Patent ID: 12256229

DETAILED DESCRIPTION OF EMBODIMENTS

Some preferred embodiments will be described in more detail with reference to the accompanying drawings, in which the preferred embodiments of the present disclosure have been illustrated. However, the present disclosure can be implemented in various manners, and thus should not be construed to be limited to the embodiments disclosed herein. On the contrary, those embodiments are provided for thorough and complete understanding of the present disclosure, and completely conveying the scope of the present disclosure to those skilled in the art.

In the following description, numerous specific details of embodiments of the present invention are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Those of ordinary skills in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. It shall be understood that the singular forms “a”, “an” and “the” include plural referents unless the context explicitly indicates otherwise.

Reference is now made toFIG.1which is a diagram of an example wireless network scenario where a method according to an embodiment of the present invention can be applied. The wireless network100comprises one or more network nodes101and103, here in the form of evolved Node B, also known as eNode Bs or eNBs, or pico eNB, femto eNB. The network nodes101could also be in the form of Node Bs, BTSs (Base Transceiver Stations), BS (Base Station) and/or BSSs (Base Station Subsystems), etc. The network nodes103may operate with different radio access technology (RAT) and/or in different frequency band than that of network node101. For example, the network node103may be a Wi-Fi access point (AP) operating in unlicensed band, while network node101is a LTE eNB operating in licensed band. In another example, both the network node101and103operate in a licensed frequency band, but using different carriers. It should be noted that it is also possible for both network node101and103to operate in same carrier. The network nodes101and103provide radio connectivity to a plurality of user equipments (UEs)102. The term user equipment is also known as mobile communication terminal, wireless terminal, mobile terminal, user terminal, user agent, machine-to-machine devices etc., and can be, for example, what today is commonly known as a mobile phone or a tablet/laptop with wireless connectivity or fixed mounted terminal. Moreover, the UEs102may, but do not need to, be associated with a particular end user. Though for illustrative purpose, the wireless network100is described to be a 3GPP LTE network, the embodiments of the present invention are not limited to such network scenarios and the proposed methods and devices can also be applied to other wireless networks, e.g., a GSM or a WCDMA network.

In the network100depicted inFIG.1, the network nodes, e.g., eNB101may firstly provide service to the UEs102via a carrier C1in a frequency band B1, and then when more frequency resources are required to serve an increased number of UE, or to provide an increased throughput, the eNB101may provide service to UEs102via another carrier C2in another frequency band B2, e.g., by using carrier aggregation (CA); or the eNB101may provide service to UEs102together with another network node, e.g., a pico eNB103which operates in another carrier C2in another frequency band B2, by using dual connectivity. In a CA scenario specified by 3GPP LTE Release 10, a UE can be configured with multiple carriers, with each carrier provided by a different network node, or with both carriers provided by same network node. The multiple carriers can belong to same or different frequency bands. Among the configured multiple carriers, one carrier is designated as primary component carrier (PCC), while others are called secondary component carriers (SCCs). In a dual connectivity scenario under discussion in 3GPP LTE for Release 12, a given UE consumes radio resources provided by at least two different network points connected with non-ideal backhaul. Furthermore, each eNB involved in the dual connectivity for a UE may assume different roles, i.e., one eNB serves as master eNB, while others serve as secondary eNBs. Those roles do not necessarily depend on the eNB's power class and can vary among UEs. Generally, a primary cell/master eNB should operate in a licensed band to guarantee accurate signaling transmission, while the secondary cell/eNB can be either licensed or unlicensed band.

In either CA or dual connectivity scenarios described above, in case the second band B2is a frequency band to be shared with other wireless network or another cell, e.g., the second band B2is an unlicensed band and is shared by the eNB101with another Wi-Fi AP103, the communication between the eNB101and the UEs102via the carrier C2in the frequency band B2may need to avoid interference to/from other networks/cells. In another example, the second band B2can be an licensed band shared by some pico eNBs103, and in such case, when utilizing the second band B2(e.g., using dual connectivity technique with eNB101as master eNB operating in the carrier C1and a pico eNB103as secondary eNB operating in the carrier C2), interference to/from other network nodes/cells should also be taken into account. In the embodiments of the invention, methods and devices are provided to enable communication in a shared frequency band which guarantees little interference to/from other wireless network/cells.

Reference is now made toFIG.2awhich illustrates a flow chart for an example method200for transmitting signal in a wireless network. The method200comprises a step S201, for determining a signal transmission pattern which defines time and frequency resources for transmitting at least one signal in a first frequency band; a step S202, for signaling via a second frequency band the signal transmission pattern to a first device (e.g., UE102shown inFIG.1); a step S203, for transmitting the at least one signal via the first frequency band, to the first device, according to the signal transmission pattern which is determined in the step S201and signaled to the UE102in the step S202, and skipping a transmission of one of the at least one signal if time and frequency resource for the transmission defined by the signal transmission pattern is detected as busy.

In one embodiment of the invention, the first frequency band is an unlicensed frequency band and the second frequency band is a licensed frequency band, but the invention is not limited to this. It can be appreciated that in another embodiment of the invention, both the first frequency band and the second frequency band can be licensed frequency bands, e.g., the first frequency band is a shared frequency band with other cells and serves as a secondary carrier, while the second frequency band serves as primary carrier; and in still another embodiment of the invention, they both can be unlicensed band. In accordance with one embodiment of the invention, the first frequency band and/or the second frequency band comprise(s) multiple carriers. In accordance with another embodiment of the invention, at least one carrier in the first frequency band and at least one carrier in the second frequency band are configured for the first device as carrier aggregation or dual connectivity.

In one embodiment of the invention, the at least one signal transmitted in the step S203includes at least one of a reference signal, a synchronization signal, and a control signal. For example, the at least one signal can be a CRS or a CSI-RS, a PSS and SSS, or some common control signaling like system information.

In one embodiment of the invention, the signal transmission pattern defines time and frequency resources for one of the following transmissions: a periodic transmission, an opportunistic transmission, and a combination thereof.

InFIGS.3a-3f, some examples of the signal transmission patterns are provided. In the example ofFIG.3a, it is assumed that a CRS/CSI-RS signal is transmitted periodically in the step S203according to a signal transmission pattern determined for it in the step S201. As shown inFIG.3a, the signal transmission pattern defined for the CRS/CSI-RS indicates in which subframe the CRS/CSI-RS should be transmitted. For example, the signal transmission pattern may indicate a transmission period (e.g., 5 ms in this example) and a subframe offset for transmitting the CRS/CSI-RS. With respect to the frequency resources to be used for transmitting the CRS/CSI-RS, it can be predefined, or also indicated by the signal transmission pattern, e.g., via a carrier index or a channel index. In this example, the CRS/CSI-RS is expected to be transmitted in subframes0and5; however, in subframe4, the first frequency band is detected to be busy, and thus the transmission of the corresponding CRS/CSI-RS in subframe5is skipped.

InFIG.3b, an example of opportunistic transmission of the CRS/CSI-RS signal is illustrated. That is, before each transmission of the CRS/CSI-RS, a listen before talk (LBT) is performed to detect whether the channel to be used for the transmission is busy or not. In an embodiment of the invention, the detection is performed in each available subframe where there is no concurrent transmission scheduled in the same frequency band, and the CRS/CSI-RS is transmitted in next subframe whenever the channel is detected as idle. If the corresponding channel is detected as busy in a subframe, then continue performing the LBT in the next subframe instead of transmitting the CRS/CSI-RS. As a result, the CRS/CSI-RS is sent aperiodically. In the example shown inFIG.3b, the eNB detects the channel in the first frequency band (e.g., an unlicensed band) in subframe0, and finds it idle, and as a result the CRS/CSI-RS is transmitted in the following subframe1; then before transmitting next CRS/CSI-RS, the channel detection is performed again in subframe2, and the channel is detected as busy. It means transmission of the CRS/CSI-RS is not allowed in subframe3, and then the channel detection continues till the channel is detected as idle in subframe4. As a result, the CRS/CSI-RS is transmitted in subframe5. The opportunistic transmission as shown inFIG.3bas an example provides more chance for CRS/CSI-RS transmission at the cost of more frequent channel detection.

In another embodiment of the invention, the signal transmission pattern determined in the step S201may define time and frequency resources for a combination of periodical and opportunistic transmission to balance between signaling overhead and CSI precision. In one embodiment of the invention, the periodical and opportunistic transmission patterns can be arranged in TDM way, e.g., when channel in the unlicensed band changes slowly, or the idle channel is easy to be obtained, periodical transmission can be applied; and when the channel in the unlicensed band changes quickly, or the channel is busy in most of the time, opportunistic transmission can be a better choice. Other factors, such as scheduling information of adjacent cells, or, assisting information on transmission characteristic of a Wi-Fi AP which shares the first frequency band with the eNB, can also be considered to determine a proper signal transmission pattern in step S201.

InFIGS.3cand3d, another two examples of the signal transmission pattern are provided, withFIG.3cfor FDD system andFIG.3dfor TDD system. In these examples, it is assumed that the at least one signal to be transmitted in the step S203is synchronization signals comprising PSS and SSS. The determined signal transmission patterns inFIG.3candFIG.3dfor PSS/SSS are consistent with current LTE-FDD and LTE-TDD specification respectively to reuse the design of current LTE system, however, it should be noted that such patterns are just presented as examples and the embodiments of the invention are not limited to this. As shown inFIG.3c, for FDD system, both the PSS and SSS are transmitted in subframes0and5, and according to an embodiment of the invention, the LBT is performed one subframe before each transmission of the PSS/SSS, i.e., the LBT is performed in subframe9of previous radio frame and subframe4in current frame. It can be appreciated that the channel detection can also be performed in other subframes than that shown inFIG.3c, e.g., it can be executed 2 subframes before each PSS/SSS transmission.FIG.3dillustrates the signal transmission pattern for a LTE-TDD system, where the PSS is transmitted in subframes1and6, and SSS is transmitted in subframes0and5in each radio frame. The channel detection (or, LBT) is shown to be performed in the same subframes as shown inFIG.3c, however, it can be appreciated that the invention is not limited to this.

In accordance with one embodiment of the invention, the time and frequency resource for the transmission of the one of the at least one signal is detected as busy when received signal power on the same frequency resource is above a threshold, the threshold is configurable, determined based on a receiver sensitivity, or fixed. In an embodiment of the invention, the threshold can be determined by eNB receiver sensitivity. In another embodiment of the invention, the threshold can be fixed, e.g., be set to be −62 dBm as in 802.11.

In accordance with another embodiment of the invention, the channel detection described above is performed in an additional step S204, for performing channel detection in the first frequency band before transmitting each of the at least one signal in the step S203, and for determining whether to skip a transmission of one of the at least one signal based on the channel detection results, as shown inFIG.2b. In accordance with another embodiment of the invention, only the latest channel detection results is taken into account during determining, and in another embodiment of the invention, both the channel detection results and some other estimation are considered during determining, e.g., an estimation for the maximum duration of an interfering transmission from, e.g., a Wi-Fi station.

In another embodiment of the invention, the channel detection step S204is not executed before each transmission. Instead, the channel detection provides a prediction on a time duration unavailable/available for the signal transmission. That is, if the channel detection indicates that a channel in the first frequency band will be idle for a period of P ms, then a signal can be transmitted according to the signal transmission pattern within the P ms without additional channel detection between each transmission. In case the channel detection indicates that the first frequency band keep busy for a period of P ms, then all the transmission of a signal defined the signal transmission pattern within the P ms will be skipped, without additional channel detection before each skipping.

In still another embodiment of the invention, the channel detection step S204may be performed by a separate device rather than an eNB which performs the steps S201to S203. For example, the channel detection can be done by a UE, which report the detection results to the eNB based on certain configuration. In a further embodiment, the channel detection may be performed by a Wi-Fi Station or AP connected to the eNB which performs the steps S201to S203. In such case, the method may further include a receiving step not shown in FIGS.2a-2c, for receiving the channel detection results for the first frequency band. In still another embodiment of the invention, the steps S203and S204are performed by a pico eNB103, while the steps S201and S202are performed by a macro eNB101, the wherein the pico eNB103and the macro eNB101provide service to a UE via CA or dual connectivity.

In accordance with still another embodiment of the invention, determining whether to skip a transmission of one of the one or more signals based on the channel detection results includes skipping a transmission of one of the one or more signals if the corresponding channel is detected as busy, and continuing the channel detection in the corresponding time-frequency resource for the skipped transmission defined by the signal transmission pattern. That is, inFIG.3d, if the channel is detected as busy in subframe4, then in the following subframes5and6, the PSS and SSS are not allowed to be transmitted, and correspondingly, the channel detection may continue in the subframes5and6. However, if the subframes5and6are detected as idle and the PSS and SSS are scheduled there, the channel detection should be avoided in same subframes. The reason is that, to avoid in-device interference and reduce implementation complexity, concurrent transmission and reception in same frequency band should be prevented. Correspondingly, when signal is being transmitted in the first frequency band, the channel detection is not allowed in same frequency band; on the other hand, once the channel is detected as busy and the signal is not allowed to be transmitted, i.e., a transmission defined by the signal transmission pattern will be skipped, the subframe corresponding to the skipped transmission can be used for channel detection, according to the embodiment of the invention.

InFIGS.3eand3f, another two example are provided, where it is assumed that the at least one signal to be transmitted in step S203is MIB and SIB1, respectively. The signal transmission patterns illustrated inFIGS.3eand3findicate periodic resources for MIB and SIB1 transmission. In these Figures, “NF” stands for index of radio frame, “Nf” stands for index of subframe, “F” denotes the first transmission in each period, and “R” denotes a repetition of the transmission. It can be seen that MIB is assigned a transmission period of 40 ms, wherein the first transmission is scheduled in subframe0of radio frames for which the SFN mod 4=0, and repetitions are scheduled in subframe0of all other radio frames. Similarly, SIB1 is assigned a transmission period of 80 ms with repetitions made within the 80 ms. The first transmission of SIB1 is scheduled in subframe5of radio frames for which the SFN mod 8=0, and repetitions are scheduled in subframe5of all other radio frames for which SFN mod 2=0. Similarly as shown inFIGS.3a-3d, in case a corresponding channel is detected as busy, the transmission of MIB/SIB1 is skipped.

In accordance with one embodiment of the invention, the method200further comprising a step S205, for determining whether to adopt a listen before talk (LTB) operating mode in the first frequency band; and, only when the LTB mode is determined to be adopted, the steps of S201, S202and S203depicted inFIG.2aare performed; otherwise, performing according to any prior art in step S206, e.g., performing normal operation as defined in current standard (e.g., LTE) for a licensed band. One example is shown inFIG.2c. In accordance with one embodiment of the invention, determining whether to adopt a listen before talk (LTB) operating mode in the first frequency band is based on regulation for the first frequency band and/or the device's capability, e.g., whether a eNB (a macro eNB101and/or a pico eNB103) is capable of LBT operation.

In one embodiment of the invention, all the steps in the method200can be implemented, for example, by the eNB101shown inFIG.1. One exemplary scenario can be that the eNB101provides service to a UE102via CA, by using both the first and the second frequency bands. In another embodiment of the invention, some steps in the method200can be implemented, for example, by the eNB101shown inFIG.1, while other steps are implemented by another network node, e.g., a pico eNB103shown inFIG.1. One exemplary scenario for this can be that the eNB101and the eNB103provides service to a UE102via dual connectivity, by using the first and the second frequency bands, respectively. In one example, steps S201and S202can be performed by the eNB101, while the step S203(or, steps S203to S205) is performed by the eNB103. This may require some signaling exchange between the eNB101and103, however, the inter-eNB interfacing for signaling exchange is well known, and thus details are omitted here. Furthermore, it should be noted that these are just examples, and other implementation can also be possible, e.g., the steps S201, S202and S205can be performed by the eNB101, while the step S203to S204are performed by the eNB103.

Though some specific signal transmission patterns are presented for the CRS/CSI-RS, PSS/SSS, MIB/SIB1, it should be appreciated that the embodiments of the invention are not limited to these signals and the signal transmission patterns, and, any other signals can be transmitted in the first frequency band (e.g., an unlicensed band) following the same principle of method200.

Referring now toFIG.4, which illustrates a flow chart for an example method400for signal reception in a wireless communication network. The method can be implemented, for example, by a UE102shown inFIG.1. The method comprises a step S401, for receiving via a second frequency band (e.g., a licensed frequency band) a configuration signaling indicating a signal transmission pattern to be used in a first frequency band (e.g., an unlicensed frequency band), the signal transmission pattern defines time and frequency resources for transmitting at least one signal; and a step S402, for receiving the at least one signal in the first frequency band, according to the signal transmission pattern.

In accordance with an embodiment of the invention, the at least one signal received in step S402is a signal transmitted by an eNB in step S203according to the method200described with reference toFIGS.3a-3f, and/or, the signal transmission pattern received in the step S401is sent by an eNB in the step S202according to the method200described with reference toFIGS.2a-2cand3a-3f. Thus, the features described for the at least one signal and the signal transmission pattern with respect toFIGS.3a-3falso apply inFIG.4, and their details will not be repeated here. For example, the signal transmission pattern defines time and frequency resources for one of a periodic transmission, an opportunistic transmission, and a combination thereof; and the at least one signal includes at least one of a reference signal, a synchronization signal, and a control signaling.

In accordance with one embodiment of the invention, the first frequency band and/or the second frequency band comprise(s) multiple carriers. In accordance with another embodiment of the invention, at least one carrier in the first frequency band and at least one carrier in the second frequency band are configured for a device as carrier aggregation or dual connectivity, as described with reference toFIGS.2a-2c.

In accordance with a further embodiment of the invention, in step S401, the configuration signaling is received from a first apparatus (e.g., a macro eNB101), while in step S402, the at least one signal is received from a second apparatus (e.g., a pico eNB103) different from the first apparatus.

To be noted that in some alternative implementations, the method steps indicated in the flow charts could also occur in a sequence different from what is indicated in the figures. For example, two sequentially indicated blocks could be executed substantially in parallel or sometimes in an inversed order, depending on the functions as involved.

It is also to be understood that methods described with reference toFIGS.2aand2bcan be implemented in various ways, by software, hardware, firmware, or any of their combinations, e.g., a processor, computer programming code stored in a computer readable storage media, etc.

Reference is now made toFIG.5a, which illustrates a block diagram of a device500for signal transmission in a wireless communication network according to an embodiment of the invention. The device500according toFIG.5acan be an eNB101inFIG.1, and may perform the example methods described with reference toFIGS.2a-2c, but is not limited to these methods. Then any feature presented above, e.g., in the description with reference toFIGS.2a-2ccan be applied to the device500presented below. It is to be noted that the methods described with reference toFIG.2amay be performed by the device500ofFIG.5abut is not limited to being performed by this device500. The device500may also be other network element than the eNB101shown inFIG.1, e.g., in an embodiment of the invention, it can be a relay node, a WLAN AP, etc.

As shown inFIG.5a, the device500comprises a determination unit501, configured for determining a signal transmission pattern which defines time and frequency resources for transmitting at least one signal in a first frequency band (e.g., an unlicensed frequency band); a first transmission unit502, configured for signaling via a second frequency band (e.g., a licensed frequency band) the signal transmission pattern to a first device; and a second transmission unit503, configured for transmitting the at least one signal via the first frequency band, to the first device, according to the signal transmission pattern and skipping a transmission of one of the at least one signal if time frequency resource for the transmission defined by the signal transmission pattern is detected as busy.

In accordance with one embodiment of the invention, the first frequency band and/or the second frequency band comprise(s) multiple carriers. In accordance with another embodiment of the invention, at least one carrier in the first frequency band and at least one carrier in the second frequency band are configured for the first device as carrier aggregation or dual connectivity.

In accordance with one embodiment of the invention, the units501to503are configured for performing the steps201to203described with reference toFIGS.2a-2c, respectively.

In another embodiment of the invention, the determined signal transmission pattern by the determination unit501can define time and frequency resources for one of a periodic transmission, an opportunistic transmission, and a combination thereof. For example, the signal transmission pattern can be any of the patterns described with reference toFIGS.3ato3f, but is not limited to this.

According to one embodiment of the invention, the at least one signal transmitted by the second transmission unit503includes at least one of a reference signal, a synchronization signal, and a control signaling. For example, the at least one signal can be a CRS/CSI-RS, a PSS/SSS, and/or MIB/SIB1 as illustrated inFIGS.3a-3f.

In one embodiment of the invention, the device500further comprises a channel detection unit504, configured for performing channel detection in the first frequency band before transmitting each of the at least one signal, and the second transmission unit503is further configured for determining whether to skip a transmission of one of the at least one signal based on the channel detection results obtained by the channel detection unit504. In another embodiment of the invention, the second transmission unit503is further configured for skipping a transmission of one of the at least one signal if the corresponding channel is detected as busy by the channel detection unit504; and the channel detection unit504is further configured for continuing the channel detection in the corresponding time and frequency resource for the skipped transmission defined by the signal transmission pattern. Such implementation is due to a consideration that to avoid in-device interference and reduce implementation complexity, concurrent transmission and reception in same frequency band should be prevented. Correspondingly, when the second transmission unit503is transmitting in the first frequency band, the channel detection unit504is not allowed to perform channel detection in same frequency band; on the other hand, once the channel is detected as busy and the second transmission unit is not allowed to transmit, i.e., a transmission defined by the signal transmission pattern will be skipped, the subframe corresponding to the skipped transmission can be used for channel detection by the channel detection unit504, according to the embodiment of the invention.

In another embodiment of the invention, the channel detection unit504is not configured for performing channel detection in the first frequency band before transmitting each of the at least one signal. Instead, the channel detection unit504is configured for providing a prediction on a time duration unavailable/available for the signal transmission. That is, if the channel detection indicates that a channel in the first frequency band will be idle for a period of P ms, then a signal can be transmitted by the second transmission unit503according to the signal transmission pattern within the P ms without additional channel detection performed by the channel detection unit504between each transmission. In case the channel detection indicates that the first frequency band keep busy for a period of P ms, then the second transmission unit503will be configured for skipping all the transmission of a signal defined the signal transmission pattern within the P ms, without additional channel detection performed by the channel detection unit504before each skipping.

In still another embodiment of the invention, the channel detection may be performed by a separate device rather than the channel detection unit504in an eNB. For example, the channel detection can be done by a UE, which reports the detection results to the eNB based on certain configuration. In a further embodiment, the channel detection may be performed by a Wi-Fi Station or AP connected to the eNB. In such case, the device500may further include a receiving unit not shown inFIG.5a, for receiving the channel detection results for the first frequency band.

In one embodiment of the invention, the time and frequency resource for the transmission of the one of the at least one signal is detected as busy when received signal power on the same frequency resource is above a threshold, the threshold is configurable, determined based on a receiver sensitivity, or fixed. In one embodiment of the invention, the threshold can be determined by the eNB based on its receiver sensitivity. In another embodiment of the invention, the threshold can be set as a fixed value, e.g., −62 dBm as in 802.11.

In one further embodiment of the invention, the device further comprises a mode determination unit505, configured for determining whether to adopt a listen before talk LTB operating mode in the first frequency band; and only when the mode determination unit505determines that LTB mode is determined to be adopted, the units of501to504are configured to perform corresponding functions as described above; otherwise, performing according to any prior art, e.g., performing normal operation as defined in current standard (e.g., LTE) for a licensed band. In accordance with one embodiment of the invention, determining whether to adopt a listen before talk (LTB) operating mode in the first frequency band is based on regulation for the first frequency band and/or the device's capability, e.g., whether a eNB (a macro eNB and/or a pico eNB) is capable of LBT operation.

In accordance with another embodiment of the invention, all the units501to505are implemented in a same device, e.g., a eNB101as shown inFIG.1. In another embodiment of the invention, some of the units501to505are implemented in a device, while other units are implemented in another device, that is, the device500is a distributed system. One example of such embodiments is shown inFIG.5b, wherein the units501and502(or,501,502and505) are implemented in a macro eNB101, while the unit503(or, both503and504) is implemented in a pico eNB103. However, the example inFIG.5bis just for illustrative purpose, it can be appreciated that other arrangement of the distributed device500is also possible. For example, all the units503to505may be implemented in a same device, e.g., in a small cell eNB. These example embodiments can be implemented, for example, in a scenario where the eNB101and the eNB103provides service to a UE102via dual connectivity, by using the first and the second frequency bands, respectively. It can be easily appreciated that in such case, there can be other additional units implemented in the eNB101and the eNB103, e.g., for signaling exchange between them, however, since the inter-eNB interfacing for signaling exchange is well known, the details are omitted here.

It should be noted that though in some embodiments the first frequency band is an unlicensed frequency band and the second frequency band is a licensed frequency band, the embodiments of the invention are not limited to this. The device500can be applied in any other scenarios, e.g., where both the first and the second frequency bands are licensed or unlicensed bands. One example can be that the second frequency band is a primary carrier dedicated for one cell, while the first frequency band is a shared carrier available to multiple cells or multiple networks/operators, and then for any transmission in the first frequency band, the eNB can follow the principles described above to avoid/reduce interference from/to other cells/wireless systems.

Reference is now made toFIG.6, which illustrates a block diagram of a device600for signal reception in a wireless communication network. In accordance with one embodiment of the invention, the device600comprises a first receiving unit601, configured for receiving via a second frequency band a configuration signaling indicating a signal transmission pattern to be used in a first frequency band, the signal transmission pattern defines time and frequency resources for transmitting at least one signal; and a second receiving unit602, configured for receiving the at least one signal via the first frequency band, according to the signal transmission pattern.

According to one embodiment of the invention, the device600may perform the example methods described with reference toFIGS.2a-2cbut is not limited to these methods. Then any feature presented above, e.g., in the description with reference toFIGS.2a-2c, if appropriate, can be applied to the device600presented below. It is to be noted that the methods described with reference toFIGS.2a-2cmay be performed by the device600ofFIG.6but is not limited to being performed by this device600. The device600may be, for example, a UE102shown inFIG.1.

In accordance with an embodiment of the invention, the at least one signal received by the second receiving unit602is a signal transmitted by eNB in step203according to the method200described with reference toFIGS.2a-2cand3a-3f, and/or, the signal transmission pattern received by the first receiving unit601is sent by an eNB in step202according to the method200described with reference toFIGS.2a-2cand3a-3f. Thus, the features described for the at least one signal and the signal transmission patterns described with respect toFIGS.2a-2cand3a-3falso apply inFIG.6, and their details will not be repeated here. For example, the signal transmission pattern defines time and frequency resources for one of a periodic transmission, an opportunistic transmission, and a combination thereof; and the at least one signal includes at least one of a reference signal, a synchronization signal, and a control signaling.

In accordance with one embodiment of the invention, the signal transmission pattern is received by the first receiving unit601via a licensed band to guarantee satisfying performance, while the at least signal is received by the second receiving unit602via an unlicensed band; but the embodiments of the invention are not limited to this.

In accordance with one embodiment of the invention, the first frequency band and/or the second frequency band comprise(s) multiple carriers. In accordance with another embodiment of the invention, at least one carrier in the first frequency band and at least one carrier in the second frequency band are configured for the UE102as carrier aggregation or dual connectivity, as described with reference toFIGS.2a-2c.

In accordance with a further embodiment of the invention, in receiving unit601, the configuration signaling is received from a first apparatus (e.g., a macro eNB101), while in receiving unit602, the at least one signal is received from a second apparatus (e.g., a pico eNB103) different from the first apparatus.

The flow charts and block diagrams in the figures illustrate the likely implemented architecture, functions, and operations of the system, method, and apparatus according to various embodiments of the present invention. In this point, each block in the flow charts or block diagrams could represent a part of a module, a program segment, or code, where the part of the module, program segment, or code comprises one or more executable instructions for implementing a prescribed logic function. It can be appreciated that the methods and devices may comprise other steps/functional blocks besides those illustrated. It should also be noted that each block in a block diagram and/or a flow chart, and a combination of the blocks in the block diagram and/or flow chart could be implemented by software, hardware, firmware, or any of their combinations. Furthermore, it should be understood that in some embodiments, function of a block can also be implemented by multiple blocks, and functions of multiple blocks shown inFIGS.5a,5band6may also be implemented by a single block in other embodiments.

The example embodiments can store information relating to various processes described herein, e.g., store the channel detection results, the received signal transmission pattern etc. The components of the example embodiments can include computer readable storage medium or memories according to the teachings of the present inventions and for holding data structures, tables, records, and/or other data described herein, or the program codes for implementing any of the methods according to the embodiments of the invention.

While the present inventions have been described in connection with a number of example embodiments, and implementations, the present inventions are not so limited, but rather cover various modifications, and equivalent arrangements, which fall within the purview of prospective claims. It is also obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.