, meeting report

[5] 3GPP RAN2 #78, meeting report

According to the new work item WI description for 3GPP Release 12 (Rel-12) new carrier type, new features may give a NCT cell some new flexibility, such as:

- flexible CSI-RS configuration, no or very low CRS, energy saving mode, also NCT may operate with standalone (SA), CA, or macro assisted modes; and

- may mix deployed with legacy carrier during migration period.

According to enhanced inter-cell interference coordination elCIC topic, some solutions for enhanced system information transmissions have been discussed. For example, in [3] the following possibility was mentioned;

- if signaling is needed, examples of possible eNB signaling solution to enable significantly improved detection of physical broadcast channel PBCH and/or system information block 1 SIB1 in the presence of dominant interferers with 9dB bias; and

- the victim cell may send its system information to the user equipment UE using higher layer signaling in the protected subframes.

In [4], the following was agreed as working assumption :

- eNB signaling solution to aid detection of PBCH in the presence of dominant interferers with 9dB bias; W 201

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- related master information block MIB information from the victim cell may also be supplied by aggressor cell during handover from aggressor to victim cells; and

- single frequency network SFN offset between victim and aggressor cell.

However, the main point with these solutions is to provide system information in protected resource to avoid interference, and these system information or handover command are not related to any information regarding new carrier type.

In [5], the CSI-RS resource configuration for coordinated multi-point CoMP measurement was discussed, with the following agreements: - CSI-RS resources on which the UE is supposed to measure are configured explicitly by the network NW, i.e., blind detection of CSI- RS resources in the UE is not required; and

- CSI-RS resource specific configurations are configured as part of the MeasurementObject (for further study how to associate them with measurement configuration and how to refer to them in measurement reports).

These configurations apply for UE which is configured with CoMP transmission mode and not related to system information acquisition, nor handover to new carrier type.

However, these new features may result in confusion in UE detection, handover and measurement. For example, an UE may need to blind detect many possibilities before identify presence of a Rel-12 carrier or legacy carrier, or even blind if certain CSI-RS is used in certain neighbor cell. This complicates UE implementation, and may introduce very unnecessary big power consumption, and may also make the delay of measurement longer. Moreover, in Rel-12, the system may handle a huge number of neighbor cells (dense small cells), which may make this issue even worse. W

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Therefore, there is the need for optimizing fast access and handover in terms of the R C connection and handover procedure.

Summary of the Invention

It is an object of the present invention to address the above problems. In particular, it is an object of the present invention to provide apparatuses, methods and a computer program product for enabling enhancement of the support of SA-NCT mobility, in particular for initial access, tracking and possible measurement.

According to a first aspect of the present invention, an apparatus comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel's common search space resource; and causing transmission of the composed assistant information to a user equipment.

According to a second aspect of the present invention, a method comprises the steps of determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and causing transmission of the composed assistant information to a network element.

According to a third aspect of the present invention, an apparatus comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform receiving transmission of composed assistant information from a base station, and processing the received assistant information, wherein the assistant information is composed by: determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro- assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel's common search space resource. W

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According to a fourth aspect of the present invention, a method comprises the steps of receiving transmission of composed assistant information from a base station, and processing the received assistant information, wherein the assistant information is composed by: determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non- standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource.

According to a fifth aspect of the present invention, there is provided a computer program product comprising computer-executable components which, when the program is run on a computer, are configured to carry out the method according to the second aspect and/or the method according to the fourth aspect.

According to a sixth aspect of the present invention, an apparatus, comprises determination means for determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, composition means for composing assistant information comprising at least one of: reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and transmission means for causing transmission of the composed assistant information to a network element. According to a seventh aspect of the present invention, an apparatus, comprises reception means for receiving transmission of composed assistant information from a base station, and processing means for processing the received assistant information, wherein the assistant information is composed by: determination means for determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, composition means for composing assistant information comprising at least one of: reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, celi-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and transmission means for causing transmission of the composed assistant information to a network element.

Advantageous further developments or modifications of the aforementioned exemplary aspects of the present invention are set out in the dependent claims.

Brief description of drawings For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which :

Fig. 1 shows a target standalone NCT scenario according to [1] ; W

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Fig. 2 shows a principle configuration of an example for an apparatus according to certain embodiments of the present invention; Fig. 3 shows a principle flowchart of an example for a method according to certain embodiments of the present invention;

Fig. 4 shows a principle configuration of an example for an apparatus according to certain embodiments of the present invention;

Fig. 5 shows a principle flowchart of an example for a method according to certain embodiments of the present invention;

Fig. 6 shows an example of the master information block MIB information element according to certain embodiments of the present invention for initial access assistance;

Fig. 7 shows an example of the system information block SIB according to certain embodiments of the present invention for initial access assistance;

Figs. 8a and 8b show an example of SystemInformationBlockType4 and SystemlnformationBlockType 5 information elements for cell measurement assistance according to certain embodiments of the present invention; Fig. 9 shows an example of the MobilityControlInfo information element for handover assistance according to certain embodiments of the present invention; and

Figs. 10a and 10b show an example of the RRCConnectionRequest message as weil as some example of the signaling design of the RRCconnectlonReject according to certain embodiments of the present invention for re-direction using RRCconnectlonReject. It is to be noted that the changes in the exemplary information elements shown in Figs. 6 to 10 are indicated in bold letters.

Description of exemplary embodiments

Exemplary aspects of the present invention will be described herein below. More specifically, exemplary aspects of the present are described hereinafter with reference to particular non-limiting examples and to what are presently considered to be conceivable embodiments of the present invention. A person skilled in the art will appreciate that the invention is by no means limited to these examples, and may be more broadly applied.

It is to be noted that the following description of the present invention and its embodiments mainly refers to specifications being used as non-limiting examples for certain exemplary network configurations and deployments. Namely, the present invention and its embodiments are mainly described in relation to 3GPP specifications being used as non-limiting examples for certain exemplary network configurations and deployments. In particular, a LTE™/LTE- Advanced communication system is used as a non-limiting example for the applicability of thus described exemplary embodiments. As such, the description of exemplary embodiments given herein specifically refers to terminology which is directly related thereto. Such terminology is only used in the context of the presented non-limiting examples, and does naturally not limit the invention in any way. Rather, any other network configuration or system deployment, etc. may also be utilized as long as compliant with the features described herein.

Hereinafter, various embodiments and implementations of the present invention and its aspects or embodiments are described using several alternatives. It is generally noted that, according to certain needs and constraints, all of the described alternatives may be provided alone or in any conceivable combination (also including combinations of individual features of the various alternatives). Fig. 1 shows a targeted scenario according to [1] and [2], wherein standalone non-backwards compatible carriers are provided to further enhance the spectrum efficiency and to improve cell deployment flexibilities.

According to certain embodiments of the present invention in a first aspect, new assistant information in system information and/or handover command for new carrier type mobility is provided. In particular, the new assistant information comprises cell type information which indicates that the cell applies a Rel-8-Rel-10 compatible carrier or a standalone SA/macro-assisted/non-standalone new carrier type.

Further, RS type information is contained for indicating the possible primary/secondary synchronization signal PSS/SSS, cell-specific reference signals CRS, channel state information reference signals CSI-RS, physical discovery channel PDCH, etc. configurations for the new carrier type NCT. Thereby, one carrier type may implicitly link to one reference signal RS configuration or/and PSS/SSS/PDCH configuration, so that only cell type need to be indicated.

Alternatively, an eNB may explicitly send such RS/PSS/SSS/PDCH configuration RS configuration or/and cell discovery signal configuration for serving cell and all/some cells in the neighbor list.

Further, the new assistant information may also indicate which RS is used for certain procedures/purpose, for example, PDCH for inter-frequency detection or PSS/SSS/CSI-RS for normal initial access and tracking. The assistant information may comprise sleep/active mode type/configuration. Hence, multiple level sleeping mode may be supported. W

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Furthermore, cell deployment type information may be provided so as to indicate a Macro/Pico/Small cell deployment, by which UE may have different preference on cell to reselect. According to certain embodiments, the new assistant information comprises ePDCCH common search space (CSS) resource indication.

In handover HO command, besides above information, according to certain embodiments of the present invention, it could further include extra dedicated RS configuration, such as CSI-RS to certain UEs to enable fast HO measurement.

According to still further embodiments of the present invention in a second aspect, an elMB may re-direct an UE to small cell during the RRC connection establishment procedure based on demand.

Thereby, the UE may report its rough establishment cause in RRCconnectionRequest IE (information element). Further, the el\IB could include new assistant info in RRCconnectionReject to re-direct UE to small cell.

The rejection cause information is mainly used to let Rel-12 UE re-select the current cell without any waiting time if no small cell is discovered.

Fig. 2 shows a principle configuration of an example for an apparatus according to certain embodiments of the present invention. The apparatus 20 comprises at least one processor 42 and at least one memory 22 including computer program code, which are connected by a bus 24 or the like. As indicated with a dashed line in Fig. 2, an interface 23 may optionally be connected to the bus 22 or the like, which may enable communication e.g. to/from a network entity, a base station, a UE, a vehicle gateway or the like. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus at least to perform determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration; cell-specific reference signal configuration; channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and causing transmission of the composed assistant information to a network element.

Fig. 3 shows a principle flowchart of an example for a method according to certain embodiments of the present invention.

In Step S31, it is determined whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration.

In Step S32, assistant information are composed, the assistant information comprising at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell-specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource.

In Step S33, transmission of the composed assistant information to a network element is caused. Fig. 4 shows a principle configuration of an example for an apparatus according to certain embodiments of the present invention. The apparatus 40 comprises at least one processor 41 and at least one memory 42 including computer program code, which are connected by a bus 44 or the like. As indicated with a dashed line in Fig. 4, an interface 43 may optionally be connected to the bus 42 or the like, which may enable communication e.g. to/from a network entity, a base station, a UE_f a vehicle gateway or the like. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus at least to perform receiving transmission of composed assistant information from a base station, and processing the received assistant information, wherein the assistant information is composed by: determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration; cell-specific reference signal configuration; channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and causing transmission of the composed assistant information to a network element.

Fig. 5 shows a principle flowchart of an example for a method according to certain embodiments of the present invention.

In Step S51, transmission of composed assistant information from a base station is received, the assistant information is composed by: determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro- assisted and non-standalone configuration, in case of a determining the new carrier type, composing assistant information comprising at least one of: reference signal type information indicating support of at least one of reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration; cell-specific reference signal configuration; channel state information reference signal configuration and physical discovery channel configuration for the new carrier type; sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and information indicating enhanced physical download control channel common search space resource; and causing transmission of the composed assistant information to a network element. In Step S52, the received assistant information is processed in operation of the apparatus.

According to certain embodiments of the present invention, the reference signal type information further comprises allocation information of the reference signal to a certain purpose, wherein the certain purpose may be one of tracking, demodulation or measurements.

According to certain embodiments of the present invention, presence of a demand for re-directing the network element during radio resource control connection establishment procedure is determined; and further assistant information indicating at least one of a rejection cause and a suggested redirect target ceil is composed.

According to certain embodiments of the present invention, information indicating an establishment cause is received from the network element, wherein the cause may be one of offloading purpose and ICIC purpose.

According to certain embodiments of the present invention, the assistant information further comprises cell measurement information about at least one neighbor cell. W 201

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All the mentioned embodiments can be formed in several alternatives as illustrated but not limited to the implementation examples shown below. Fig. 6 shows an example of the master information block MIB information element according to certain embodiments of the present invention for initial access assistance. Fig. 7 shows an example of the system information block SIB according to certain embodiments of the present invention for initial access assistance.

The modified master information block MIB/ system information block SIB can be used to indicate the assistant information such as carrier type, RS type, sleep mode status. Further, the UE can make use of the info and reduce blind detection and enable faster detection and power efficient for UE during initial access. One example is shown here for MIB/SIB1. Note that these new IEs are just for illustration purpose; maybe only part of them is used.

The possible cell type and RS are:

- R8-R10 type (PSS/SSS+CRS); if the cell type is Rel8-Rell0 carrier, then the RS will be known;

- R12 IMCT type

o PSS/SSS+CSI-RS configuration/density/position (CSI-RS for tracking, for measurement);

o PDCH+CSI-RS (if use PDCH for initial access).

Figs. 8a and 8b show an example of SystemInformationBlockType4 and SystemlnformationBlockType 5 information elements for cell measurement assistance according to certain embodiments of the present invention.

For neighbor cell detection which aims for cell reselection or handover, those info of neighbor cells can be indicated in NeighCelllnfo in SIB4/5 to help reduce UE power consumptions, and reduce delay. One example is shown here for intra- frequency neighbor cell, and inter-frequency neighbor cells.

Especially since the neighbor can be large for small cells which is likely to be deployed with for high frequency carriers, blind detection can be large, and those info can help reduce blind detection greatly.

Fig. 9 shows an example of the MobilityControlInfo information element for handover assistance according to certain embodiments of the present invention.

Within handover command, UE can be informed those info of the target to assist on fast and reliable handover. Besides, certain CSI-RS can be configured temporarily dedicatedly for certain UE to facilitate fast handover. And this handover-assistant CSI-RS should be included in handover command. This dedicated handover CSI-RS can help reduce delay of handover. One example is shown here (in green). The IE MobilityControlInfo includes parameters relevant for network controlled mobility to/within E-UTRA.

Figs. 10a and 10b show an example of the RRCConnectionRequest message as well as some example of the signaling design of the RRCconnectionReject according to certain embodiments of the present invention for re-direction using RRCconnectionReject.

To re-direct UE to small cell during the RRC connection establishment procedure, eNB needs to insert some new signaling in the RRCconnectionReject in Msg4, and also before that, eNB needs to have some rough knowledge about the UE information, e.g. establishment cause, UE release, etc. This could leave to eNB implementation to handle the offloading / re-direct, and it is possible to also take UE speed into account, W

17 and it is possible to report some initial measurement result to eIMB to help the re-direct in Msg3.

Some of the advantages of the present invention are as follows:

- for the first aspect:

o for dense deployment (number of neighboring cell is large) or mixed deployment (hypothesis are more often than pure new carrier or legacy carrier deployment), the proposal can help UE simplify its blind detection, save power and reduce handover delay.

- for the second aspect, compared to first establish the connection in macro cell and then do HO procedure, it could

o avoid traffic interruption due to the possibility that there maybe no X2 interface between macro and small cell (easy to deploy-^ SI interface might be used)

o if UE is in the coverage of the small cell, the HO procedure

could be seen as overhead and not necessary

o eNB has better flexibility on controlling initial access of UEs, by considering UE request reason, traffic delay sensitivity, load status, legacy and new UE number, etc.

In the foregoing exemplary description of the apparatus, only the units that are relevant for understanding the principles of the invention have been described using functional blocks. The apparatuses may comprise further units that are necessary for its respective function. However, a description of these units is omitted in this specification. The arrangement of the functional blocks of the apparatuses is not construed to limit the invention, and the functions may be performed by one block or further split into sub- blocks.

According to exemplarily embodiments of the present invention, a system may comprise any conceivable combination of the thus depicted devices/apparatuses and other network elements, which are arranged to cooperate as described above. Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware generally, but not exclusively, may reside on the devices' modem module. In an example embodiment, the application logic, software or an 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 can 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 or smart phone, or user equipment.

As used in this application, the term "circuitry" refers to all of the following : (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) to combinations of circuits and software (and/or firmware), such as (as applicable) : (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessors), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device. The present invention relates in particular but without limitation to mobile communications, for example to environments under LTE™, LTE-A, WCDMA, WIMAX and WLAN and can advantageously be implemented in user equipments or smart phones, or personal computers connectable to such networks. That is, it can be implemented as/in chipsets to connected devices, and/or modems thereof.

According to the present invention, user equipment may refer to a portable computing device. Such computing devices include wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: mobile phone, smartphone, personal digital assistant (PDA), handset, laptop computer. If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

The following meanings for the abbreviations used in this specification apply:

Component Carrier DL Downlink

eNB Enhanced Node B (name for Node B in LTE)

HARQ Hybrid Acknowledge ReQuest

LTE Long Term Evolution

LTE- A Long Term Evolution Advanced

PCC Primary Cell Carier

PS Power Saving

RRC Radio Resource Control

SCC Secondary Cell Carrier

UE User Equipment

UL Uplink

SA Stand Alone

NCT New Carrier Type

PSS Primary Synchronisation Signal

sss Secondary Synchronisation Signal

CRS Cell-Specific Reference Signal

CSI-RS Channel State Information Reference Signal

PDCH Physical Discovery Channel

ePDCCH enhanced Physical Downlink Control Channel

CSS Common Search Space

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration;

in case of a determining the new carrier type, composing assistant information comprising at least one of:

reference signal type information indicating support of at least one of a primary/secondary synchronization signal configuration, cell- specific reference signal configuration, channel state information reference signal configuration and physical discovery channel configuration for the new carrier type;

sleep/active mode type information;

cell deployment type information indicating a macro/pico/small cell deployment; and

information indicating enhanced physical download control channel common search space resource; and

causing transmission of the composed assistant information to a network element.

2. The apparatus according to claim 1, wherein the reference signal type information further comprises allocation information of certain configuration of reference signal to a certain purpose.

3. The apparatus according to claim 2, wherein the certain purpose is one of tracking, demodulation or measurements.

4. The apparatus according to any of claims 1 to 3, wherein the apparatus is further caused to perform determining presence of a demand for re- directing the network element during radio resource control connection establishment procedure; and composing further assistant information indicating at least one of a rejection cause and a suggested re-direct target cell.

5. The apparatus according to claim 4, wherein the apparatus is further caused to perform receiving information indicating an establishment cause from the network element.

6. The apparatus according to claim 5, wherein the cause is one of offloading purpose and ICIC purpose.

7. The apparatus according to any of claims 1 to 6, wherein the assistant information further comprising cell measurement information about at least one neighbor cell.

8. The apparatus according to any of claims 1 to 7, wherein the apparatus is a base station.

9. The apparatus according to any of claims 1 to 8, wherein the network element is a user equipment.

10. The apparatus according to any of claims 1 to 9, wherein the apparatus and/or the network element is operating according to the long-term evolution or according to the long-term evolution advanced.

11. A method, comprising :

determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration;

sleep/active mode type information;

receiving transmission of the composed assistant information to a network element.

12. An apparatus comprising

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform : receiving transmission of composed assistant information from a base station; and

processing the received assistant information,

wherein the assistant information is composed by:

sleep/active mode type information;

information indicating enhanced physical download control channel common search space resource.

13. The apparatus according to claim 12, wherein receiving the reference signal type information further comprises allocation information of certain configuration of the reference signal to a certain purpose.

14. The apparatus according to claim 13, wherein the certain purpose is one of tracking, demodulation or measurements.

15. The apparatus according to any of claims 11 to 14, wherein the apparatus is further caused to receiving further assistant information indicating at least one of a rejection cause and a suggested re-direct target cell.

16. The apparatus according to claim 15, wherein the apparatus is further adapted to cause transmission of information indicating an establishment cause from to the base station.

17. The apparatus according to claim 16, wherein the cause is one of offloading purpose and ICIC purpose.

18. The apparatus according to any of claims 11 to 17, wherein receiving the assistant information further comprising cell measurement information about at least one neighbor cell.

19. The apparatus according to any of claims 11 to 18, wherein the apparatus is a user equipment.

20. The apparatus according to any of claims 9 to 15, wherein the apparatus is operating according to the long-term evolution or according to the long-term evolution advanced.

21. A method, comprising:

receiving transmission of composed assistant information from a base station ; and processing the received assistant information,

wherein the assistant information is composed by:

sleep/active mode type information;

cell deployment type information indicating a macro/pico/small ceil deployment; and

22. A computer program including a program for a processing device, comprising software code portions for performing the steps according claim

11 or 21 when the program is run on the processing device.

23. The computer program product according to claim 22, wherein the computer program product comprises a computer-readable medium on which the software code portions are stored.

24. The computer program product according to claim 22, wherein the program is directly loadable into an internal memory of the processing device.

25. An apparatus, comprising

determination means for determining whether the carrier type to be used for communication is a legacy carrier or a new carrier type which supports at least one of a standalone, macro-assisted and non-standalone configuration;

composition means for composing assistant information comprising at least one of:

sleep/active mode type information;

transmission means for causing transmission of the composed assistant information to a network element.

26. An apparatus, comprising

reception means for receiving transmission of composed assistant information from a base station; and

processing means for processing the received assistant information, wherein the assistant information is composed by:

sleep/active mode type information; cell deployment type information indicating a macro/pico/small cell deployment; and