WO2016183768A1

WO2016183768A1 - Method and apparatus of enhanced paging

Info

Publication number: WO2016183768A1
Application number: PCT/CN2015/079187
Authority: WO
Inventors: Huamin Chen; Min Wu; Feifei SUN; Tao Chen
Original assignee: MediaTek Singapore Pte Ltd
Current assignee: MediaTek Singapore Pte Ltd
Priority date: 2015-05-18
Filing date: 2015-05-18
Publication date: 2016-11-24
Anticipated expiration: 2017-11-18
Also published as: US10292132B2; US20180070332A1; US10602481B2; US20190230628A1; EP3219160A4; WO2016184401A1; CN107637147A; EP3219160A1; CN107534951A; EP3219160B1

Abstract

Methods and apparatus are provided for method and apparatus of enhanced paging. In one novel aspect, the paging narrow-band is introduced for paging message monitoring /transmission. Several paging narrow-bands within one PO are used for different UEs. UEs with similar CE levels or one CE level are multiplexed within one common paging narrow-band. The paging narrow-band are determined based on UE ID, CE level, and PO index in time domain. In another novel aspect, the paging narrow-bands are allocated according to a predefined rule/or fixed, and UE-specific paging narrow-band are (re) configured dynamically e.g. signaled by a higher layer message or semi-static. In another example, multiple specific narrow-bands are fixed for paging message transmission. The frequency hopping is. Additional resources in time domain is introduced to further reduce the blocking rate, indicated By DCI, or by paging message, or predefined.

Description

METHOD AND APPARATUS OF ENHANCED PAGING

TECHNICAL FIELD

The disclosed embodiments relate generally to wireless communication, and, more particularly, to paging enhancement for low cost (LC) machine type communication (MTC) UEs.

BACKGROUND

Machine-Type Communication (MTC) is an important revenue stream for operators and has a huge potential from the operator perspective. Lowering the cost of MTC user equipment (UEs) /devices is an important enabler for the implementation of the concept of "internet of things" (IOT) . Many MTC devices are targeting low-end (low average revenue per user, low data rate) applications that can be handled adequately by GSM/GPRS. In order to ensure that there is a clear business benefit to MTC UE vendors and operators for migrating low-end MTC devices from GSM/GPRS to LTE networks, there are many discussions within 3GPP scope about a new type of terminal, i.e. a low cost (LC) MTC UE, from Rel-11 to Rel-13. The cost of the LC-MTC UEs is tailored for the low-end of the MTC market to be competitive with that of GSM/GPRS terminals. The LC-MTC UEs are characterized by: 1) One Rx antenna； 2) Downlink and uplink maximum TBS size of 1000 bits； 3) Bandwidth reduction–resources for each channel transmission are limited to contiguous 6 PRBs (1.4MHz) for cost reduction, and 4) Coverage enhancement (CE) –some applications of LC-MTC UEs will require 15-20dB coverage extension and repeated transmission is a common technique to compensate penetration losses. Due to the limitations and repeatedly transmission requirement, LC-MTC UEs with or without coverage enhancement, and the UEs in CE mode cause larger overhead for signaling processes, such as the paging process.

In a wireless network like LTE/LTE-A, one main purpose of a paging message is to page UEs for RRC connections. The paging message can be also used to inform UEs of system-information (SI) update, wherein SI comprises master information block (MIB) , system information block-1 (SIB-1) and other SIB-x (SIB-2～ SIB-16For UEs in the LC MTC mode where the data blocks are repeatedly transmitted, it adds a large overhead and degrades UE battery life. Further, since a paging message is broadcasted, the repeated transmission adds system overheads to a large number of cells as well.

Enhancement of the paging messages and procedures are needed for LC MTC mode UEs.

SUMMARY

Methods and apparatus are provided for paging enhancement.

In one novel aspect, the paging narrow-band is introduced for paging message monitoring /transmission. In one example, several paging narrow-bands within one PO are used for different UEs. UEs with similar CE levels or with only one CE level are multiplexed within one paging narrow-band. And other UEs are paged within another paging narrow-band if a maximal number of UEs within one paging narrow-band achieves. And UE determines the paging narrow-band based on its UE ID, CE level, and PO index in time domain.

The paging narrow-bands are allocated /according to a predefined rule/or according to a fixed rule in a first embodiment, and UE-specific paging narrow-band can be (re) configured dynamically or semi-dynamically in a second embodiment. And the UE-specific paging narrow-band could be also signaled by a broadcast higher layer message (e.g., M-SIB2) in a third embodiment. The frequency hopping is enabled for the paging message transmission. The resources used for frequency hopping are among different paging narrow-bands. In alternatively, the resources used for frequency hopping are among a paging narrow-band and some narrow-bands which are not dedicated for paging. Additional resources in time domain is introduced to further reduce the blocking rate. Additional resources, i.e. the number of the virtual POs are indicated By DCI, or by paging message, or predefined.

In one novel aspect, a method is provided comprising: determining if a user equipment (UE) is in CE mode in a wireless communication system； determining a paging occasion to monitor paging messages by the UE； obtaining a set of narrow-band associated with the paging occasion； decoding a first paging and a second paging message within the obtained sub-band； and combining the first paging and the second paging message. The UE is in LC MTC mode upon detecting one or more condition comprising: the UE is a LC MTC device, and the UE is in a coverage extension (CE) mode. And the location of the paging occasion is predetermined.

In another novel aspect, a method is provided comprising: obtaining a set of common paging narrow-bands from a higher layer configuration by a UE in a mobile communication system； determining a paging occasion to monitor paging message； and decoding paging messages within a obtained common paging narrow-band during a set of subframes and perform combination.

Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention.

FIG. 1 illustrates an exemplary mobile communication network with low cost MTC UEs in accordance with embodiments of the current invention.

FIG. 2 shows some examples of some embodiments of this invention.

FIG. 3-5 show some examples for paging narrow-band configuration.

FIG. 6-FIG. 7 show some examples of the mapping rule design.

FIG. 8 shows one example to determine a paging narrow-band by a predefined rule.

FIG. 9-10 illustrates an exemplary of paging message transmission without M-PDCCH according to one embodiment of this invention.

FIG. 11 illustrates an exemplary method flow of UE reception procedure according to the embodiment of FIG. 9 this invention

FIG. 12 illustrates an exemplary of paging transmission with M-PDCCH according to one embodiment of this invention.

FIG. 13 illustrates an exemplary method flow of UE reception procedure according the embodiment of FIG. 12 of this invention.

FIG. 14 illustrates the first exemplary of paging resources with frequency hopping according to one embodiment of this invention.

FIG. 15 illustrates the second exemplary of paging resources with frequency hopping according to one embodiment of this invention.

FIG. 16 illustrates an exemplary method flow of UE reception procedure according to one embodiment of this invention.

DETAILED DESCRIPTION

Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 illustrates an exemplary mobile communication network 100 with low cost MTC UEs in accordance with embodiments of the current invention. Wireless communication system 100 includes one or more fixed base infrastructure units, such as base stations 102 103, and 104, forming a network distributed over a geographical region. The base unit may also be referred to as an access point, an access terminal, a base station, a Node-B, an eNode-B, or by other terminology used in the art. Each of the

base stations

102, 103 and 104 serves a geographic area such as

cell

107, 106, and 108, respectively. Backhaul connections 113, 114 and 115 connect the non-co-located base stations, such as 102, 103 and 104. These backhaul connections can be either ideal or non-ideal.

Amobile station 101 in wireless network 100 is served by base station 102 via uplink 111 and downlink 112. In one embodiment, mobile communication network 100 is an OFDM/OFDMA system comprising a base stations eNBs 102, 103 and 104, and a plurality of mobile stations, such as mobile station 101. Mobile station 101 is a real LC MTC UE actually in one embodiment. In another mobile station 101 is a normal or regular UE which is served/regarded as LC MTC UEs, i.e., a normal UE operating in LC-MTC mode. Then, an LC-MTC UE or UE in LC-MTC mode can be originated from a regular UE, a LC MTC UE, an MTC UE or any other type of UE. When there is a downlink packet to be sent from eNodeB to mobile station, each mobile station gets a downlink assignment, e.g., a set of radio resources in a physical downlink shared channel (PDSCH) . When a UE needs to send a packet to eNodeB in the uplink, the mobile station gets a grant from the eNodeB that assigns a physical downlink uplink shared channel (PUSCH) consisting of a set of uplink radio resources. The mobile station gets the downlink or uplink scheduling information from a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (EPDCCH) or a physical downlink control channel for MTC UEs (M-PDCCH) dedicated for LC MTC UEs. The downlink or uplink scheduling information and the other control information, carried by PDCCH/EPDCCH/M-PDCCH, is referred to as downlink control information (DCI) .

Base stations such as 102, 103 and 104 are connected to a network entity, such as a mobility management entity (MME) 105, via links of 116, 117 and 118. In wireless network 100, paging procedures (e.g., for RRC connection setup) are initiated by a network entity such as MME 105, and a paging message is transmitted to cells within a same tracking area. One or more cells form a tracking area for a UE. For example, a track area 109 is formed for UE 101 including

cells

106, 107 and 108, served by

base stations

103, 102 and 104, respectively.

FIG. 1 further shows simplified block diagrams of mobile 101, base station 102 and MME 105 in accordance with the current invention. MME 105 has a transceiver module 153, receives signals from links with base stations, and sends them to processor 152. Transceiver 153 receives signals from processor 152, and sends out to links to the base stations. Processor 152 processes the received signals and invokes different functional modules to perform features in MME 105. Memory 151 stores program instructions and data 154 to control the operations of MME 105. Except for the normal paging management module used for normal UEs, MME 105 also includes a set of control modules, such as modified paging (M-paging) for LC MTC UEs module 155 that carry out functional tasks to communicate with mobile stations.

Base station 102 has an antenna 126, which transmits and receives radio signals. A RF transceiver module 123, coupled with the antenna, receives RF signals from antenna 126, converts them to baseband signals and sends them to processor 122. RF transceiver 123 also converts received baseband signals from processor 122, converts them to RF signals, and sends out to antenna 126. Processor 122 processes the received baseband signals and invokes different functional modules to perform features in base station 102. Memory 121 stores program instructions and data 124 to control the operations of base station 102. Base station 102 also includes a set of control modules, expect for the normal paging management module, such as M-paging module 125 that carry out functional tasks to communicate with mobile stations.

Mobile station 101 has an antenna module 135 comprising one or more antennas, which transmit /receive radio signals. A RF transceiver module 134, coupled with the antenna, receives RF signals from antenna 135, converts them to baseband signals and sends them to processor 132. RF transceiver 134 also converts received baseband signals from processor 132, converts them to RF signals, and sends out to antenna 135. Processor 132 processes the received baseband signals and invokes different functional modules to perform features in mobile station 101. Memory 131 stores program instructions and data 136 to control the operations of mobile station 101.

Mobile station 101 also includes a set of control modules that carry out functional tasks. A LC-MTC detecting module 191 monitors and detects whether UE 101 is in the LC MTC mode. A paging occasion module 192 obtains the information about paging occasions, and sub-band handler 193 obtains the associated information of paging sub-band, and paging decoding module 194 decodes the paging messages and perform combination if the UE is in CE mode.

Legacy paging messages causes large overhead to a network supporting UEs in CE mode by a repeated transmission mechanism, or in normal coverage wherein repetition is also applied to guarantee coverage, and shortens the battery life of UE under the repeated transmission mechanism. Further, with reduced bandwidth and limited TBS, some enhancement for paging is needed. Therefore, a modified paging for LC MTC UEs (M-Paging) is desired. Further, dynamic resource allocation for paging by common search space (CSS) within PDCCH cannot be supported for LC UEs due to bandwidth reduction, since PDCCH is distributed to whole channel bandwidth. Thirdly, the blocking rate is expected to be high in CE mode with a repeated transmission. Especially there are a massive number of devices. Large repetition will introduce a lack of resources at time domain. Therefore, this invention proposes an enhanced resource allocation for paging message transmission for LC MTC UE/CE UE. There are embodiments of two directions in this invention.

The first issue to use the M-paging mechanism is to determine whether the M-paging message or process applies to the UE. The UE needs to determine whether the UE is in the LC MTC mode. A UE can be categorized as a normal UE or a LC-MTC UE. A real LC-MTC UE operates in the LC MTC mode, which has limited TBS size, and reduced bandwidth, one Rx antenna, etc. Different from the real LC-MTC UE, a normal UE without coverage extension operates in the normal mod without any limitation to bandwidth, TBS, etc. A normal UE may operate either in a normal mode or in a CE mode. In one embodiment of the current invention, the normal UE operates in the CE mode is considered to be in the LC MTC mode, which may require repeatedly transmission just as a LC-MTC UE. It means that normal UE in the CE mode can be a LC-MTC UE. If the normal UE is not in a coverage extension mode, the UE determines that the UE is a normal mode. Upon determining whether the UE is in the LC MTC mode, M-paging message can be used for the LC MTC mode UEs.

To receive M-paging, M-paging transmission is with an associated control signaling within M-PDCCH in one embodiment. The information for M-Paging reception can be indicated within the associated DCI, such as payload size, paging location number within a paging cycle, etc. For UEs in normal coverage with a not large CE requirement, dynamic scheduling of M-Paging is feasible. The resources for the associated DCI can be regarded as a common search space within M-PDCCH. The M-PDCCH CSS is a common resource region within the whole channel bandwidth used to schedule or transmit broadcast/multicast /unicast data. Different UEs may have different M-PDCCH CSS in frequency domain.

In another embodiment, M-Paging is transmitted without an associated control signaling. The parameters for M-Paging reception, such as payload size, paging resources at frequency domain, etc, can be predefined or (re) configured by a higher layer message semi-statically. This design is feasible for UEs in CE mode or with a large CE requirement, since large repetition of control signaling will introduce large power consumption.

In one novel aspect, paging narrow-band is introduced. The paging narrow-band is used for paging message transmission in one embodiment. In another embodiment, the paging narrow-band is used for control signaling which is used to indicate some information for M-Paging repetition.

A basic resource granularity smaller than the size of a paging narrow-band can be defined in one design option. In one embodiment, one paging narrow-band comprises multiple basic resources granularities and one M-Paging message or control signaling for M-Paging message is transmitted within one or multiple basic resource granularity. That means multiple M-Paging messages can multiplex within one narrowband. In another design option, only one M-Paging message or only one control signaling is transmitted within a paging narrow-band.

FIG. 2 shows some examples of some embodiments of this invention. Within a paging narrow-band 211, there are two paging messages 201 and 202, while only one paging message 203 is transmitted within a paging narrow-band 213. Here, it’s assumed that a paging narrow-band occupies 6 PRB pairs and a basic resource granularity is of 3 PRB pairs.

The paging narrow-band can be (re) configured by a higher layer message in a first design option. The higher layer message can be broadcast in one embodiment, or UE-specific in another embodiment. For example, a broadcast higher layer message like SIB2 for LC MTC UEs configures a set of DL narrow-band dedicated for paging message transmission from a starting point at time domain. Here, a starting point for paging message is named as a paging occasion (PO) . M-Paging is repeated at following available subframes configured by the higher layer message. In one embodiment, M-Paging is repeated within the PO. After RRC connection setup, one or more UE-specific paging narrow-bands can be (re) configured by a UE-specific higher layer message. Then, the UE can monitor its paging message within the configured UE-specific paging narrow-bands. Multiple UEs can be configured the same UE-specific paging narrow-bands.

In a second design option, a set of dedicated paging narrow-bands are specified. For example, a narrow-band with 6 PRB pairs at one channel edge is reserved for paging message transmission and used for other information transmission if there is no paging message.

In a third design option, paging narrow-bands are derived from a predefined rule. For example, a specific narrow band is fixed or configured, and several paging narrow-bands are obtained by adding a shift to the specific narrow-band. The shift value can be a function of at least one of the following parameters like UE ID, UE CE level, etc. The UE ID can be a function of IMSI, S-TMSI, a UE-specific P-RNTI, or a multicast P-RNTI shared by a group of UEs, etc.

In the first design option of paging narrow-band configured by a higher layer message, the number of configured paging narrow-bands is a multiple times of the number of POs in a first embodiment. In a second embodiment, the number of configured paging narrow-bands is the same as the number of PO within a paging radio frame. That is only one paging narrow-band from the configured set is used within on PO. More narrow-bands for paging within the same PO can be derived from the configured one paging narrow-band by a predefine rule. In a third embodiment, all configured paging narrow-bands are used within one PO. Consider signaling overhead, the number of configured paging narrow-bands could be restricted.

FIG. 3-5 show some examples for paging narrow-band configuration. In FIG. 3, within a layer configuration ration 310, an indicator 312 configures a set of 4 paging narrow-bands for two POs. Then, within the first PO, narrow-band #0 starting from logical RB pair 0 to logical RB pair 5 (resource 340) and narrow-band #1 starting from logical RB pair 33 to logical RB pair 38 (resource 342) are used, while resource 344 i.e., narrow-band #2 starting from logical RB pair 10 to logical RB pair 15, and resource 346, narrow-band #3 starting from logical RB pair 21 to logical RB pair 27, are used within the second PO. In FIG. 4, a set of two paging narrow-bands are informed to the UE by an indicator 412 within a higher layer message 410. Then, paging narrow-band #0 (resource 440 starting from logical RB pair 0 to logical RB pair 5) and narrow-band #1 (resource 442 starting from logical RB pair 33 to logical RB pair 38) are used within the first PO and the second PO, respectively. In FIG. 5, a set of two paging narrow-bands are configured by a field 512 within a higher layer message 510, and all configured resources can be used within each PO. In this example, two narrow-band indexed #2 and #5 are selected a set of logical narrow-bands.

Note that the configured narrow-bands are logical resources, and mapped to physical narrow-bands according to a mapping rule in one design option. In a first embodiment, the physical narrow-band depends on eNB scheduling. In another embodiment, the physical narrow-bands are obtained by dividing the whole system bandwidth by a division rule. The division rule can specify that the whole system bandwidth is divided into several narrow-bands from a channel edge in one embodiment. In another embodiment, the division rule can specify that the whole system bandwidth is divided into several narrow-bands from some contiguous central PRB pairs. The number of narrow-bands by division can be expressed as

Wherein N_narrow denotes the number of narrow-bands, WBW is the bandwidth of whole system, and NBW is the bandwidth of a narrow-band.

The mapping rule between logical narrow-band and physical narrow-band is localized in one embodiment. That means logical narrow-band and physical narrow-band have same index. In another embodiment, the mapping rule between logical narrow-band and physical narrow-band is distributed. That means logical narrow-band and physical narrow-band have different index. One design option is a physical narrow-band is obtained by adding a shift to the index of logical narrow-band. The shift value is a function of cell ID in one example, and expressed as

wherein I_phy and I_logical are the index of a physical narrow-band and a logical narrow-band,

is the cell ID.

FIG. 6-FIG. 7 show some examples of the mapping rule design. In FIG. 6, a localized mapping is used, i.e., a logical narrow-band is mapped to a physical narrow band with the same index. In FIG. 7, a distributed mapping with a function of cell ID is used. In this example, a system with a bandwidth 20MHz and a cell ID 2 is assumed. Then, a logical narrow-band maps to a physical narrow-band by adding a shift value 2 to the logical index.

Considering an application of a massive number of LC MTC UEs, the number of UEs paged at a same PO is quite limited. Further, if multiple UEs multiplex within a same paging message, a higher blocking rate can be also expected since a long repetition is expected in case of a large CE requirement. To solve this problem, the embodiments of present invention propose that multiple paging narrow-bands are allocated at the same starting point to receive paging message or control signaling for paging message reception without introducing additional PO number at time domain, in a first novel aspect. The starting point is a determined PO according to a predefined rule. In legacy LTE systems, there is only one PO within a paging cycle for one UE. At one starting point, one UE detects paging or scheduling signaling for paging within one paging narrow-band, and a number of UEs are paged within different paging narrow-bands.

In a first design option, the UE determines a paging narrow-band, according to a predefined narrow-band determination rule, from a set of paging narrow-bands which are configured by a higher layer message, or specified, or known to UEs without signaling. One embodiment is the predefined narrow-band determination rule is a function of UE ID. For example, the selected paging narrow-band is obtained by following expression

I ＝ UE ID ％M

wherein I is a narrow-band index within the configured set, M is the number of configured/specified paging narrow-bands, or the number of the set of narrow-bands known to UE without configuration (e.g., M＝ N_narrow) ) . The UE ID can be a function of IMSI, S-TMSI, a UE-specific or group specific P-RNTI, etc. Further, the UE ID calculation is a function of a maximal UE number within a paging message.

In a second embodiment, by adding a UE-specific shift, a UE-specific paging narrow-band is derived from a configured narrow-band by a broadcast message, or a specified paging narrow-band. For example, the broadcast message configures a paging narrow-band, and the UE obtains its own paging narrow-band by adding a shift, calculated as

Δ ＝ UE ID modN_max

Wherein Δis the shift, N_max is a maximal UE number within a paging message.

In a third embodiment, the predefined narrow-band determination rule is a function of UE CE level. For example, a group of CE level are specified, like {0dB, 5dB, 10dB, 15dB} , and several sets of paging narrow-bands are configured or predefined for each CE level. Then, the UE can select one set of narrow-bands based on its CE level. Further, based on UE ID, the UE determines one paging narrow-band from the selected set according to a predefined rule like the first design option, if there are more than one narrow-bands for each set.

In a fourth embodiment, one or more paging narrow-band are indicated to the UE via a dynamic control signaling within M-PDCCH, wherein the indicated paging narrow-band is selected from a set of configured or predefined paging narrow-bands.

In a fifth embodiment, one or more paging narrow-bands are obtained directly from a higher layer message.

FIG. 8 shows one example to determine a paging narrow-band by a predefined rule. In FIG. 8, a set of 4 paging narrow-band is known to UE by configuration. It’s assumed that IMSI value of the UE is 2 and a maximal number is 16 in this example. Then, an index of 2 is obtained, i.e., paging narrow-band #4 is determined by the UE.

In a second novel aspect, additional resources for paging at time domain are introduced, in addition to frequency resources. That is PO number within a radio frame or within a paging cycle is increased. One paging cycle should accommodate enough subframes for repetitions. That means the paging cycle should be extended compared to legacy paging cycles. In one novel aspect, the frequency locations of paging messages at different POs within one paging cycle are identical, or different from each other in another novel aspect. For differentiation, a PO that can be determined by a predefined rule is named an actual PO, and a PO that is determined by other signaling is named as a virtual PO.

In a first design option, more than one actual PO for one UE are introduced by a predefined rule. That is a UE can monitor multiple actual POs within a paging cycle. The parameters of the predefined rule can be from higher layer configurations, and comprise at least UE ID, UE CE level, etc.

In a second design option, additional virtual POs are introduced by a paging message which is obtained from an actual PO.. For one UE, there is only one actual PO within a paging cycle, and multiple virtual POs within a paging cycle.

In a first embodiment of the second design option, at the determined actual PO, a first paging message indicates that there is a second paging at following second virtual PO with a gap between the first determined actual PO. Further, at a second virtual PO, the second paging message indicates that there is a third paging at following third virtual PO with a same gap. The gap, a distance between every two POs, is predefined or configured by a higher layer message. Note that the UE will stop monitoring paging if it’s paged by the paging message within the determined PO, otherwise the UE will continue to perform monitoring.

In a second embodiment of the second design option, the total number of the virtual POs following the current determined PO is indicated by the paging message within the determined PO. And the locations of virtual POs are predefined and associated with the determined actual PO location (e.g. a gap) .

FIG. 9-10 illustrates an exemplary of paging message transmission without M-PDCCH according to one embodiment of this invention. In FIG. 9, for the first paging message #0 940 of the first actual PO, its starting point in time domain is 920 by a predefined rule. And 940 indicates that there is another paging message at 922. Then, if the UE is not paged with 940, the UE will monitor the paging message 942 at 922. The starting point 922 is a logical value obtained from the point 920, or the logical value between point 922 and point 920 is a function which could be determined, so at the starting point 922, the UE could detect the paging message 942 for itself, for example, paging message#1 942.

In FIG. 10, at a determined actual PO 1011, paging message#0 1030 indicates the total number of POs with a paging cycle, for example, two virtual POs. Then, the UE know there are another two paging messages for monitoring if it is not paged within 1030. The UE obtains the starting point of paging message #1 1031 form a predetermined gap , the starting point is a logical value between point 1012 and point 1011, or the logical value between point 1012 and point 1011 is a function which could be determined, so at the starting point 1012, the UE could detect the paging message, for example, paging message#1 1031. In one novel aspect, the frequency location of paging message#1 1031 is the same as paging message#0, in another novel aspect, the frequency location of paging message#1 1031 is different from paging message#0 1030, e.g. with a shift. The distance between the starting point 1014 and the starting point 1012 could be the same. And in this case, the second virtual PO starts from the starting point 1014, and UE detects detect the paging message, for example, paging message#1 1032.

FIG. 11 illustrates an exemplary method flow of UE reception procedure according to the embodiment of FIG. 9 this invention. First, UE determine a PO according to a predefined rule to monitor paging messages in step 1101. UE decodes the paging message within a determined set of time-frequency resources in step 1102. Then, UE checks if the paging for itself in this PO in step 1103. If yes in step 1103, and end the procedure. If no in step 1103, and UE further checks if there is any indication for a second virtual PO in step 1104. If yes in step 1104, UE goes to step 1106 to decode a second paging message within another set of frequency resources at a second virtual PO. If no in step 1104, UE goes to step 1105 to set a timer to monitor a new paging message in a new cycle, and end the procedure.

In a third design option, additional virtual paging occasions are indicated by a control signaling at a paging monitoring point. That is paging DCI for scheduling paging message indicates the number of additional virtual POs in one embodiment. In another embodiment, DCI indicates whether there is more than one PO within this paging cycle. In one case, the paging DCI is transmitted within M-PDCCH CSS. M-PDCCH CSS is transmitted within a common resource region to schedule or transmit broadcast/multi-cast/uni-cast data. The paging monitor point is obtained from a predefined rule, and is ahead of a starting point for paging transmission.

Transmission window of paging messages at each PO (virtual or actual) is orthogonal or overlap. Within each virtual PO, the paging narrow-band can be same as those within the previous determined PO, or a function of those paging narrow-bands within the previous determined PO.

FIG. 12 illustrates an exemplary of paging transmission with M-PDCCH according to one embodiment of this invention. In FIG. 12, there is DCI indicating the total number of Pos, for example 2 virtual POs. So for the first paging message #0 1230 of the first actual PO, its starting point in time domain is 1211. But UE does not known the position of the next repetition of paging message#0, so from the paging message#0 1230, the UE obtain some information about the starting point of the next repetition of paging message#0 1230, in one case , the starting point is a logical value between point 1212 and point 1211, or the logical value between point 1212 and point 1211 is a function which could be determined, so at the starting point 1212, the UE could detect the paging narrow-band for itself, for example, paging message#1 1231. In one novel aspect, the frequency location of paging message#1 1231 is the same as paging message#0, in another novel aspect, the frequency location of paging message#1 1231 is different from paging message#0 1230, e.g. with a shift. The distance between the starting point 1214 and the starting point 1212 could be the same. And in this case, the second virtual PO starts from the starting point 1214, and UE detects detect the paging narrow-band for itself, for example, paging message#1 1232.

FIG. 13 illustrates an exemplary method flow of UE reception procedure according the embodiment of FIG. 12 of this invention. Firstly, UE determines a position in time domain to monitor control information for paging message in step 1301, and decodes control signaling within a set of frequency resources in step 1302. Then UE determines the number of POs within this cycle to monitor paging message in step 1303, the number of POs could be indicated in DCI with M-PDCCH. UE decodes paging message within a set of frequency resources at the PO in step 1304, then UE checks if there it is paged at the PO in step 1305, if no, UE goes to step 1306 to determine if all the POs have been monitored in step 1306. If yes in step 1305, end the procedure. If no in step 1306, UE goes back to step 1304. If yes in step 1306, UE sets a timer to monitor a new paging message in a new cycle in step 1307.

In a fourth embodiment of the second design option, additional virtual POs are indicated by higher layer message. The locations of all virtual POs are predefined. In one embodiment, time locations of virtual POs are a function of the actual PO. UEs perform irrelative decoding among all possible POs. Transmission window of paging message at each PO (virtual or actual) is orthogonal or overlap. Within each virtual PO, the paging sub-band can be same as those within the previous determined PO, or a function of those known paging narrow-band.

The paging narrow-bands are those narrow-bands within a set of bundled subframes starting from a (virtual or actual) PO under a repeated transmission mechanism. The PO is a starting point for CE UE to monitor paging message with a repetition number. Without repetition (repetition number is one) , the paging message is only transmitted within a PO. In one embodiment, the paging message is transmitted from a PO at time domain within a paging window. The paging window comprises multiple discrete/contiguous subframes to guarantee an extended coverage of paging message. The length of paging window can be 1 subframe without repetition in time domain, or with repetitions within one subframe. Multiple paging windows can be accommodated within a (extended) paging cycle. The set of subframes within a PO window for paging repetition/transmission is indicated by a higher layer message, or specified. And the paging message can be repeated within a subframe or within a limited number of subframes to reduce delay. In some embodiment of this invention, frequency hopping could be enabled to achieve diversity gain by transmitting message among multiple narrow-bands. In one case, the frequency resources hop at frequency domain among a determined paging narrow-band and other narrow-bands not configured/specified for paging. The position of other narrow-bands are obtained by a predefine hopping rule, which is a function of at least subframe index, bundle index, UE ID. In yet another case, the frequency resources hop in frequency domain among multiple known paging narrow-bands. The hopping pattern is configured or predefined. For example, resources hop among the higher-layer configured narrow-bands one by one with time. Note that each narrow-band is used within a bundled set of subframes during frequency hopping. The bundled size can be one or more subframes.

FIG. 14 illustrates the first exemplary of paging resources with frequency hopping according to one embodiment of this invention. In FIG. 14, from the higher layer message, UE obtains the frequency resources with a starting indexPOs, for example, for the first PO, a paging narrowband #0 starting from logical RB pair #0 is allocated, and for the second PO, a paging narrow-band #1starting logical RB pair #33 is allocated. A paging message 1401 is transmitted from the first PO 1420 by a bundled repetition 1451 within paging narrow-band #0. Starting from 1422, another bundled repetition 1452 of 1401 is transmitted within narrow-band 1470, which is obtained by adding a shift to paging narrow-band #0 in frequency domain. Another paging message 1402 starts from the second PO1421 in time domain, and its first bundled repetition 1461 is within paging narrow-band #1. A second bundled repetition of 1402 is 1462 starting from 1423 within a narrow-band 1480. The narrow-band 1480 is obtained by adding a shift value to paging narrow-band #1.

FIG. 15 illustrates the second exemplary of paging resources with frequency hopping according to one embodiment of this invention. Different from FIG. 14, resources for a paging message repetition are identical at all subframes in time domain. For example, a paging message 1520 is repeated by 1530 starting from the first PO 1500 within a paging narrow-band #0. Another bundled repetition 1531 of 1520 starts from 1503 at a narrow-band1591, which has same frequency location as paging narrow-band #0 for 1530. At a second PO 1501, another paging message 1521 is transmitted. At the first bundled repetition 1540 of 1521, paging narrow-band #1 is occupied for transmission. At another bundled repetition 1541 starting from 1502 of 1521, narrow-band 1590 is occupied for transmission, and 1590 is same as paging narrow-band #1 at frequency domain.

FIG. 16 illustrates an exemplary method flow of UE reception procedure according to one embodiment of this invention. First, in step 1601, UE obtains a set of paging narrow-bands from the high layer configuration. In step1 602, the UE determines the paging occasion to monitor the paging messages. Then, UE decodes the paging message within the obtained paging narrow-band during a set of subframes and perform combination in step 1603. And then, UE determines if the transmission of the paging message finishes in step 1604. If yes, then UE end the procedure, if not, then UE goes to step 1605 to check if the frequency hopping is enabled, if enabled, then UE goes to step 1606 to determine a second narrow-band for reception and perform combination after decoding. If there is no frequency hopping in step 1605, UE goes to step 1604 to determine if the transmission finishes.

Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.

Claims

A method comprising:

determining if a user equipment (UE) is in CE mode in a wireless communication system；

determining a paging occasion to monitor paging messages by the UE；

obtaining a set of narrow-band associated with the paging occasion；

decoding a first paging and a second paging message within the obtained sub-band； and

combining the first paging and the second paging message.
The method of Claim 1, wherein the UE is in LC MTC mode upon detecting one or more condition comprising: the UE is a LC MTC device, and the UE is in a coverage extension (CE) mode.
The method of Claim 1, wherein the location of the paging occasion is predetermined.
The method of Claim 1, wherein the locations of the set of narrow-band are obtained from a higher layer message, the locations comprise the narrow-band index and the PRB starting index.
The method of Claim 1, wherein before decoding the second paging message, the UE further checks if frequency hopping is enabled.
The method of Claim 5, wherein if the frequency hopping is enabled, the UE finds the narrow-band with a hopping pattern.
The method of Claim 1, wherein before decoding the second paging message, the UE further checks if a number of virtual PO is indicated in DCI.
The method of Claim 7, wherein before decoding the second paging message, if the number of virtual PO is not indicated, the UE obtains the narrow-band for the second paging message from the first paging message.
The method of Claim 7, wherein before decoding the second paging message, if the number of virtual PO is indicated, the UE obtains the narrow-bands for the number of the virtual PO, and decodes the number of virtual paging message.
A method comprising:

obtaining a set of common paging narrow-bands from a higher layer configuration by a UE in a mobile communication system；

determining a paging occasion to monitor paging message； and

decoding paging messages within a obtained common paging narrow-band during a set of subframes and perform combination.
The method of claim 10, further comprising: determining if a frequency hopping is enabled.