US20140112170A1

US20140112170A1 - Broadcast of information to assist system selection by user equipments

Info

Publication number: US20140112170A1
Application number: US13/785,887
Authority: US
Inventors: Yan Zhou; Jay Kumar Sundararajan; Amaud Meylan; Peerapol Tinnakornsrisuphap; Mehmet Yavuz
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2012-10-22
Filing date: 2013-03-05
Publication date: 2014-04-24
Also published as: US20140113590A1; US9226306B2; WO2014066181A2; CN104737586A; CN104737588A; JP2015536604A; JP5992630B2; TW201419894A; JP6339086B2; CN104770008A; US20140113631A1; KR102129642B1; US9232531B2; KR20150080530A; US9185715B2; CN104737587A; EP2910055B1; TWI520636B; EP2910053A1; WO2014066406A1

Abstract

Techniques for supporting system selection by user equipments (UEs) are disclosed. In one design, a UE may receive an indication that a first wireless system supports system selection by UEs. The UE may be within the coverage of a plurality of wireless systems, which may include the first wireless system. The UE may receive system selection information from at least one of the plurality of wireless systems. The system selection information may convey system loading, UE performance, system recommendation, etc. The UE may determine performance metrics for the plurality of wireless systems based on the system selection information. The UE may then select one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

Description

The present application claims priority to provisional U.S. Application Ser. No. 61/716,999 [Docket No. 122870P1], entitled “METHOD AND APPARATUS FOR SUPPORTING WIRELESS COMMUNICATION VIA A SMALL CELL,” filed Oct. 22, 2012, and incorporated herein by reference in its entirety.

BACKGROUND

I. Field
The present disclosure relates generally to communication, and more specifically to techniques for supporting wireless communication.
II. Background
Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless system may include one or more base stations that can support communication for one or more user equipments (UEs). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.
Multiple wireless systems utilizing different radio technologies may be deployed in a given geographic area. Any number of UEs may be located with the geographic area, and each wireless system may serve any number of UEs. It may be desirable to efficiently serve the UEs.

SUMMARY

Techniques for supporting system selection by UEs are disclosed herein. The techniques may be used for system selection for a plurality of wireless systems that may be deployed in any manner. For example, the techniques may be used for system selection in a small cell. A small cell may include an access point for a wireless local area network (WLAN) system and a femto cell for a cellular system. A wireless system in the small cell may support system selection by UEs and may broadcast system selection information to assist the UEs perform system selection.
In one design, a UE may receive an indication that a first wireless system supports system selection by UEs. The UE may be within the coverage of a plurality of wireless systems, which may include the first wireless system. The UE may determine performance metrics for the plurality of wireless systems. The UE may then select one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs. In one design, the UE may receive system selection information from at least one of the plurality of wireless systems, e.g., after receiving the indication that the first wireless system supports system selection by UEs. The system selection information may include any pertinent information to enable UEs to more intelligently select suitable wireless systems to serve the UEs. For example, the system selection information may convey system loading, UE performance, system recommendation, etc. The UE may determine the performance metrics for the plurality of wireless systems based on the system selection information. The UE may then select the one wireless system based on the performance metrics for the plurality of wireless systems.
In another design, a UE may send an indication that the UE supports system selection. The UE may also send information indicative of a wireless system selected by the UE from among a plurality of wireless systems. The UE may receive system selection information from at least one of the plurality of wireless systems and may select the wireless system based on the system selection information. The UE may receive a decision on whether the UE is admitted to the wireless system selected by the UE.
Various aspects and features of the disclosure are described in further detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary system deployment.

FIG. 2 shows a call flow for performing system selection by a UE.

FIG. 3 shows a process for performing system selection.

FIG. 4 shows a process for supporting system selection.

FIG. 5 shows another process for performing system selection.

FIG. 6 shows another process for supporting system selection.

FIG. 7 shows a block diagram of a network entity and a UE.

FIG. 8 shows a block diagram of a small cell and a UE.

DETAILED DESCRIPTION

The techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other wireless systems. The terms “system” and “network” are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA), Time Division Synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 includes IS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi and Wi-Fi Direct), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A), in both frequency division duplexing (FDD) and time division duplexing (TDD), are recent releases of UMTS that use E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, GSM, UMTS, LTE and LTE-A are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the wireless systems and radio technologies mentioned above as well as other wireless systems and radio technologies.
FIG. 1 shows an exemplary system deployment 100 in which various aspects of the present disclosure may be implemented. A small cell 120 may support communication for a small geographic area such as a home, an apartment, an office, a shop, etc. Small cell 120 may include an access point (AP) 122 supporting communication via a first radio technology and a femto cell 124 supporting communication via a second radio technology. Access point 122 may be part of a wireless local area network (WLAN) system providing WiFi service, and femto cell 124 may be part of a cellular system providing cellular service. A WLAN system is a wireless system supporting communication for a small geographic area, e.g., a home, an office, etc. A cellular system is a wireless system supporting communication for a large geographic area, e.g., a city, a state, a country, etc. Small cell 120 may thus support communication for multiple co-existence wireless systems, which are wireless systems with overlapping coverage and under the control of a common network entity. A network entity may be any entity that is not a UE and may also be referred to as a wireless node, etc.
Access point 122 may support a radio technology such as WiFi, Hiperlan, or some other WLAN radio technology. Access point 122 may support communication for a basic service set (BSS), which includes a set of stations that can communicate with each other. The BSS may also be referred to as a WLAN system.
Femto cell 124 may support a radio technology such as LTE, WCDMA, CDMA 1X, GSM, etc. Femto cell 124 may also be referred to as a home base station (HBS), a home access point (HAP), a home Node B (HNB), a home evolved Node B (HeNB), etc. Femto cell 124 may be configured to provide restricted access for a group of UEs, which may belong in a closed subscriber group (CSG). Femto cell 124 may allow a network operator to extend the coverage of a cellular system, to increase capacity, and/or to obtain other advantages. Femto cell 124 may be considered as part of the cellular system and may communicate with other network entities in the cellular system. Femto cell 124 may operate as described in 3GPP TR 25.820, entitled “3G Home NodeB Study Item Technical Report,” which is publicly available. Femto cell 124 may also operate as described in documents for other radio technologies. Femto cell 124 may include a radio network controller (RNC), which may perform some functions normally performed by an RNC in a cellular system.
Access point 122 and femto cell 124 may be coupled to a router 126, which may be coupled to the Internet 148 or some other data network. Router 126 may route traffic data between access point 122 and femto cell 124 and other entities. Access point 122 and femto cell 124 may further be coupled to a small cell controller 140, which may perform coordination and control functions for these entities. Small cell controller 140 may include various modules to perform coordination and control functions, such as an system selection manager 142 that can support system selection by UEs. Small cell controller 140 may communicate with entities in a core network 150, which may include various network entities supporting communication and other services for UEs.
In an exemplary design, small cell 120 may be a physical hardware module or unit (e.g., a commercially available product), which may be purchased by a user and installed in a home, an apartment, etc. The hardware module for small cell 120 may include a first module (e.g., an integrated circuit (IC) chip or a circuit board) for access point 122, a second module for femto cell 124, a third module for router 126, and a fourth module for small cell controller 140. The fourth module for small cell controller 140 may include a memory storing various software modules, one of which may be switching manager 142. In general, small cell 120 may include any number of hardware modules. Each hardware module may perform any set of functions and may support access point 122, or femto cell 124, or router 126, or small cell controller 140, or a combination thereof. The functions of each of access point 122, femto cell 124, router 126, and small cell controller 140 may be implemented in software and/or hardware on one or more hardware modules of small cell 120.
In general, a small cell may support any number of wireless systems and any radio technology. A small cell may also support communication for a coverage area of any size. The plurality of wireless systems of a small cell may have (i) the same or different transmit power levels and (ii) the same or different coverage areas. A small cell may be deployed (i) indoors and/or outdoors and (ii) by a user or a network operator. A small cell may be coupled to a public backhaul (e.g., the Internet) and/or a private/dedicated backhaul of a network operator. A small cell may include a macro cell and/or may have characteristics of a macro cell. A macro cell may be characterized by a larger coverage area, a dedicated backhaul, outdoors deployment by a network operator, etc.
A base station 132 may support communication for a relatively large geographic area, e.g., up to 10 kilometer (Km) in radius. A coverage area of base station 132 and/or a base station subsystem serving this coverage area may be referred to as a macro cell. Small cell 120 may be within the coverage of base station 132 and/or other neighboring base stations for macro cells. Base station 132 may be part of a cellular system 130, which may include other base stations not shown in FIG. 1 for simplicity. Cellular system 130 may support the same radio technology as femto cell 124 or a different radio technology. Base station 132 may couple to a system controller 134, which may provide coordination and control for base station 132 and other base stations. System controller 134 may further couple to core network 150.
UEs 110 to 116 may be dispersed throughout the coverage area of small cell 120, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station (STA), etc. A UE may be a cellular phone, a smartphone, a tablet, a wireless communication device, a personal digital assistant (PDA), a wireless modem, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a netbook, a smartbook, etc. A UE may be able to communicate with access point 122 and/or femto cell 124 in small cell 120. A UE may also be able to communicate with base station 132 in cellular system 130. A UE may be referred to as a station (e.g., when communicating with access point 122), a user, etc.
As shown in FIG. 1, small cell 120 may include co-located access point 122 providing WLAN service and femto cell 124 providing cellular service. Any number of UEs (i.e., stations or users) may be located within the coverage of small cell 120. Each UE may support only WLAN service, or only cellular service, or both WLAN and cellular services. Any number of UEs in small cell 120 may be active at any given moment. Each UE may also have certain capabilities with respect to the WLAN system and the cellular system in small cell 120. The active UEs may have different capabilities and/or data requirements. The active UEs may also observe different channel conditions for access point 122 and femto cell 124.
The WLAN system and the cellular system in small cell 120 may each serve any number of UEs. Any number of UEs may be within the coverage of each wireless system in small cell 120. Each UE may have certain data requirements, which may be dependent on active applications running in the UE.
In an aspect of the present disclosure, a wireless system may support system selection by UEs and may broadcast pertinent information to assist the UEs perform system selection. System selection refers to selection of a suitable wireless system to serve a UE. Supporting system selection by UEs may include (i) broadcasting information for use by UEs to compare performance of different wireless systems and select suitable wireless systems and (ii) deferring system selection decisions to UEs and honoring selections of wireless systems made by the UEs. Information broadcast by a wireless system to assist UEs perform system selection may be referred to as system selection information (as used in much of the description herein), system information, broadcast information, cell broadcast information, etc. System selection information broadcast by a wireless system may enable UEs to more intelligently select suitable wireless systems to serve these UEs. This manner of system selection may provide better performance than selecting a wireless system based on a fixed/predetermined order, e.g., selecting a wireless system that is available and is at the top or nearest to the top of the fixed order.
As shown in FIG. 1, small cell 120 may support WLAN services and cellular services via co-located access point 122 and femto cell 124 within small cell 120. UEs capable of performing system selection (which may be referred to as system selection-capable UEs) may be located within the coverage of small cell 120. Small cell 120 may broadcast information to assist these UEs perform system selection. The system selection information transmitted by a given wireless system may indicate the current operating conditions of the wireless system, the current operating conditions of one or more other wireless systems, etc.
In general, system selection information may be broadcast over only the WLAN system, or only the cellular system, or both the WLAN and cellular systems in small cell 120. In particular, system selection information may be broadcast by access point 122 in the WLAN system and/or by femto cell 124 in the cellular system in small cell 120. The system selection information may comprise different types of information for different wireless systems. The system selection information may also be sent in different manners in different wireless systems. For example, the system selection information may be carried in information elements (IEs), which may be sent in system information blocks (SIBs) of a third generation (3G)/fourth generation (4G) cellular system or in beacon frames of a WLAN system.
Various types of information may be broadcast in system selection information to assist UEs perform system selection. In one design, one or more of the following information may be broadcast in the system selection information:

- 1. Identifiers (IDs) of co-located femto cells and/or access points in wireless systems in the small cell,
- 2. Indication of support for UEs capable of performing system selection,
- 3. Indication of whether selection of a particular wireless system (e.g., WLAN system) is recommended,
- 4. Timer for UEs to read system selection information,
- 5. System load information for each wireless system in the small cell,
- 6. UE performance information for each wireless system in the small cell,
- 7. System load information for external wireless system outside of the small cell,
- 8. UE performance information for external wireless system, and
- 9. Other information

The system selection information may include cell IDs of femto cells in the cellular system and/or BSS IDs of access points in the WLAN system in the small cell. The ID information may enable system selection-capable UEs to identify co-located cells and access points in different wireless systems. For example, the ID information may enable the UEs to recognize femto cells and access points that are part of a small cell and/or share the same backhaul when making system selection decisions.
The system selection information may include an indicator of the small cell's capability to support system selection-capable UEs. For example, an indicator may be set to a first value (e.g., ‘1’) to indicate the small cell supporting system selection-capable UEs and broadcasting system selection information to aid system selection by UEs. The indicator may be set to a second value (e.g., ‘0’), or may be omitted, to indicate the small cell does not support system selection-capable UEs. The indicator may be used for various purposes. For example, the indicator may be transmitted by the small cell to encourage system selection-capable UEs to detect and read the system selection information.
The system recommendation information may indicate whether a particular wireless system is recommended. In one design, the system recommendation information may comprise an indicator (e.g., a bit) for each wireless system in the small cell. The indicator for a given wireless system X may be set to (i) a first value (e.g., ‘1’) to indicate that selection of wireless system X is recommended or (ii) a second value (e.g., ‘0’) to indicate that selection of wireless system X is not recommended. For example, the system recommendation information for the WLAN system in the small cell may comprise a WLAN access bit. This WLAN access bit may be set to (i) a first value (e.g., ‘1’) to indicate accessing the WLAN system is recommended or (ii) a second value (e.g., ‘0’) to indicate accessing the WLAN system not recommended. The timer may indicate how often the UEs should read the WLAN access bit in order to obtain up-to-date WLAN recommendation information. For example, a timer value of Y may mean that the WLAN access bit will be set to the same value for at least Y seconds, so that the UEs do not need to read the WLAN access bit within this time period.
The system load information for each wireless system may convey the load observe by the wireless system. The system load information for each wireless system may comprise various types of information. In one design, the system load information for each wireless system may include the average number of active UEs on the downlink and/or uplink, the average number of available channel elements for the downlink and/or uplink, the average amount of available resources for the downlink and/or uplink, etc.
The system load information for the cellular system in the small cell may be dependent on the radio technology supported by the cellular system. The cellular system may support LTE, WCDMA, etc. The system load information for LTE may include the percentage of resource blocks used for the downlink and/or uplink, the total number of available resource blocks per subframe for the downlink and/or uplink, etc. The system load information for WCDMA may include the average number of orthogonal codes available for the downlink and/or uplink, the maximum allowed transmit power for the downlink, the percentage of available received signal strength indicator (RSSI) for the uplink, the maximum allowed RSSI for the uplink, etc. A WCDMA system may support High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), etc. System load information for HSDPA may include the average number of orthogonal codes available for HSDPA, the percentage of occupied transmission time intervals (TTIs), the percentage of available downlink transmit power for HSDPA, the maximum allowed downlink transmit power for HSDPA, etc. The system load information for HSUPA may include the percentage of available uplink RSSI for HSUPA, the maximum allowed uplink RSSI for HSUPA, etc. The system load information for each wireless system may also comprise other information, which may be dependent on the radio technology utilized by the wireless system.
UE performance information for each wireless system may convey the average or expected performance of UEs served by the wireless system. The UE performance information may comprise various types of information. In one design, the UE performance information for each wireless system may include an average data rate of existing UEs, an average throughput of existing UEs, an average packet error rate (PER) of existing UEs, an average packet drop rate of existing UEs, an average packet delay of existing UEs, etc. Different performance metrics may be defined for different types of UE performance information. For example, performance metrics may be defined for throughput, PER, etc.
In one design, the WLAN system and/or the cellular system in the small cell may broadcast system load information and/or UE performance information for one or more macro cells. The macro cells may be neighbor cells of the small cell. The system load information for the macro cells may comprise any of the system load information described above and/or other information. The UE performance information for the macro cells may comprise any of the UE performance information described above and/or other information.
A UE may perform various tasks in response to receiving an indication of a wireless system supporting system selection by UEs. In a first design, the UE may locate and read system selection information (which may be sent via cell broadcast information) and may use the system selection information to perform system selection. For example, a cell may indicate the availability of different performance metrics for each supported wireless system in a system-specific field, e.g., of beacons transmitted in the WLAN system. The availability of each performance metric may be indicated by a bit in a bitmap or via some other mechanism. In a second design, the UE may request a cell to send system selection information if this information is not broadcast by the cell. For example, the UE may send a request for UE throughput on a cellular system if the UE determines that the cell has this information available (e.g., as determined via the action described above). In a third design, the UE may send information about itself to a wireless system. For example, the UE may send its UE IDs on different wireless systems to enable the wireless system to better identify the UE. The UE may also perform other tasks in response to receiving an indication of a wireless system supporting system selection by UEs.
A UE may perform various tasks in response to not receiving an indication of a wireless system supporting system selection by UEs. In one design, the UE may search for other wireless systems or cells supporting system selection by UEs and may try to access such a wireless system if found.
In one design, a UE may send information to the small cell to convey the UE's capability to perform system selection. This information may comprise an indicator, which may be sent via a Radio Resource Control (RRC) connection request to the cellular system or via an association request to the WLAN system. The small cell may use the information regarding UE system selection capability for various purposes. In one design, the small cell may use the information regarding UE system selection capability for system admission and/or load balancing. For example, if the WLAN system and/or the cellular system in the small cell is loaded, then the small cell may admit only UEs that do not support system selection since these UEs may be unable to select another wireless system that is not loaded or is less loaded. The small cell may also influence system selection-capable UEs to select a wireless system that is not loaded or is less loaded by broadcasting appropriate system selection information to these UEs.
In one design, a UE may determine performance metrics for a plurality of wireless systems based on system selection information received from one or more wireless systems. A performance metric for a given wireless system X may be indicative of measured or expected performance of wireless system X. A performance metric for wireless system X may indicate expected performance for the UE if wireless system X is selected for the UE. A performance metric for wireless system X may relate to over-the-air load of wireless system X, backhaul usage of wireless system X, signal strength at wireless system X, etc. A performance metric for wireless system X may be determined based on information (e.g., system load, backhaul usage, etc.) included in system selection information broadcast by wireless system X or another wireless system. Performance metrics for a plurality of wireless systems may be used by the UE to select a suitable wireless system, e.g., select the wireless system with the best performance metric.
FIG. 2 shows an exemplary call flow 200 for performing system selection. Access point 122 may periodically determine its operating conditions and may generate or obtain system selection information for the WLAN system (step 212). Access point 122 may broadcast the system selection information for the WLAN system (step 216). Similarly, femto cell 124 may periodically determine its operating conditions and may generate or obtain system selection information for the cellular system (step 214). Femto cell 124 may broadcast the system selection information for the cellular system (step 218).
UE 114 may be powered on or may enter the coverage of small cell 120. UE 114 may be capable of performing system selection and may receive system selection information broadcast by access point 122 in the WLAN system (step 216). Alternatively or additionally, UE 114 may receive system selection information broadcast by femto cell 124 in the cellular system (step 218). The system selection information from the WLAN system and/or the cellular system may include an indication of support of system selection by UEs.
UE 114 may determine performance metrics for a plurality of wireless systems based on the system selection information received from the WLAN system and/or the system selection information received from the cellular system (step 220). The performance metric(s) for each wireless system may be indicative of the current operating conditions of the wireless system, or the expected performance of UE 114 if the wireless system is selected to serve UE 114, etc. The current operating conditions of the wireless system may include the loading of the wireless system, the available resources in the wireless system, the ability of the wireless system to serve UE 114, etc. UE 114 may determine one or more performance metrics for the WLAN system and one or more performance metrics for the cellular system in small cell 120. UE 114 may also determine one or more performance metrics for cellular system 130 external to small cell 120.
UE 114 may select a wireless system from among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication of support of system selection by UEs (step 222). UE 114 may then attempt to access the selected wireless system (step 224). For example, UE 114 may transmit a probe request to access point 122 if the WLAN system is selected. Alternatively, UE 114 may transmit a random access request to femto cell 124 if the cellular system is selected.
FIG. 3 shows a design of a process 300 for performing system selection. Process 300 may be performed by a UE (as described below) or by some other entity. The UE may receive an indication that a first wireless system supports system selection by UEs (block 312). The UE may be within the coverage of a plurality of wireless systems, which may include the first wireless system. The UE may determine performance metrics for the plurality of wireless systems (block 314). The UE may then select one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs (block 316).
The plurality of wireless systems may include a WLAN system, a cellular system, some other wireless system, or a combination thereof. In one design, the plurality of wireless systems may be part of a small cell. In other designs, the plurality of wireless systems may include wireless systems deployed in any manner.
In one design, the UE may receive IDs of the plurality of wireless systems from at least one of the plurality of wireless systems, e.g., after receiving the indication that the first wireless system supports system selection by UEs. The UE may determine that the plurality of wireless systems are part of a small cell based on the IDs of the plurality of wireless systems. The UE may send an ID of the wireless system selected by the UE to the first wireless system.
In one design, the UE may receive system selection information from at least one of the plurality of wireless systems, e.g., after receiving the indication that the first wireless system supports system selection by UEs. In one design, the first wireless system may broadcast the system selection information to UEs. In another design, the UE may send a request for system selection information to the first wireless system after receiving the indication that the first wireless system supports system selection by UEs. The UE may then receive the system selection information, which may be sent by the first wireless system in response to the request from the UE. For both designs, the UE may select the one wireless system based further on the system selection information.
In one design, the system selection information may convey loading at the plurality of wireless systems. The performance metrics for the plurality of wireless systems may be determined based on the loading at the plurality of wireless systems. In another design, the system selection information may convey performance of UEs served by at least one of the plurality of wireless systems. The performance metrics for the plurality of wireless systems may be determined based on the performance of the UEs. In yet another design, the system selection information may indicate whether one or more of the plurality of wireless systems are recommended. The UE may select the one wireless system based further on recommendation from the system selection information. In yet another design, the system selection information may indicate a time period for which the system selection information is valid. The UE may use the system selection information during the time period and may receive updated system selection information after the time period.
In one design, the UE may send information related to the UE to the first wireless system after receiving the indication that the first wireless system supports system selection by UEs. The information related to the UE may include UE IDs of the UE for the plurality of wireless systems and/or other information.
In one design, the UE may determine performance metrics for the plurality of wireless systems, which may include at least one wireless system in a small cell and at least one wireless system external to the small cell. The UE may receive system selection information conveying loading, user performance, and/or other information for the at least one wireless system external to the small cell. The system selection information may be broadcast by at least one wireless system in the small cell and may comprise information for the at least one wireless system external to the small cell.
FIG. 4 shows a design of a process 400 for supporting system selection. Process 400 may be performed by a network entity (as described below) or by some other entity. The network entity may be small cell controller 140, access point 122, or femto cell 122 in FIG. 1. The network entity may also be an entity that is not part of a small cell. The network entity may send an indication that a first wireless system supports system selection by UEs (block 412). The network entity may receive, from a UE, selection of one wireless system among a plurality of wireless systems including the first wireless system (block 414). The one wireless system may be selected by the UE based on performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.
In one design, IDs of the plurality of wireless systems may be sent from at least one of the plurality of wireless systems. The IDs may be used by UEs to determine that the plurality of wireless systems are part of a small cell and/or for other purposes.
In one design, system selection information for at least one of the plurality of wireless systems may be sent. For example, the system selection information may be broadcast by one or more wireless systems (e.g., in a small cell) to UEs. Alternatively, a request for system selection information may be received from the UE, and the system selection information may be sent to the UE in response to the request. The UE may send the request for system selection information after receiving the indication that the first wireless system supports system selection by UEs. The system selection information may convey loading at at least one of the plurality of wireless systems, or performance of UEs served by at least one of the plurality of wireless systems, or whether one or more of the plurality of wireless systems are recommended, or a time period for which the system selection information is valid, or some other information, or a combination thereof. The system selection information may also convey loading, or UE performance, or some other information, or a combination thereof, for at least one wireless system external to a small cell. The one wireless system may be selected by the UE based further on the system selection information.
The network entity may receive information related to the UE. The information may comprise UE IDs of the UE for the plurality of wireless systems and/or other information. The information may be sent by the UE to the first wireless system after the UE receives the indication that the first wireless system supports system selection by UEs.
FIG. 5 shows a design of a process 500 for performing system selection. Process 500 may be performed by a UE (as described below) or by some other entity. The UE may send an indication that the UE supports system selection (block 512). The UE may send information indicative of a wireless system selected by the UE from among a plurality of wireless systems (block 514). The UE may receive a decision on whether the UE is admitted to the wireless system selected by the UE (block 516).
In one design, the UE may receive system selection information from at least one of the plurality of wireless systems. The UE may determine performance metrics for the plurality of wireless systems based on the system selection information. The UE may select the wireless system from among the plurality of wireless systems based on the system selection information, e.g., based on the performance metrics for the plurality of wireless systems.
FIG. 6 shows a design of a process 600 for supporting system selection. Process 600 may be performed by a network entity (e.g., small cell controller 140, access point 122, or femto cell 122 in FIG. 1) or by some other entity. The network entity may receive, from a UE, an indication that the UE supports system selection (block 612). The network entity may receive information indicative of a wireless system selected by the UE from among a plurality of wireless systems (block 614). The plurality of wireless systems may be supported by a small cell and/or may include other wireless systems. The network entity may determine whether to admit the UE to the wireless system selected by the UE based on the indication that the UE supports system selection (block 616). The network entity may send a decision on whether the UE is admitted to the wireless system selected by the UE (block 618).
In one design, system selection information may be sent by at least one of the plurality of wireless systems. The wireless system may be selected by the UE based on the system selection information.
In one design, the network entity may defer system selection to the UE in response to receiving the indication that the UE supports system selection. The network entity may admit the UE to the wireless system selected by the UE in response to receiving the indication that the UE supports system selection.
FIG. 7 shows a block diagram of a design of a network entity 710 and a UE 750. Network entity 710 may support system selection by UEs and may correspond to small cell controller 140, access point 122, or femto cell 124 in FIG. 1 or some other network entity. UE 750 may correspond to any of UEs 110 to 116 in FIG. 1.
At network entity 710, a module 712 may determine or gather system selection information, which may comprise any of the information described above. The system selection information may be for one or more wireless systems in small cell 120 and possibly one or more wireless systems external to small cell 120. A module 714 may send an indication that a wireless system supports system selection by UEs as well as the system selection information. A module 720 may receive indication of wireless systems selected by UEs, e.g., based on the system selection information sent by network entity 710. A module 718 may determine whether to admit UEs to the wireless systems selected by these UEs or to deny admission. Module 718 may make this determination for each UE based on performance metrics (e.g., system loading) of the selected wireless systems, capabilities of the UEs (e.g., whether the UEs support system selection), etc. A module 724 may support communication with UEs and/or other network entities. A transmitter 716 may generate and send signals comprising control information such as system selection decisions for UEs. A receiver 722 may receive and process signals sent by UEs and/or other entities. The various modules within network entity 710 may operate as described above. A controller/processor 726 may direct the operation of various modules within network entity 710. A memory 728 may store data and program codes for network entity 710.
At UE 750, a module 754 may receive indications of whether wireless systems support system selection by UEs and system selection information. A module 756 may determine performance metrics for available wireless systems based on the system selection information and/or other information. A module 760 may select a wireless system based on the performance metrics for different wireless systems. A module 762 may support communication with base stations and/or other network entities. A receiver 752 may receive and process signals sent by base stations and/or other entities. A transmitter 758 may generate and send signals comprising information being sent by UE 750. The various modules within UE 750 may operate as described above. A controller/processor 766 may direct the operation of various modules within base station 110 x. A memory 768 may store data and program codes for UE 750.
FIG. 8 shows a block diagram of a small cell 800 and a UE 850. UE 850 may correspond to any of UEs 110 to 116 in FIG. 1. Small cell 800 may be one design of small cell 120 in FIG. 1 and may include a base station 810 and a small cell controller 890. Small cell controller 890 may correspond to small cell controller 140 in FIG. 1. Base station 810 may correspond to access point 122 or femto cell 124 in FIG. 1. Base station 810 may be equipped with T antennas 834 a through 834 t, and UE 850 may be equipped with R antennas 852 a through 852 r, where in general T≧1 and R≧1.
At base station 810, a transmit processor 820 may receive data from a data source 812 and control information (e.g., system selection information, indication of support for system selection by UEs, etc.) from a controller/processor 840. Processor 820 may process (e.g., encode and modulate) the data and control information to obtain data symbols and control symbols, respectively. Processor 820 may also generate reference symbols for synchronization signals, reference signals, etc. A transmit (TX) multiple-input multiple-output (MIMO) processor 830 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 832 a through 832 t. Each modulator 832 may process a respective output symbol stream (e.g., for OFDM, SC-FDMA, CDMA, etc.) to obtain an output sample stream. Each modulator 832 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 832 a through 832 t may be transmitted via T antennas 834 a through 834 t, respectively.
At UE 850, antennas 852 a through 852 r may receive the downlink signals from base station 810 and other base stations. Antennas 852 a through 852 r may provide received signals to demodulators (DEMODs) 854 a through 854 r, respectively. Each demodulator 854 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 854 may further process the input samples (e.g., for SC-FDMA, OFDMA, CDMA, etc.) to obtain received symbols. A MIMO detector 856 may obtain received symbols from all R demodulators 854 a through 854 r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 858 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 850 to a data sink 860, and provide decoded control information to a controller/processor 880. A channel processor 884 at UE 850 may receive downlink signals from base station 810 and/or other base stations. Processor 880 may determine channel quality for base station 810 and/or other base stations based on the received downlink signals.
On the uplink, at UE 850, a transmit processor 864 may receive data from a data source 862 and control information (e.g., indication of a selected wireless system) from controller/processor 880. Processor 864 may process (e.g., encode and modulate) the data and control information to obtain data symbols and control symbols, respectively. Processor 864 may also generate reference symbols for reference signals. The symbols from transmit processor 864 may be precoded by a TX MIMO processor 866 if applicable, further processed by modulators 854 a through 854 r (e.g., for OFDMA, SC-FDMA, CDMA, etc.), and transmitted to base station 810 and other base stations. At base station 810, the uplink signals from UE 850 and other UEs may be received by antennas 834, processed by demodulators 832, detected by a MIMO detector 836 if applicable, and further processed by a receive processor 838 to obtain decoded data and control information sent by UE 850 and other UEs. Processor 838 may provide the decoded data to a data sink 839 and the decoded control information to controller/processor 840.
Controllers/ processors 840 and 880 may direct the operation at base station 810 and UE 850, respectively. Processor 840 and/or other processors and modules at base station 810 may perform or direct process 400 in FIG. 4, process 600 in FIG. 6, and/or other processes for the techniques described herein. Processor 880 and/or other processors and modules at UE 850 may perform or direct process 200 in FIG. 2, process 300 in FIG. 3, process 500 in FIG. 5, and/or other processes for the techniques described herein. Memories 842 and 882 may store data and program codes for base station 810 and UE 850, respectively. A communication (Comm) unit 844 may enable base station 810 to communicate with other network entities. A scheduler 846 may schedule UEs for communication and may assign resources to the scheduled UEs.
Within small cell controller 890, a controller/processor 892 may perform various functions to support communication for UEs. Processor 892 and/or other processors and modules at small cell controller 890 may perform or direct process 400 in FIG. 4, process 600 in FIG. 6, and/or other processes for the techniques described herein. A memory 894 may store program codes and data for small cell controller 890. A storage unit 894 may store information for UEs and/or wireless systems within the control of small cell controller 890. A communication unit 896 may enable small cell controller 890 to communicate with other network entities.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

What is claimed is:

1. A method for wireless communication, comprising:

receiving, by a user equipment (UE), an indication that a first wireless system supports system selection by UEs;

determining performance metrics for a plurality of wireless systems by the UE, the plurality of wireless systems including the first wireless system; and

selecting, by the UE, one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

2. The method of claim 1, further comprising:

receiving system selection information from at least one of the plurality of wireless systems, wherein the one wireless system is selected by the UE based further on the system selection information.

3. The method of claim 2, wherein the system selection information conveys loading at at least one of the plurality of wireless systems, and wherein the performance metrics for the plurality of wireless systems are determined based on the loading at the plurality of wireless systems.

4. The method of claim 2, wherein the system selection information conveys performance of UEs served by at least one of the plurality of wireless systems, and wherein the performance metrics for the plurality of wireless systems are determined based on the performance of the UEs.

5. The method of claim 2, wherein the system selection information indicates whether one or more of the plurality of wireless systems are recommended, and wherein the wireless system is selected by the UE based further on recommendation from the system selection information.

6. The method of claim 2, wherein the system selection information indicates a time period for which the system selection information is valid.

7. The method of claim 1, further comprising:

sending, from the UE to the first wireless system, a request for system selection information after receiving the indication that the first wireless system supports system selection by UEs, and

receiving the system selection information sent by the first wireless system in response to the request from by the UE.

8. The method of claim 1, further comprising:

receiving identities (IDs) of the plurality of wireless systems from at least one of the plurality of wireless systems after receiving the indication that the first wireless system supports system selection by UEs; and

determining that the plurality of wireless systems are part of a small cell based on the IDs of the plurality of wireless systems.

9. The method of claim 1, further comprising:

sending information related to the UE to the first wireless system after receiving the indication that the first wireless system supports system selection by UEs.

10. The method of claim 10, wherein the information related to the UE includes UE identities (IDs) of the UE for the plurality of wireless systems.

11. The method of claim 1, further comprising:

sending an identity (ID) of the one wireless system selected by the UE to the first wireless system after receiving the indication that the first wireless system supports system selection by UEs.

12. The method of claim 1, wherein the plurality of wireless systems include a wireless local area network (WLAN) system and a cellular system.

13. The method of claim 1, wherein the plurality of wireless systems include at least one wireless system in a small cell and at least one wireless system external to the small cell.

14. The method of claim 13, further comprising:

receiving system selection information conveying loading, or user performance, or both for the at least one wireless system external to the small cell.

15. The method of claim 13, further comprising:

receiving system selection information broadcast by one or more of the at least one wireless system in the small cell, the system selection information comprising information for the at least one wireless system external to the small cell.

16. An apparatus for wireless communication, comprising:

at least one processor configured to:

receive, by a user equipment (UE), an indication that a first wireless system supports system selection by UEs;

determine performance metrics for a plurality of wireless systems by the UE, the plurality of wireless systems including the first wireless system; and

select, by the UE, one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

17. The apparatus of claim 16, wherein the at least one processor is further configured to:

receive system selection information from at least one of the plurality of wireless systems; and

select the one wireless system based further on the system selection information.

18. The apparatus of claim 16, wherein the at least one processor is further configured to:

sending, from the UE to the first wireless system, a request for system selection information after receiving the indication that the first wireless system supports system selection by UEs; and

receive the system selection information sent by the first wireless system in response to the request from by the UE.

19. An apparatus for wireless communication, comprising:

means for receiving, by a user equipment (UE), an indication that a first wireless system supports system selection by UEs;

means for determining performance metrics for a plurality of wireless systems by the UE, the plurality of wireless systems including the first wireless system; and

means for selecting, by the UE, one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

20. The apparatus of claim 19, further comprising:

means for receiving system selection information from at least one of the plurality of wireless systems, wherein the one wireless system is selected by the UE based further on the system selection information.

21. The apparatus of claim 19, further comprising:

means for sending, from the UE to the first wireless system, a request for system selection information after receiving the indication that the first wireless system supports system selection by UEs; and

means for receiving the system selection information sent by the first wireless system in response to the request from by the UE.

22. A computer program product, comprising:

a non-transitory computer-readable medium comprising:

code for causing at least one processor to receive, by a user equipment (UE), an indication that a first wireless system supports system selection by UEs;

code for causing the at least one processor to determine performance metrics for a plurality of wireless systems by the UE, the plurality of wireless systems including the first wireless system; and

code for causing the at least one processor to select, by the UE, one wireless system among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

23. A method for wireless communication, comprising:

sending an indication that a first wireless system supports system selection by user equipments (UEs); and

receiving, from a UE, selection of one wireless system among a plurality of wireless systems including the first wireless system, the one wireless system being selected by the UE based on performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

24. The method of claim 23, further comprising:

sending system selection information for at least one of the plurality of wireless systems, wherein the one wireless system is selected by the UE based further on the system selection information.

25. The method of claim 24, wherein the system selection information conveys at least one of loading at at least one of the plurality of wireless systems, performance of UEs served by at least one of the plurality of wireless systems, whether one or more of the plurality of wireless systems are recommended, or a time period for which the system selection information is valid.

26. The method of claim 24, wherein system selection information conveys loading, or UE performance, or both of at least one wireless system of a small cell and at least one wireless system external to the small cell.

27. The method of claim 23, further comprising:

receiving, from the UE, a request for system selection information, the request being sent by the UE after receiving the indication that the first wireless system supports system selection by UEs, and

sending the system selection information to the UE in response to the request.

28. The method of claim 23, further comprising:

sending identities (IDs) of the plurality of wireless systems from at least one of the plurality of wireless systems, the IDs being used by UEs to determine that the plurality of wireless systems are part of a small cell.

29. The method of claim 23, further comprising:

receiving information related to the UE, the information being sent by the UE to the first wireless system after the UE receives the indication that the first wireless system supports system selection by UEs.

30. An apparatus for wireless communication, comprising:

at least one processor configured to:

send an indication that a first wireless system supports system selection by user equipments (UEs); and

receive, from a UE, selection of one wireless system among a plurality of wireless systems including the first wireless system, the one wireless system being selected by the UE based on performance metrics for the plurality of wireless systems and the indication that the first wireless system supports system selection by UEs.

31. The apparatus of claim 30, wherein the at least one processor is further configured to send system selection information for at least one of the plurality of wireless systems, and wherein the one wireless system is selected by the UE based further on the system selection information.

32. The apparatus of claim 30, wherein the at least one processor is further configured to:

receive, from the UE, a request for system selection information, the request being sent by the UE after receiving the indication that the first wireless system supports system selection by UEs, and

send the system selection information to the UE in response to the request.

33. A method for wireless communication, comprising:

sending, from a user equipment (UE), an indication that the UE supports system selection;

sending information indicative of a wireless system selected by the UE from among a plurality of wireless systems; and

receiving a decision on whether the UE is admitted to the wireless system selected by the UE.

34. The method of claim 33, further comprising:

receiving system selection information from at least one of the plurality of wireless systems; and

selecting the wireless system from among the plurality of wireless systems based on the system selection information.

35. The method of claim 34, further comprising:

determining performance metrics for the plurality of wireless systems based on the system selection information; and

selecting the wireless system from among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems.

36. An apparatus for wireless communication, comprising:

at least one processor configured to:

send, from a user equipment (UE), an indication that the UE supports system selection;

send information indicative of a wireless system selected by the UE from among a plurality of wireless systems; and

receive a decision on whether the UE is admitted to the wireless system selected by the UE.

37. The apparatus of claim 36, wherein the at least one processor is further configured to:

select the wireless system from among the plurality of wireless systems based on the system selection information.

38. The apparatus of claim 37, wherein the at least one processor is further configured to:

determine performance metrics for the plurality of wireless systems based on the system selection information; and

select the wireless system from among the plurality of wireless systems based on the performance metrics for the plurality of wireless systems.

39. A method for wireless communication, comprising:

receiving, from a user equipment (UE), an indication that the UE supports system selection;

receiving information indicative of a wireless system selected by the UE from among a plurality of wireless systems; and

determining whether to admit the UE to the wireless system selected by the UE based on the indication that the UE supports system selection.

40. The method of claim 39, further comprising:

sending system selection information, wherein the wireless system is selected by the UE based further on the system selection information.

41. The method of claim 39, further comprising:

admitting the UE to the wireless system selected by the UE in response to receiving the indication that the UE supports system selection.

42. The method of claim 39, further comprising:

sending a decision on whether the UE is admitted to the wireless system selected by the UE.

43. An apparatus for wireless communication, comprising:

at least one processor configured to:

receive, from a user equipment (UE), an indication that the UE supports system selection;

receive information indicative of a wireless system selected by the UE from among a plurality of wireless systems; and

determine whether to admit the UE to the wireless system selected by the UE based on the indication that the UE supports system selection.

44. The apparatus of claim 43, wherein the at least one processor is further configured to send system selection information, and wherein the wireless system is selected by the UE based further on the system selection information.

45. The apparatus of claim 43, wherein the at least one processor is further configured to admit the UE to the wireless system selected by the UE in response to receiving the indication that the UE supports system selection.