US20170280507A1

US20170280507A1 - Multiple sim multiple standby strategy on a ue with carrier aggregation

Info

Publication number: US20170280507A1
Application number: US15/503,689
Authority: US
Inventors: Sheng-Chieh WANG
Original assignee: MediaTek Inc
Current assignee: MediaTek Inc
Priority date: 2014-11-19
Filing date: 2015-11-19
Publication date: 2017-09-28
Also published as: US10433368B2; WO2016078555A1; WO2016078600A1; CN106714283A; US20160142992A1; CN105874875B; CN105874875A

Abstract

A method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation is proposed. A UE performs CC selection from the multiple CCs associated with a first SIM to suffer from other-SIM-occupancy to minimize potential service degradation. In a first option, the UE selects one or more CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. In a second option, the UE schedules other-SIM-occupancy on more than one CCs of the first SIM to reduce the frequency and duration of the other-SIM-occupancy affected to each chosen CC of the first SIM.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 from U.S. Provisional Application No. 62/081,692, entitled “eGemini (Evolved Gemini) inventions,” filed on Nov. 19, 2014, the subject matter of which is incorporated herein by reference.

TECHNICAL FIELD

The disclosed embodiments relate generally to mobile communication networks, and, more particularly, to multiple SIM multiple standby (MSMS) strategy on a UE with carrier aggregation (CA).

BACKGROUND

Dual-SIM Dual-Standby (DSDS) is a very popular feature in smart phone markets today, especially in developing countries such as China and India. Many mobile phone users have multiple SIM cards for various purposes—having different phone numbers for different uses (e.g., one for business and one for personal), saving roaming fee, compensating non-contiguous network coverage, and sharing one device for multiple family members. With DSDS feature, mobile phone users can use single device to enjoy multiple SIM services. DSDS UE (User Equipment) can generally be categorized into two types. A first type is called Single Talk, where two baseband modules share the same RF module. Single Talk device has low cost and no RF coexistence interference. However, Single Talk requires complex implementation to support Dual-Standby. Single Talk only supports one voice call, and requires gap to monitor paging signals. A second type is called Dual Talk, where two baseband modules utilize two individual RF modules. Dual Talk only requires simple implementation to support dual standby and can support voice calls over both SIM cards simultaneously. However, Dual Talk device has high cost and RF coexistence interference.
The exponential growth of mobile subscribers and smart phone applications require substantial increase of wireless bandwidth. The long-term evolution (LTE) system is an improved universal mobile telecommunication system (UMTS) that provides higher data rate, lower latency and improved system capacity. In the LTE system, an evolved universal terrestrial radio access network includes a plurality of base stations, referred as evolved Node-Bs (eNBs), communicating with a plurality of mobile stations, referred as user equipment (UE). A UE may communicate with a base station or an eNB via the downlink and uplink. The downlink refers to the communication from the base station to the UE. The uplink refers to the communication from the UE to the base station.
To provide higher peak rate, LTE introduces carrier aggregation (CA) to provide higher bandwidth capable of supporting the high data rate. In the carrier aggregation system, multiple component carriers (CCs) are aggregated and jointly used for transmission to/from a single device. In LTE Rel-10, CA operation defines a number of serving cells, one for each CC. The functionalities of Radio Resource Control (RRC) connection are only handled by one cell, defined as the Primary Serving Cell (PCell) served by the Primary component carrier (PCC). One or more Secondary Serving Cells (SCell) are designed to add more bandwidth. The demand for higher bandwidth may require exploiting further on CA operation to aggregate cells from different base stations to serve a single UE, called inter-eNB carrier aggregation (inter-eNB CA).
To support carrier aggregation in LTE, an UE might have multiple sets of RF transceivers and baseband or digital signal processor (BB/DSP) for multiple CCs. To support Multiple SIM Multiple Standby (MSMS), an UE might apply the same hardware (HW) resource (i.e., RF transceiver and BB/DSP) to several CCs that are associated with different SIMs. For a first SIM1 CC that shares the HW resource with CCs associated with another SIM2, the LTE transmission on the SIM1 CC might be suspended for performing activities at CCs associated with SIM2, such as receiving paging to keep UE in standby state. The time when the HW resource of a CC is occupied by a CC associated with another SIM is called “other-SIM-occupancy”. LTE data transmission in uplink and downlink will be suspended during other-SIM-occupancy. For a CC suffering other-SIM-occupancy, the ongoing LTE service on the CC will be affected. The performance of service including MO/MT call, high-speed data transmission, VoLTE, MBMS, and so on might degrade. The degradation range of performance depends on the frequency and duration of other-SIM-occupancy, i.e., how frequently other-SIM-occupancy is presented and how long each other-SIM-occupancy takes.
Typically, eNB is not aware that the phenomenon of other-SIM-occupancy results from UE's intention of MSMS. If other-SIM-occupancy takes place too frequently or keeps up for a long time, a sensitive eNB might think the UE is under severe channel condition. In this case, eNB might perform several mechanism such as lower down the resource for UE, adjust the transmit power and timing of UE, or take other actions that are harmful to UE. This problem may become more serious because more and more smart handheld devices (e.g. smart phone) will be equipped with multiple radio transceivers and possibly support multiple SIM cards with shared RF resources.

SUMMARY

A method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation is proposed. A UE performs CC selection from the multiple CCs associated with a first SIM to suffer from other-SIM-occupancy to minimize potential service degradation. In a first option, the UE selects one or more CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. In a second option, the UE schedules other-SIM-occupancy on more than one CCs of the first SIM to reduce the frequency and duration of the other-SIM-occupancy affected to each chosen CC of the first SIM.
In a first embodiment, a UE establishes a data connection under carrier aggregation in a mobile communications network. The UE is equipped with a first subscriber identity module (SIM) card and a second SIM card. The UE performs ongoing data communication over multiple component carriers (CCs) associated with the first SIM using a set of RF hardware resources. The UE selects a CC having the lowest priority based on a list of factors. The UE monitors incoming activities from the second SIM card over the selected CC with a predefined frequency and a predefined duration using the same set of RF hardware resources.
In a second embodiment, a UE establishes a data connection under carrier aggregation in a mobile communications network. The UE is equipped with a first subscriber identity module (SIM) card and a second SIM card. The UE performs ongoing data communication over multiple component carriers (CCs) associated with the first SIM using a set of RF hardware resources. The UE selects multiple CCs in accordance with a predetermined rule. The UE monitors incoming activities from the second SIM card over the multiple CCs, each CC monitors with a predefined frequency and a predefined duration using the same set of RF hardware resources.
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

FIG. 1 illustrates a user equipment (UE) having dual SIM dual standby (DSDS) or multiple SIM multiple standby (MSMS) feature under carrier aggregation in accordance with one novel aspect.

FIG. 2 is a simplified block diagram of a UE having DSDS feature under carrier aggregation in accordance with one novel aspect.

FIG. 3 illustrates an example of different options of a DSDS UE under carrier aggregation to minimize service degradation caused by other-SIM-occupancy.

FIG. 4 illustrates one embodiment of a DSDS UE under carrier aggregation prioritizing each of the component carriers of one SIM for suffering other-SIM-occupancy.

FIG. 5 illustrates another embodiment of a DSDS UE under carrier aggregation distributing multiple component carriers associated with one SIM for suffering other-SIM-occupancy.

FIG. 6 is a flow chart of one method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation in accordance with one novel aspect.

FIG. 7 is a flow chart of another method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation in accordance with one novel aspect.

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 a user equipment (UE) 101 having dual SIM dual standby (DSDS) or multiple SIM multiple standby (MSMS) feature under carrier aggregation (CA) in a mobile communication system 100 in accordance with one novel aspect. Mobile communication system 100 comprises UE 101 and a first network # 1 and a second network # 2. UE 101 supports DSDS feature such that multiple SIM cards can be used to access multiple networks, e.g., SIM1 is used to access network # 1 and SIM2 is used to access network # 2. In the example of FIG. 1, UE 101 is a Single Talk UE with DSDS feature, where two baseband modules share the same RF module. Single Talk device has low cost and no RF coexistence interference. However, Single Talk requires complex implementation to support Dual-Standby. Single Talk UE only supports one voice call, and requires gap to monitor paging signals. In the example of FIG. 1, UE 101 also supports carrier aggregation, where multiple component carriers (CCs), e.g., CC# 1 and CC# 2, are aggregated and jointly used for transmission to/from a single device.
As illustrated in FIG. 1, UE 101 establishes an active data connection under carrier aggregation with Network # 1 registered by SIM1. UE 101 transmits and/or receives ongoing data traffic over multiple component carriers CC# 1 and CC# 2 of the data connection. In addition, UE 101 also monitors paging signals or system information over Network # 2 registered by SIM2 over a specific component carrier. UE 101 applies the same HW resource (i.e., RF transceiver and BB/DSP) to the multiple CCs associated with different SIMs. This creates several problems. Network # 1 does not know UE 101 needs to monitor the paging or system information over Network # 2. The eNodeB radio resource control (e.g., link adaptation) algorithms in Network # 1 may be sensitive to the unexpected gaps and take proactive actions.
The time when the HW resource of a CC is occupied by a CC associated with another SIM is called “other-SIM-occupancy”. LTE data transmission in uplink and downlink will be suspended during other-SIM-occupancy. For a CC suffering other-SIM-occupancy, the ongoing LTE service on the CC will be affected. The performance of service including MO/MT call, high-speed data transmission, VoLTE, MBMS, and so on might degrade. The degradation range of performance depends on the frequency and duration of other-SIM-occupancy, i.e., how frequently other-SIM-occupancy is presented and how long each other-SIM-occupancy takes. Typically, eNB is not aware that the phenomenon of other-SIM-occupancy results from UE's intention of MSMS. If other-SIM-occupancy takes place too frequently or keeps up for a long time, a sensitive eNB might think the UE is under severe channel condition. In this case, eNB might perform several mechanism such as lower down the resource for UE, adjust the transmit power and timing of UE, or take other actions that are harmful to UE.
In one novel aspect, UE 101 performs CC selection from the multiple CCs associated with SIM1 to suffer from other-SIM-occupancy to minimize potential service degradation. In a first option, UE 101 selects one or more SIM1 CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. In a second option, UE 101 schedules other-SIM-occupancy on more than one SIM1 CCs to reduce the frequency and duration of the other-SIM-occupancy affected to each chosen SIM1 CC.
FIG. 2 is a simplified block diagram of a UE 201 having DSDS feature under carrier aggregation in accordance with one novel aspect. UE 201 comprises two RF transceivers and BB/ DSP modules 207 and 208 and a duplexer/switch 209 coupled with multiple antennas 210, receives RF signals from antenna 210, converts them to baseband signals, and sends them to processor 202. RF and BB/DSP modules also convert received baseband signals from processor 202, convert them to RF signals, and send out to antenna 210 via duplexer/switch 209. Processor 202 processes the received baseband signals and invokes different functional modules to perform features in the UE. Memory 203 stores program instructions and data 204 to control the operations of the UE. UE 201 comprises two SIM cards, SIM1 and SIM2. UE 201 supports carrier aggregation, where CC# 1 and CC# 2 associated with SIM1 are coupled to their corresponding RF and BB/DSP modules respectively in active state. UE 201 also supports DSDS feature, where an RF and BB/DSP module might be shared with both SIM1 and SIM2 to keep SIM2 in standby state while SIM1 is in active state.
FIG. 2 further illustrates different functional modules in the UE that carry out embodiments of the current invention. The functional modules comprises circuits that may be implemented and configured by hardware, firmware, software, and any combination thereof. For example, UE 201 comprises a RRC configuration module 211 manages radio resource control (RRC) layer configuration and RRC connection establishment, a carrier aggregation module 212 manages carrier aggregation functionalities for both PCC and SCCs including SCC addition and deletion, and a CC selector 213 that prioritizes multiple CCs under carrier aggregation and selects one or more CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. Furthermore, the CC selector may schedule other-SIM-occupancy on more than one CCs to reduce the frequency and duration of the other-SIM-occupancy affected to each chosen CC.
FIG. 3 illustrates an example of different options of a DSDS UE under carrier aggregation to minimize service degradation caused by other-SIM-occupancy. In step 311, UE 301 establishes data connection under carrier aggregation with a first network # 1 through a first SIM1. In step 312, UE 301 starts ongoing data transmission with network # 1 over multiple CCs through SIM1. In a first option, in step 321, UE 301 determines one or more CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. For example, CC# 1 is determined to suffer less harm from other-SIM-occupancy. In step 322, UE 301 receives paging from a second network # 2 over the determined CC# 1. In step 323, UE 301 continues to receive paging from network # 2 over CC# 1. Later on, the CC configuration under CA may have changed, or other network conditions may have changed. Additional CCs may have been added, or some CCs may have been deleted. In step 331, UE 301 detects such change and re-determines one or more CCs that are relatively harmless from other-SIM-occupancy to share HW resource with CCs associated with other SIMs. For example, CC# 2 is now determined to suffer less harm from other-SIM-occupancy. In step 332, UE 301 receives paging from a second network # 2 over the determined CC# 2. In step 333, UE 301 continues to receive paging from network # 2 over CC# 2.
In an alternative embodiment, in a second option, in step 341, UE 301 determines more than one CCs to be scheduled for other-SIM-occupancy, to reduce the frequency and duration of the other-SIM-occupancy affected to each chosen CC. For example, both CC# 1 and CC# 2 are selected based on a predetermined rule. In step 342, UE 301 receives paging from a second network # 2 over the determined CC# 1. In step 343, UE 301 continues to receive paging from network # 2 over CC# 2. Note that the two options can be combined together. For example, if there are total four CCs, then the UE can select two of the lower priority CCs and schedule other-SIM-occupancy on both lower priority CCs.
FIG. 4 illustrates one embodiment of a DSDS UE under carrier aggregation prioritizing each of the component carriers of one SIM for suffering other-SIM-occupancy. In the embodiment of FIG. 4, each of the component carriers are assigned to a priority according to a list of factors. The list of factors include (but are not limited to): ongoing or potential service on that CC; the UE capability on that CC; the bandwidth; duplex support; TDD configuration; the allocated resource; whether the CC is primary or not; whether the CC is associated with master eNB or not; and so on. Typically, a CC that has ongoing MO/MT call, high-speed data transmission, VoLTE, MBMS has higher priority, a CC has more capability has higher priority, a CC has higher bandwidth has higher priority, a CC has duplex support (both downlink and uplink) has higher priority, a CC with certain TDD configuration has higher priority, a CC with SPS resource has higher priority, a primary CC has higher priority than a secondary CC, and a CC associated with a master eNB has higher priority than a CC associated with a secondary eNB. Generally, CCs with the lowest priority should be considered first to suffer other-SIM-occupancy.
FIG. 4 depicts two examples on how to prioritizing each CC for other-SIM-occupancy purpose. In a first example depicted by table 410, the priority assignment on each CC associated with SIM1 is based on carrier aggregation. CC# 1 is the primary CC, with BW=20 MHz, support FDD mode and DL/UL full duplex. CC# 1 is also allocated with SPS resource and has ongoing VoLTE service. CC# 2 is a secondary CC, with BW=20 MHz, support FDD mode and DL/UL full duplex. CC# 2 has ongoing MBMS service. CC# 3 is a secondary CC, with BW=10 MHz, support FDD mode and DL/UL full duplex. CC# 4 is a secondary CC, with BW=10 MHz, support FDD mode and DL only. As a result, CC# 1 to CC# 4 are assigned from higher priority to lower priority respectively. Because CC# 4 has the lowest priority among all CCs, the UE will use CC# 4 to perform activities associated with other SIMs.
In a second example depicted by table 420, the priority assignment on each CC associated with SIM1 is based on dual connectivity. CC# 1 is the primary cell (PCELL) associated with a master eNB. CC# 2 is the primary secondary cell (PSCELL) associated with a secondary eNB. CC# 3 is a secondary cell (SCELL) associated with the master eNB. CC# 4 is a secondary cell (SCELL) associated with the secondary eNB. As a result, CC# 1 to CC# 4 are assigned from higher priority to lower priority respectively. Because CC# 4 has the lowest priority among all CCs, the UE will use CC# 4 to perform activities associated with other SIMs to minimize performance degradation.
FIG. 5 illustrates another embodiment of a DSDS UE under carrier aggregation distributing multiple component carriers associated with one SIM for suffering other-SIM-occupancy. In the embodiment of FIG. 5, if a UE has multiple SIM1 CCs to choose from, then the UE schedules other-SIM-occupancy on more than one SIM1 CCs to reduce the frequency and duration of the other-SIM-occupancy impact on each chosen CC. For example, during certain scheduling period, SIM1 CC#i may be scheduled to monitor paging information from SIM2, as depicted by box 510. In a first example, SIM1 CC#i and SIM1 CC#j are both scheduled to monitor paging information from SIM2, as depicted by box 520. Under this example, the frequency of other-SIM-occupancy is reduced by half, while the duration of each other-SIM-occupancy remains the same. In a second example, SIM1 CC#i and SIM1 CC#j are both scheduled to monitor paging information from SIM2, as depicted by box 530. Under this example, the duration of other-SIM-occupancy is reduced by half, while the frequency of other-SIM-occupancy remains the same. When multiple CCs are selected, round robin is one way to schedule other-SIM-occupancy. By distributing other-SIM-occupancy over multiple CCs, the impact on each CC is reduced and the overall performance degradation is reduced.
FIG. 6 is a flow chart of one method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation in accordance with one novel aspect. In step 601, a UE establishes a data connection under carrier aggregation in a mobile communications network. The UE is equipped with a first subscriber identity module (SIM) card and a second SIM card. In step 602, the UE performs ongoing data communication over multiple component carriers (CCs) associated with the first SIM using a set of RF hardware resources. In step 603, the UE selects a CC having the lowest priority based on a list of factors. In step 604, the UE monitors incoming activities from the second SIM card over the selected CC with a predefined frequency and a predefined duration.
FIG. 7 is a flow chart of another method of minimizing service degradation caused by other-SIM-occupancy of a DSDS or MSMS UE under carrier aggregation in accordance with one novel aspect. In step 701, a UE establishes a data connection under carrier aggregation in a mobile communications network. The UE is equipped with a first subscriber identity module (SIM) card and a second SIM card. In step 702, the UE performs ongoing data communication over multiple component carriers (CCs) associated with the first SIM using a set of RF hardware resources. In step 703, the UE selects multiple CCs in accordance with a predetermined rule. In step 704, the UE monitors incoming activities from the second SIM card over the multiple CCs, each CC monitors with a predefined frequency and a predefined duration.
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

1. A method, comprising:

establishing a data connection under carrier aggregation by a user equipment (UE) in a mobile communication network, wherein the UE is equipped with the first Subscriber Identity Module (SIM) card and a second SIM card;

performing ongoing data communication over multiple component carriers (CCs) associated with the first SIM card using a set of radio frequency hardware resources;

selecting a component carrier with the lowest priority based on a list of factors; and

monitoring incoming activities from the second SIM card over the selected CC with a predefined frequency and a predefined duration using the same set of radio frequency hardware resources.

2. The method of claim 1, wherein a primary CC has a higher priority than a secondary CC.

3. The method of claim 1, wherein a CC associated with a master base station has a higher priority than a CC associated with a secondary base station.

4. The method of claim 1, wherein a CC has an ongoing service has higher priority than a CC has no ongoing service.

5. The method of claim 1, wherein the list of factors for selecting a CC comprises at least one of UE capability, a bandwidth, a duplex mode, a time division duplex (TDD) configuration, and allocated resource.

6. The method of claim 1, wherein two CCs are selected for monitoring the incoming activities from the second SIM card with a round robin fashion.

7. The method of claim 6, wherein each CC monitors the incoming activities from the second SIM card with a reduced frequency or a reduced duration.

8. A method, comprising:

selecting multiple CCs in accordance with a predetermined rule; and

monitoring incoming activities from the second SIM card over the multiple selected CCs, wherein each CC monitors with a predefined frequency and a predefined duration using the same set of radio frequency hardware resources.

9. The method of claim 8, wherein the multiple CCs are selected to monitor the incoming activities based on a round robin fashion.

10. The method of claim 8, wherein if more CCs are selected, then each CC monitors the incoming activities with a reduced frequency or with a reduced duration.

11. A user equipment (UE), comprising:

a first Subscriber Identity Module (SIM) card;

a second Subscriber Identity Module (SIM) card;

a radio resource control (RRC) module that establishes a data connection under carrier aggregation in a mobile communication network, wherein the UE performs ongoing data communication over multiple component carriers (CCs) associated with the first SIM card;

a CC selector that selects a component carrier in accordance with a predetermined rule; and

a radio signal transceiver that monitors incoming activities from the second SIM card over the selected CC with a predefined frequency and a predefined duration.

12. The UE of claim 11, wherein the predetermined rule is for assigning priorities to each CC based on a list of factors.

13. The UE of claim 12, wherein a primary CC has a higher priority than a secondary CC.

14. The UE of claim 12, wherein a CC associated with a master base station has a higher priority than a CC associated with a secondary base station.

15. The UE of claim 12, wherein a CC has an ongoing service has higher priority than a CC has no ongoing service.

16. The UE of claim 12, wherein the list of factors for selecting a CC comprises at least one of UE capability, a bandwidth, a duplex mode, a time division duplex (TDD) configuration, and allocated resource.

17. The UE of claim 11, wherein two CCs are selected for monitoring the incoming activities from the second SIM card with a round robin fashion.

18. The UE of claim 17, wherein each CC monitors the incoming activities from the second SIM card with a reduced frequency or a reduced duration.

19. The UE of claim 11, wherein the predetermined rule is to select multiple CCs to monitor the incoming activities based on a round robin fashion.

20. The UE of claim 19, wherein if more CCs are selected, then each CC monitors the incoming activities with a reduced frequency or with a reduced duration.