WO2015083063A2

WO2015083063A2 - Non-paging base stations in lte systems

Info

Publication number: WO2015083063A2
Application number: PCT/IB2014/066489
Authority: WO
Inventors: Christopher Richards; Leonard Lightstone; Karl Mann; Adrien Comeau
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2013-12-02
Filing date: 2014-12-01
Publication date: 2015-06-11
Also published as: WO2015083063A3

Abstract

According to the techniques disclosed herein, base stations are allowed to be "non-paging" base stations, either entirely or partially. Generally, a non-paging mode according to these approaches is only valid for paging of specific mobile terminals or specific groups of mobile terminals. An example method is suitable for implementation in a base station, and includes: determining that the base station is to operate in a non-paging mode, in which mode the base station does not broadcast paging messages for all mobile terminals in its coverage area; and broadcasting a non-paging indicator, said indicator indicating that the base station is operating in non-paging mode. The non-paging indicator may comprise a parameter in a System Information Block (SIB) message in some embodiments, or an extended paging cycle parameter in other embodiments.

Description

Non-Paging Base Stations in LTE Systems

TECHNICAL FIELD

The present disclosure is related generally to wireless communication networks and is more particularly related to techniques and apparatus for paging of mobile terminals in such networks.

BACKGROUND

In a forum known as the 3^rd-Generation Partnership Project (3GPP),

telecommunications suppliers propose and agree upon standards for third generation networks generally and specifically for a network formally known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and investigate techniques to enhance wireless data rates and radio capacity. Several releases for the E-UTRAN specification have issued, and the standards continue to evolve. The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) is generally understood to include two major parts: a radio access network (RAN) part referred to as Long Term Evolution (LTE), and a core network part referred to as System Architecture Evolution (SAE).

Long Term Evolution (LTE) is a variant of a 3GPP radio access technology where the radio base station nodes are connected to a core network, via Access Gateways (AGWs), rather than to radio network controller (RNC) nodes. In general, in LTE systems the functions of a radio network controller (RNC) node are distributed between the AGWs and the system's radio base stations nodes, referred to in the specifications for LTE as eNodeBs or eNBs. As a result, the radio access network (RAN) of an LTE system has what is sometimes termed a "flat" architecture, including radio base station nodes that do not report to radio network controller (RNC) nodes.

In 3GPP LTE, when the mobile terminal, known as a "user equipment" or "UE" in 3GPP terminology, is in an idle state (RRCJDLE), its location is known to the network only to the granularity of a Tracking Area (TA). A TA consists of a set of eNBs in a particular area. Accordingly, when the network needs to contact a UE in idle state, paging requests are sent from a Mobility Management Entity (MME) to all of the base stations (known as eNodeBs or eNBs in 3GPP terminology) in the TA last associated with the UE.

Each eNB must schedule and allocate air interface resources in order to broadcast each paging request it receives for UEs, even though the eNB does not know whether any of the UEs are actually within range of the eNB. For a small cell eNB that has a very limited coverage range, the probability that the paged UE is in the small cell is low, even while the number of UEs that are in the TA for the small cell may be very high. Accordingly, improved solutions for paging, especially in networks that include small cells, are needed. SUMMARY

According to embodiments of the presently disclosed techniques, eNBs are allowed to be "non-paging" eNBs, either entirely or partially. Generally, a non-paging mode according to these approaches is only valid for paging of specific mobile terminals or groups of mobile terminals. It should not affect paging broadcasts for System Information Modification updates or ETWS (Earthquake and Tsunami Warning System) service, for example.

An eNB according to the presently disclosed techniques may be configured so as to always be "non-paging," or to be non-paging only in certain conditions. In various embodiments, the determination can be under the control of:

• The network operator (e.g., via static configuration of the eNB);

• A Mobility Management Entity (MME), e.g., based on the eNB deployment, past history, availability of macro coverage, operator paging policies, time of day, etc. An MME may instruct each eNB to set an appropriate paging mode indicator, as described in more detail below, using a new S1 -C signaling message and/or parameter.

• The eNB itself (e.g., based on the eNB deployment, past history,

availability of macro coverage, operator paging policies, time of day, etc.) in which case the eNB may autonomously inform the MME of its paging operating mode.

In addition, for backwards compatibility purposes, the MME in some embodiments may override the non-paging mode of an eNB for mobile terminals that only support the existing paging process (e.g., LTE UEs compliant only to Release 8 or 9 of the 3GPP standards) by sending a paging request for a mobile terminal to a non-paging eNB, the paging request instructing the non-paging eNB that it should broadcast the page for that UE regardless of the eNBs current paging mode.

According to some embodiments of the presently disclosed techniques, eNBs may broadcast an "I don't page" indication, i.e., a non-paging indication, over the air. This can be done, for example, by adding a new specific parameter to an existing System Information Block (SIB) message or by extending the existing paging cycle parameter with a new value, e.g. in SIB2.

A UE that wishes to enter RRCJDLE mode, upon detecting a non-paging indication (an "I don't page indication") transmitted by an eNB, would then camp on an alternative eNB, i.e. , an eNB that is broadcasting paging requests. UEs would avoid camping on non-paging eNB cells, even if a non-paging eNB cell provides the strongest signal. If there is no alternative (paging) eNB, a UE may perform a location update with the non-paging eNB in order to notify the system that it needs to receive downlink data indications from the non- paging eNB. A non-paging eNB may also change its paging state and become a paging eNB and may need to tell the MME of its paging mode. This may occur for example, when there is a change in paging macro coverage underlying the paging eNB.

When a UE receives a paging request, from the paging eNB on which it is camping, the UE attaches to the network, but not necessarily to the eNB that sent the page, instead attaching to the eNB to which the UE has the best radio frequency (RF) connection. The UE should perform the cell selection/reselection procedure following normal 3GPP procedures.

If the UE is not able to camp on multiple eNB cells, the UE may attach to the paging eNB and would then follow a normal handover process to the non-paging eNB if required. Effectively, the UE may use the macro eNB as a paging beacon only.

While several embodiments are described below in the context of an LTE system, it should be appreciated that the disclosed techniques may be applied to other wireless systems.

Accordingly, one example method according to the techniques disclosed herein is suitable for implementation in a base station, such as an LTE eNodeB, in a wireless network. This example method includes: determining that the base station is to operate in a non- paging mode, in which mode the base station does not broadcast paging messages for all mobile terminals in its coverage area; and broadcasting a non-paging indicator, said indicator indicating that the base station is operating in non-paging mode. The non-paging indicator may comprise a parameter in a System Information Block (SIB) message in some embodiments, or an extended paging cycle parameter in other embodiments. In some embodiments, the base station determines that it is to operate in non-paging mode by receiving a message from another node in the wireless network, such as a Mobility

Management Entity (MME), the message indicating that the base station should operate in a non-paging mode. In other embodiments, the base station autonomously determines that it is to operate in non-paging mode, e.g., based on one or more of a base station type for the base station, a past history of operation for the base station, an availability of macro coverage in the region of the base station, one or more operator paging policies, and a time of day.

In some embodiments, the method further includes receiving a paging message from another node in the wireless network, the paging message indicating that a mobile terminal should be paged even though the base station is operating in non-paging mode. The method continues with paging the mobile terminal, in response to the message. In some embodiments, the indication that the mobile terminal should be paged even though the base station is operating in non-paging mode is determined by the receipt of a unicast or multicast paging message. In other embodiments or in other instances, the paging message includes an explicit indication that the mobile terminal should be paged even though the base station is operating in non-paging mode.

Another example method according to the techniques disclosed herein is suitable for implementation in a mobile terminal, such as an LTE UE. The method includes: monitoring broadcasted information from a first base station ; detecting that the first base station is operating in a non-paging mode, based on the broadcasted information; and camping on a second base station, in response to detecting that the first base station is operating in non- paging mode. The non-paging indicator may comprise a parameter in a System Information Block (SIB) message in some embodiments, or an extended paging cycle parameter in some other embodiments. In some embodiments, the method further includes continuing to monitor broadcasted information from the first base station, while also monitoring broadcasted information from the second broadcasted information. In other embodiments, the method further includes storing information corresponding to the first base station, the information including at least frequency-identifying information for the first base station. In any of these embodiments, the method may further include receiving a page from the second base station, and attempting to attach to the first base station. In some of these latter embodiments, this attempting to attach to the first base station uses the stored information mentioned above; in others, the attempting to attach is based on the continuing to monitor broadcasted information from the first base station. In some embodiments, an attempt to attach to the first base station is followed by an attempt to attach to a base station other than the first base station in the event that the attempt to attach to the first base station is unsuccessful.

An alternative method for implementation in a mobile terminal may be implemented separately or in a mobile terminal that is also configured to carry out one of the previously described methods. According to this method, the mobile terminal monitors broadcasted information from a first base station; detects that the first base station is operating in a non- paging mode, based on the broadcasted information; unsuccessfully attempts to camp on a base station other than the first base station, in response to detecting that the first base station is operating in non-paging mode; and attaches to the first base station and performs a location update in response to unsuccessfully attempting to camp on a base station other than the first base station.

Still another example method according to the techniques disclosed herein is suitable for implementation in a network node, such as an LTE MME, connected to one or more base stations. This example method includes determining that a first base station is to operate in a non-paging mode, in which mode the first base station does not broadcast paging messages for all mobile terminals in its coverage area; and sending a message to the first base station, the message indicating that the bases station should operate in a non-paging mode. In some embodiments, the network node determines that the first base station is to operate in non-paging mode, e.g., based on one or more of a base station type for the base station, a past history of operation for the base station, an availability of macro coverage in the region of the base station, one or more operator paging policies, and a time of day.

Another example method is also implemented in a network node, such as an LTE MME, connected to one or more base stations. According to this method, which may be implemented separately or in a network node that is also configured to carry out the preceding method, the network node determines that a UE is to be paged and determines that the UE is not capable of detecting whether a base station is operating in non-paging method. The method continues with sending a paging message to at least one base station operating in non-paging mode, the paging message indicating that the UE is to be paged even though the base station is operating in non-paging mode. In some embodiments, the indication that the mobile terminal should be paged even though the base station is operating in non-paging mode is determined by the sending of a unicast or multi-cast paging message. In other embodiments or in other instances, the paging message includes an explicit indication that the mobile terminal should be paged even though the base station is operating in non-paging mode.

Corresponding apparatus, i.e., mobile terminals, base stations, and other wireless nodes configured to carry out one or more of the methods summarized above are also described in detail in the description that follows. Of course, the present invention is not limited to the above-summarized features and advantages. Indeed, those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram illustrating components of the LTE wireless network.

Figure 2 is a signal flow diagram illustrating current paging procedures.

Figure 3 illustrates a scenario in which a UE within the coverage of both a paging macro eNB and a non-paging pico eNB camps on the paging macro eNB, to receive paging broadcast requests.

Figure 4 is a process flow diagram illustrating an example method suitable for implementation in a base station.

Figure 5 is a process flow diagram illustrating an example method suitable for implementation in a mobile terminal.

Figure 6 is still another process flow diagram illustrating another example method suitable for implementation in a mobile terminal. Figure 7 is a process flow diagram illustrating an example method suitable for implementation in a network node, such as an MME.

Figure 8 is a process flow diagram illustrating another example method suitable for implementation in a network node, such as an MME.

Figure 9 is a block diagram illustrating components of an example mobile terminal, according to some of the techniques and apparatus described herein.

Figure 10 is a block diagram illustrating components of an example base station, according to some of the techniques and apparatus described herein.

DETAILED DESCRIPTION

In the discussion that follows, specific details of particular embodiments of the present invention are set forth for purposes of explanation and not limitation. It will be appreciated by those skilled in the art that other embodiments may be employed apart from these specific details. Furthermore, in some instances detailed descriptions of well-known methods, nodes, interfaces, circuits, and devices are omitted so as not obscure the description with unnecessary detail. Those skilled in the art will appreciate that the functions described may be implemented in one or in several nodes. Some or all of the functions described may be implemented using hardware circuitry, such as analog and/or discrete logic gates interconnected to perform a specialized function, ASICs, PLAs, etc. Likewise, some or all of the functions may be implemented using software programs and data in conjunction with one or more digital microprocessors or general purpose computers. Where nodes that communicate using the air interface are described, it will be appreciated that those nodes also have suitable radio communications circuitry. Moreover, the technology can additionally be considered to be embodied entirely within any form of computer-readable memory, including non-transitory embodiments such as solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein.

Hardware implementations of the present invention may include or encompass, without limitation, digital signal processor (DSP) hardware, a reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) (ASIC) and/or field programmable gate array(s) (FPGA(s)), and (where appropriate) state machines capable of performing such functions.

In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer, processor, and controller may be employed interchangeably. When provided by a computer, processor, or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, the term "processor" or "controller" also refers to other hardware capable of performing such functions and/or executing software, such as the example hardware recited above.

Referring now to the drawings, Figure 1 illustrates an exemplary mobile

communication network for providing wireless communication services to mobile terminals 100. Three mobile terminals 100, which are referred to as "user equipment" or "UEs" in 3GPP terminology, are shown in Figure 1 . The mobile terminals 100 may comprise, for example, cellular telephones, personal digital assistants, smart phones, laptop computers, handheld computers, machine-type communication/machine-to-machine (MTC/M2M) devices, or other devices with wireless communication capabilities. It should be noted that the term "mobile terminal," as used herein, refers to a terminal operating in a mobile communication network and does not necessarily imply that the terminal itself is mobile or moveable. Thus, the term as used herein should be understood to be interchangeable with the term "wireless device," and may refer to terminals that are installed in fixed

configurations, such as in certain machine-to-machine applications, as well as to portable devices, devices installed in motor vehicles, etc.

The mobile communication network comprises a plurality of geographic cell areas or sectors 12. Each geographic cell area or sector 12 is served by a base station 20, which is referred to as an eNodeB in the context of an LTE radio access network, formally known as the Evolved Universal Terrestrial Radio Access Network, or E-UTRAN. One base station 20 may provide service in multiple geographic cell areas or sectors 12. The mobile terminals 100 receive signals from base station 20 on one or more downlink (DL) channels, and transmit signals to the base station 20 on one or more uplink (UL) channels.

In an LTE network, base station 20 is an eNodeB and may be connected to one or more other eNodeBs via an X2 interface (not shown). An eNodeB is also connected to an MME 130 via an S1 -MME interface, and may be connected to one or more other network nodes, such as a Serving Gateway (not shown).

For illustrative purposes, several embodiments of the present invention will be described in the context of an E-UTRAN system. Those skilled in the art will appreciate, however, that several embodiments of the present invention may be more generally applicable to other wireless communication systems.

A few concepts already well known to those familiar with 3GPP networks are reviewed here, to provide some context and background for the following discussion. The UE operation corresponding to these concepts is currently specified in the 3GPP document "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode," 3GPP TS 36.304, available at www.3gpp.org. First is the operation known as "camping." A UE in idle mode, i.e., without an active Radio Resource Control (RRC) connection to a base station, has completed the cell selection/reselection process and has chosen a cell, and is thus "camping" on this cell. A UE in camping mode monitors system information and (in most cases) paging information. Second is an operation known as "cell selection." To perform cell selection, the UE:

• Performs measurements needed to support cell selection. The UE detects and synchronizes to a broadcast channel. The UE receives and handles broadcast information. The UE receiver forwards non-access stratum (NAS) system information to a NAS entity in the UE, and searches for a suitable cell. Each cell broadcasts at least one Public Land Mobile Network (PLMN) identity in the system information. The UE responds to NAS whether such cell is found or not. If an associated radio access technology (RAT) is set for the PLMN, the UE performs the search in this RAT and any other RATs for that PLMN, as specified in 3GPP TS 36.304. If such a cell is found, the cell is selected to camp on.

Another UE operation is known as "cell reselection." To perform cell reselection, the UE:

• Performs measurements needed to support cell reselection. The UE detects and synchronizes to a broadcast channel, and receives and handles broadcast information, forward NAS system information to NAS. The UE changes the cell for camping if a more suitable cell is found.

Small eNBs, such as so-called pico eNBs, generally do not have the same level of compute resources (CPU capabilities and system memory) as traditional macro eNBs. As a result, a pico eNB can be easily overloaded with paging requests, even to the extent that the pico eNB is unable to provide any wireless service. One solution to deal with this problem is to simply discard received paging requests when the eNB reaches a pre-defined load level, without informing either the MME or the UEs of this action.

The air interface paging resources are limited and are shared with resources that are otherwise used to transfer data to UEs. The more paging requests that are received, the more of the air interface resources are used for paging. Thus, excessive paging reduces the available resources for data transmission.

A paged UE will only receive the paging request from one of the eNBs, the eNB that it is camped on. As a result, the pages broadcasted from all the other eNBs in the TA are ultimately wasted.

This waste will be magnified by the following changes in the network and devices:

1 . Given the reduction in cell size (due to improving the capacity of the

Radio Access Network (RAN)) and the widespread deployment of indoor and outdoor small cells, the number of eNBs within a TA will increase significantly. 2. The RAN is not static. New eNBs are added frequently. Coverage changes due to environmental factors such as new building development, changes in plant foliage, etc.

A better approach would be to reduce the amount of air interface resources used for paging, ideally assigning the function of paging to specific eNBs within a network, thus freeing up the air interface resources that would have been used for paging so that they can be used for data transmission. This would be especially beneficial for small cells, since:

• Small cells are often added as capacity enhancers where there is already coverage from a macro eNB layer.

• The number of UEs that camp on a particular small cell eNB is generally small compared to a macro eNB (due to the limited coverage of the small cell).

• With many small cell eNBs in a TA, if each had to broadcast every paging request for UEs in its TA, it would quickly exhaust the available resources of each eNB.

The current 3GPP paging process is illustrated by the message sequence chart shown in Figure 2. Incoming data for the UE is received at the Public Data Network (PDN) Gateway (PGW) and forwarded to the Serving Gateway (SGW), which informs the MME for the UE, using a General Packet Radio Service (GPRS) Tunneling Protocol, GTP-C. The MME then contacts each of the eNBs in the UE's TA, to initiate the paging of the UE. As seen in the figure, Radio Resource Control (RRC) paging is initiated at each of several eNBs, but the UE only receives the paging from one of the eNBs, to which it then establishes a connection.

When a UE enters idle mode (RRCJ DLE), the data bearer contexts for that UE are removed from the eNB and Serving Gateway (SGW). The network only tracks the location of the UE at a TA level. Thus, the UE is free to move from eNB to eNB without informing the network, as long as the eNBs are within the same TA. The UE only needs to perform a location update with the network when it moves to an eNB in a different TA.

The paging procedure is initiated by the Serving Gateway (SGW) when it receives data for a UE from the PDN (Packet Data Network) Gateway (PGW) and does not have any bearer sessions setup for that UE.

For example, the PGW may receive an email notification, or IMS message or notification of an incoming SIP voice call from the operator's servers or from an external server. The notification or message will be in the form of one or more IP packets, where the destination IP address is the IP address last assigned to the UE. The IP packet(s) will be buffered in the SGW memory while the UE context is attempted to be established. The SGW will request the MME to "find" the UE so that the UE can re-establish a network connection allowing the SGW to route the received and buffered data packets. An S1 -AP Paging Request is sent from the MME to all eNBs in the TA where the UE is registered. Each eNB schedules and allocates air interface resources that include the identifier of each UE being paged. All UEs monitor the paging resources and will initiate a connection to the network if the UE finds its own identifier in the list of identities being paged.

The number of paging requests broadcast over the air by an eNB is proportional to the number of eNBs within a TA, the number of UEs in each TA, and the type of applications and the application usage model by the UEs (e.g., voice or video calling). Both the number of eNBs and number of UEs in a TA are rising and are expected to rise steeply as LTE is more extensively deployed and as LTE coverage is enhanced by the deployment of small cells. As an example of the paging activity that might be expected, a recent small cell trial observed that each small cell node was being asked to broadcast over 900 paging requests per second, even though the cell had a very small coverage area. Small cell eNBs are generally not engineered to serve this rate of signaling requests. As a result, the current LTE paging procedures will not scale with the introduction of small cells.

Problems with existing solutions thus include that the air interface resources for paging are limited and shared with UE downlink data transmissions. The existing 3GPP solution attempts to balance the number of eNBs in each TA with the geographical size of the TA. Thus, fewer eNBs in a TA means that fewer eNBs have to broadcast paging requests for a given UE. However, this approach also implies a smaller geographical area of the TA, for a given density of users, which means that UEs more frequently cross TA boundaries and must perform location updates with the network, increasing network load and reducing the UEs battery life.

In other words, larger TAs are better for UE battery life and reduce network signaling associated with UE location updates. However, larger TAs increase the wasted air interface resources due to paging since more eNBs are in the TA. This is compounded by the introduction of small cells, as the use of small cells implies that there are more eNBs in a given TA.

The existing 3GPP specifications and UE behavior assume that all eNBs broadcast paging requests and that there is no way for the eNB to indicate that it does not broadcast paging requests to UEs. The simple approach of reducing paging load at the eNB, by allowing the eNB to discard paging requests when it determines it is in an overloaded state, does not provide the UE or the MME an indication of the actions that the eNB is taking. UEs will expect to receive paging requests even though the eNB is discarding them. The MME will be sending paging requests only for the eNB to discard them. According to several embodiments of the presently disclosed techniques, these problems are addressed by allowing eNBs to be "non-paging" eNBs, either entirely or partially. Note that a non-paging mode according to these approaches is only valid for UE paging, i.e., paging directed to a specific mobile terminal or a specific group of mobile terminals. It does not affect paging broadcasts for System Information Modification updates or ETWS (Earthquake and Tsunami Warning System) service.

An eNB according to the presently disclosed techniques may be configured so as to always be "non-paging," or to be non-paging only in certain conditions. The determination can be under the control of:

• The network operator (e.g., via static configuration of the eNB);

• The MME (e.g., based on the eNB deployment, past history, availability of macro coverage, operator paging policies, time of day, etc.). An MME may instruct each eNB to set an appropriate paging mode indicator, as described in more detail below, using a new S1 -C signaling message and/or parameter.

• The eNB itself (e.g., based on the eNB deployment, past history,

In addition, for UE backward compatibility, the MME in some embodiments may override the non-paging mode of an eNB for UEs that only support the existing paging process (e.g., Release 8 or 9 UEs) by sending a paging request for a UE to a non-paging eNB, where the paging request instructs the non-paging eNB that it should broadcast the page for that UE regardless of the eNBs current paging mode.

According to some embodiments of the presently disclosed techniques, eNBs may broadcast an "I don't page" indication over the air. This can be done, for example, by adding a new specific parameter to an existing System Information Block (SIB) message or by extending the existing paging cycle parameter with a new value, e.g. in SIB2.

A UE that wishes to enter RRCJDLE mode, upon detecting an "I don't page indication," would then camp on an alternative eNB, i.e., an eNB that is broadcasting paging requests). UEs would avoid camping on such non-paging eNB cells, even if a non-paging eNB cell provides the strongest signal. If there is no alternative (paging) eNB, a UE may perform a location update with the non-paging eNB in order to receive downlink data indications.

A non-paging eNB may also change its paging state and become a paging eNB, and may need to tell the MME of its paging mode. This may occur for example, when the paging macro coverage of the non-paging eNB changes. When a UE receives a paging request, from the paging eNB on which it is camping, the UE attaches to the network, but not necessarily to the eNB that sent the page, instead attaching to the eNB to which the UE has the best radio frequency (RF) connection. The UE should perform a cell selection/reselection procedure following normal 3GPP procedures, i.e. , as specified in the 3GPP document "Evolved Universal Terrestrial Radio Access (E- UTRA); User Equipment (UE) procedures in idle mode," 3GPP TS 36.304, available at www.3gpp.org.

An eNB configured according to the presently disclosed techniques broadcasts its paging mode to all UEs monitoring the eNBs broadcast control channels. This can be done by adding a new parameter to one of the existing SIB messages or by extending the parameter range of an existing SIB parameter. In some embodiments, only eNBs configured to operate in a non-paging mode need to broadcast an indication that the eNB is a non- paging eNB; with this approach, UEs camped on the eNB can assume that the eNB is a paging eNB if no non-paging indication is broadcast. In other embodiments, each eNB broadcasts a paging mode indication that explicitly indicates whether the eNB is in paging mode or non-paging mode.

Some embodiments of the presently disclosed techniques may include additional features to support UEs that do not support non-paging process (e.g., Release 8 or 9 UEs). For example:

• A UE that does not support this new non-paging procedure may camp on a non-paging eNB, unaware that the eNB is non-paging.

• When the MME receives a paging request for a UE, the MME can use the UE's identifier to determine the UE capabilities (e.g., what release of the 3GPP standards the UE supports). This is an existing 3GPP capability.

• If the UE capabilities indicate that the UE does not support the non-paging process described in this document, the MME sends paging requests, including to those non-paging eNBs. The paging request sent by the MME for the UE may include a new indicator that is used by the non-paging eNB to instruct the non-paging eNB to "page this UE regardless of non- paging mode" - the new indicator is optional if paging requests are sent over unicast or multicast IP by the MME, but required if paging requests are sent using a broadcast IP destination address. • The non-paging eNBs receive the paging request (and the optional new indicator) and broadcast the paging request over the air as per the normal paging procedure, regardless of the current paging operation of the eNB. The non-paging eNB only does this on a per-UE basis and does not change its paging mode broadcast to UEs over the air.

New UEs may be configured to recognize non-paging eNBs. Such a UE, when in RRCJDLE mode, monitors the eNB's broadcast channel when entering the eNB's coverage area, and obtains the eNB's paging mode. If the eNB is a non-paging eNB, the UE should attempt to camp on an alternative eNB that is providing paging service, even if the alternative eNB has a poorer downlink signal quality than the non-paging eNB. This is shown in Figure 3, which shows a scenario where the UE is in the coverage area of both a macro (paging) eNB and a non-paging pico eNB. The UE camps on the paging macro eNB, in order to receive paging broadcast requests. The UE, if capable, may continue to camp on the pico eNB, or it may remember its details, so that it may attempt to attach to the pico eNB in the event that a page is received from the macro eNB.

As noted above, in some embodiments, the UE "remembers" the frequency and carrier details of the non-paging eNB (i.e., storing this information temporarily in the UE system memory). In some embodiments, the UE may be adapted to simultaneously monitor Master Information Block (MIB) and SIB broadcasts of the non-paging eNB in addition to those of a paging eNB, thus effectively camping on multiple eNBs. This will speed up the attach procedure to the non-paging eNB, in the event that a page is received from the paging eNB and the radio link to the non-paging eNB is better or an attachment to the non- paging eNB is preferred for other reasons.

If a UE determines that the paging mode of the eNB that it is camped on changes to non-paging, the UE may perform the cell re-selection procedure in order to camp on a paging eNB, if one is available. If the UE cannot camp on a paging eNB, the UE should perform an attach procedure, immediately followed by a location update procedure in order to inform the MME of the UEs location. A MME receiving a location update from a UE attached to a non-paging eNB may override the paging mode of the eNB using the previously described new S1 -C message / parameter - since the receipt of the location update indicates that there are no paging eNBs available. The overridden paging mode of the eNB can be cleared by either the MME or eNB once the UE is no longer attached to the eNB.

LTE paging procedures are initiated by the network as normal. If a UE detects its own identity in the paging channel of an eNB that it is camped on, it retrieves the frequency and carrier details of the non-paging eNB from its memory and attempts to attach to that eNB, instead of the eNB that it was camped on. If the UE is unable to successfully attach to the non-paging eNB, it attempts to attach to the paging eNB or any eNB. In other words, the UE attaches to the best eNB. The rest of the UE LTE cell selection/reselection and attach procedures continue as normal.

With the above discussion in mind, it should be appreciated that Figures 4-8 are process flow diagrams illustrating several example methods, each of which is suitable for implementation in a mobile terminal, a base station, or a wireless network node, such as an MME, controlling one or more base stations.

Figure 4 illustrates an example method that is suitable for implementation in a base station, such as an LTE eNodeB, in a wireless network. As shown at block 410, this example method includes determining that the base station is to operate in a non-paging mode, in which mode the base station does not broadcast paging messages for all mobile terminals in its coverage area. As shown at block 420, the method continues with broadcasting a non-paging indicator, said indicator indicating that the base station is operating in non-paging mode. The non-paging indicator may comprise a parameter in a System Information Block (SIB) message in some embodiments, or an extended paging cycle parameter in other embodiments. In some embodiments, the base station determines that it is to operate in non-paging mode by receiving a message from another node in the wireless network, such as a Mobility Management Entity, the message indicating that the bases station should operate in a non-paging mode. In other embodiments, the base station autonomously determines that it is to operate in non-paging mode, e.g., based on one or more of a base station type for the base station, a past history of operation for the base station, an availability of macro coverage in the region of the base station, one or more operator paging policies, and a time of day.

In some embodiments, the method further includes receiving a paging message from another node in the wireless network, the paging message indicating that a mobile terminal should be paged even though the base station is operating in non-paging mode. This is shown at block 430, which is illustrated with a dashed outline to indicate that it does not necessarily occur in every embodiment or instance of the illustrated method. In this case, the method continues, as shown at block 440, with paging the mobile terminal, in response to the message. In some embodiments, the indication that the mobile terminal should be paged even though the base station is operating in non-paging mode is determined by the receipt of a unicast or multi-cast paging message. In other embodiments or in other instances, the paging message includes an explicit indication that the mobile terminal should be paged even though the base station is operating in non-paging mode.

Another example method according to the techniques disclosed herein is illustrated in Figure 5 and is suitable for implementation in a mobile terminal, such as an LTE UE. The method includes: monitoring broadcasted information from a first base station, as shown at block 510; detecting that the first base station is operating in a non-paging mode, based on the broadcasted information, as shown at block 520; and camping on a second base station, in response to detecting that the first base station is operating in non-paging mode, as shown at block 530. The non-paging indicator may comprise a parameter in a System Information Block (SIB) message in some embodiments, or an extended paging cycle parameter in some other embodiments.

In some embodiments, the method further includes continuing to monitor broadcasted information from the first base station, while also monitoring broadcasted information from the second broadcasted information. This is shown at block 540, which is shown with a dashed outline to indicate that this operation does not appear in every embodiment or instance of the illustrated method. In other embodiments, the method further includes storing information corresponding to the first base station, the information including at least frequency-identifying information for the first base station. In any of these embodiments, the method may (but does not necessarily) further include receiving a page from the second base station, as shown at block 550, and attempting to attach to the first base station, as shown in block 560. In some of these latter embodiments, this attempting to attach to the first base station uses the stored information mentioned above; in others, the attempting to attach is based on the continuing to monitor broadcasted information from the first base station. In some embodiments, an attempt to attach to the first base station is followed by an attempt to attach to a base station other than the first base station in the event that the attempt to attach to the first base station is unsuccessful.

An alternative method for implementation in a mobile terminal may be implemented separately or in a mobile terminal that is also configured to carry out one of the previously described methods, and is shown in Figure 6. According to this method, the mobile terminal monitors broadcasted information from a first base station, as shown at block 610; detects that the first base station is operating in a non-paging mode, based on the broadcasted information, as shown at block 620; unsuccessfully attempts to camp on a base station other than the first base station, in response to detecting that the first base station is operating in non-paging mode, as shown at block 630; and attaches to the first base station and performs a location update in response to unsuccessfully attempting to camp on a base station other than the first base station, as shown at block 640.

Still another example method according to the techniques disclosed herein is suitable for implementation in a network node, such as an LTE MME, connected to one or more base stations. This example method, illustrated in Figure 7, includes determining that a first base station is to operate in a non-paging mode, in which mode the first base station does not broadcast paging messages for all mobile terminals in its coverage area (block 710); and sending a message to the first base station, the message indicating that the bases station should operate in a non-paging mode (block 720). In some embodiments, the network node determines that the first base station is to operate in non-paging mode, e.g., based on one or more of a base station type for the base station, a past history of operation for the base station, an availability of macro coverage in the region of the base station, one or more operator paging policies, and a time of day.

Another example method is also implemented in a network node, such as an LTE MME, connected to one or more base stations. According to this method, which is illustrated in Figure 8 and which may be implemented separately or in a network node that is also configured to carry out the preceding method, the network node determines that a UE is to be paged and determines that the UE is not capable of detecting whether a base station is operating in non-paging method. This is shown at block 810. The method continues, as shown at block 820, with sending a paging message to at least one base station operating in non-paging mode, the paging message indicating that the UE is to be paged even though the base station is operating in non-paging mode. In some embodiments, the indication that the mobile terminal should be paged even though the base station is operating in non-paging mode is determined by the sending of a unicast or multi-cast paging message. In other embodiments or in other instances, the paging message includes an explicit indication that the mobile terminal should be paged even though the base station is operating in non-paging mode.

Several of the methods described above may be implemented using radio circuitry and electronic data processing circuitry provided in a mobile terminal, such as an LTE UE. Figure 9 illustrates features of an example wireless node 900 according to several embodiments of the present invention, in this case embodied as a mobile terminal. Mobile terminal 900, which may be a UE configured for operation in an LTE system, comprises a transceiver 920 for communicating with one or more base stations as well as a processing circuit 910 for processing the signals transmitted and received by the transceiver 920.

Transceiver 920 includes a transmitter 925 coupled to one or more transmit antennas 928 and receiver 930 coupled to one or more receiver antennas 933. The same antenna(s) 928 and 933 may be used for both transmission and reception. Receiver 930 and transmitter 925 use known radio processing and signal processing components and techniques, typically according to a particular telecommunications standard such as the 3GPP standards for LTE. Because the various details and engineering tradeoffs associated with the design and implementation of such circuitry are well known and are unnecessary to a full understanding of the invention, additional details are not shown here.

Processing circuit 910 comprises one or more processors 940 coupled to one or more memory devices 950 that make up a data storage memory 955 and a program storage memory 960. Processor 940, identified as CPU 940 in Figure 9, may be a microprocessor, microcontroller, or digital signal processor, in some embodiments. More generally, processing circuit 910 may comprise a processor/firmware combination, or specialized digital hardware, or a combination thereof. Memory 950 may comprise one or several types of memory such as read-only memory (ROM), random-access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Again, because the various details and engineering tradeoffs associated with the design of baseband processing circuitry for mobile devices are well known and are unnecessary to a full understanding of the invention, additional details are not shown here.

Typical functions of the processing circuit 910 include modulation and coding of transmitted signals and the demodulation and decoding of received signals, as well as for managing operations such as camping, cell selection, cell reselection, handover, and the like. In several embodiments, processing circuit 910 is adapted, using suitable program code stored in program storage memory 960, for example, to carry out one of the techniques described above. Accordingly, in various embodiments of the invention, processing circuits are configured to carry out one or more of the techniques described in detail above, including the techniques described in connection with Figures 5 and 6. Likewise, other embodiments include mobile terminals (e.g., LTE UEs) including one or more such processing circuits. In some cases, these processing circuits are configured with appropriate program code, stored in one or more suitable memory devices, to implement one or more of the techniques described herein. Of course, it will be appreciated that not all of the steps of these techniques are necessarily performed in a single microprocessor or even in a single module.

Figure 10 is a schematic illustration of an example wireless node 1000, here embodied as a base station in which a method embodying one or more of the above- described techniques can be implemented. A computer program for controlling the base station to carry out a method embodying the present invention is stored in a program storage 1030, which comprises one or several memory devices. Data used during the performance of a method embodying the present techniques is stored in a data storage 1020, which also comprises one or more memory devices. During performance of a method embodying the present techniques, program steps are fetched from the program storage 1030 and executed by a Central Processing Unit (CPU) 1010, which retrieves data as required from the data storage 1020. Output information resulting from performance of a method embodying the present invention can be stored back in the data storage 1030, or sent to an Input/Output (I/O) interface 1040, which may comprise a transmitter for transmitting data to other nodes, such as an RNC, as required. Likewise, the input/output (I/O) interface 1040 may comprise a receiver for receiving data from other nodes, for example for use by the CPU 1010. The CPU 1010, data storage 1020, and program storage 1030 together make up a processing circuit 1060. Base station 1000 further comprises radio communications circuitry 1050, which includes a receiver circuit 1052 and transmitter circuit 1055 adapted according to well- known designs and techniques to communicate with one or more mobile terminals.

According to several embodiments of the present invention, base station apparatus 1000 generally and radio communications circuitry 1050 more specifically are configured to communicate with one or more mobile terminals. The base station apparatus 1000 is further configured to communicate with one or more other nodes in the wireless network, such as MME, using I/O interface circuit 1040. Processing circuit 1060 is configured to control the receiver circuit and the transmitter circuit 1055 in radio communications circuitry 1050, as well as the I/O interface circuit 1040. Processing circuit 1060 is further configured to carry out one or more of the techniques described in detail above, including the techniques described in connection with Figure 4. Likewise, other embodiments include base stations including one or more such processing circuits. In some cases, these processing circuits are configured with appropriate program code, stored in one or more suitable memory devices, to implement one or more of the techniques described herein. Of course, it will be appreciated that not all of the steps of these techniques are necessarily performed in a single microprocessor or even in a single module.

Other embodiments of the present invention include network node apparatus configured to communicate with one or more base stations and to carry out one or more of the methods described above, including the techniques described above in connection with MMEs generally and in connection with Figures 7 and 8 in particular. Such a network node may have a configuration similar to the base station illustrated in Figure 10, but may omit the radio communications circuitry 1050, in some embodiments. In such embodiments, the I/O interface circuitry 1040 is configured for communication with one or more base stations and may further be configured for communication with other network nodes, such as an SGW or PGW. The processing circuit 1060 in such embodiments is configured, e.g., with appropriate program code stored in program storage 1030, to carry out one or more of the techniques described above for a network node, including one or more of those methods described in connection with Figures 7 and 8.

Various aspects of the above-described embodiments can also be understood as being carried out by functional "modules" or "units," which may be program instructions executing on an appropriate processor circuit, hard-coded digital circuitry and/or analog circuitry, or appropriate combinations thereof. Thus, for example, a processor 950 like the one shown in the mobile terminal of Figure 9 can be understood to include a monitoring module/unit for monitoring broadcasted information from a first base station, a detecting module/unit for detecting that the first base station is operating in a non-paging mode, based on the broadcasted information, and a camping unit for camping on a second base station, in response to this detecting. Similarly, a processing circuit 1060 like the one shown in the base station of Figure 10 may be understood to include a determining module/unit for determining that the base station is to operate in a non-paging mode, in which non-paging mode the base station does not broadcast paging messages targeted to specific mobile terminals in its coverage area, and a broadcasting module/unit for broadcasting a non- paging indicator indicating that the base station is operating in non-paging mode. It should be understood that other embodiments of the apparatus described herein include similar modules/units for carrying out operations in the various methods and processes described herein.

Still further, it will be understood that embodiments of the presently disclosed technology include computer programs comprising instructions for carrying out one or more of the methods described herein, or variants thereof, when those instructions are executed by one or more processors in an appropriate apparatus (e.g., a network node or mobile terminal). Other embodiments include carriers containing such computer programs, such as electronic signals, optical signals, radio signals, or non-transitory computer-readable storage medium such as a computer memory, optical disc, magnetic storage medium, or the like.

Example features that may be applicable to one or more embodiments of the present invention are listed below. It should be appreciated that some embodiments may include none, one, or several of the following:

1 . An LTE eNB may not broadcast paging requests on the air interface.

2. Paging operation or mode may be controlled by configuration.

3. Paging operation or mode may be controlled by the MME.

4. Paging operation or mode may be controlled by the eNB.

5. Paging operation or mode can be changed dynamically under the control of the eNB or MME or by manual operator configuration

6. If Paging operation or mode is be controlled by the MME, the MME signals the paging mode over the S1 -C interface to the eNB.

7. If Paging operation or mode is be controlled by the eNB, the eNB signals its paging mode over the S1 -C interface to the MME.

8. The MME may override the non-paging operation of the eNB for specific UEs implicitly by sending a paging request for a UE to the eNB.

9. The MME may override the non-paging operation of the eNB for specific UEs explicitly by sending a paging request for a UE to the eNB with a new indicator indicating that the UE should be paged regardless of the eNBs paging mode.

10. The UE decodes the new paging mode indicator broadcast by the eNB.

1 1 . The UE camps on a paging eNB even if the DL signal quality is poorer. 12. The UE may temporarily store the carrier frequency and timing offset of a non- paging eNB that it is not camped on.

13. The UE may camp on multiple eNBs.

14. If the UE cannot camp on a paging eNB, it should perform a location update in order to inform the MME of the UEs location.

15. When the UE receives a paging request for itself, the UE may attempt to perform cell selection/reselection and attach procedures to an eNB other than the eNB that sent the paging request.

16. If an MME receives a location update from a UE attached to a non-paging eNB, it may temporarily override the non-paging operation of the eNB.

The techniques and apparatus described above may be used to obtain a drastic reduction of paging load for selected eNB cells, which can be especially important for dense deployments of eNBs, e.g. small cells, while exploiting the coverage that other paging eNBs provide. Some embodiments of these techniques provide backwards compatibility for UEs that do not support the new "paging mode" indicator broadcast by the eNB (e.g., release 8 UEs). This is provided by the MME overriding the paging mode of the eNB for a particular UE. Only minor changes to the standards for LTE are required to implement these techniques in the MME and eNBs. For instance, the ASN.1 definition of paging cycle parameter in SIB2 may be extended, or a new parameter added to SIB2, to advertise the eNB's paging mode. Similarly, only relatively minor changes in UE LTE behavior, e.g., where to camp and where to attach, based on the new SIB parameter or value, are required.

Other advantages of the presently disclosed techniques include MME load reduction - as there are fewer eNBs to unicast paging requests to. The paging modes for eNBs can be dynamically self-configuring (additional SON capability), in some embodiments. The eNB may change its paging mode depending on several factors (operator policy, traffic load, coverage) and do this automatically.

Examples of several embodiments of the present invention have been described in detail above, with reference to the attached illustrations of specific embodiments. Because it is not possible, of course, to describe every conceivable combination of components or techniques, those skilled in the art will appreciate that various modifications may be made to the above described embodiments without departing from the scope of the present invention. For example, it will be readily appreciated that although the above embodiments are described with reference to parts of a 3GPP network, an embodiment of the present invention will also be applicable to like networks, such as a successor of the 3GPP network, having like functional components. Therefore, in particular, the terms 3GPP and associated or related terms used in the above description and in the enclosed drawings and any appended claims now or in the future are to be interpreted accordingly. Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

ABBREVIATIONS

3GPP 3^rd-Generation Partnership Project

AGW Access Gateway

ASIC Application-Specific Integrated Circuit

CPU Central Processing Unit

DL Downlink

DSP Digital Signal Processor

eNB evolved Node B

ETWS Earthquake and Tsunami Warning System

E-UTRA Evolved Universal Terrestrial Radio Access

E-UTRAN Evolved Universal Terrestrial Radio Access Network

FPGA Field Programmable Gate Array

GPRS General Packet Radio Service

GTP GPRS Tunneling Protocol

IMS IP Multimedia Subsystem

I/O Input/Output

IP Internet Protocol

LTE Long-Term Evolution

M2M Machine-to-Machine

MIB Master Information Block

MME Mobility Management Entity

MTC Machine-Type Communication

NAS Non-Access Stratum

PDN Public Data Network

PGW PDN Gateway

PLA Programmable Logic Array

PLMN Public Land Mobile Network

RAM Random-Access Memory

RAN Radio Access Network RAT Radio Access Technology

RF Radio Frequency

RNC Radio Network Controller

ROM Read-only Memory

RRC Radio Resource Control

SAE System Architecture Evolution

SGW Serving Gateway

SIB System Information Block

TA Tracking Area

UE User Equipment

UL Uplink

Claims

CLAIMS What is claimed is:

1 . A method, in a base station of a wireless network, the method comprising:

determining that the base station is to operate in a non-paging mode, in which non- paging mode the base station does not broadcast paging messages targeted to specific mobile terminals in its coverage area; and

broadcasting a non-paging indicator, the non-paging indicator indicating that the base station is operating in non-paging mode.

2. The method of claim 1 , wherein broadcasting the non-paging indicator comprises broadcasting the non-paging indicator as a parameter in a System Information Block, SIB, message.

3. The method of claim 1 , wherein broadcasting the non-paging indicator comprises broadcasting the non-paging indicator as an extended paging cycle parameter.

4. The method of any of claims 1 -3, wherein determining that the base station is to operate in the non-paging mode comprises receiving a message from another node in the wireless network, the message indicating that the base station is to operate in the non-paging mode.

5. The method of claim 4, wherein the another node is a Mobility Management Entity, MME.

6. The method of any of claims 1 -3, wherein determining that the base station is to operate in the non-paging mode is performed autonomously by the base station, based on one or more parameters comprising:

a base station type for the base station;

a past history of operation for the base station;

an availability of macro coverage in the region of the base station ;

one or more operating paging policies; and

a time of day.

7. The method of any of claims 1 -6, further comprising:

receiving a paging message from another node in the wireless network, the paging message indicating that a mobile terminal should be paged even though the base station is operating in non-paging mode;

paging the mobile terminal, in response to the paging message.

8. The method of claim 7, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in a non-paging mode by being a unicast paging message.

9. The method of claim 7, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in a non-paging mode by being a multicast paging message.

10. A method, in a mobile terminal, the method comprising:

monitoring broadcasted information from a first base station;

detecting that the first base station is operating in a non-paging mode, based on the broadcasted information; and

camping on a second base station, in response to said detecting.

1 1 . The method of claim 10, wherein detecting that the first base station is operating in a non-paging mode comprises detecting a parameter in a System Information Block, SIB, message.

12. The method of claim 1 1 , wherein detecting that the first base station is operating in a non-paging mode comprises detecting an extended paging cycle parameter.

13. The method of any of claims 10-12, further comprising continuing to monitor broadcasted information from the first base station, while also monitoring broadcasted information from the second base station.

14. The method of any of claims 10-13, further comprising storing information corresponding to the first base station, the information comprising frequency-identifying information for the first base station.

15. The method of any of claims 10-14, further comprising receiving a page from the second base station, and attempting to attach to the first base station, in response to receiving the page.

16. The method of claim 15, wherein attempting to attach to the first base station comprises using stored information corresponding to the first base station, the information comprising frequency-identifying information for the first base station.

17. The method of claim 15, wherein attempting to attach to the first base station comprises using information obtained by monitoring broadcasted information from the first base station while also monitoring broadcasted information from the second base station.

18. The method of claim 16 or 17, further comprising attempting to attach to a base station other than the first base station, in response to an unsuccessful attempt to attach to the first base station.

19. A method, in a mobile terminal, the method comprising:

monitoring broadcasted information from a first base station;

detecting that the first base station is operating in a non-paging mode, based on the broadcasted information;

attempting to camp on a base station other than the first base station, in response to said detecting; and

attaching to the first base station and performing a location update, in response to unsuccessfully attempting to camp on the base station other than the first station.

20. A method, in a network node connected to one or more base stations in a wireless network, the method comprising:

determining that a first base station is to operate in a non-paging mode, in which non- paging mode the first base station does not broadcast paging messages targeted to specific mobile terminals in its coverage area; and sending a message to the first base station, the message indicating that the first base station should operate in the non-paging mode.

21 . The method of claim 20, wherein determining that the first base station is to operate in the non-paging mode is based on one or more of:

a base station type for the base station;

a past history of operation for the base station;

an availability of macro coverage in the region of the base station ;

one or more operating paging policies; and

a time of day.

22. A method, in a network node connected to one or more base stations in a wireless network, the method comprising:

determining that a mobile terminal is to be paged; determining that the mobile terminal is not capable of detecting whether a base station is operating in non-paging mode;

sending a paging message to at least one base station operating in non-paging mode, the paging message indicating that the UE is to be paged even though the base station is operating in non-paging mode.

23. The method of claim 22, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in non-paging mode by being a unicast paging message.

24. The method of claim 22, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in non-paging mode by being a multicast paging message.

25. A base station adapted for use in a wireless network, the base station comprising a radio transceiver adapted for communication with one or more mobile terminals and a processing circuit adapted to:

determine that the base station is to operate in a non-paging mode, in which non- paging mode the base station does not broadcast paging messages targeted to specific mobile terminals in its coverage area; and

broadcast a non-paging indicator, using the radio transceiver, the non-paging

indicator indicating that the base station is operating in non-paging mode.

26. The base station of claim 25, wherein the processing circuit is adapted to broadcast the non-paging indicator as a parameter in a System Information Block, SIB, message.

27. The base station of claim 25, wherein the processing circuit is adapted to broadcast the non-paging indicator as an extended paging cycle parameter.

28. The base station of any of claims 25-27, wherein the base station comprises a network interface adapted to communicate with one or more other nodes in the wireless network, and wherein the processing circuit is adapted to determine that the base station is to operate in the non-paging mode by receiving a message from another node in the wireless network, via the network interface, the message indicating that the base station is to operate in the non- paging mode.

29. The base station of any of claims 25-27, wherein the processing circuit is adapted to autonomously determine that the base station is to operate in the non-paging mode, based on one or more parameters comprising:

a base station type for the base station;

a past history of operation for the base station;

an availability of macro coverage in the region of the base station ;

one or more operating paging policies; and

a time of day.

30. The base station of any of claims 25-29, wherein the base station comprises a network interface adapted to communicate with one or more other nodes in the wireless network, and wherein the processing circuit is further adapted to:

receive a paging message from another node in the wireless network, via the

network interface, the paging message indicating that a mobile terminal should be paged even though the base station is operating in non-paging mode; and

page the mobile terminal, using the radio transceiver, in response to the paging

message.

31 . A mobile terminal adapted for use in a wireless network, the mobile terminal comprising a radio transceiver adapted for communicating with one or more base stations, and further comprising a processing circuit adapted to control the radio transceiver and to:

monitor broadcasted information from a first base station, using the radio transceiver; detect that the first base station is operating in a non-paging mode, based on the broadcasted information; and

camp on a second base station, using the radio transceiver, in response to said

detecting.

32. The mobile terminal of claim 31 , wherein the processing circuit is adapted to detect that the first base station is operating in a non-paging mode by detecting a parameter in a System Information Block, SIB, message.

33. The mobile terminal of claim 31 , wherein the processing circuit is adapted to detect that the first base station is operating in a non-paging mode by detecting an extended paging cycle parameter.

34. The mobile terminal of any of claims 31 -33, wherein the processing circuit is further adapted to monitor broadcasted information from the first base station, while also monitoring broadcasted information from the second base station.

35. The mobile terminal of any of claims 31 -34, wherein the processing circuit is further adapted to store information corresponding to the first base station, the information comprising frequency-identifying information for the first base station.

36. The mobile terminal of any of claims 31 -35, wherein the processing circuit is further adapted to receive a page from the second base station, via the radio transceiver, and to attempt to attach to the first base station, in response to receiving the page.

37. The mobile terminal of claim 36, wherein the processing circuit is further adapted to use stored information corresponding to the first base station in attempting to attach to the first base station, the information comprising frequency-identifying information for the first base station.

38. The mobile terminal of claim 36, wherein the processing circuit is further adapted to use information obtained by monitoring broadcasted information from the first base station while also monitoring broadcasted information from the second base station, in attempting to attach to the first base station.

39. The mobile terminal of claim 37 or 38, wherein the processing circuit is further adapted to attempt to attach to a base station other than the first base station, in response to an unsuccessful attempt to attach to the first base station.

40. A mobile terminal adapted for use in a wireless network, the mobile terminal comprising a radio transceiver adapted for communicating with one or more base stations, and further comprising a processing circuit adapted to control the radio transceiver and to:

monitor broadcasted information from a first base station, using the radio transceiver; detect that the first base station is operating in a non-paging mode, based on the broadcasted information;

attempt to camp on a base station other than the first base station, using the radio transceiver, in response to said detecting; and

attach to the first base station and performing a location update, using the radio transceiver, in response to unsuccessfully attempting to camp on the base station other than the first station.

41 . A network node adapted for use in a wireless network node, the network node comprising a network interface adapted to connect the network node to one or more base stations in the wireless network and further comprising a processing circuit operatively connected to the network interface and adapted to:

determine that a first base station is to operate in a non-paging mode, in which non- paging mode the first base station does not broadcast paging messages targeted to specific mobile terminals in its coverage area; and send a message to the first base station, via the network interface, the message indicating that the first base station should operate in the non-paging mode.

42. The network node of claim 41 , wherein the processing circuit is adapted to determine that the first base station is to operate in the non-paging mode based on one or more of: a base station type for the base station;

a past history of operation for the base station;

an availability of macro coverage in the region of the base station ;

one or more operating paging policies; and

a time of day.

43. A network node adapted for use in a wireless network node, the network node comprising a network interface adapted to connect the network node to one or more base stations in the wireless network and further comprising a processing circuit operatively connected to the network interface and adapted to:

determine that a mobile terminal is to be paged;

determine that the mobile terminal is not capable of detecting whether a base station is operating in non-paging mode;

send a paging message to at least one base station operating in non-paging mode, via the network interface, the paging message indicating that the UE is to be paged even though the base station is operating in non-paging mode.

44. The network node of claim 43, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in non-paging mode by being a unicast paging message.

45. The network node of claim 43, wherein the paging message indicates that the mobile terminal should be paged even though the base station is operating in non-paging mode by being a multicast paging message.

46. A computer program comprising instructions that, when executed on at least one processor in a network node of a wireless network, cause the at least one processor to carry out a method according to any one of claims 1 -9 and 20-24.

47. A carrier containing the computer program of claim 46, wherein the carrier is one of an electronic signal, optical signal, radio signal, or non-transitory computer-readable storage medium.

48. A computer program comprising instructions that, when executed on at least one processor in a mobile terminal, cause the at least one processor to carry out a method according to any one of claims 10-19.

49. A carrier containing the computer program of claim 48, wherein the carrier is one of an electronic signal, optical signal, radio signal, or non-transitory computer-readable storage medium.