Patent Description:
The subject matter disclosed herein relates generally to Carrier Aggregation (CA) between licensed and unlicensed frequency bands.

Carrier Aggregation is a means to bundle a number of wireless channels in order to achieve a larger aggregated bandwidth and hence a larger possible peak bitrate in cellular networks. Carrier Aggregation is defined as part of the LTE-Advanced standard in 3GPP Rel-<NUM> [www. org] as well as in the WiMAX (IEEE <NUM>) standard. Further related documents include <CIT>, and <NPL>.

Carrier Aggregation is not limited to channels / bands which are adjacent, but also inter-band Carrier Aggregation is supported.

Due to the expected massive growth of mobile broadband data, cellular operators currently look at alternative solutions to manage the cost of their networks.

In contrast to the initial years of WLAN and cellular networks, where both technologies co-existed without any interaction, the standardisation organisations have developed a number of enhancements to interconnect WLAN with cellular technologies. For example I-WLAN (Interworked-Wireless LAN) has been added by 3GPP in its Rel-<NUM> to provide access via WLAN and a gateway to the 3GPP system. As an enhancement to this connection between WLAN and 3GPP systems with the event of Evolved Packet System (EPS), the so-called "untrusted access" using PMIP/GTP (Proxy Mobile Internet Protocol / General Packet Radio Service (GPRS Tunnelling Protocol) or Proxy Mobile IPv6 (PMIPv6) via the S2b interface has been introduced. Even further interoperability between WLAN and Evolved Packet System (EPS) has been defined in 3GPP Rel-<NUM> with the work on "IP flow mobility", which allows concurrent operation of a single terminal using WLAN access on the one hand, while being connected via UMTS or LTE radio network on the other. Selective IP flow routing enables an improved user experience as depending on the Quality-of-Service (QoS) or operator requirements, Internet Protocol (IP) flows can be routed selectively on the one or the other radio access. Furthermore this feature package also allows seamless authentication and seamless mobility between cellular and WLAN radio networks.

However, there is still a separation in the Internet Protocol (IP) flows between the integration between WLAN access and UMTS/LTE.

The object of the present invention is to propose an improved manner of using an access point of a radio access network of a telecommunications network in order to enhance the usable bandwidth between the access point and a User Equipment, and especially to provide a method, a public land mobile network (PLMN), and a program for carrier aggregation between licensed and unlicensed bands.

The object of the present invention is achieved by a method according to claim <NUM>.

Thereby, it is advantageously possible to use the mobile communication technology not only in the respective standardized and licensed radio frequency bands of a provider or an operator of the telecommunications network but also to use that same mobile communication technology in a frequency range outside of the standardized and licensed radio frequency bands for that specific mobile communication technology. This means that an aggregation of a wireless link is proposed which uses licensed bands and an aggregation link which used an unlicensed band. For example, it is possible to use frequencies (as a second carrier frequency) of the ISM frequency band to establish a communication link according to the Long Term Evolution (LTE) or Long Term Evolution advanced (LTE advanced) communication technologies such that carrier aggregation is realized between.

In the context of the present invention, an antenna device comprises.

wherein the antenna element is used for transmitting electromagnetic RF signals that are provided by the baseband unit as electrical signals to the antenna element (transmission path), and wherein the antenna element is used for receiving electromagnetic RF signals that are received and processed by the baseband unit as electrical signals (reception path).

According to the present invention, the second carrier frequency is an unlicensed frequency, especially a frequency of the ISM-radio frequency band (Industrial Scientific and Medical radio frequency band).

Furthermore, according to the present invention, the first carrier frequency is a licensed frequency assigned to be used by the telecommunications network.

In the context of the present invention, the terms licensed frequency and licensed band refer to a frequency or frequency band which is for example defined for utilisation with UMTS/HSPA or LTE radio technology, defined in [3GPP TS <NUM> and 3GPP TS <NUM>] respectively.

Furthermore in the context of the present invention, the terms unlicensed frequency, unlicensed band or ISM-radio frequency band refer to the bands defined for Industry, Science and Medical application ("ISM bands") in which wireless technologies like Bluetooth or Wireless LAN (WLAN / WiFi) but also microwave ovens or the like are operated.

The carrier aggregation concept (CA) here is exemplarily described - but not limited to - using the 3GPP concept of LTE-Advanced carrier aggregation and the 3GPP notation. An overview of LTE-A carrier aggregation and the used terminology can be found in [3GPP TS <NUM>.

The key elements of the 3GPP Release <NUM> carrier aggregation is the usage of a so-called Primary Cell (PCell) which uses LTE radio technology and acts as a kind of anchor. It also acts as the control instance for the connection towards the UE using CA. For the aggregation of additional bandwidth the so-called additional Component Carrier (CC) on a Secondary Cell (SCell) is used. An aggregated communication connection consists of a single PCell plus at least a single SCell to combine the capabilities (bandwidth) of the PCell and the at least one SCell.

Carrier aggregation allows the expansion of effective bandwidth delivered to a user terminal through concurrent utilization of radio resources across multiple carriers. Multiple component carriers are aggregated to form a larger overall transmission bandwidth.

According to a further example not part of the present invention, an antenna device of the access point is used for transmitting radio frequency signals to the User Equipment and/or for receiving radio frequency signals from the User Equipment, wherein during a first time interval, the antenna device is used for transmitting and/or receiving radio frequency signals on the second carrier frequency and according to the standardized mobile communication technology, wherein during a second time interval, the antenna device is used for transmitting and/or receiving radio frequency signals according to a further mobile communication technology, and wherein the first time interval and the second time interval are alternating, wherein especially the further mobile communication technology is a technology according one of the IEEE-<NUM>-family of mobile communication standards.

Thereby, is particularly advantageous to be able to use the access point both for a transmission - using carrier aggregation - applying the mobile communication technology and (at other points in time or within other time slots of an alternating time slot scheme) applying the further mobile communication technology.

According to the present invention, it is particularly preferred to implement an alternating time slot scheme such that the first time interval and the second time interval occur or alternate within a predetermined time period of, e.g., <NUM> seconds, or <NUM> second or <NUM> milliseconds. It is also possible and preferred according to the present invention that within the predetermined time period, two first time intervals occur but only one second time interval or vice versa. Furthermore, other alternating time slot schemes can be applied such that - within the predetermined time period - a first number of first time intervals and a second number of second time intervals occur, the first number and the second number being integers starting at <NUM> (i.e. <NUM>, <NUM>, <NUM>, <NUM>, etc.).

It is furthermore preferred according to the present invention that the mobile communication technology is one out of the following:.

According to the present invention, it is furthermore preferred that the carrier aggregation is used to enhance the usable bandwidth in uplink direction from the User Equipment to the telecommunications network and/or wherein the carrier aggregation is used to enhance the usable bandwidth in downlink direction from the telecommunications network to the User Equipment.

Thereby, it is advantageously possible according to the present invention that the enhancement of usable bandwidth is not restricted to either an uplink or a downlink connection, but that also both in uplink and downlink direction, an inventive enhancement of the usable bandwidth is possible.

The present invention also relates to a system according to claim <NUM>.

According to the present invention, it is - also with regard to the inventive system - such:.

Furthermore, it is preferred - in a related example not part of the claimed invention - that an antenna device of the access point is used for transmitting radio frequency signals to the User Equipment and/or for receiving radio frequency signals from the User Equipment, wherein during a first time interval, the antenna device is used for transmitting and/or receiving radio frequency signals on the second carrier frequency and according to the standardized mobile communication technology, wherein during a second time interval, the antenna device is used for transmitting and/or receiving radio frequency signals according to a further mobile communication technology, and wherein the first time interval and the second time interval are alternating, wherein especially the further mobile communication technology is a technology according one of the IEEE-<NUM>-family of mobile communication standards.

The present invention also relates to an access point according to claim <NUM>.

Furthermore, it is preferred - in a related example not falling within the claimed invention - that an antenna device of the access point is used for transmitting radio frequency signals to the User Equipment and/or for receiving radio frequency signals from the User Equipment, wherein during a first time interval, the antenna device is used for transmitting and/or receiving radio frequency signals on the second carrier frequency and according to the standardized mobile communication technology, wherein during a second time interval, the antenna device is used for transmitting and/or receiving radio frequency signals according to a further mobile communication technology, and wherein the first time interval and the second time interval are alternating, wherein especially the further mobile communication technology is a technology according one of the IEEE-<NUM>-family of mobile communication standards.

Furthermore, the present invention relates to a User Equipment according to claim <NUM>.

It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described of illustrated herein.

In <FIG>, a representation of a communication situation using carrier aggregation is schematically represented. A User Equipment <NUM> is connected with a telecommunications network <NUM> via an radio access network <NUM> of the telecommunications network <NUM>. The telecommunications network <NUM> typically also comprises a core network <NUM> linked to the radio access network <NUM> via a communication link <NUM>. A radio frequency communication link, providing communication services to the User Equipment <NUM>, is maintained between an access point <NUM> of the radio access network <NUM> of the telecommunications network <NUM> on the one hand and the User Equipment <NUM> on the other hand. According to the present invention, a first communication carrier and a second communication carrier are aggregated according to a carrier aggregation scheme to provide an enhanced usable bandwidth between the User Equipment <NUM> and the access point <NUM>. The first communication carrier has a first carrier frequency <NUM> and the second communication carrier has a second carrier frequency <NUM>. It is to be understood in the context of the present invention that the terms "first carrier frequency <NUM>" and "second carrier frequency <NUM>" are also meant to designated a "first carrier frequency band <NUM>" and a "second carrier frequency band <NUM>" in case that such frequency bands are to be used according to the used mobile communication technology.

In the context of the present invention, the access point <NUM> is a device providing access to the telecommunications network <NUM> for the User Equipment <NUM>. Especially, such an access point <NUM> can be an eNodeB according to the Long Term Evolution (LTE) technology or a femto cell eNodeB or the like. Via the first communication carrier and first carrier frequency <NUM>, a PCell is realized or provided to the User Equipment <NUM>. Via the second communication carrier and second carrier frequency <NUM>, a SCell is realized or provided to the User Equipment <NUM>. According to the present invention, the access point <NUM> comprises either an antenna device for providing both the radio link or air interface for the first communication carrier, and the radio link or air interface for the second communication carrier. Alternatively, the access point <NUM> comprises the antenna device in the form of a first part (for providing the radio link or air interface for the first communication carrier) of the antenna device and a second part (for providing the radio link or air interface for the second communication carrier) of the antenna device, wherein such parts of the antenna device are, in the following, also called first antenna device and second antenna device respectively.

According to the example of <FIG>, the access point <NUM> comprises a first antenna device <NUM> for providing the radio link or air interface for the first communication carrier, and a second antenna device <NUM> for providing the radio link or air interface for the second communication carrier. The User Equipment <NUM> can comprise a third antenna device <NUM> for providing the radio link or air interface for the first communication carrier, and a fourth antenna device <NUM> for providing the radio link or air interface for the second communication carrier. Of course, it is to be understood that the "first antenna device", "second antenna device", "third antenna device" and/or "fourth antenna device" can comprise a multitude of antennas (or antenna elements) to realize MIMO (multiple input, multiple output) functionality.

It is to be understood that the antenna capabilities of the access point <NUM> and/or of the User Equipment <NUM> do not necessarily be split between two physically distinct antenna devices (first and second antenna device for the access point / third and fourth antenna device for the User Equipment), but it is possible to provide in the access point <NUM> or in the User Equipment <NUM> or in both an integrated antenna device such that both the first communication carrier and the second communication carrier are handled (i.e. the air interface provided) by the integrated antenna device. Furthermore one antenna at the access point <NUM> or the User Equipment <NUM> can also be understood as multiple antennas in case MIMO technologies are used (MIMO = Multiple Input Multiple Output antenna).

In <FIG>, the aggregation of resources on the MAC layer of the OSI model is schematically shown. The first carrier frequency <NUM> (or first communication carrier) provides a physical PCell (PCell PHY) communication link. The second carrier frequency <NUM> (or second communication carrier) provides a physical SCell (SCell PHY) communication link. On a MAC layer <NUM> (Media Access Control) of the OSI (Open System Interconnection) communication model, the carrier aggregation is realized by means of a Hybrid Automatic Repeat Request (HARQ) entity <NUM> related to the first communication carrier, a HARQ <NUM> related to the second communication carrier, and a multiplexing entity <NUM>.

Toward higher level layers of the OSI model, the further layers above the MAC layer <NUM>, namely the Radio Link Control (RLC) layer <NUM>, the Packet Data Convergence Protocol (PDCP) layer <NUM> and the Internet Protocol (IP) layer <NUM> are schematically shown in <FIG>.

In <FIG>, an example of time slot sharing between different mobile communication technologies is schematically shown for the example of using a communication ling according to the Long Term Evolution (LTE) communication technology and according to the WLAN communication technology. The first communication carrier on the first carrier frequency <NUM> (and hence the associated antenna device), providing the PCell functionality, works according to the Long Term Evolution (LTE) communication technology (of course, alternatively the use of another communication technology could implemented). The second communication carrier on the second carrier frequency <NUM> (and hence the associated antenna device), providing the SCell functionality, works.

Of the examples mentioned in the above paragraph, the present invention covers the case where both the PCell and Scell apply Long Term Evolution technology.

According to the present invention and in contrast to the state of the art, carrier aggregation is performed between a PCell using a licensed band and at least one SCell using an unlicensed band.

Alternatively, in an example not covered by the present invention, it is also possible to use an aggregation of a first technology operating in at least a single licensed band, a second technology operating in at least a single licensed band and either the first or the second technology operating in at least a first unlicensed band.

In order to efficiently bundle licensed and unlicensed bands it is proposed by the present invention that while a PCell is configured using LTE on licensed band, the unlicensed band also applies the same radio technology LTE as SCell.

Alternatively an example not covered by the present invention is proposed where - while a PCell is configured using LTE on licensed band - the unlicensed band applies a different cellular radio technology than LTE as SCell; so for example HSPA/HSPA+.

Alternatively another example not covered by the present invention is proposed where - while a PCell is configured using LTE on licensed band - the unlicensed band applies a different cellular radio technology than LTE as SCell; so for example WLAN.

This concept of using a SCell on unlicensed bands allows the opportunistic boosting and selective traffic flow control using the capacities of both accesses.

Due to the regulatory limitations in terms of maximum allowed transmission power (Tx power) in the unlicensed bands, which are typically lower than the allowed Tx Powers on licensed bands, this kind of opportunistic carrier aggregation is especially useful, when small cells are utilised. Depending on the national regulations, the maximum achievable range of a cells using unlicensed spectrum is limited to a couple of <NUM> (ETSI regulation for Europe) and about <NUM> for the North-American FCC regulation (exemplarily for the <NUM> ISM band).

The present invention also proposes to allow the control of resource allocation in the unlicensed band being controlled by the cellular technology using the PCell. any allocation of resources of the SCell (using the unlicensed band) is controlled by the PCell.

Traditional interworking between licensed technologies such as LTE and unlicensed technologies, such as WLAN, allow at best a selective routing of IP flows to a UE, including the control by the cellular operator as to which radio technology a particular IP flow is mapped. So particularly a single IP flow is already mapped to either the licensed or the unlicensed radio technology, but not to both. With other word one can say that the flows are controlled on IP level and not in the lower layers of the stack.

In contrast to the state of art, the present invention calls for carrier aggregation between licensed and unlicensed bands, where the aggregation of resources is done in the MAC layer, cf.

One embodiment of the present invention uses the additional component carrier in the unlicensed band for the same mode of operation as the component carrier in the licensed band. This is either the Frequency Division Duplexing (FDD) or the Time Division Duplexing (TDD) mode.

An alternative of the present invention uses the additional component carrier in the unlicensed band for a different mode of operation than the component carrier in the licensed band. the component carrier in the licensed band operates in the Frequency Division Duplexing (FDD) mode while the component carrier in the unlicensed band operates in the Time Division Duplexing (TDD) mode. Alternatively the component carrier in the licensed band operates in the Time Division Duplexing (TDD) mode while the component carrier in the unlicensed band operates in the Frequency Division Duplexing (FDD) mode.

A specific form of the mode of operation is the configuration, where the component carrier in the licensed band operates in the Frequency Division Duplexing (FDD) mode while the component carrier in the unlicensed band operates also in the Frequency Division Duplexing (FDD) mode, but does not provide an associated uplink operating in Frequency Division Duplexing (FDD) mode in the unlicensed band. this configuration allocates all or a large part of the unlicensed spectrum in downlink only to improve the downlink performance by using additional downlink spectrum, while the required uplink in Frequency Division Duplexing (FDD) mode of operation is associated solely or at least partly to the component carrier using the licensed band (i.e. using the first carrier frequency <NUM>).

Similarly the inverse configuration is possible, where the component carrier on the unlicensed band (i.e. the second carrier frequency <NUM>) only operates in uplink direction using Frequency Division Duplexing (FDD) mode, while the required downlink in Frequency Division Duplexing (FDD) mode of operation is associated solely or at least partly to the component carrier using the licensed band.

The invention also propose a method where parts of the radio modem typically operating in unlicensed band (e.g. the part of the communication device which provides for example WLAN connectivity) is dynamically reconfigured in order to operate in a mode typically used in licensed bands (e.g. LTE/LTE-A). By doing this, part of the available (radio) hardware can be used to aggregate available unlicensed bands (i.e. the second communication carrier) with licensed band (i.e. the first communication carrier) in a carrier aggregation mode of operation.

Therefore, the present application proposes the arrangement of a base station (or access point) providing simultaneous connectivity of a radio node (or User Equipment) using.

Claim 1:
A method for enhancing the usable bandwidth between on the one hand an access point (<NUM>) of a radio access network (<NUM>) of a telecommunications network (<NUM>), and on the other hand a User Equipment (<NUM>) of a subscriber of the telecommunications network (<NUM>), wherein the User Equipment (<NUM>) and the access point (<NUM>) mutually communicate based on a Long Term Evolution technology using carrier aggregation of at least a first communication carrier and a second communication carrier, wherein the first communication carrier has a first carrier frequency (<NUM>) and wherein the second communication carrier has a second carrier frequency (<NUM>), wherein the first carrier frequency (<NUM>) is a standardized and licensed frequency and related to the Long Term Evolution technology, and the second carrier frequency (<NUM>) is an unlicensed frequency, wherein a primary cell, PCell, is configured using the Long Term Evolution technology on the licensed frequency, wherein on the unlicensed frequency the Long Term Evolution technology is applied as a secondary cell, SCell.