WO2014179921A1

WO2014179921A1 - Dormant mode - active mode switch

Info

Publication number: WO2014179921A1
Application number: PCT/CN2013/075194
Authority: WO
Inventors: Chunyan Gao; Na WEI; Pengfei Sun; Wei Bai; Wei Hong; Lili Zhang; Jing HAN; Haiming Wang
Original assignee: Broadcom Corporation
Priority date: 2013-05-06
Filing date: 2013-05-06
Publication date: 2014-11-13

Abstract

It is provided a method, comprising detecting, in a dormant mode, an assistance information, wherein the assistance information is received from a terminal device in a wake up procedure for causing the apparatus to switch into an active mode; deciding, based on the assistance information, whether or not the apparatus will switch into the active mode; indicating, to the user device, whether or not the apparatus will switch into the active mode.

Description

DORMANT MODE - ACTI VE MODE SW I TCH

Field of the invention The present invention relates to an apparatus, a method, and a computer program product for a improving the dormant mode - active mode switch of an eNB. More particularly, the present invention relates to an apparatus, a method, and a computer program product for an efficient dormant mode - active mode switch of the eNB.

Background of the invention

Abbreviations

3GPP 3^rd Generation Partnership Project

CA Carrier Aggregation

CRS Cell-Specific Reference Signal

CSI Channel State Information

DL Downlink

DRX Discontinuous Reception

DTX Discontinuous Transmission

eNB Enhanced Node B (Node B in LTE)

GSM Global System for Mobile Communication

HetNet Heterogeneous Network

HO Handover

LA Local Area

LTE™ Long Term Evolution

LTE-A™ Long Term Evolution Advanced

MAC Medium Access Control

NCT New Carrier Type

PDCCH Physical Downlink Control Channel

PUCCH Physical Uplink Control Channel

RACH Random Access Channel

RAN Radio Access Network

RAT Radio Access Technology

RRC Radio Resource Control

RRM Radio Resource Management

RS Reference Signal

SCH Shared Channel

Scell Secondary Cell

SFN System Frame Number

TTI Transmission Timing Interval

UE User Equipment

UL Uplink

WLAN Wireless LAN

Wl Work Item WiFi Wireless Fidelity

UE User Equipment

UL Uplink Due to the recent booming of the wireless internet, it is expected that the requirement for wireless data service will keep on fast soaring in the near future. Among those advanced technologies proposed to meet the challenging request, reducing the cell size is one of the most prominent one. In the past 50 years, the wireless network capacity has been increased by more than 2700 times from smaller cells. Therefore, the local area (LA) network may become the next research hotspot in LTE evolution.

Therefore, 3GPP has agreed to study the small cell enhancement from the higher layer aspects [1] and physical layer aspects [2]. The enhancements are supposed to target the scenarios and requirements captured in [3]. In [3], it is stated that dense deployment of small cells should be one scenario, which was not properly studied in the previous HetNet work. Such dense deployed small cells result in excessive power consumption and inter-cell interference. Thus, a dormant mode (sometimes also named sleep mode) for small cell has been proposed to reduce the power consumption and interference level. That is, the small cell may turn to dormant mode if no traffic or low traffic is identified to save network power consumption. Then, the small cell wakes up from the dormant cell when extra capacity is needed. Therefore, in [3], it is stated: Small cell enhancement should target the network energy efficiency to be as high as possible, given a reasonable system complexity with considering the traffic characteristics of small cell enhancement described in clause 6.3. Furthermore, placing small cells in a dormant mode could be supported considering the increased likelihood of small cells not serving any active users. The trade-off between user throughput/capacity per unit area and network energy efficiency should be considered.

In addition, this dormant mode has been captured by the new NCT Wl [4], in which it is stated that: If justified by the small cell related studies, specify necessary means to support a dual dormant / active state, which means DTX like eNB behaviour (with long DTX cycles) and corresponding UE procedures, with or without reduced CRS in the active state. (Note that "state" instead of "mode is used, but these two terms are equivalent in the present context).

During the dormant mode, the small cell may transmit DL signals with a long duty cycle to support cell discovery while it turns off the transmitter during the rest of time. More in detail, for example, if the cell device is in the dormant mode, the cell device may not transmit a cell specific reference signal, or, the cell device may only transmit a cell specific reference signal with a period much longer than that in the active mode, or, the cell device may be totally muted without transmit anything. Thus, the small cell may transit between dormant mode and active mode from time to time.

It is obvious that a long sleep duration results in more energy saving at the eNB, however, on the other hand, it may result in degraded UE experience. Similarly, a short sleep duration enables prompt reaction to a potential request from UE side, while the energy saving is reduced. Accordingly, a method is needed to get a balance between eNB power saving and QoS.

Reference

[1] RP-122033, "New Study Item Description: Small Cell Enhancements for E- UTRA and E-UTRAN-Higher-layer Aspects", NTT DOCOMO

[2] RP-122032, "New Study Item Proposal for Small Cell Enhancement for E- UTRA and E-UTRAN- Physical- layer Aspects", Huawei

[3] 3GPP TR36.932, "Scenarios and Requirements for Small Cell Enhancement for E-UTRA and E-UTRAN"

[4] RP-121415, "New Wl Proposal: New Carrier Type for LTE", Ericsson

Summary of the invention

It is an object of the present invention to improve the prior art. For example, it is an object to improve interference mitigation. According to a first aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform: providing an assistance information to a cell device which is detected to be in a dormant mode, wherein the assistance information is provided in a wake up procedure for causing the cell device to switch into an active mode, and the assistance information aims to assist the cell device in deciding whether or not to switch into the active mode.

According to a second aspect of the invention, there is provided an apparatus, comprising providing means adapted to provide an assistance information to a cell device which is detected to be in a dormant mode, wherein the assistance information is provided in a wake up procedure for causing the cell device to switch into an active mode, and the assistance information aims to assist the cell device in deciding whether or not to switch into the active mode.

According to a third aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform: detecting a time indication broadcasted from a cell device, wherein the time indication indicates a time duration; determining if the time duration is above a threshold; and at least one of if it is determined that the cell device is in the active mode and the time duration is not above the threshold: preventing at least one of measuring and reporting for the cell device; and if it is determined that the cell device is in the dormant mode and the time duration is above the threshold: preventing starting a wake up procedure to the cell device.

According to a fourth aspect of the invention, there is provided an apparatus, comprising detecting means adapted to detect a time indication broadcasted from a cell device, wherein the time indication indicates a time duration; determining means adapted to determine if the time duration is above a threshold; and at least one of first preventing means adapted to prevent at least one of measuring and reporting for the cell device if it is determined that the cell device is in the active mode and the time duration is not above the threshold; and second preventing means adapted to prevent starting a wake up procedure to the cell device if it is determined that the cell device is in the dormant mode and the time duration is above the threshold.

According to fifth aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform: detecting, in a dormant mode, an assistance information, wherein the assistance information is received from a terminal device in a wake up procedure for causing the apparatus to switch into an active mode; deciding, based on the assistance information, whether or not the apparatus will switch into the active mode; indicating, to the user device, whether or not the apparatus will switch into the active mode.

According to a sixth aspect of the invention, there is provided an apparatus, comprising detecting means adapted to detect, in a dormant mode, an assistance information, wherein the assistance information is received from a terminal device in a wake up procedure for causing the apparatus to switch into an active mode; deciding means adapted to decide, based on the assistance information, whether or not the apparatus will switch into the active mode; indicating means adapted to indicate, to the user device, whether or not the apparatus will switch into the active mode.

According to a seventh aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform: broadcasting a time indication, wherein the time indication indicates a time duration for which the apparatus will stay in one of the dormant mode and the active mode. According to an eighth aspect of the invention, there is provided an apparatus, comprising broadcasting means adapted to broadcast a time indication, wherein the time indication indicates a time duration for which the apparatus will stay in one of the dormant mode and the active mode.

Further details of the first to eighth aspects are defined in the dependent claims.

According to a ninth aspect of the invention, there is provided a method, comprising providing an assistance information to a cell device which is detected to be in a dormant mode, wherein the assistance information is provided in a wake up procedure for causing the cell device to switch into an active mode, and the assistance information aims to assist the cell device in deciding whether or not to switch into the active mode.

According to a tenth aspect of the invention, there is provided a method, comprising detecting a time indication broadcasted from a cell device, wherein the time indication indicates a time duration; determining if the time duration is above a threshold; and at least one of, if it is determined that the cell device is in the active mode and the time duration is not above the threshold: preventing at least one of measuring and reporting for the cell device; and, if it is determined that the cell device is in the dormant mode and the time duration is above the threshold: preventing starting a wake up procedure to the cell device. According to an eleventh aspect of the invention, there is provided a method, comprising detecting, in a dormant mode, an assistance information, wherein the assistance information is received from a terminal device in a wake up procedure for causing the apparatus to switch into an active mode; deciding, based on the assistance information, whether or not the apparatus will switch into the active mode; indicating, to the user device, whether or not the apparatus will switch into the active mode.

According to a twelfth aspect of the invention, there is provided a method, comprising broadcasting a time indication, wherein the time indication indicates a time duration for which the apparatus will stay in one of the dormant mode and the active mode.

Each of the methods of the ninth to twelfth aspects corresponds to each of two of the apparatuses of the first to eighths aspects, respectively. Further details of these methods correspond to those defined in the respective dependent apparatus claims.

Each of the methods of the ninth to twelfth aspects may be a method of switching between dormant mode and active mode.

According to a thirteenth aspect of the invention, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any one of the ninth to twelfth aspects. The computer program product may be embodied as a computer-readable medium or may be directly loadable into the apparatus.

According to some embodiments of the invention, for example at least one of the following advantages is achieved:

• power savings and network performance are balanced;

• a more efficient eNB mode switch between dormant mode and active mode is enabled;

• unnecessary transmission of wake up requests from UE and corresponding frequent detection of the request at eNB side are avoided; and

• ping-pong operation in mode switch is avoided.

It is to be understood that any of the above modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives.

Brief description of the drawings Further details, features, objects, and advantages are apparent from the following detailed description of some embodiments of the present invention which is to be taken in conjunction with the appended drawings, wherein

Fig. 1 an apparatus according to an embodiment of the invention;

Fig. 2 a method according to an embodiment of the invention;

Fig. 3 an apparatus according to an embodiment of the invention;

Fig. 4 a method according to an embodiment of the invention;

Fig. 5 an apparatus according to an embodiment of the invention;

Fig. 6 a method according to an embodiment of the invention;

Fig. 7 an apparatus according to an embodiment of the invention; and

Fig. 8 a method according to an embodiment of the invention.

Detailed description of certain embodiments

Herein below, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein the features of the embodiments can be freely combined with each other unless otherwise described. However, it is to be expressly understood that the description of certain embodiments is given for by way of example only, and that it is by no way intended to be understood as limiting the invention to the disclosed details.

Moreover, it is to be understood that the apparatus is configured to perform the corresponding method, although in some cases only the apparatus or only the method are described.

As discussed hereinabove, the length of eNB sleep duration determines how much power saving can be obtained, and at the same time, it affects the network performance, e.g., link quality, HO delay. Hence an optimization method is needed to get a balance, e.g. to provide good performance while at the same time getting satisfactory power saving. For example, it is not desirable to wake up one eNB only to serve a single UE if the UE can be served by another active eNB. On the other hand, in urgent cases such as HO, RRC connection request, the cell should wake up immediately regardless of the power saving concern. In addition, it is also not desirable to make one eNB switch between dormant mode and active mode frequently and cause Ping-Pong operation. These will reduce the power saving gain that can be obtained, and may cause unnecessary signaling, e.g, to reconfigure the UEs' measurement due to possible different RS pattern for dormant mode and active mode.

According to some embodiments of the invention, UE send assistance information to eNB in dormant mode which helps eNB to decide whether need to switch to active mode.

The assistance information may be send during RACH procedure. Conventionally, a (contention based) RACH procedure is started by UE by sending a preamble to the eNB (hereinafter: Message 1 (Msg1)). There are several reasons triggering the RACH procedure such as RRC_Connection_Request, dual connection establishment, handover, eNB measurement. Further reasons are e.g. Initial access from RRCJDLE; Initial access after radio link failure; DL data arrival during RRC_CONNECTED when UL synchronisation status is "non-synchronised"; UL data arrival during RRC_CONNECTED when UL synchronisation status is "non- synchronised" or there are no PUCCH resources for SR available.

Conventionally, if RACH preamble is received, eNB responds by RACH response (Message 2 (Msg2)). Then, UE sends a Scheduled Transmission on UL-SCH (Message 3 (Msg3)), the content of which depends on the reason for starting the RACH procedure. Finally, in response to message 3, eNB sends Contention Resolution on DL-SCH (Message 4 (Msg4)). If eNB is in dormant mode and the RACH procedure is successfully finalized, the eNB is switched into active mode. That is, RACH procedure is a wake up procedure for the eNB in the dormant mode. Hence, according to some embodiments of the invention, during RACH procedure to an eNB in dormant mode, the UE indicates assistance information to help eNB to decide whether to switch to active mode: The assistance information may be the reason for sending RACH, e.g, it is for RRC_Connection_Request, or, for dual connection establishment, or for HO, or for eNB measurement. For example, the values of assistance information may be defined for different reasons of RACH transmission as follows:

• 00: RRC_Connection_Request

• 01: Dual connection establishment

• 10: For HO

· 11 : For eNB to measure and report to UE's serving eNB.

For example, if the assistance information comprises 00 or 10, eNB may decide to switch to active mode to serve the UE, while if the assistance information indicates 01 or 11 , eNB may stay in dormant mode.

In some embodiments, the assistance information may be an indication of UE status: e.g, whether or not the dormant eNB is the only eNB being detected, and/or the mobility status of the UE (such as low mobility/high mobility), and/or whether the UE detecting another cell is at the center or at the edge of the other cell;

E.g, the following statuses may be defined:

• 00: UE is out of coverage of other cells, and with low mobility;

• 01 : UE has one serving cell, but at cell edge, and with low mobility; · 10: UE is out of coverage of other cells, and with high mobility;

• 11 : UE has one serving cell, but at cell edge, and with high mobility;

In one embodiment, if UE indicates 00 to eNB, the eNB may decide to switch to active mode quickly to serve the UE because otherwise, the UE might stay in the undesirable status due to its low mobility.

In some embodiments of the invention, the eNB decides whether to switch to active mode based on assistance information from more than one UE. E.g, if there are multiple UEs requesting a mode switch to the active mode and more than one of them is with low mobility, then eNB may decide to serve them by switching into the active state. On the other hand, if only one or none is with low mobility, the eNB may decide not to switch into the active state. In another example, if eNB only detects one request, but the request shows that the UE is out of other cell's coverage, eNB may decide to switch to active mode, whereas it will not switch to active mode if the one request indicates that the UE is still within coverage of the other cell.

The assistance information may be sent explicitly via Msg3 or via Msg1 (as part of the preamble). In some embodiments, the assistance information may be sent implicitly by selecting a preamble from a certain preamble group, e.g, by selecting one preamble from group#0, the UE indicates 00 to eNB, while if selecting a preamble from group#3, the UE indicate 11 to eNB, etc.. The latter has the advantage that eNB is earlier in the RACH procedure aware of the assistance information and may provide its indication whether or not it will switch to active mode earlier via Msg2 (explicitly or implicitly by blind detection, see below), such that the RACH procedure may be terminated earlier.

In some embodiments of the invention, after the assistance information is received, eNB indicates whether or not it will switch to active mode. This may be done e.g. in one of the following ways:

• It is indicated explicitly in at least one of Msg2 and Msg4; and/or

• If eNB switches to active mode, it sends Msg2 to UE; otherwise it does not respond to the preamble by Msg2. Hence, eNB lets UE know via blind detection that it will not switch to active mode. In detail, e.g, if

UE does not receive Msg2 within a predefined time window, potentially even after N times retransmission of RACH preamble, UE assumes that the eNB will not switch to active mode. Then UE stops the RACH procedure to the eNB in dormant mode. The value N can be predefined or configured by a serving eNB.

Some embodiments of the invention help the eNB to switch from dormant mode to active mode only when necessary. Fig. 1 shows an apparatus according to an embodiment of the invention. The apparatus may be user device such as a UE, or a part thereof (e.g. a modem). Fig. 2 shows a method according to an embodiment of the invention. The apparatus according to Fig. 1 may perform the method of Fig. 2 but is not limited to this method. The method of Fig. 2 may be performed by the apparatus of Fig. 1 but is not limited to being performed by this apparatus.

The apparatus comprises at least one processor 10 and at least one memory 20. The at least one memory 20 includes computer program code, and the at least one processor 10, with the at least one memory 20 and the computer program code is arranged to cause the apparatus to at least perform:

Providing (S10) an assistance information to a cell device which is detected to be in a dormant mode. The assistance information is provided in a wake up procedure such as a RACH procedure for causing the cell device to switch into an active mode. The assistance information aims to assist the cell device in deciding whether or not to switch into the active mode. However, the cell device may still decide not to switch into the active mode, in spite of the started wake up procedure.

Fig. 3 shows an apparatus according to an embodiment of the invention. The apparatus may be cell device such as a base station, an eNB etc., or a part thereof. Fig. 4 shows a method according to an embodiment of the invention. The apparatus according to Fig. 3 may perform the method of Fig. 4 but is not limited to this method. The method of Fig. 4 may be performed by the apparatus of Fig. 3 but is not limited to being performed by this apparatus.

The apparatus comprises at least one processor 110 and at least one memory 120. The at least one memory 120 includes computer program code, and the at least one processor 110, with the at least one memory 120 and the computer program code is arranged to cause the apparatus to at least perform: Detecting (S110), in a dormant mode, an assistance information. The assistance information is received from a terminal device in a wake up procedure such as a RACH procedure for causing the apparatus to switch into an active mode. According to step S120, the apparatus decides, based on the assistance information, whether or not the apparatus will switch into the active mode. That is, the apparatus may decide not to switch into the active mode in spite of the received wake up procedure. In step S130, the apparatus indicates the decision to the user device.

According to some embodiments of the invention, eNB broadcasts a time indication which helps the UE to decide whether it can send wake up request in a certain time duration (T). The time indication may be sent periodically. It indicates for at least how long the current mode (active mode or dormant mode) will take.

• For an active eNB, the time indication indicates that the eNB will not switch to dormant mode at least within time duration T;

• For a dormant eNB, the time indication indicates that the eNB will not switch to active mode at least within time duration T;

• The broadcast period of the time indication (i.e. the period with which the time indication is broadcasted) may be different for active and dormant eNBs. The time duration T may or may not be related to the respective broadcast period.

As a consequence of receiving the time indication, according to some embodiments of the invention, the UE reacts as follows:

• UE will not measure and/or report for the cell even if the cell is active, if the timer is below a threshold; and/or

· UE will not send a wake up request to the cell even if the cell is in the dormant mode, if the timer is above a threshold; and/or,

• UE derives a time window for sending a wake up request based on the broadcasted time indication if the cell is in the dormant mode. A wake up request may be a part of a wake up procedure such as a RACH procedure. In particular, sending the RACH preamble may be awake up request.

According to some embodiments of the invention, eNB broadcasts the time indication periodically, e.g, with a same period as the discovery signal, indicating that it will keep in dormant mode for at least the time duration T. Then based on the broadcasted time indication, UE can derive a time window to send a wake up request. In such way, unnecessary transmission of wake up requests from UE and corresponding frequent detection of the request at eNB side are avoided.

According to some embodiments of the invention, an active eNB broadcasts the time indication periodically, e.g, together with the system information, indicating that it will keep in active mode for at least the time duration T. When one UE detects that the time duration is lower than a threshold, which means the eNB may soon enter into the dormant mode, then the UE may put low priority for the measurement and/or report for this eNB. In case the UE needs HO, the serving eNB may handover it to another cell rather than the eNB which will soon enter into dormant mode. Some embodiments of the invention wherein the time indication is provided help to avoid ping-pong operation, i.e, to avoid frequent dormant mode - active mode switch.

Fig. 5 shows an apparatus according to an embodiment of the invention. The apparatus may be user device such as a UE, or a part thereof. Fig. 6 shows a method according to an embodiment of the invention. The apparatus according to Fig. 5 may perform the method of Fig. 6 but is not limited to this method. The method of Fig. 6 may be performed by the apparatus of Fig. 5 but is not limited to being performed by this apparatus.

The apparatus comprises at least one processor 210 and at least one memory 220. The at least one memory 220 includes computer program code, and the at least one processor 210, with the at least one memory 220 and the computer program code is arranged to cause the apparatus to at least perform: Detecting (S210) a time indication broadcasted from a cell device, wherein the time indication indicates a time duration. In step S220, it is determined if the time duration is above a threshold. More in detail, it is determined if the indicated time duration is longer than a predetermined time duration (threshold). The time duration may be indicated e.g. in msec, or as a number of TTIs.

According to some embodiments of the invention, then, the apparatus may perform one or both of the following sequences of steps:

If it is determined that the cell device is in the active mode (S230) and the time duration is not above the threshold: preventing (S240) at least one of measuring and reporting for the cell device. If it is determined that the cell device is in the dormant mode (S250) and the time duration is above the threshold: preventing (S260) starting a wake up procedure such as a RACH procedure to the cell device.

Typically, the measuring/reporting and starting the wake up procedure, respectively, is prevented for the indicated time duration.

In equivalent embodiments of the invention, it is first checked if the cell is in active mode or dormant mode, and then, it is checked if the time duration is above the threshold.

The check, if the cell is in active mode or in dormant mode may be performed by the apparatus according to some embodiments of the invention, but it may also be performed by a second apparatus which is not an embodiment of the invention. In the latter case, the second apparatus provides the result of this check to the apparatus according to some embodiments of the invention.

Fig. 7 shows an apparatus according to an embodiment of the invention. The apparatus may be cell device such as a base station, an eNB etc., or a part thereof. Fig. 8 shows a method according to an embodiment of the invention. The apparatus according to Fig. 7 may perform the method of Fig. 8 but is not limited to this method. The method of Fig. 8 may be performed by the apparatus of Fig. 7 but is not limited to being performed by this apparatus. The apparatus comprises at least one processor 310 and at least one memory 320. The at least one memory 320 includes computer program code, and the at least one processor 310, with the at least one memory 320 and the computer program code is arranged to cause the apparatus to at least perform: Broadcasting (S310) a time indication, wherein the time indication indicates a time duration for which the apparatus will stay in one of the dormant mode and the active mode. Namely, the time indication indicates for how long the apparatus will remain in its present mode, i.e. the mode in which he is when broadcasting the time indication.

In some embodiments of the invention, both assistance information and time indication are provided. If the corresponding information is in conflict with each other, one of them has prevalence over the other, e.g. according to predetermined rules.

In some embodiments of the invention, assistance information has always prevalence over time indication, while, according to other embodiments, time indication has always prevalence over assistance information. However, in this way, an optimum balance between power savings and network performance might not be achieved. Therefore, in some embodiments of the invention, more complex rules are employed.

For example, the cell is in dormant mode and indicates that it will stay in dormant mode for time duration T. On the other hand, UE is in status 00 (as defined hereinabove), i.e. UE is out of coverage of other cells and with low mobility. In this case, UE may send a wake up request such as RACH preamble indicating its status as assistance information, irrespective of the indicated time duration. If the status is different from 00, UE must not send the wake up request. That is, according to this example rule, assistance information has prevalence over time indication if the assistance information indicates the status 00, and time indication has prevalence over assistance information otherwise.

According to another example rule, assistance information has prevalence over time indication if the assistance information indicates RRC_Connection_Request as reason for RACH procedure, and time indication has prevalence over assistance information otherwise.

According to still another example rule, time indication has prevalence over assistance information if the indicated time duration is larger than a certain threshold, and assistance information has prevalence over time indication otherwise.

Embodiments of the invention are described based on a LTE-A system but embodiments of the invention may be applied to other radio access technologies such as LTE, WiFi, WLAN, UMTS, HSPA, GSM, e.g. if a mode switch between a dormant mode and an active mode is foreseen.

A terminal device may be a machine type device, a user equipment, a mobile phone, a laptop, a smartphone, a tablet PC, or any other device that may attach to a radio network. A cell device may be a base station (or a respective part thereof serving a cell) such as a NodeB, or an eNodeB or any other kind of base station of the corresponding radio network. E.g., in some embodiments, a user equipment may serve as a cell device, too. A cell may be a macro cell, a pico cell, a femto cell, etc. Throughout this description, the terms eNB, base station, cell, and cell device are used synonymously if not otherwise clear from the context.

If not otherwise stated or otherwise made clear from the context, the statement that two entities are different means that they are differently addressed in their respective network. It does not necessarily mean that they are based on different hardware. That is, each of the entities described in the present description may be based on a different hardware, or some or all of the entities may be based on the same hardware. According to the above description, it should thus be apparent that example embodiments of the present invention provide, for example a receiver such as an iterative receiver, or a component thereof, an apparatus such as a terminal or a base station embodying the same, a method for controlling and/or operating the same, and computer program(s) controlling and/or operating the same as well as mediums carrying such computer program(s) and forming computer program product(s).

According to example embodiments of the present invention, a system may comprise any conceivable combination of the thus depicted devices/apparatuses and other network elements, which are configured to cooperate with any one of them .

In general, it is to be noted that respective functional blocks or elements according to above-described aspects can be implemented by any known means, either in hardware and/or software/firmware, respectively, if it is only adapted to perform the described functions of the respective parts. The mentioned method steps can be realized in individual functional blocks or by individual devices, or one or more of the method steps can be realized in a single functional block or by a single device.

Generally, any structural means such as a processor or other circuitry may refer to one or more of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) 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) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. Also, it may 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, any integrated circuit, or the like. Generally, any procedural step or functionality is suitable to be implemented as software/firmware or by hardware without changing the idea of the present invention. Such software may be software code independent and can be specified using any known or future developed programming language, such as e.g. Java, C+ + , C, and Assembler, as long as the functionality defined by the method steps is preserved. Such hardware may be hardware type independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components. A device/ apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device/ apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor. A device may be regarded as a device/ apparatus or as an assembly of more than one device/ apparatus, whether functionally in cooperation with each other or functionally independently of each other but in a same device housing, for example. Apparatuses and/or means or parts thereof can be implemented as individual devices, but this does not exclude that they may be implemented in a distributed fashion throughout the system, as long as the functionality of the device is preserved. Such and similar principles are to be considered as known to a skilled person.

Software in the sense of the present description comprises software code as such comprising code means or portions or a computer program or a computer program product for performing the respective functions, as well as software (or a computer program or a computer program product) embodied on a tangible medium such as a computer-readable (storage) medium having stored thereon a respective data structure or code means/portions or embodied in a signal or in a chip, potentially during processing thereof.

The present invention also covers any conceivable combination of method steps and operations described above, and any conceivable combination of nodes, apparatuses, modules or elements described above, as long as the above- described concepts of methodology and structural arrangement are applicable.

It is to be understood that what is described above is what is presently considered the preferred embodiments of the present invention. However, it should be noted that the description of the preferred embodiments is given by way of example only and that various modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

WHAT I S CLAI MED I S:

1. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform:

providing an assistance information to a cell device which is detected to be in a dormant mode, wherein the assistance information is provided in a wake up procedure for causing the cell device to switch into an active mode, and the assistance information aims to assist the cell device in deciding whether or not to switch into the active mode.

2. The apparatus according to claim 1 , wherein the wake up procedure comprises a random access channel procedure.

3. The apparatus according to claim 2, wherein the assistance information comprises a reason for starting the random access channel procedure.

4. The apparatus according to any of claims 2 to 3, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

selecting a preamble depending on the assistance information; and providing the preamble to the cell device in the random access channel procedure.

5. The apparatus according to any of claims 2 to 3, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

providing the assistance information in a scheduled transmission of the random access channel procedure.

6. The apparatus according to any of claims 1 to 5, wherein the assistance information comprises an information about at least one of a coverage status of the apparatus and a mobility status of the apparatus.

7. The apparatus according to any of claims 1 to 6, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

detecting, in response to the providing of the assistance information, an indication from the cell device indicating whether or not the cell device will switch into the active mode; and

preventing setting up an access to the cell device if the indication indicates that the cell device will not switch into the active mode.

8. The apparatus according to claim 7 dependent on claim 4 wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

monitoring if a random access response is received in response to the preamble within a certain time; and

concluding, if the random access response is not received within the certain time, that the cell device will not switch into the active mode.

9. The apparatus according to claim 7 dependent on claim 2, wherein the indication is received in at least one of a random access response and a contention resolution of the random access channel procedure.

10. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

detecting a time indication broadcasted from a cell device, wherein the time indication indicates a time duration;

determining if the time duration is above a threshold; and at least one of, if it is determined that the cell device is in the active mode and the time duration is not above the threshold: preventing at least one of measuring and reporting for the cell device; and,

if it is determined that the cell device is in the dormant mode and the time duration is above the threshold: preventing starting a wake up procedure to the cell device.

11. The apparatus according to claim 10, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform,

if it is determined that the cell device is in the dormant mode, calculating a time window for starting the wake up procedure;

providing the wake up request to the cell device in the time window.

12. The apparatus according to any of claims 10 and 11 , wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform,

starting, if the apparatus is in a predefined state and the cell device is in the dormant mode, the wake up procedure, irrespective of the time duration, and

providing, in the wake up procedure, an assistance information informing about the predefined state to the cell device.

13. The apparatus according to any of claims 10 to 12, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform,

calculating a point in time when the time duration is over; and

starting the wake up procedure when at or after the point in time.

14. The apparatus according to any of claims 1 to 13, belonging to a long term evolution standard.

15. User equipment comprising an apparatus according to any of claims 1 to 14.

16. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

detecting, in a dormant mode, an assistance information, wherein the assistance information is received from a terminal device in a wake up procedure for causing the apparatus to switch into an active mode;

deciding, based on the assistance information, whether or not the apparatus will switch into the active mode;

indicating, to the user device, whether or not the apparatus will switch into the active mode.

17. The apparatus according to claim 16, wherein the wake up procedure comprises a random access channel procedure.

18. The apparatus according to claim 17, wherein the assistance information comprises a reason for starting the random access channel procedure.

19. The apparatus according to any of claims 17 to 18, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

deriving the assistance information from a preamble used in the random access channel procedure.

20. The apparatus according to any of claims 17 to 18, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

deriving the assistance information from a scheduled transmission of the random access channel procedure.

21. The apparatus according to claim 19, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform prohibiting providing a random access response in response to the preamble if the apparatus does not switch into the active mode.

22. The apparatus according to any of claims 17 to 20, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform

generating at least one of a random access response and a contention resolution message of the random access procedure, wherein the at least one of the random access response and the contention resolution message comprises an indication indicating whether or not the apparatus will switch into the active mode;

providing the at least one of the random access response and the contention resolution message to the user device.

23. The apparatus according to any of claims 16 to 22, wherein the assistance information comprises an information about at least one of a coverage status of the apparatus and a mobility status of the apparatus.

24. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

broadcasting a time indication, wherein the time indication indicates a time duration for which the apparatus will stay in one of the dormant mode and the active mode.

25. The apparatus according to claim 24, wherein,

if the apparatus is in the dormant mode, the broadcasting is performed periodically with a first period; and,

if the apparatus is in the active mode, the broadcasting is performed periodically with a second period different from the first period.

26. The apparatus according to claim 24, wherein, if the apparatus is in the dormant mode, the broadcasting is performed periodically with a third period; and,

if the apparatus is in the active mode, the broadcasting is performed periodically with the third period.

27. The apparatus according to any of claims 24 to 26, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform, if the apparatus is in the dormant mode,

checking if an assistance information indicates a predefined state of a user device, wherein the assistance information is received in a wake up procedure started by the user device;

switching into the active mode if the assistance information indicates the predefined state, irrespective of the time duration.

28. The apparatus according to any of claims 16 to 27, belonging to a long term evolution standard.

29. Base station comprising an apparatus according to any of claims 16 to 28.

30. A method, comprising

31. A method, comprising

determining if the time duration is above a threshold; and at least one of, if it is determined that the cell device is in the active mode and the time duration is not above the threshold: preventing at least one of measuring and reporting for the cell device; and, if it is determined that the cell device is in the dormant mode and the time duration is above the threshold: preventing starting a wake up procedure to the cell device.

32. A method, comprising

33. A method, comprising

34. A computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any one of claims 30 to 33.

35. The computer program product according to claim 34, embodied as a computer-readable medium or directly loadable into the apparatus.