OA19339A - Methods and nodes for cell selection in a wireless communication network - Google Patents

Abstract

A method for selecting a cell by a wireless device in a wireless communication network is disclosed. The method comprises: receiving a signal from a cell associated with a network node; determining whether the signal from the cell satisfies a cell selection criterion, wherein the cell selection criterion is based at least in part on a parameter that controls a compensation to the cell selection criterion, the compensation being associated with a power class of the wireless device; and selecting the cell in response to a determination that the signal from the cell satisfies the cell selection criterion. A wireless device for carrying out this method is also disclosed

Description

Certain problems can be envisioned with respect to the Internet of Things networks that hâve previously been proposed. For example, it is expected that the number of loT devices will grow exponentially over the years to corne. The loT devices usually belong to the ultra-low end segment of loT with very low average revenue per user (ARPU). So, the power is in numbers for the operator that need to make a profit out of deploying the devices. However, the more devices that are present in the network the more capacity will be taken, which could negatively impact the more high-end users. Adding on top of this that the ultralow end devices are often placed in remote locations that the radio signal has difficulty reaching, the above-mentioned répétitions are required to establish network communication, and by this even more capacity is taken. Even in a network where only low-end loT devices are expected to operate, e.g., NB-IoT, in which case there is no compétition for the resources with more high-end devices, users that are in more challenging coverage conditions will take up a disproportionate amount of resources, which might quickly drain capacity.

Figure 1 provides an example of a network distribution of coupling loss for loT, which can be used as a 3GPP model of an loT network. The term coupling loss (CL) on the x-axis can be considered as a measurement of coverage, and the higher the CL, the worse coverage the device is in. Ail above-mentioned Systems hâve been developed to reach 20 dB better coverage than GSM, which hâve been agreed by 3GPP can be considered to be at 144 dB CL. Hence, a 20 dB improvement would mean being able to operate at 164 dB CL. In Figure 1, CL 164 dB, 154 dB, and 144 dB are shown using dashed black line.

Assume further that a certain number of répétitions are needed to reach the device if placed at CL 144-154 dB, a second number of blind répétitions are needed at CL 154-164 dB. For the région of 154-164 dB for example, each user need to use blind répétitions dimensioned for the 164 dB CL case, i.e., several of the users will use more resources than required. This may seem like a suboptimal system implémentation but should be seen as a trade-off between implémentation complexity and resource usage. Exactly this approach has also been taken for the NB-loT Random Access procedure where a UE is required to select one out of three, by the NW supported, répétition levels based on its estimated coupling loss (see TS 36.213). An alternative would be for the system to support any number of blind répétitions, in which case complexity is increased but resource usage is decreased.

Assume, for users between 154-164 dB CL, that 100 répétitions are needed (10*logl0(100) =20 dB) and that for the région 144-154 dB CL, 10 répétitions are needed (10*logl0(10)=10 dB).

The ratio of users in each coverage bin can be roughly read from the Cumulative Distribution Function (CDF) (see Figure 1):

164-154 dB : 4% of ail UEs require 100 répétitions;

154-144 dB : 14% of ail UEs require 10 répétitions;

< 144 dB : 82% of ail UEs require no répétitions.

Hence, users in extended coverage compared to GSM (>144 dB) takes up roughly 87% ((0.04*100+0.14*10)/(0.04*100+0.14*10+0.82*1)) of the network resources.

This is not a balanced network in terms of resource usage, and it gets even worse if allowing UEs of a lower output power class to access the network. A lower output power class is already supported by the EC-GSM-IoT spécifications (see 3GPP TS 45.005 V13.1.0), and is being discussed for NB-loT in the scope of ongoing 3GPP Release 14 work (see RP-161901). If adopting the same spécification in terms of allowed number of répétitions as the higher output power classes (which is typically what is assumed for the above-mentioned technologies) more users will end up out-of-coverage, and more users using répétitions.

For example, in case a new NB-loT low power UE is introduced that supports roughly 10 dB lower output power than what currently is the case, this will force UEs in the CL range above 154 dB out of coverage, and increase the number of répétitions required by the UEs in coverage approximately as follows:

164-154 dB : 4% of ail UEs goes out-of-coverage;

154-144 dB : 14% of ail UEs require 100 blind répétitions;

144-134 dB : 30 % of ail UEs require 10 blind répétitions;

< 134 dB : 52 % of ail UEs require no blind répétitions.

In this case, users using blind répétitions takes up roughly 97% of the network resources.

Figure 2 illustrâtes this case, with a network distribution of coupling loss for loT with 10 dB lower output power.

To combat the above-mentioned potential problem with unevenly distributed resource usage amongst devices using different output power classes in the same system, certain embodiments of the présent disclosure re-define the cell suitability criterion to get a nonlinear dependency of the cell suitability criterion and the maximum output power capability of the UE.

It should be noted that the terms “cell suitability criterion” and “cell sélection criterion” refer to the same thing and could be used interchangeably. The cell suitability criterion means that the criterion used to détermine if a cell is suitable for a user to use. For example, if a cell meets the cell suitability criterion, then the cell is suitable for a user device to select it and access it.

Usually a linear dependency is already in place in the cell suitability criterion where, for example, a UE needs to expérience a 10 dB stronger downlink signal level in order to access the cell, compared to a UE with a 10 dB higher output power level. The low power UE needs to select a cell based on its weakest link, which is the uplink. For the majority of UEs (e.g. UEs within the power class of 23dBm), the UL/DL are assumed to be balanced. However, this is to take into account the above-mentioned balancing of the UL and DL, and has no relation to the capacity issue.

In a general way, the non-linear component to the cell suitability criterion can be implemented by a power class spécifie shift.

Cell suitability criterion = C + P_sflif_t [1]

Where C is the current cell suitability criterion, and Ρ^ρ is the power class spécifie shift of the suitability criterion.

For a cell to be suitable, both Srxlev and Squal hâve to be greater than zéro in NBloT. In other words, the cell sélection criterion S (or equivalently C) is fulfilled when (see 3GPP TS 36.304 V13.2.0, section 5.2.3.2a):

Srxlev > 0 AND Squal > 0 where. Srxlev Qrxievmeas Qrxievmin Pcompensation - Qojfseîf_emp

Squal Qqualmeas Qqualmin Qoff^^ltemp with

Srxlev	Cell sélection RX level value (dB)
Squal	Cell sélection quality value (dB)
Q0ffsetterrip	Offset temporarily applied to a cell as specified in [3] (dB)
Qfxlevmeas	Measured cell RX level value (RSRP)
Qqualmeas	Measured cell quality value (RSRQ)
Qrxievmin	Minimum required RX level in the cell (dBm) If UE is not authorized for enhanced coverage and Qoffsetaufhorization ÎS Valîd then Qrxlevmin — Qrxlevmin Qoffsetauthorization·
Qqualmin	Minimum required quality level in the cell (dB)

If the UE supports the multiNS-Pmax-rl3 and an additionalPmax is broadcasted in SIB1-NB, SIB3-NB or SIB5-NB, then the UE uses this additionalPmax instead of the P-max of the cell:

Pcompensation = max (P-max-P_powerciass, θ)- (min (additionalPmax, PpowerCiass) - min (P-maX, PpmverClass) else: Pcompensation = max (P-max —Pp_OwerCiass, 0) wherein P-max is the maximum uplink transmission power in the cell and P_pmverciass is the maximum output power according to the UE power class (see 3GPP TS 36.101). P-max can be can also correspond to the maximum Radio Frequency (RF) output power of the 10 wireless device.

It should be noted that compared to the notation in 3GPP TS 36.304 V13.2.0, section

5.2.3.2a, P-max is équivalent to Pemaxi and additionalPmax is équivalent to Pemax2.

It should be understood that the Pcompensation factor is a fixed value for ail UEs within the same power class. Indeed, the Pcompensation factor is used to compensate or 15 take into account the power class of the UE. For example, loT devices are part of the low power class of UEs.

This compensation factor can be written as (as shown above):

Pcompensation = max(P-max —Ppowerciass, 0)

[2]

As shown in Equation 2, the Pcompensation factor punishes UEs of a low power class with the différence to the P-max of the cell. For example, when P-max is set to 23 dBm, then a 14 dBm UE has a -9 dB penalty as given by the Pcompensation factor of équation 2.

However, it would be bénéficiai if this penalty/compensation can be more flexible (and thus configurable) such that it can “promote” or “demote” the cell suitability for UEs within a low power class. For example, by having more control over the compensation, the network is able to deny certain devices of a low power class to access the system/cell at a coupling loss where the devices need to use répétitions. As such, a network node or base station will hâve control over the trade-off between the coverage enhancements a low power UE can enjoy and the amount of network resources these coverage enhancements require.

More specifically, in an embodiment, the control over the compensation can be implemented as a non-linear component. As an exemplary embodiment, the control can be implemented by a configurable parameter, referred to as a Low Power Class (LPC) offset, within the Pcompensation factor of équation 2 of the cell suitability criterion. For example, the LPC offset can be incorporated in the Pcompensation équation, as indicated by the bold parameter LPC-offset in the équation below.

Pcompensation = max(P-max -(Pp_owerciass—LPC-Offset), 0) [3]

This parameter (e.g. the offset parameter) allows to control the compensation associated with the power class of the UE, provided by the Pcompensation factor. As such, it allows more flexibility for the network to détermine when to allow certain low power class UEs to camp on the cell (and thus to access the cell, and consume network resources). In a broad sense, this parameter allows to control the adjustment associated with the power class of the UE. For example, this offset parameter, provided by the parameter LPC-Offset, allows both positive and négative offset, i.e. enabling the low power class UE to consume more or less network resources. As such, the LPC-Offset offset Controls the compensation for lower power class UEs by varying and configuring the offset parameter to hâve different exemplary values as shown below:

LPC-Of fset : := ENPMEBATÈD ' { “ B1B-6, dB-3, dBÎi dB3, dB6, ^Β1Ό,_Λ

This configurable and variable parameter can be transmitted to the UEs in a System information block, such as SIB1-NB, SIB3-NB and SIB5-NB. It should be noted that, when the low power class offset is omitted in SIB1-NB, the default value of “0 dB” shall be used. This power class correction is not needed when the UE supports additionalPmax, i.e. when the UE supports a power class higher than the allowed P-max in the cell.

In another embodiment, the power compensation is replaced by a more generic function dépendent on the maximum allowed UE power, P-max, and the output power capability of a UE attempting to evaluate suitability of a cell:

Pcompensation = F(P-max - PpawerCiass) [4]

As such the parameter that Controls the compensation to the cell sélection criterion is given by the generic function F.

In a simpler form, the function applies a compensation linearly increasing with the différence between P-max and the UE power class:

Pcompensation = a-(P-max - Pp_owerciass) [5]

In équation [5], the alpha (a) parameter can be defined to penalize certain UEs supporting a low power class, in order to minimize their impact on the System capacity.

In another embodiment, the alpha parameter is made dépendent on the power class of the device, such as:

P compensation = a(Pp_owerctass)fP-max - Ppowciass) [6]

This increases the flexibility to define a generic cell suitability criterion that could e.g., be designed to not allow devices of low power classes to access the system at a coupling loss where they need to use répétitions.

The alpha parameter may be signaled by the network by System Information Blocks (SIBs) or RRC signaling.

Embodiments of the présent disclosure may be implemented in any suitable network, such as the wireless network 100 illustrated in FIGURE 3 below.

Wireless network 100 includes wireless devices 110a-110b (which may be referred to interchangeably as user equipments, UEs) and a plurality of radio access nodes or network nodes 120a-120b (e.g., enhanced Node Bs (eNBs), gNBs, etc.) connected to one or more core network nodes 130 via an interconnecting network 125. Wireless devices 110 within coverage area 115 may each be capable of communicating directly with radio access nodes 120 over a wireless interface. In certain embodiments, wireless devices may also be capable of communicating with each other via device-to-device (D2D) communication. In certain embodiments, radio access nodes 120a-120b may also be capable of communicating with each other via various interfaces/protocols (e.g. X2 in LTE, or other similar interface/protocol).

As an example, wireless device 110a may communicate with radio access node 120a over a wireless interface. That is, wireless device 110a may transmit wireless signais and/or receive wireless signais from radio access node 120a. The wireless signais may contain voice traffic, data traffic, control signais, and/or any other suitable information. In some embodiments, an area of wireless signal coverage associated with a radio access node 120 may be referred to as a cell.

In some embodiments wireless device 110 may be interchangeably referred to by the non-limiting term user equipment (UE). Wireless device 110 can be any type of wireless device capable of communicating with network node or another UE over radio signais. The UE may also be radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine-to-machine communication (M2M), a sensor equipped with UE, iPAD, Tablet, mobile terminais, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), etc. An example embodiment of wireless device 110 is described in more detail below with respect to FIGURE 4.

In some embodiments, generic terminology “network node” is used. It can be any kind of network node which may comprise of a radio network node such as radio access node 120 (which can include a base station, radio base station, base transceiver station, base station controller, network controller, gNB, NR BS, evolved Node B (eNB), Node B, Multicell/multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU), Remote Radio Head (RRH), a multi-standard BS (also known as MSR BS), etc.), a core network node (e.g., mobile management entity, MME, selforganizing network node, SON node, a coordinating node, positioning node, minimization of drive test node, MDT node, etc.), or even an extemal node (e.g., 3rd party node, a node external to the current network), etc. The network node may also comprise test equipment. The term “radio node” may be used to dénoté a UE (e.g., wireless device 110) or a radio network node (e.g., radio access node 120). An example embodiment of radio access node 120 is described in more detail below with respect to FIGURE 5.

In certain embodiments, radio access nodes or network nodes 120 may interface with a radio network controller. The radio network controller may control radio access nodes 120 and may provide certain radio resource management functions, mobility management functions, and/or other suitable functions. In certain embodiments, the functions of the radio network controller may be included in radio access node 120. The radio network controller may interface with a core network node 130. In certain embodiments, the radio network controller may interface with the core network node 130 via an interconnecting network 125.

The interconnecting network 125 may refer to any interconnecting system capable of transmitting audio, video, signais, data, messages, or any combination of the preceding. The interconnecting network 125 may include ail or a portion of a public switched téléphoné network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, régional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

In some embodiments, the core network node 130 may manage the establishment of communication sessions and various other functionalities for wireless devices 110. Examples of core network node 130 may include mobile switching center (MSC), MME, serving gateway (SGW), packet data network gateway (PGW), operation and maintenance (O&M), operations support system (OSS), SON, positioning node (e.g. Enhanced Serving Mobile Location Center, E-SMLC), MDT node, etc. Wireless devices 110 may exchange certain signais with the core network node using the non-access stratum layer. In non-access stratum signaling, signais between wireless devices 110 and the core network node 130 may be transparently passed through the radio access network. In certain embodiments, radio access nodes 120 may interface with one or more network nodes over an intemode interface. For example, radio access nodes 120a and 120b may interface over an X2 interface.

Although FIGURE 3 illustrâtes a particular arrangement of network 100, the présent disclosure contemplâtes that the various embodiments described herein may be applied to a variety of networks having any suitable configuration. For example, network 100 may include any suitable number of wireless devices 110 and radio access nodes 120, as well as any additional éléments suitable to support communication between wireless devices or between a wireless device and another communication device (such as a landline téléphoné). The embodiments may be implemented in any appropriate type of télécommunication system supporting any suitable communication standards and using any suitable components, and are applicable to any radio access technology (RAT) or multi-RAT Systems in which the wireless device receives and/or transmits signais (e.g., data). While certain embodiments are described for NR and/or LTE, the embodiments are applicable to any RAT, such as Universal Mobile Télécommunications System Terrestrial Radio Access Network (UTRA), enhanced UTRA (E-UTRA), narrow band internet of things (NB-IoT), WiFi, Bluetooth, next génération RAT (NR, NX), 4G, 5G, LTE FDD/TDD, Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA), Global System for Mobile Communication (GSM), GSM Edge Radio Access Network (GERAN), WLAN, CDMA2000, etc.

FIGURE 4 is a block diagram of an exemplary wireless device 110, in accordance with certain embodiments.

Wireless device 110 includes a transceiver 150, processor 152, and memory 154. In some embodiments, the transceiver 150 facilitâtes transmitting wireless signais to and receiving wireless signais from radio access node 120 (e.g., via an antenna), the processor 152 executes instructions to provide some or ail of the functionality described above as being provided by wireless device 110, and the memory 154 stores the instructions for execution by the processor.

The processor may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or ail of the described functions of wireless device 110, such as the functions of wireless device 110 described above. In some embodiments, the processor may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application spécifie integrated circuits (ASICs), one or more field programmable gâte arrays (FPGAs) and/or other logic.

The memory 154 is generally opérable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and/or other instructions capable of being executed by a processor. Examples of memory include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or or any other volatile or non-volatile, non-transitory computer-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processor of wireless device 110.

Other embodiments of wireless device 110 may include additional components beyond those shown in FIGURE 4 that may be responsible for providing certain aspects of the wireless device’s functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solution described above). As just one example, wireless device 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor. Input devices include mechanisms for entry of data into wireless device 110. For example, input devices may include input mechanisms, such as a microphone, input éléments, a display, etc. Output devices may include mechanisms for outputting data in audio, video and/or hard copy format. For example, output devices may include a speaker, a display, etc.

FIGURE 5 is a block diagram of an exemplary radio access node or network node 120, in accordance with certain embodiments.

Radio access node or network node 120 may include one or more of a transceiver 160, processor 162, memory 166, and network interface 164. In some embodiments, the transceiver 160 facilitâtes transmitting wireless signais to and receiving wireless signais from wireless device 110 (e.g., via an antenna), the processor 162 executes instructions to provide some or ail of the functionality described above as being provided by a radio access node 120, the memory 166 stores the instructions for execution by the processor 162, and the network interface 164 communicates signais to backend network components, such as a gateway, switch, router, Internet, Public Switched Téléphoné Network (PSTN), core network nodes or radio network controllers, etc.

The processor 162 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or ail of the described functions of radio access node 120, such as those described above. In some embodiments, the processor 162 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application spécifie integrated circuits (ASICs), one or more field programmable gâte arrays (FPGAs) and/or other logic.

The memory 166 is generally opérable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and/or other instructions capable of being executed by a processor. Examples of memory include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or or any other volatile or non-volatile, non-transitory computer-readable and/or computer-executable memory devices that store information.

In some embodiments, the network interface 164 is communicatively coupled to the processor 162 and may refer to any suitable device opérable to receive input for radio access node 120, send output from radio access node 120, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. The network interface 164 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

Other embodiments of radio access node or network node 120 may include additional components beyond those shown in FIGURE 5 that may be responsible for providing certain aspects of the radio network node’s functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solutions described above). The various different types of network nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

Processors, interfaces, and memory similar to those described with respect to FIGURES 4-5 may be included in other network nodes (such as core network node 130). Other network nodes may optionally include or not include a wireless interface (such as the transceiver described in FIGURES 4-5).

FIGURE 6 below illustrâtes an example of a method 200 that may be performed by a wireless device 110, in accordance with certain embodiments of the présent disclosure. First, the method déterminés a maximum output power capability associated with the wireless device (block 202). The maximum output power capability may be determined in any other suitable way. As an example, the wireless device may be configured with one or more parameters related to maximum output power, and the method may détermine the maximum output power capability based on the settings of the one or more parameters. In certain embodiments, the wireless device may belong to a power class and the maximum output power capability may refer to the power class.

Second, the method receives a signal from a cell associated with a radio access node (block 204). Third, the method détermines whether the signal from the cell satisfies a cell suitability criterion, wherein the cell suitability criterion is based at least in part on the maximum output power capability associated with the wireless device (block 206). That is, the cell suitability criterion may be non-linear depending on the maximum output power capability of the wireless device. In certain embodiments, the cell suitability criterion is satisfied if the signal received form the radio access node meets or exceeds a threshold. For example, the cell suitability criterion is satisfied if the received signal meets or exceeds a threshold for RSSI, signal level estimate, quality estimate, C/I, SNR, SINR, and/or other suitable threshold.

In certain embodiments, the cell suitability criterion may comprise a baseline cell suitability criterion plus a power class spécifie shift that dépends on the maximum output power capability of the wireless device. The cell suitability criterion (e.g., baseline criterion and power class spécifie shift) may be determined in any suitable manner, such as according to one or more pre-defined rules, one or more pre-defined parameters, and/or one or more network configured parameters.

As an example, the wireless device may belong to either a first power class (if the wireless device has a higher maximum output power capability) or a second power class (if the wireless device has a lower maximum output power capability). The first power class may be associated with a first power class spécifie shift value, and the second power class may be associated with a second power class spécifie shift value. The first and second power class spécifie shift values may be configured to allow wireless devices in the first power class to select a cell during coverage conditions that wireless devices in the second power class would not select the cell, such as coverage conditions toward the edge of the cell. This may reduce the number of blind répétitions in the network because wireless devices with lower maximum output power capability would not satisfy the cell suitability criterion in coverage conditions that would otherwise require them to send répétitive transmissions. For simplicity, the preceding example has described two power classes, however, any suitable number of power classes can be used.

Fourth, the method selects the cell in response to a détermination that the signal from the cell satisfies the cell suitability criterion (block 208). Selecting the cell may refer to camping on the cell or communicating with the cell in order to connect a call, data session, etc. If, on the other hand, a détermination is made that the cell suitability criterion is not met, the method may search for another cell that satisfies the cell suitability criterion.

FIGURE 7 below illustrâtes an example of a method 300 in a network node, such as radio access node 120. In certain embodiments, the method comprises determining that network capacity dépendent cell suitability criterion is enabled (block 302) and, in response, communicating to a wireless device a cell suitability criterion that dépends on a maximum output power capability of the wireless device (block 304). For example, the method may détermine that network capacity dépendent cell suitability criterion is enabled if one or more pre-defined rules and/or one or more pre-defined parameters hâve been configured that (1) expressly enable the criterion (e.g., by confîguring an on/off setting), or (2) implicitly enable the criterion (e.g., by confîguring rules or parameters that associate the cell suitability criterion with the maximum output power capability of the wireless device). Similarly, the method can détermine the particular cell suitability criterion to communicate according to one or more pre-defined rules and/or one or more pre-defmed parameters, for example. The cell suitability criterion may be communicated in any suitable manner. As one example, the method broadcasts a plurality of cell suitability criterion for a plurality of power classes, and each wireless device may détermine the cell suitability criterion for its respective power class. As another example, a wireless device may communicate its power class information to the network node and, in response, the network node may send a message to the wireless device indicating cell suitability criterion for that power class.

FIGURE 8 below illustrâtes examples of modules that may be included in wireless device 110. In certain embodiments, the modules perform the method described with respect to FIGURE 6. As an example, cell détection module (A) may receive a signal from a cell associated with a radio access node. Cell suitability configuration module (B) may détermine cell suitability criterion that is based at least in part on the maximum output power capability associated with the wireless device. For example, the criterion may be determined based on one or more pre-defined rules, one or more pre-defined parameters, and/or one or more network configured parameters. Cell sélection module (C) selects the cell (e.g., for camping on the cell or communicating a call or session with the cell) in response to a détermination that the cell suitability criterion has been satisfied (e.g., the signal received by module (A) satisfies RSSI, signal level estimate, quality estimate, C/I, SNR, SINR, and/or other requirement of the cell suitability criterion determined by module (B)). In certain embodiments, the modules are implemented using one or more processors discussed with respect to FIGURE 4. The modules may be integrated or separated in any manner suitable for performing the described functionality.

FIGURE 9 below illustrâtes examples of modules that may be included radio access node 120. In certain embodiments, the modules perform the method described with respect to FIGURE 7. For example, network capacity dépendent cell suitability module (A) may détermine whether network capacity dépendent cell suitability is enabled and, if so, may détermine cell suitability criterion (e.g., based on pre-defmed rules or pre-defined parameters). Cell suitability criterion communication module (B) may communicate the cell suitability criterion to one or more wireless devices. In certain embodiments, the modules are implemented using one or more processors discussed with respect to FIGURE 5. The modules may be integrated or separated in any manner suitable for performing the described functionality.

Figure 10 illustrâtes a flow chart of a method 400 for selecting a cell in a wireless communication, according to another embodiment. The method 400 can be carried out by the wireless device 110a or 110b, for example.

Method 400 comprises receiving a signal from a cell associated with a network node (block 404).

Method 400 comprises determining whether the signal from the cell satisfies a cell sélection criterion, wherein the cell sélection criterion is based at least in part on a parameter that Controls a compensation to the cell sélection criterion, the compensation being associated with a power class of the wireless device (block 406).

Method 400 also comprises selecting the cell in response to a détermination that the signal from the cell satisfies the cell sélection criterion (block 408).

Method 400 also comprises an optional step of determining a maximum output power capability associated with the wireless device (block 402).

In some embodiments, the received signal is a reference signal.

In some embodiments, the wireless device measures a received power of the reference signal when determining if the signal satisfies the cell sélection criterion.

In some embodiments, the parameter that Controls the compensation associated with the power class of the wireless device is received in a System information block (SIB).

In some embodiments, the parameter is an offset value that shifts the compensation to either allow the wireless device to access the cell or deny the wireless device to access the cell.

In some embodiments, the compensation, referred to as P compensation, comprises: Pcompensation = max(P-max -(Ppowerciass -LPC-Offset), 0) where P-max is the maximum uplink transmission power in a cell, Pp_owerciass is the maximum RF output power of the wireless device according to its power class and LCPoffset is the offset value or parameter.

In some embodiments, the parameter is provided by a function of a maximum allowed UE power and an output power of the wireless device, see for example équation 4.

In some embodiments, the function is a linear function.

In some embodiments, the linear function is further dépendent on the power class of the wireless device.

In some embodiments, the method 400 détermines a maximum output power capability associated with the wireless device.

In some embodiments, the cell sélection criterion is further based at least in part on the maximum output power capability associated with the wireless device.

It should be noted that the method 400 may be performed by the modules of a wireless device 110, as shown in FIGURE 8, for example. The cell détection module A is configured to receive a signal from a cell associated with a network node. The Cell Suitability Configuration module B is configured to détermine if the received signal satisfies a cell sélection criterion, wherein the cell sélection criterion is based at least in part on a parameter that Controls a compensation to the cell sélection criterion, the compensation being associated with a power class of the wireless device. The cell sélection module C is configured to select the cell in response to a détermination that the signal from the cell satisfies the cell sélection criterion.

The method 400 can be also performed by the processor 152 in combination with the memory 154 of FIGURE 4.

Turning to Figure 11, a flow chart illustrating a method 500 for controlling cell access in a wireless communication is described, according to another embodiment. The method 500 can be carried out by a network node or a radio access node 120, for example.

Method 500 comprises determining a parameter that Controls a compensation to a cell sélection criterion, the compensation being associated with a power class of a wireless device (block 502).

Method 500 comprises transmitting a signal to a cell with which the network node is associated, the signal comprising the determined parameter (block 504).

In some embodiments, the network node or radio access node sends a reference signal.

In some embodiments, the signal comprises a system block information (SIB) which carries the determined parameter.

In some embodiments, the signal comprises additional parameters related to the cell sélection criterion.

In some embodiments, the network node détermines the parameter based on a tradeoff between coverage enhancements and an amount of network resources that the coverage enhancements require.

In some embodiments, the parameter is an offset value that shifts the cell sélection criterion to either allow the wireless device to access the cell or deny the wireless device to access the cell.

In some embodiments, the compensation is referred to as Pcompensation and comprises: Pcompensation = max(P-max -(Pp_owerciass-LPC-Offset), 0) where P-max is the maximum uplink transmission power in a cell, Pp_Oy_Verciass is the maximum Radio Frequency (RF) output power of the wireless device according to its power class and LCP-offset is the offset value/parameter.

In some embodiments, the parameter comprises a function of a maximum allowed UE power and an output power of the wireless device.

In some embodiments, the function is a linear function.

In some embodiments, the linear function is further dépendent on the power class of the wireless device.

In some embodiments, the cell sélection criterion is further based at least in part on a maximum output power capability associated with the wireless device.

In some embodiments, the network node receives a connection request for establishing a connection with the cell in response to a détermination that the signal from the cell satisfies the cell sélection criterion.

It should be noted that the method 500 can be implemented in the modules of a wireless device 110 as illustrated in FIGURE 9, for example. The network capacity dépendent cell suitability criterion module A is configured to détermine a parameter that Controls a compensation to a cell sélection criterion, the compensation being associated with a power class of a wireless device. The Cell suitability criterion communication module B is configured to transmit a signal to a cell with which the network node is associated, the signal comprising the determined parameter.

The method 500 can be also performed by the processor 162 in combination with the memory 166 of FIGURE 5.

Modifications, additions, or omissions may be made to the Systems and apparatuses described herein without departing from the scope of the disclosure. The components of the Systems and apparatuses may be integrated or separated. Moreover, the operations of the Systems and apparatuses may be performed by more, fewer, or other components. Additionally, operations of the Systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.

The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. Generally, ail terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. Ail references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not hâve to be performed in the exact order disclosed, unless explicitly stated.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, and/or computer program product. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects ail generally referred to herein as a “circuit” or “module.” Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, Systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (which then forms a spécial purpose computer), spécial purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a sériés of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procédural programming languages, such as the C programming language. The program code may execute entirely on the user's computer, partly on the user’s computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scénario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments hâve been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, ail embodiments can be combined in any way and/or combination, and the présent spécification, including the drawings, shah be construed to constitute a complété written description of ail combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shah support claims to any such combination or subcombination.

Claims (10)

1. A method for selecting a cell by a wireless device in a wireless communication network, the method comprising:

receiving a signal from a network node associated with a cell;

determining whether the signal from the network node satisfies a cell sélection criterion, wherein the cell sélection criterion is based at least in part on a parameter, referred to as LCP-offset, that Controls a compensation to the cell sélection criterion, the compensation being referred to as Pcompensation and being associated with a power class of the wireless device, and comprising:

Pcompensation = max(P-max -(Pp_OwerCiass -LPC-Offset), 0) where P-max is a maximum uplink transmission power in a cell, Pp_mverciass is a maximum Radio Frequency (RF) output power of the wireless device according to a power class of the wireless device and LCP-offset is the parameter; and selecting the cell in response to a détermination that the signal from the cell satisfies the cell sélection criterion.

2. A method for controlling cell access in a wireless communication network, the method comprising:

determining a parameter, referred to as LPC-Offset, that Controls a compensation to a cell sélection criterion, the compensation being associated with a power class of a wireless device and being referred to as Pcompensation and comprising:

Pcompensation = max(P-max -(P p_OwerCiass -LPC-Offset), 0) where P-max is a maximum uplink transmission power in a cell, PpowCiass is a maximum Radio Frequency (RF) output power of the wireless device according to a power class of the wireless device and LCP-offset is the parameter; and transmitting a signal to a cell with which the network node is associated, the signal comprising the determined parameter.

3. A wireless device for selecting a cell in a wireless communication network, the wireless device comprising:

a processor and a memory connected thereto, wherein the memory comprises instructions that, when executed, cause the processor to:

receive a signal from a network node associated with a cell;

détermine whether the signal from the cell satisfies a cell sélection criterion, wherein the cell sélection criterion is based at least in part on a parameter, referred to as LCP-offset, that Controls a compensation to the cell sélection criterion, the compensation being associated with a power class of the wireless device and being referred to as Pcompensation an comprising: Pcompensation = max(P-max -(Ppowerciass -LPC-Offset), 0) where P-max is the maximum uplink transmission power in a cell, PpowerCiass is the maximum Radio Frequency (RF) output power of the wireless device according to a the power class of the wireless device and LCP-offset is parameter; and select the cell in response to a détermination that the signal from the cell satisfies the cell sélection criterion.

4. The wireless device of claim 3, wherein the processor is further configured to receive a system information block (SIB) that carries the parameter that Controls the compensation.

5. The wireless device of claim 3, wherein the parameter is an offset value that shifts the cell sélection criterion to either allow the wireless device to access the cell or deny the wireless device to access the cell.

6. The wireless device of claim 3, wherein the parameter comprises a function of a maximum allowed UE power and an output power of the wireless device according to the power class of the wireless device.

7. A network node for controlling cell access in a wireless communication network, comprising:

a processor and a memory connected thereto, the memory comprising instructions that, when executed, cause the processor to:

détermine a parameter, referred to as LPC-Offset, that Controls a compensation to a cell sélection criterion, the compensation being associated with a power class of a wireless device and being referred to as Pcompensation and comprising:

Pcompensation = max(P-max -(Ppawerciass -LPC-Offset), 0) where P-max is a maximum uplink transmission power in a cell, Pp_OwerCiass is a maximum Radio Frequency (RF) output power of the wireless device according to a power class of the wireless device and LCP-offset is the parameter; and transmit a signal to a cell with which the network node is associated, the signal comprising the determined parameter.

8. The network node of claim 7, wherein the signal comprises a system block information (SIB) which provides the determined parameter.

9. The network node of claim 7, wherein the parameter is an offset value that shifts the cell sélection criterion to either allow the wireless device to access the cell or deny the wireless device to access the cell.

10. The network node of claim 7, wherein the parameter comprises a function of a maximum 5 allowed UE power and an output power of the wireless device according to the power class of the wireless device.