HK1157565B - Timing of component carriers in multi-carrier wireless networks - Google Patents

Description

Timing of component carriers in a multi-carrier wireless network

Technical Field

The disclosed technology relates to the timing of component carriers used for communication between a user equipment and a base station in a wireless network.

Background

The evolution of cellular systems promises to increase effective data rates to 1Gb/s and higher in the future. Higher data rates generally require greater system bandwidth. For IMT (international mobile telecommunications) advanced (i.e. fourth generation mobile communication) systems, bandwidths of up to 100MHz are discussed. Unfortunately, radio spectrum is a limited resource, and finding a free 100MHz continuous spectrum is problematic since many operators and systems need to share the same radio resource.

One approach to address this problem is to aggregate multiple narrow bandwidths (or component carriers), which may be continuous or discontinuous to aggregate together to achieve a wide bandwidth, as illustrated in fig. 1. In the example of fig. 1, a 50MHz bandwidth spectrum is achieved by aggregating individual narrower bandwidth component carriers, which in this example are 20MHz, and 10MHz wide component carriers. One benefit of this solution is that it is possible to generate a sufficiently large bandwidth for supporting data rates up to and exceeding 1 Gb/s. Moreover, this solution also makes it possible to adapt the spectrum portion to various situations and geographical locations, thereby making this solution very flexible.

A direct evolution of current cellular systems supporting continuous and discontinuous spectrum, such as LTE (long term evolution), is to introduce multiple carriers. That is, for each spectrum "chunk (chunk)" representing a "legacy LTE" system carrier, it is possible to enable a "4G" user equipment to receive multiple LTE carriers of different bandwidths transmitted at different carrier frequencies.

While this approach appears straightforward, designing LTE-advanced capable user equipment is a burdensome task. The aggregated spectrum approach implies that the radio receiver architecture for user equipment will become more complex than that of user equipment capable of receiving only a small and continuous system bandwidth. The reason is that the front-end radio needs to be able to suppress blocking signals between "chunks" of spectrum. Different kinds of radio architectures can be used to handle this problem. However, they are generally accompanied by drawbacks in power consumption compared to standard continuous system bandwidth receivers.

Disclosure of Invention

An aspect of the present invention is to provide a mechanism for efficiently transmitting a large amount of DL (download) data from a base station to a user equipment in a multi-carrier environment that minimizes power consumption on the user equipment. In this regard, the base station has the capability to transmit signals (control and data) on multiple component carriers, and the user equipment has the capability to receive signals (control and data) on multiple component carriers. One or more of the plurality of carriers are used to carry control signals from the base station to the user equipment. That is, one or more carriers are anchor carriers for the user equipment. On the user equipment side, one or more receivers configured to receive signals on component carriers instead of anchor carriers may be placed in a power saving mode.

When it is decided that a large amount of DL data needs to be transmitted from the base station to the user equipment in a relatively short time, the base station divides the DL data into a plurality of data parts and transmits each data part through a separate component carrier. The data portions may be transmitted to overlap each other in time. That is, the data portions may be transmitted simultaneously.

To accomplish this task, the base station first notifies the user equipment that DL data will be transmitted over multiple component carriers. If any of the selected carriers is an anchor carrier for the user equipment, the data portion corresponding to the anchor carrier may be transmitted immediately because the user equipment has actively listened to on the carrier.

However, if any of the selected component carriers is not the anchor carrier, the base station waits for a predetermined delay after notifying the user equipment. In effect, a time offset is introduced between the selected anchor carrier and the non-anchor carrier. In a simple example when selecting one anchor carrier and one non-anchor carrier, the time offset between the two carriers may be about half a TTI (transmission time interval).

The predetermined delay provides the user equipment with sufficient time to prepare itself to receive DL data over the corresponding non-anchor carrier. For example, a user equipment may turn on, or otherwise activate, a fixed bandwidth receiver configured to listen on a corresponding non-anchor carrier. As another example, the user equipment may configure the adaptable bandwidth receiver to receive on the selected non-anchor carrier.

The base station may provide other information to the user equipment. For example, the base station may provide information about the RBs (resource blocks) of the selected component carrier assigned to carry DL data. Information regarding RBs of the non-anchor carriers may be provided through the anchor carrier or through the corresponding non-anchor carrier. Information on RBs may be provided on a PDCCH (physical downlink control channel) of an anchor carrier and/or a non-anchor carrier.

In other instances, it may be decided that the DL data will not be transmitted using the anchor carrier. That is, it may be decided that one or more non-anchor component carriers will be used. When this occurs, it is preferable that the base station waits for a predetermined delay after notifying the user equipment before transmitting DL data on the non-anchor component carrier. There are many reasons for using non-anchor component carriers. For example, the quality of the non-anchor carriers may be better than the anchor carriers.

One advantage of introducing time offsets on different component carriers is that an optimal trade-off between user equipment power consumption and DL data throughput can be achieved. Another advantage is that system reliability can be enhanced by allowing for non-anchor carrier transmissions.

Drawings

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

Fig. 1 illustrates an example of aggregation of multiple narrow bandwidth carriers into an aggregated wide bandwidth carrier;

fig. 2 illustrates an embodiment of a wireless network in which component carrier timing may be implemented;

fig. 3 illustrates an example timing offset between two component carriers carrying DL data;

fig. 4 illustrates an example method of determining whether DL data should be transmitted over multiple component carriers;

fig. 5 illustrates an example method of determining timing of transmissions on different component carriers;

fig. 6 illustrates an example method of informing a user equipment about component carrier resources assigned to transmit DL data;

fig. 7 illustrates an example method of transmitting DL data over an anchor carrier or a non-anchor carrier;

fig. 8 illustrates an example method of informing a user equipment about non-anchor component carrier resources assigned to transmit DL data;

fig. 9 illustrates an embodiment of a base station;

fig. 10 illustrates an example method of receiving DL data from the perspective of a user equipment; and

fig. 11 illustrates an embodiment of a user equipment.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular architecture, interfaces, techniques, etc., in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.

In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Moreover, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the art that the block diagrams herein can represent conceptual views of illustrative circuitry embodying the principles of the technology. Also, it will be appreciated that any flow charts, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

The functions of the various elements including functional blocks labeled or described as "processors" or "controllers" may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may include, without limitation, Digital Signal Processor (DSP) hardware, Read Only Memory (ROM) for storing software, Random Access Memory (RAM), and non-volatile storage.

In systems such as LTE, scalable carrier bandwidths of 5, 10, 15 and 20MHz are supported. To increase flexibility, component carriers with bandwidths less than 5MHz may be supported. The downlink transmission scheme may be based on OFDM (orthogonal frequency division multiplexing). In an OFDM system, the available component carrier bandwidth is divided into a number of sub-carriers that are orthogonal to each other. Each of these subcarriers is independently modulated by a low rate data stream. In LTE, the standard spacing between adjacent subcarriers is 15kHz, that is Δ f ═ 15 kHz. A subcarrier spacing of 7.5kHz at Δ f is also supported. Downlink access to user equipment may be provided by OFDMA (orthogonal frequency division multiple access), where different groups of subcarriers are assigned to different user equipment.

The user equipment is allocated data by RBs (resource blocks) defined in the frequency and time domains. For a standard subcarrier spacing of Δ f 15kHz, a physical RB contains 12 consecutive subcarriers in the frequency domain. In the time domain, a physical block contains 7 consecutive OFDM symbols of 94 total REs (resource elements), which is the number of symbols available in a slot (0.5ms duration). The resource block size is the same for all bandwidths, so the number of available physical resource blocks depends on the component carrier's bandwidth. Each user equipment may be allocated one or more resource blocks in each TTI (transmission time interval) of 1ms according to a required DL data rate.

In a wireless network, a base station can transmit signals (data and control) carried over multiple component carriers, and a user equipment can receive signals (data and control) carried over multiple component carriers, where each component carrier can have the characteristics described above. In a multi-carrier system such as LTE, the multiple component carriers need not be contiguous. That is, there may be at least one gap in the spectrum represented by the multiple carriers illustrated in fig. 1.

Fig. 2 illustrates an example embodiment of a wireless network 200 in which component carrier timing may be implemented. For simplicity of illustration, the network 200 in fig. 2 includes a base station 210 and a user equipment 220. Note that the concepts discussed can be extended to multiple base stations 210 and multiple user equipments 220. The arrowed lines of the bi-directional zigzag between the base station 210 and the user equipment 220 each represent a component carrier aggregating a wide bandwidth spectrum. In this particular example, there are three component carriers, one of which serves as an anchor carrier (solid line with arrows), and two of which are non-anchor carriers.

The anchor carrier carries control signals, such as L1/L2 control signals, from the base station 210 to the user equipment 220. The control signal informs the user equipment 220 about the specific downlink and uplink resources scheduled for the user equipment, such as resource block identities of the component carriers, modulation schemes to be used, user equipment transmit power levels, and so on.

In fig. 2, it is assumed that the user equipment 220 is equipped to receive signals carried over multiple component carriers. For example, the user equipment 220 may include at least three fixed bandwidth receivers, each configured to receive signals on one of three component carriers. Assuming that no data is transmitted between the base station 210 and the user equipment 220 on the non-anchor carrier, it is desirable to place the receiver corresponding to the non-anchor carrier in a power saving mode. The power saving mode includes turning off the receiver, placing the receiver in a periodic monitoring mode, and enabling a DRX (discontinuous reception) mode, etc.

In another example, the user equipment 220 may include one or more adaptable bandwidth receivers. An adaptable bandwidth receiver is a receiver whose frequency range can be dynamically adjusted as the need arises. In this example, placing the receiver in the power save mode may also include narrowing the frequency range of the adaptable receiver to exclude non-anchor carriers. By narrowing the frequency range, less power is consumed. Of course, the user equipment 220 may comprise a fixed and adaptable bandwidth receiver.

When it is decided that a large amount of DL (download) data will be transmitted from the base station 210 to the user equipment 220 in a relatively short time, that is, when it is decided that a large DL data transmission bandwidth is required, a plurality of carriers may be used for this purpose. For ease of illustration, fig. 3 illustrates a scenario in which DL data is divided into first and second data portions (for ease of illustration) that may be carried over first and second component carriers, respectively. In fig. 3, frames of component carriers f1 and f2 are illustrated. Component carrier f1 is assumed to be an anchor carrier and component carrier f2 is assumed to be a non-anchor carrier.

For purposes of illustration, assume that user device 220 is actively listening on carrier f1, but is not actively listening on carrier f 2. If the user equipment 220 contains multiple fixed bandwidth receivers, the receiver configured to listen to carrier f1 (the first receiver) may be active, while the receiver configured to listen to carrier f2 (the second receiver) may be in a power saving mode. If the user equipment 220 includes an adaptable bandwidth receiver, the frequency range of the adaptable receiver can be adjusted to actively listen to the carrier f1 and exclude the listening carrier f 2.

For LTE carriers, a TTI (transmission time interval) length of 1ms consists of two slots each 0.5ms long. Control signaling such as PDCCH (physical downlink control channel) and PHICH (physical HARQ indicator channel) is provided within the first three OFDM (orthogonal frequency division multiplexing) symbols. Typical PDCCH decoding time is about 100-. When large DL data is to be received, the user equipment 220 may turn on or activate the receiver for the second carrier. In the case of an adaptable bandwidth receiver, the frequency range of the receiver may be adjusted to include the second carrier.

Preferably, the base station 210 waits for a predetermined delay before transmitting the second data portion over the second carrier. In other words, a timing offset should be introduced between transmissions on the anchor carrier and the non-anchor carrier, as illustrated in fig. 3. In this particular example, the timing offset is up to half a TTI. However, this is not the only possibility. When the data portion is to be transmitted over a non-anchor carrier, it is only necessary that the predetermined delay be at least as long as the amount of time required for the user equipment 220 to prepare to receive signals on that non-anchor carrier.

Fig. 4 illustrates an example method M400 of determining whether DL data should be transmitted over multiple component carriers. The method M400 is from the perspective of the base station 210. In a410 of the method, the base station 210 establishes a connection with the user equipment 220 through one or more anchor carriers. In this approach, it is assumed that the first carrier is one of the anchor carriers.

At a420, the base station 210 makes a determination whether a wide DL data transmission bandwidth is required. That is, the base station 210 determines whether DL data destined for the user equipment 220 should be transmitted through the first carrier and additionally at least through the second carrier, which is a non-anchor carrier. If so, the base station 210 transmits a first data portion and a second data portion of the DL data over the first carrier and the second carrier, respectively, at A430. There is a predetermined delay between transmission over the first carrier and the second carrier. As explained above, the predetermined delay is an amount of time sufficient for the user equipment 220 to prepare to receive DL data over the second carrier. As seen in fig. 3, after a predetermined delay, the first data portion and the second data portion are transmitted simultaneously, which effectively increases the data transmission bandwidth.

Fig. 5 illustrates an example method of implementing a430 of fig. 4 for transmitting DL data over a first carrier and a second carrier. At a510, the base station 210 divides the DL data into a first data portion and a second data portion. Then, in a520, the base station 210 notifies the user equipment 220 of DL data transmission over the first carrier and the second carrier. At a530, the first data portion is transmitted over a first carrier, and at a540, the second data portion is transmitted over a second carrier.

At a530, the first data portion is transmitted immediately after the user equipment 220 is notified, i.e. the first data portion is transmitted without waiting. Since the first carrier is one of the anchor carriers for the user equipment 220, the user equipment 220 has actively listened to the signal on that carrier. Thus, no waiting is required.

In contrast, the second carrier is not one of the anchor carriers. Thus, it is possible that the user equipment 220 does not actively listen on the second carrier due to being in the power saving mode. Thus, at a540, a predetermined delay is waited before the base station 210 transmits the second data portion over the second carrier.

Returning to a520, the base station 210 may select which component carriers will be used to transmit DL data, including the first carrier and the second carrier. To prepare the user equipment 220, the base station informs the user equipment 220 of the selection of the carrier. In the notification, information regarding one or more resource blocks of a second carrier assigned to carry the second data portion may also be included.

Fig. 6 illustrates an example method of implementing a520, i.e., notifying the user device 220. In the method, at a610, the base station 210 provides information on the second carrier through the first carrier. Then, in a620, the base station also provides resource block information of the second carrier through the first carrier or the second carrier.

In one embodiment, information about the second carrier and the second RB (resource block) is provided over the first carrier. As one example, the base station 210 may reserve a portion of a PDSCH (physical downlink shared channel) of the first carrier to provide information. In one embodiment, the base station 210 provides the information through a PDCCH (physical downlink control channel) of the first carrier. In another embodiment, the identification of the second carrier is provided by the first carrier (e.g. in the PDSCH and PDCCH) and the information about the resource blocks of the second carrier is provided by the second carrier itself, e.g. by the PDCCH of the second carrier.

Referring back to fig. 4, at a420, the base station 210 may determine that a wide DL data transmission bandwidth is not required. That is, the base station 210 may determine that one of the first or second component carriers is sufficient for DL data transmission. When this occurs, the base station 210 transmits DL data over the first carrier or the second carrier at a 440. If it is decided to transmit DL data over the first carrier, the base station 210 may do so without waiting for any delay. If it is decided that the second carrier will be used, the base station 210 may wait before transmitting.

The base station 210 may decide to transmit DL data over the second (i.e., non-anchor) carrier instead of over the first (i.e., anchor) carrier, even if latency is involved. There are many reasons why this decision can be made. In general, if the non-anchor carrier is more suitable, i.e., the quality of the second carrier is better, it may be advantageous to use the second carrier because it is more reliable. As an example of the quality measurement, the CQI (channel quality indicator) of the second carrier may be higher than the CQI of the first carrier. Other examples of quality measurements may be based on signal-to-interference ratio (SIR) (higher better), Received Signal Reference Power (RSRP) (higher better), data transmission rate (higher better), error rate (lower better), repeat request rate (lower better), and so forth.

In addition to quality considerations, network system capabilities may also be a factor considered in the decision. In one example, the first carrier may be over-utilized with respect to the second carrier. Thus, a consideration for switching to the second carrier may be that the remaining data carrying capacity of the second carrier is greater than the remaining data carrying capacity of the first carrier by a predetermined amount.

Fig. 7 illustrates an example method of implementing a440 of fig. 4 for transmitting DL data over an anchor carrier (first carrier) or a non-anchor carrier (second carrier). At a710, the base station 210 decides whether the DL data should be transmitted using the second carrier instead of the first carrier based on the considerations discussed above. If it is decided not to use the second carrier, the base station 210 transmits the DL data without delay through the first carrier at a 720. If it is decided to use the second carrier, the base station 210 informs the user equipment 220 to transmit DL data over the second carrier, at a 730. Then, after waiting for a predetermined delay, the base station 210 transmits the DL data through the second carrier at a 740.

Fig. 8 illustrates an example method of implementing a730 of informing the user equipment 220 about transmitting DL data over the second carrier. At a810, the base station 210 informs the user equipment 220 about the second carrier over the first carrier. Then at a820, information about the resource blocks assigned to the second carrier carrying the DL data is provided over the first carrier (e.g. in the PDSCH or PDCCH) or the second carrier (e.g. in the PDCCH).

Fig. 9 illustrates an embodiment of the base station 210 depicted in fig. 2. The base station 210 comprises a processing unit 910, a monitoring unit 920 and a communication unit 930. The monitoring unit 910 is arranged to monitor the load on the component carriers used by the base station 210, for example. The communication unit 930 is arranged to communicate with the user equipment 220 in the network 200. The processing unit 910 is arranged to control the operation of the components of the base station 210 to perform the method as described above.

Fig. 10 illustrates an example method M1000 of receiving DL data from a base station 210 from the perspective of a user equipment 220. In a1010 of the method, the user equipment 220 establishes a connection with the base station 210 over one or more anchor carriers including the first carrier. At a1020, the user equipment 220 receives a notification from the base station 210 about a DL data transmission. At a1030, based on the notification, the user equipment 220 determines whether the base station will transmit DL data over the first carrier and additionally over the second (non-anchor) carrier. If the user equipment 220 makes such a determination, the user equipment 220 activates a receiver to receive a first data portion of the DL data over the first carrier and a second data portion over the second carrier at a 1040. At a1040, the user equipment 220 actively prepares the receiver so that it can prepare to receive signals on the second carrier after a predetermined delay.

If it is determined at a1030 that the DL data will not be carried over the plurality of component carriers, the user equipment 220 determines at a1050 whether the base station 210 will transmit the DL data over the first carrier or the second carrier. If it is determined that DL data will be received through the first carrier, the user equipment 220 receives data without delay at a 1070. However, if it is determined that DL data will be received over the second carrier, at a1060, the user equipment 220 actively prepares the receiver so that it is ready to receive DL data over the second carrier at or before the predetermined delay has elapsed since the notification was received.

Fig. 11 illustrates an embodiment of a user equipment 220. The user equipment 220 comprises a processing unit 1110 and a communication unit 1120. The communication unit 1120 is arranged to communicate with a base station 210 in the network 200. Communication unit 1120 may include any combination of fixed narrow bandwidth receivers and adaptable bandwidth receivers. If only fixed bandwidth receivers are considered, the communication unit 1230 preferably includes a plurality of receivers, each of which is configured to listen on one of the plurality of component carriers. If only adaptable bandwidth receivers are considered, one or more of these may be present. If combining is considered, there may be one or more fixed bandwidth receivers and one or more adaptable bandwidth receivers. The processing unit 1110 is arranged to control the operation of the components of the user equipment 220 to perform the method as described above.

While the above description contains many specifics, these should not be construed as limitations on the scope of the invention, but merely as exemplifications of some of the presently preferred embodiments thereof. Thus, it will be appreciated that the scope of the present invention fully encompasses other embodiments that may become obvious to those of ordinary skill in the art and that the scope of the present invention is not limited accordingly. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed thereby. Moreover, it is not necessary for a device or method to address each and every problem described herein or sought to be solved by the present technology to be encompassed thereby. Furthermore, no element, component, or method that is useful in the disclosure of the present invention is intended to be dedicated to the public.

Claims (22)

1. A method in a base station (210) of a wireless network (200) for transmitting download, DL, data to user equipments of the wireless network, the method comprising:

establishing (A410) a connection over one or more anchor carriers comprising a first carrier, wherein control signals are provided from the base station (210) to the user equipment (220) using the anchor carriers;

making a determination (a420) as to whether DL data destined to the user equipment (220) should additionally be transmitted over a second carrier; and

transmitting (A430) the DL data over the first and second carriers when it is determined that the second carrier should additionally be used,

wherein there is a predetermined delay between transmission over the first carrier and the second carrier, an

Wherein the act of transmitting (A430) the DL data over the first and second carriers comprises:

dividing (A510) the DL data into at least a first data portion and a second data portion;

informing (A520) the user equipment (220) of the DL data transmission over the first carrier and a second carrier, including providing (A610) an identification of the second carrier over the first carrier;

transmitting (A530) the first data portion over the first carrier; and

transmitting (A540) the second data portion over the second carrier after waiting the predetermined delay;

wherein the predetermined delay is an amount of time sufficient for the user equipment (220) to prepare to receive over the second carrier.

2. The method of claim 1, wherein the second carrier is not one of the anchor carriers.

3. The method of claim 1, wherein the act of notifying (a520) the user equipment (220) further comprises:

providing (A620) information on resource blocks, RBs, of the second carrier assigned to carry the DL data over the first carrier or the second carrier.

4. The method of claim 3, wherein the information about the RBs is provided on a Physical Downlink Shared Channel (PDSCH) or a Physical Downlink Control Channel (PDCCH) of the first carrier or on the PDCCH of the second carrier.

5. The method of claim 1: further comprising:

transmitting (A440) the DL data over the first carrier or a second carrier when it is determined that the second carrier should not be additionally used,

wherein the DL data is transmitted after the predetermined delay when the DL data is transmitted over the second carrier.

6. The method of claim 5, wherein in the act of transmitting (A440) the DL data over the first carrier or second carrier, it is determined that the DL data should be carried over the second carrier when any one or more of the following is true:

the channel quality of the second carrier is higher than the channel quality of the first carrier;

the signal-to-interference ratio, SIR, of the second carrier is higher than the SIR of the first carrier;

the RSRP of the second carrier is higher than the RSRP of the first carrier;

the data transmission rate of the second carrier is higher than the data transmission rate of the first carrier;

the error rate of the second carrier is lower than the error rate of the first carrier; and

the remaining data carrying capacity of the second carrier is greater than the remaining data carrying capacity of the first carrier.

7. A base station (210), comprising:

a communication unit (930) arranged to communicate with a user equipment (220); and

a processing unit (910) arranged to:

establishing a connection via the communication unit (930) over one or more anchor carriers comprising a first carrier, wherein control signals are provided from the base station (210) to the user equipment (220) using the anchor carrier;

making a determination as to whether download DL data intended for the user equipment (220) should additionally be transmitted over a second carrier; and

transmitting the DL data over the first carrier and the second carrier via the communication unit (930) when it is determined that the second carrier should be additionally used,

wherein there is a predetermined delay between transmission over the first carrier and the second carrier,

wherein the processing unit (910) is arranged to transmit the DL data over the first carrier and a second carrier by: dividing the DL data into at least a first data portion and a second data portion; and informing the user equipment (220), via the communication unit (930), of the DL data transmission over the first carrier and a second carrier, including providing an identification of the second carrier over the first carrier, and transmitting the first data portion over the first carrier and the second data portion over the second carrier; wherein the second data portion is transmitted over the second carrier after waiting a predetermined delay, an

Wherein the predetermined delay is an amount of time sufficient for the user equipment (220) to prepare to receive over the second carrier.

8. The base station (210) of claim 7 wherein the second carrier is not one of the anchor carriers.

9. The base station (210) according to claim 7 wherein the processing unit (910) is arranged to provide information on resource blocks, RBs, of the second carrier assigned to carry the DL data over the first carrier or second carrier.

10. The base station (210) according to claim 9 wherein the information on the RBs is provided on a physical downlink shared channel, PDSCH, or a physical downlink control channel, PDCCH, of the first carrier or on a PDCCH of the second carrier.

11. The base station (210) of claim 7, wherein the processing unit (910) is arranged to:

transmitting the DL data over the first carrier or a second carrier when it is determined that the second carrier should not be additionally used,

wherein the DL data is transmitted after the predetermined delay when the DL data is transmitted over the second carrier.

12. The base station (210) of claim 11, the processing unit (910) being arranged to: determining that the DL data should be carried over the second carrier when any one or more of:

the channel quality of the second carrier is higher than the channel quality of the first carrier;

the signal-to-interference ratio, SIR, of the second carrier is higher than the SIR of the first carrier;

the RSRP of the second carrier is higher than the RSRP of the first carrier;

the data transmission rate of the second carrier is higher than the data transmission rate of the first carrier;

the error rate of the second carrier is lower than the error rate of the first carrier; and

the remaining data carrying capacity of the second carrier is greater than the remaining data carrying capacity of the first carrier.

13. A method in a user equipment (220) of a wireless network (200) for receiving download, DL, data from a base station of the wireless network, the method comprising:

establishing (A1010) a connection over one or more anchor carriers comprising a first carrier, wherein the anchor carriers are used by the base station (210) to provide control signals to the user equipment (220);

receiving (A1020) a notification from the base station (210), the notification containing information about a second carrier, the information being carried over the first carrier;

making a determination (A1030) based on the notification whether the base station (210) will additionally use the second carrier to transmit the DL data; and

receiving (A1040) the DL data over the first and second carriers when it is determined that the base station (210) will additionally use the second carrier;

wherein a first data portion of the DL data is received over the first carrier and a second data portion of the DL data is received over the second carrier after a predetermined delay, an

Wherein the predetermined delay is an amount of time sufficient for the user equipment (220) to prepare to receive over the second carrier.

14. The method of claim 13: further comprising:

making a determination (A1050) whether the base station (210) will alternately transmit the DL data using the second carrier based on the notification;

receiving (A1060) the DL data over the second carrier after the predetermined delay when it is determined that the base station (210) will alternately use the second carrier; and

receiving (A1070) the DL data over the first carrier when it is determined that the base station (210) will not use the second carrier alternately.

15. The method of claim 13, wherein the notification includes information on resource blocks, RBs, of the second carrier assigned for DL data carried over the first carrier or the second carrier.

16. The method of claim 15, wherein the information about the RBs is provided on a physical downlink shared channel, PDSCH, or a physical downlink control channel, PDCCH, of the first carrier or on a PDCCH of the second carrier.

17. The method of claim 13, wherein the second carrier is not one of the anchor carriers.

18. A user equipment (220) in a wireless network (200) capable of communicating with a base station (210) over a plurality of carriers, comprising:

a communication unit (1120) arranged to communicate with the base station (210); and

a processing unit (1110) arranged to:

establishing a connection via the communication unit (1120) over one or more anchor carriers comprising a first carrier, wherein the anchor carriers are used by the base station (210) to provide control signals to the user equipment (220);

receiving a notification from the base station (210) via the communication unit (1120), the notification containing information about a second carrier, the information being carried over the first carrier;

making a determination based on the notification whether the base station (210) will additionally transmit download DL data using the second carrier; and

receiving the DL data over the first carrier and the second carrier via the communication unit (1120) when it is determined that the base station (210) will additionally use the second carrier,

wherein a first data portion of the DL data is received over the first carrier and a second data portion of the DL data is received over the second carrier after a predetermined delay, an

Wherein the predetermined delay is an amount of time sufficient for the user equipment (220) to prepare to receive over the second carrier.

19. The user equipment (220) according to claim 18, wherein the processing unit (1110) is arranged to:

making a determination based on the notification whether the base station (210) will alternately transmit the DL data using the second carrier;

receiving the DL data over the second carrier via the communication unit (1120) after the predetermined delay when it is determined that the base station (210) will alternately use the second carrier; and

receiving the DL data over the first carrier via the communication unit (1120) when it is determined that the base station (210) will not alternately use the second carrier.

20. The user equipment (220) according to claim 19, wherein the notification comprises information on resource blocks, RBs, of the second carrier assigned for DL data carried over the first carrier or the second carrier.

21. The user equipment (220) according to claim 20, wherein the information on the RBs is provided on a physical downlink shared channel, PDSCH, or a physical downlink control channel, PDCCH, of the first carrier or on the PDCCH of the second carrier.

22. The user equipment (220) of claim 18, wherein the second carrier is not one of the anchor carriers.