Base station, user equipment, transmission control method for the base station and data transmission method for the user equipment

A base station (BS), a user equipment (UE), a transmission control method for the BS and a data transmission method for the UE are provided. Based on user group information, the base station transmits uplink transmission control information to a plurality of the UEs in a group to make each UE contend for a plurality of subframes in the allocated unlicensed band radio resource pool. If a UE successfully contends for a subframe, the UE transmits a reservation signal and transmits an uplink data signal in the contended subframe. If the UE detects another reservation signal when contending for the subframe, the UE determines whether the another reservation signal is associated with the ID of its group. If associated, the UE transmits the uplink data signal in the subframe.

FIELD

The present invention relates to a base station, a user equipment (UE), a transmission control method for the base station and a data transmission method for the UE. In particular, the base station of the present invention groups a plurality of users together and allocates each of the users an unlicensed band radio resource pool of an unlicensed band. When the unlicensed band radio resource pools of UEs in the group have overlapped subframes therebetween, the UEs can commonly use the overlapped subframes without interfering with each other.

BACKGROUND

With the vigorous development of the wireless communication technology, more and more users are using various mobile devices (e.g., intelligent mobile phones, tablet computers or the like) to transmit data for purposes of communication and multimedia audio & video (AV) transmission or the like. To ensure that mobile communication services of superior quality are provided for users, mobile communication operators obtain licensed bands by bidding for the licensed bands.

However, because of the growing number of users and the limited licensed band radio resources, it is often the case that a base station in a particular region (e.g., a user-intensive region such as a commercial zone, a traffic hub or the like) cannot provide sufficient radio resources for users in the region at the same time, and this results in the decrease of the transmission speed. For example, in order to serve a large number of UEs at the same time, the radio resource allocated by the base station to each UE will be limited. In this case, if the user wants to transmit a relatively large volume of data (e.g., upload films or pictures having a relatively large volume of data), then the limited licensed band radio resource usually cannot satisfy the transmission demand of the user, and thus the user will feel less satisfied with the mobile communication service quality.

To solve the problem of the limited licensed band radio resource, currently specialists and operators in the fourth generation long term evolution (4G LTE) mobile communication field have proposed use of unlicensed bands to assist in the signal transmission, i.e., the Licensed Assisted Access (LAA) technology. However, the conventional base station allocates the radio resources of the unlicensed bands to UEs individually and independently.

In detail, when a user needs to transmit uplink data, the base station can allocate a radio resource of an unlicensed band in response to the transmission demand of the user. For example, the base station may allocate part of radio resources of a specific subframe on a specific carrier to a UE so that the UE contends for the subframe through the listen before talk (LBT) procedure. That is, a clear channel assessment (CCA) is performed on the subframe to determine whether the carrier is available, and after it is determined that the carrier is available, a reservation signal is transmitted to ensure that the uplink data can be subsequently transmitted.

However, if the UE fails the contention in the current LAA mechanism, then the base station needs to reschedule to allocate a new radio resource of the unlicensed band to the UE until the UE has successfully contended for the radio resource and transmitted the uplink data. These repeated and ineffective scheduling operations will cause a serious delay in the uplink data transmission and an additional burden for the base station.

Moreover, to enable the radio resource of the unlicensed band to be used by the UEs that it serves, the base station may allocate a same subframe to several UEs so that the UEs content for the same subframe at the same time. However, for the current LAA mechanism, inter-blocking might occur between the UEs. In this case, even if each UE only uses part of the radio resource of the subframe, the radio resource of the subframe still cannot be allocated to different UEs for use. In other words, when a user has successfully contended for a subframe and transmitted a reservation signal, the reservation signal will be detected by other UEs and thus the other UEs fail the contention and cannot use the subframe. Accordingly, the conventional LAA mechanism still cannot make full use of the radio resources of the unlicensed band.

Accordingly, an urgent need exists in the art to provide an uplink transmission control mechanism which can make full use of the radio resources of the unlicensed band to meet the transmission demands of the users.

SUMMARY

The disclosure includes an uplink transmission control mechanism which groups UEs together and allocates each of the UEs in the group an unlicensed band radio resource pool. In a case where the unlicensed band radio resource pools of a plurality of UEs in the group have overlapped subframes therebetween, the UEs in the group can still commonly use the overlapped subframes without inter-blocking with each other. In this way, the plurality of UEs in the group can transmit uplink data signals respectively via different radio resources of the same subframe to achieve the multiplexing transmission. Accordingly, the uplink transmission control mechanism of the present invention can not only make full use of the radio resources of the unlicensed band, but also reduce the number of times of rescheduling caused by the contention failure of the UE to avoid imposing an additional loading on the base station.

The disclosure includes a base station (BS) for a wireless communication system. The base station comprises a transceiver and a processor. The processor is electrically connected to the transceiver. The processor is configured to execute the following operations: generating first uplink transmission control information and second uplink transmission control information, the first uplink transmission control information indicating a first unlicensed band radio resource pool of an unlicensed band and the second uplink transmission control information indicating a second unlicensed band radio resource pool of the unlicensed band; and transmitting the first uplink transmission control information and the second uplink transmission control information to a first user equipment (UE) and a second UE of a user group respectively via the transceiver so that the first UE contends for a first subframe of the first unlicensed band radio resource pool according to the first uplink transmission control information and the second UE contends for a second subframe of the second unlicensed band radio resource pool according to the second uplink transmission control information. When the first UE transmits a first reservation signal after having successfully contended for the first subframe and the first subframe is the same subframe as the second subframe, the first UE transmits a first uplink data signal in the same subframe, and the second UE determines that the first reservation signal is associated with an identity (ID) of the user group so as to transmit a second uplink data signal in the same subframe. The processor further receives the first uplink data signal and the second uplink data signal in the same subframe via the transceiver.

The disclosure also includes a transmission control method for a base station. The base station is used in a wireless communication system and comprises a transceiver and a processor. The processor is electrically connected to the transceiver. The transmission control method is executed by the processor and comprises the following steps of: (a) generating first uplink transmission control information and second uplink transmission control information, the first uplink transmission control information indicating a first unlicensed band radio resource pool of an unlicensed band and the second uplink transmission control information indicating a second unlicensed band radio resource pool of the unlicensed band; (b) transmitting the first uplink transmission control information and the second uplink transmission control information to a first UE and a second UE of a user group respectively via the transceiver so that the first UE contends for a first subframe of the first unlicensed band radio resource pool according to the first uplink transmission control information and the second UE contends for a second subframe of the second unlicensed band radio resource pool according to the second uplink transmission control information; and (c) when the first UE transmits a first reservation signal after having successfully contended for the first subframe and the first subframe is the same subframe as the second subframe, receiving a first uplink data signal and a second uplink data signal in the same subframe via the transceiver. The first uplink data signal is transmitted by the first UE in the same subframe, and the second uplink data signal is transmitted by the second UE in the same subframe after determining that the first reservation signal is associated with an ID of the user group.

The disclosure further includes a UE for a wireless communication system. The UE comprises a transceiver and a processor. The processor is electrically connected to the transceiver. The processor is configured to execute the following operations: receiving uplink transmission control information from a base station via the transceiver, the uplink transmission control information indicating an unlicensed band radio resource pool of an unlicensed band; contending for a specific subframe of the unlicensed band radio resource pool via the transceiver according to the uplink transmission control information; after the contention for the specific subframe via the transceiver succeeds, transmitting a reservation signal and transmitting on the specific subframe an uplink data signal via the transceiver, the reservation signal being associated with an ID of a user group to which the UE belongs; and when the contention for the specific subframe fails and another reservation signal is detected via the transceiver, determining whether the another reservation signal is associated with the ID, and when the another reservation signal is associated with the ID, transmitting the uplink data signal on the specific subframe via the transceiver.

The disclosure additionally includes a data transmission method for a UE. The UE is used in a wireless communication system and comprises a transceiver and a processor. The processor is electrically connected to the transceiver. The data transmission method is executed by the processor and comprises the following steps of: (a) receiving uplink transmission control information from a base station via the transceiver, the uplink transmission control information indicating an unlicensed band radio resource pool of an unlicensed band; (b) contending for a specific subframe of the unlicensed band radio resource pool via the transceiver according to the uplink transmission control information; (c) after the contention for the specific subframe via the transceiver succeeds, transmitting a reservation signal and transmitting on the specific subframe an uplink data signal via the transceiver, the reservation signal is associated with an ID of a user group to which the UE belongs; and (d) when the contention for the specific subframe fails and another reservation signal is detected via the transceiver, determining whether the another reservation signal is associated with the ID, and when the another reservation signal is associated with the ID, transmitting the uplink data signal on the specific subframe via the transceiver.

DETAILED DESCRIPTION

In the following description, the present invention will be explained with reference to certain example embodiments. However, these example embodiments are not intended to limit the present invention to any specific examples, embodiments, environment, applications or implementations described in these example embodiments. Therefore, description of these example embodiments is only for purpose of illustration rather than to limit the scope of the present invention. It shall be appreciated that, in the following example embodiments and the attached drawings, elements unrelated to the present invention are omitted from depiction.

A first embodiment of the present invention is as shown inFIG. 1andFIG. 2.FIG. 1is a schematic view of a wireless communication system WCS of the present invention. The wireless communication system WCS may be a 4G LTE wireless communication system, or a similar wireless communication system based on the OFDMA technology. To simplify the description,FIG. 1only depicts a base station1, a user equipment UE1and a user equipment UE2in the wireless communication system WCS. However, as can be readily appreciated by those of ordinary skill in the art, the wireless communication system WCS may comprise several base stations and several UEs in practical use scenarios, and each base station may serve a plurality of UEs.

The base station1is configured with a licensed band so as to serve UEs within the signal coverage thereof. In this embodiment, the user equipment UE1and the user equipment UE2are located within the signal coverage of the base station1and are connected with the base station1. Meanwhile, the base station1puts the user equipment UE1and the user equipment UE2into a same user group G1. The base station1may put all the UEs connected thereto into the same user group G1. Moreover, the base station1may also put several adjacent UEs into the same user group G1according to the position relationships between the UEs. However, how the base station1puts the several UEs into the same user group G1is not intended to limit the claimed scope of the present invention. How the present invention achieves the multiplexing transmission by grouping several UEs together shall be readily appreciated by those of ordinary skill in the art based on the subsequent description.

FIG. 2is a schematic view illustrating the signal transmission among the base station1, the user equipment UE1and the user equipment UE2. When the user equipment UE1and the user equipment UE2want to transmit uplink data, the user equipment UE1uses the licensed band to transmit a first resource request message102to the base station1, and the user equipment UE2uses the licensed band to transmit a second resource request message104to the base station1. Thereafter, the base station1allocates the radio resources of the unlicensed band respectively according to the first resource request message102and the second resource request message104for use by the user equipment UE1and the user equipment UE2.

Further speaking, the unlicensed band may be the 2.4 GHz band and the 5 GHz band used by the wireless local area network, but is not limited thereto. The unlicensed band may have several carriers (also called channels). As shown inFIG. 3A, the unlicensed band has several carriers (e.g., a carrier CA1and a carrier CA2), each of the carriers may be further divided into several frames in the time and based on the OFDMA architecture, and each of the frames may be further divided into several subframes. Taking the 4G LTE wireless communication system as an example, one frame in the carrier CA1may include10subframes, i.e., a subframe CA1SF1, a subframe CA1SF2, a subframe CA1SF3, a subframe CA1SF4, . . . , and a subframe CA1SF10. Moreover, as shown inFIG. 3B, taking the 4G LTE wireless communication system as an example, each subframe has12resource blocks when the carrier bandwidth is 1.4 MHz.

In this embodiment, as shown inFIG. 4A, it is assumed that the base station1allocates part of the resource blocks in the subframes CA1SF1and CA1SF2of the carrier CA1and subframes CA2SF2and CA2SF3of the carrier CA2of the unlicensed band to the user equipment UE1to constitute a first unlicensed band radio resource pool RP1; and it is assumed that the base station1allocates part of the resource blocks in the subframes CA1SF2and CA1SF3of the carrier CA1and subframes CA2SF1and CA2SF2of the carrier CA2of the unlicensed band to the user equipment UE2to constitute a second unlicensed band radio resource pool RP2. As can be seen therefrom, the first unlicensed band radio resource pool RP1and the second unlicensed band radio resource pool RP2have overlapped subframes CA1SF2and CA2SF2. In this case, the user equipment UE1and the user equipment UE2will certainly contend for the subframes CA1SF1and CA2SF2at the same time.

In the present invention, the base station1further divides the resource blocks of the subframe into a plurality of resource block sets to allocate different block sets to different UEs for use. The size of each block set may be fixed or depend on requirements of the UEs. For example, as shown inFIG. 4B, the base station1divides the resource blocks of the subframe CA1SF2into a first resource block set RBS1and a second resource block set RBS2. The first resource block set RBS1is used by the user equipment UE1, and the second resource block set RBS2is used by the user equipment UE2.

After the radio resources of the unlicensed band are allocated according to the first resource request message102and the second resource request message104, the base station1generates first uplink transmission control information106and second uplink transmission control information108. The first uplink transmission control information106indicates a first unlicensed band radio resource pool RP1of an unlicensed band and the second uplink transmission control information indicates a second unlicensed band radio resource pool RP2of the unlicensed band. Next, the base station1transmits the first uplink transmission control information106and the second uplink transmission control information108to a first user equipment UE1and a second user equipment UE2of the user group G1respectively via the licensed band. In this way, the first user equipment UE1and the second user equipment UE2can know the resource blocks of each subframe allocated thereto respectively according to the uplink transmission control information106and the second uplink transmission control information108.

It shall be appreciated that, the first resource request message102and the second resource request message104may be transmitted via the uplink radio resource defined by the wireless communication system WCS itself, e.g., the physical uplink control channel (PUCCH) in the 4G LTE wireless communication system. Additionally, the first uplink transmission control information106and the second uplink transmission control information108may be transmitted via the downlink radio resource defined by the wireless communication system WCS itself, e.g., the physical downlink control channel (PDCCH) in the 4G LTE wireless communication system.

Moreover, the first uplink transmission control information106and the second uplink transmission control information108may respectively indicate the user group G1where the first user equipment UE1and the second user equipment UE2are located. For example, the first uplink transmission control information106may carry a group identity (ID) of the user group G1or user IDs of all the UEs in the user group G1. In another embodiment, the base station1may further generate user group information and transmit the user group information through broadcasting to notify the UEs served by the base station1of the user groups to which the UEs belong. For example, the user group information may be represented in the form of a data table and the data table may record one or more group IDs and one or more user IDs corresponding to each group ID, or individually record one or more user IDs corresponding to each user group. Additionally, in another embodiment, when the UEs connected to the base station all belong to the same user group, it may be unnecessary for the base station to provide the user group information.

Thereafter, the first user equipment UE1can contend for a first subframe (i.e., any one of the subframes CA1SF1, CA1SF2, CA2SF2and CA2SF3, usually contend in time sequence) of the first unlicensed band radio resource pool RP1according to the first uplink transmission control information106. Similarly, the second user equipment UE2can contend for a second subframe (i.e., any one of the subframes CA1SF2, CA1SF3, CA2SF1and CA2SF2, usually contend in time sequence) of the second unlicensed band radio resource pool RP2according to the second uplink transmission control information108.

The first user equipment UE1transmits a first reservation signal110after having successfully contended for the first subframe so as to inform other UEs that it will transmit a first uplink data signal112in the first subframe. Specifically, the first user equipment UE1first performs the CCA before the arrival of the first subframe, and transmits the first reservation signal110after the CCA succeeds, and then transmits the first uplink data signal112in the first subframe. For example, if the first user equipment UE1wants to contend for the subframe CA1SF2, then the first user equipment UE1will first perform the CCA at the end of the subframe CA1SF1. If the CCA succeeds, then a first reservation signal110is transmitted, which means that the contention for the subframe CA1SF2has succeeded. After the contention succeeds, the user equipment UE1can transmit the first uplink data signal112in the subframe CA1SF2, i.e., transmit the first uplink data signal112via the first resource block set RBS1.

Furthermore, when the first subframe for which the first user equipment UE1contends and the second subframe for which the second user equipment UE2contends are the same subframe (e.g., the subframe CA1SF2), the second user equipment UE2will find the existence of the first reservation signal110during the CCA and then further determine whether the first reservation signal110is associated with an ID of the user group G1. For example, the ID may be one of a group ID, a cell ID, a UE ID and any combination thereof. If the second user equipment UE2determines that the first reservation signal110is associated with the ID of the user group G1, then the second user equipment UE2transmits a second uplink data signal114in the same subframe (i.e., the subframe CA1SF2). In this way, the base station1can receive the first uplink data signal112and the second uplink data signal114in the subframe CA1SF2.

In the present invention, the reservation signal generated by each UE may be a specific sequence, and different sequences are well orthogonal to each other (e.g., the Zadoff-Chu sequences). There is a one-to-one correspondence between those sequences and different group IDs, cell IDs or the combination thereof. In this way, when the sequence is decided according to the group ID, the cell ID or the combination thereof, the reservation signals transmitted by UEs in different user groups will not interfere with each other. When the IDs are the UE IDs, there is no mutual interference even if the UEs in the user group all transmit the reservation signals.

Now, this will be further illustrated. As shown inFIG. 5A, after confirming that the carrier CA1is clean and available during a first CCA, the user equipment UE1transmits a first reservation signal110and waits for the arrival of the subframe CA1SF2. Upon the arrival of the subframe CA1SF2, the user equipment UE1transmits the first uplink data signal112in the subframe CA1SF2. On the other hand, the user equipment UE2finds during a second CCA that the carrier CA1is not clean and available but has a signal (i.e., the first reservation signal110) thereon. In this case, different from the prior art, the user equipment UE2of the present invention further receives the first reservation signal110and identifies whether the first reservation signal110is an identifiable sequence.

In other words, the user equipment UE2attempts to identify a sequence based on the first reservation signal110, and determines whether the sequence is associated with the group ID of the user group G1to which the user equipment UE2belongs, the cell ID or the combination thereof. If it is determined that the first reservation signal110is associated with the group ID of the user group G1or the cell ID, then the user equipment UE2waits for the arrival of the subframe CA1SF2, and transmits the second uplink data signal114in the subframe CA1SF2upon the arrival of the subframe CA1SF2.

Additionally, in an implementation where the ID is the UE ID or is the combination of the UE ID and both or either of the group ID and the cell ID, there is a one-to-one correspondence between the sequences represented by the reservation signals and the different UE IDs, or between the sequences represented by the reservation signals and the combinations of the UE IDs and both or either of the group IDs and the cell IDs. For example, as shown inFIG. 5B, after identifying a sequence from the first reservation signal110, the user equipment UE2determines whether the sequence is associated with the UE ID of one of the UEs in the user group G1to which the user equipment UE2belongs, i.e., determines whether the sequence corresponds to an UE ID in the user group G1or corresponds to the combination of the UE ID and both or either of the group ID and the cell ID.

If it is determined that the first reservation signal110is associated with the UE ID of one of the UEs in the user group G1, then the user equipment UE2may also generate and transmit a second reservation signal210based on the sequence corresponding to the UE ID of the user equipment UE2itself or corresponding to the combination of the UE ID and both or either of the group ID and the cell ID. Thereafter, the user equipment UE2waits for the arrival of the subframe CA1SF2, and transmits the second uplink data signal114in the subframe CA1SF2upon the arrival of the subframe CA1SF2. As described earlier, the first reservation signal110and the second reservation signal210are generated based on sequences that are well orthogonal to each other, so mutual interference therebetween can be avoided. Moreover, by having each of the UEs transmit the reservation signal corresponding to the sequence of the user ID thereof, the base station1can confirm in advance which UEs will transmit the uplink data signal.

Additionally, the reservation signal of the present invention not only can be generated based on the associated sequence corresponding to the ID, but may also be the same as the reservation signal in the prior art. In this case, in addition to transmitting the reservation signal, the UE succeeding in the contention needs to further transmit a message or an indication on the uplink channel in the licensed band to notify the surrounding UEs and the base station1that it has transmitted the reservation signal. The uplink channel may be a reservation channel that is newly defined and used for transmitting the broadcast information or an uplink channel defined by the wireless communication system WCS itself (e.g., the PUCCH in the 4G LTE wireless communication system). The transmitted message or indication may be a simple indication signal or one of the group ID, the cell ID, the UE ID and any combination thereof.

Please refer toFIG. 6AandFIG. 6Bfor a second embodiment of the present invention. This embodiment differs from the first embodiment in that, the base station1allocates the radio resources of the unlicensed band in units of user groups. In this case, each UE in the user group contends for the same set of subframes. For example, as shown inFIG. 6, the base station1allocates part of the resource blocks in the subframes CA1SF1, CA1SF2of the carrier CA1and the subframes CA2SF2, CA2SF3of the carrier CA2of the unlicensed band to the user equipment UE1to constitute the first unlicensed band radio resource pool RP1. Meanwhile, the base station1also allocates part of the resource blocks in the subframes CA1SF1, CA1SF2of the carrier CA1and the subframes CA2SF2, CA2SF3of the carrier CA2of the unlicensed band to the user equipment UE2to constitute the second unlicensed band radio resource pool RP2. As can be seen therefrom, the subframes in the first unlicensed band radio resource pool RP1and those in the second unlicensed band radio resource pool RF2are completely overlapped. In this case, the user equipment UE1and the user equipment UE2will certainly contend for all the subframes at the same time.

Please refer toFIG. 7for a third embodiment of the present invention, which is an extension of the second embodiment. In this embodiment, the base station1may further indicate in the uplink transmission control information transmitted to each UE a contention priority in which each UE contends for the subframes allocated thereto so that the contention for the radio resources of the unlicensed band can be fairer, thereby avoiding the case where other user groups or systems cannot successfully contend for the radio resource of the unlicensed band.

For example, the first uplink transmission control information106may indicate that the subframes of the first user equipment UE1in a descending contention priority are the subframe CA2SF2, the subframe CA1SF1, the subframe CA1SF2, and the subframe CA2SF3, and the second uplink transmission control information108may indicate that the subframes of the second user equipment UE2in a descending contention priority are the subframe CA1SF1, the subframe CA2SF1, the subframe CA2SF2, and the subframe CA1SF2. In this case, the user equipment UE1needs to first contend for the subframe CA2SF2, and it contends for a subframe of a lower contention priority level only if the contention for the subframe CA2SF2fails or if there is still other uplink data to be transmitted.

It shall be noted that, the contention priority level of the subframe CA1SF1is lower than that of the subframe CA2SF2; however, when the user equipment UE1fails in the contention for the subframe CA2SF2, the subframe CA1SF1becomes obsolete in time and thus the user equipment UE1cannot perform the CCA to contend for the subframe CA1SF1. Moreover, when the user equipment UE1fails in the contention for the subframe CA2SF2, it is also too late for the user equipment UE1to perform the CCA to contend for the subframe CA1SF2. In this case, the user equipment UE1has no alternative but to contend for the subframe CA2SF3.

Similarly, the user equipment UE2will first contend for the subframe CA1SF1. When the user equipment UE2fails in the contention for the subframe CA1SF1, the user equipment UE2will contend for the subframe CA2SF3. However, when user equipment UE2fails in the contention for the subframe CA2SF3, the subframe CA2SF2and the subframe CA1SF2becomes obsolete in time and thus the user equipment UE2cannot perform the CCA to contend for the subframe CA2SF2and the subframe CA1SF2.

Although the UE needs to contend for the subframes in sequence based on the contention priority of the subframes, the UE may also detect whether other UEs in the user group have successfully contended for a subframe, and transmit the uplink data signal to the base station1in the subframe for which other UEs have successfully contended. For example, although the user equipment UE1has not successfully contended for the subframe CA1SF1with priority over other UEs, the user equipment UE1still detects whether there is a reservation signal transmitted by a UE in the same user group before the arrival of the subframe CA1SF1. Therefore, when the user equipment UE2transmits the second reservation signal210after having successfully contended for the subframe CA1SF1, the user equipment1can transmit the first uplink data signal112in the subframe CA1SF1in response to the detection of the second reservation signal210.

As can be seen from the above description, there is a contention priority among the UEs in the contention for the subframes allocated to the UEs; however, as long as a UE in a user group has successfully contended for a subframe, other UEs in the same user group can transmit the uplink data signal via the subframe, thereby achieving the multiplexing effect. It shall be appreciated that, the contention priority among the UEs is generated randomly, although it is not limited thereto.

Please refer toFIG. 8for a fourth embodiment of the present invention, which is an extension of the first embodiment and the second embodiment. In this embodiment, although the base station1further divides the resource blocks of the subframe into a plurality of resource block sets (e.g., resource block sets RBS1, RBS2and RBS3ofFIG. 8), it is unnecessary to specifically allocate the resource block sets in the subframe to specific UEs. In other words, the uplink transmission control information transmitted to each UE only needs to indicate the subframes in the unlicensed band radio resource pool rather than the allocated resource block sets in each subframe. It shall be noted that, although the resource blocks of the subframe is evenly divided into three equal parts by the resource block sets RBS1, RBS2and RBS3depicted inFIG. 8, the base station1may also decide, depending on the practical operation status, how many parts the resource blocks are evenly divided into (which for example may be decided according to the number of the UEs) or the division proportions (which for example may be decided according to the uplink resource demand of each UE).

To achieve the aforesaid effect, there is a user priority among the UEs to decide the right to the use of the resource block sets. The user priority may be decided based on the value of the user IDs or based on the sequence in which the reservation signals are transmitted. For example, taking the case where the user priority is decided based on the user IDs as an example, if the user ID of the first user equipment UE1is smaller than that of the second user equipment UE2, then the first user equipment UE1has the higher priority to use the resource block set RBS1with the smallest number, and the second user equipment UE2uses the resource block set RBS2with the second smallest number. Similarly, if the user priority is decided based on the sequence in which the reservation signals are transmitted, then the user, who has successfully contended for the subframe and transmitted the reservation signal first, certainly has the higher priority over other users to use the resource block set RBS1with the smallest number.

In this way, according to the user priority, the first user equipment UE1selects the first resource block set (i.e., the resource block set RBS1) of the resource block sets of the same subframe (any one of the subframes CA1SF1and CA2SF2in the first embodiment, or any one of the subframes CA1SF1and CA2SF2in the second embodiment), and the second user equipment UE2selects the second resource block set (i.e., the resource block set RBS2) of the resource block sets of the same subframe. Next, the first user equipment UE1uses the resource block set RBS1to transmit the first uplink data signal112, and the second user equipment UE2uses the resource block set RBS2to transmit the second uplink data signal114.

It shall be appreciated that, in this embodiment, both the first user equipment UE1and the second user equipment UE2need to learn the UE ID of each other by transmitting the reservation signal (as shown inFIG. 5B) or transmitting a specific signal through a reservation channel. Additionally, although only two UEs are described in the aforesaid embodiments as an example, the implementation with more than three UEs shall be readily appreciated by those of ordinary skill in the art based on the aforesaid description, and thus will not be further described herein. Furthermore, there is inter-blocking among UEs of different user groups as can be appreciated by those of ordinary skill in the art, and this will not be further described herein.

A fifth embodiment of the present invention is as shown inFIG. 9AandFIG. 9B. Different from the first embodiment, the UE first detects whether at least one carrier of the unlicensed band is clean and available (e.g., by performing the CCA) in this embodiment. If the carrier is clean and available, then a pre-reservation signal is transmitted on the clean and available carrier. In other words, in the present invention, the UE may transmit the pre-reservation signal instead of the resource request message and the pre-reservation signal carries the resource request information.

Similarly, the pre-reservation signal may be a specific sequence, and different sequences are well orthogonal to each other (e.g., the Zadoff-Chu sequences). Here, each sequence may correspond to an uplink resource size. Moreover, each sequence may also correspond to the combination of an uplink resource size and a UE ID. Accordingly, after receiving the pre-reservation signal, the base station1can identify the UE and learn the uplink resource size required by the UE.

Additionally, transmitting the pre-reservation signal on the clean and available carrier is equivalent to that the UE has successfully contended for the right to the use of the carrier in advance. Then, the base station1only needs to allocate the subframe of at least one carrier having the pre-reservation signal to the UEs in the user group G1for use according to the at least one carrier. In other words, in this embodiment, if the UE has transmitted the pre-reservation signal, then it means that the upcoming subframe in this carrier can be used by the UE to transmit the uplink data signal.

As shown inFIG. 9A, the user equipment UE1performs the CCA on at least one carrier, and if the CCA succeeds, then the user equipment UE1transmits a pre-reservation signal902on the carrier on which the CCA is successfully performed. Similarly, the user equipment UE2performs the CCA on at least one carrier, and if the CCA succeeds, then the user equipment UE2transmits a pre-reservation signal904on the carrier on which the CCA is successfully performed. The sequence of the pre-reservation signal902corresponds to the user ID of the user equipment UE1and the uplink resource size required by the user equipment UE1. The sequence of the pre-reservation signal904corresponds to the user ID of the user equipment UE2and the uplink resource size required by the user equipment UE2. It shall be appreciated that, the number of pre-reservation signals transmitted by the UE is not limited in the present invention. For example, the UE may transmit several pre-reservation signals on several available carriers at the same time.

Thereafter, if the pre-reservation signal902is detected on a carrier by the base station1, then the base station1can identify the user equipment UE1, learn the uplink resource size required by the user equipment UE1, and allocate the next subframe on this carrier to the user equipment UE1so as to transmit the first uplink transmission control information106to the user equipment UE1. Similarly, if the pre-reservation signal904is detected on a carrier by the base station1, then the base station1can identify the user equipment UE2, learn the uplink resource size required by the user equipment UE2, and allocate the next subframe on this carrier to the user equipment UE2so as to transmit the second uplink transmission control information108to the user equipment UE2.

After receiving the first uplink transmission control information106, the user equipment UE1generates the first reservation signal110to determine that the contention for the subframe succeeds. For example, as shown inFIG. 9B, the user equipment UE1confirms that the carrier CA1is clean and available during the first CCA, so it transmits the pre-reservation signal902. After the pre-reservation signal902is detected on the carrier CA1by the base station1, the base station1decides to allocate the next subframe CA1SF2to the user equipment UE1for use so as to generate and transmit the first uplink transmission control information106to the user equipment UE1. Thereafter, the user equipment UE1generates and transmits the first reservation signal110to confirm that the contention for the subframe CA1SF2succeeds. Next, the user equipment UE1waits for the arrival of the subframe CA1SF2to transmit the first uplink data signal112.

Here, it is assumed that the user equipment UE2transmits a reservation signal904in other carriers and has not successfully contended for the carrier CA1in advance. In this case, after the pre-reservation signal904is detected on other carriers by the base station1, the base station1may also allocate the subframe CA1SF2to the user equipment UE2which belongs to the same user group G1so as to generate and transmit the second uplink transmission control information108to the user equipment UE2in order to make full use of the resources of the carrier CA1. In this way, after the first reservation signal110is detected on the CA1by the user equipment UE2, the user equipment UE2waits for the arrival of the subframe CA1SF2and transmits the second uplink data signal114on the subframe CA1SF2.

It shall be appreciated that, it is assumed that the base station1allocates the same subframe to the user equipment UE1and the user equipment UE2in the same user group G1in the aforesaid example. However, the base station1may also directly allocate the next coming subframe on the carrier for which the user equipment UE2has successfully contended in advance to the user equipment UE2for use. In this case, the user equipment UE2can transmit the second reservation signal210on the carrier to confirm that it has successfully contended for the subframe, and waits for the arrival of the subframe to transmit the second uplink data signal in this subframe. Moreover, the base station1may also allocate the subframe to other UEs so that the UEs can share the subframe, thereby achieving the multiplexing effect.

Furthermore, although the UE can transmit several pre-reservation signals on several available carriers at the same time, part of the carriers may be found having other interference signals at the same time when the base station is monitoring these carriers. In this case, the base station can determine the channel quality of each of the carriers according to the degree of interference of these carriers, and then allocate the subframes on one or more carriers having relatively good channel quality among these carriers to the UEs according to the channel quality of each of the carriers. In other words, by using the subframe of the carrier having relatively good channel quality, the UE can be prevented from transmitting the uplink data signal on the carrier having more interference signals, which would otherwise make the base station unable to decode the uplink data signal successfully. Various variants of the implementations can be readily appreciated by those of ordinary skill in the art based on the aforesaid description, and thus will not be further described herein.

A sixth embodiment of the present invention is as shown inFIG. 10, which is a schematic view of the base station1. The base station1comprises a transceiver11and a processor13. It shall be noted that, other elements (e.g., elements unrelated to the present invention, such as a storage, a power supply module or the like) of the base station1are omitted from depiction in the attached drawings for simplification of the description. The transceiver11is electrically connected with the processor13. The processor13is configured to generate information, signals, and messages and make determinations or the like. The transceiver11is configured to transmit and receive information, signals, messages or the like.

For the first embodiment, the processor13is configured to receive the first resource request message102and the second resource request message104via the transceiver11. Thereafter, the processor13generates the first uplink transmission control information106and the second uplink transmission control information108based on the first resource request message102and the second resource request message104. As described earlier, the first uplink transmission control information indicates the first unlicensed band radio resource pool RP1of an unlicensed band and the second uplink transmission control information indicates the second unlicensed band radio resource pool RP2of the unlicensed band.

Next, the processor13transmits the first uplink transmission control information106and the second uplink transmission control information108to the first user equipment UE1and the second user equipment UE2of the user group G1respectively via the transceiver11. In this way, the first user equipment UE1can contend for a first subframe of the first unlicensed band radio resource pool RP1according to the first uplink transmission control information106, and the second user equipment UE2can contend for a second subframe of the second unlicensed band radio resource pool RP2according to the second uplink transmission control information108.

When the first UE1transmits the first reservation signal110after having successfully contended for the first subframe (e.g., the subframe CA1SF2) and the first subframe is the same subframe as the second subframe (e.g., both of the first subframe and the second subframe are the subframe CA1SF2), the first user equipment UE1transmits the first uplink data signal112in the same subframe, and the second user equipment UE2determines that the first reservation signal110is associated with the ID of the user group G1so as to transmit the second uplink data signal114in the same subframe. Thereafter, the processor13further receives the first uplink data signal112and the second uplink data signal114via the transceiver11.

As described earlier, the first unlicensed band radio resource pool and the second unlicensed band radio resource pool comprise a plurality of subframes, the subframes are distributed on at least one carrier and include the first subframe and the second subframe, i.e., as shown inFIG. 3A,FIG. 3BandFIG. 4A. Moreover, each of the subframes comprises a plurality of resource block sets, as shown inFIG. 4BandFIG. 8. The first user equipment UE1is configured to use the first resource block set RBS1among the resource block sets of the same subframe (e.g., the subframe CA1SF2) to transmit the first uplink data signal112. The second user equipment UE2is configured to use a second resource block set RBS2among the resource block sets of the same subframe (e.g., the subframe CA1SF2) to transmit the second uplink data signal114. Because the first resource block set RBS1is different from the second resource block set RBS2, the first user equipment UE1and the second user equipment UE2can commonly use the same subframe to respectively transmit the uplink data signal thereof.

Moreover, for the third embodiment, the first user equipment UE1further contends for a first subframe (e.g., the subframe CA2SF2) of the first unlicensed band radio resource pool RP1according to a contention priority, and the second user equipment UE2further contends for a second subframe (e.g., the subframe CA1SF1) of the second unlicensed band radio resource pool RP2according to another contention priority.

Additionally, for the fourth embodiment, there is a user priority among the UEs. In this case, the first user equipment UE1and the second user equipment UE2respectively decide the first resource block set RB1and the second resource block set RB2among the resource block sets of the same subframe (e.g., the subframe CA1SF2) according to the user priority, and use the first resource block set RB1and the second resource block set RB2to transmit the first uplink data signal112and the second uplink data signal114respectively. Similarly, because the first resource block set RBS1is different from the second resource block set RBS2, the first user equipment UE1and the second user equipment UE2can commonly use the same subframe to respectively transmit the uplink data signal thereof.

On the other hand, for the fifth embodiment, the processor13further receives a pre-reservation signal902from the first user equipment UE1via the transceiver11, and generates the first uplink transmission control information106according to the pre-reservation signal902. As described earlier, the pre-reservation signal902is transmitted on at least one carrier of the unlicensed band after the first user equipment UE1has detected that the at least one carrier is available.

A seventh embodiment of the present invention is as shown inFIG. 11, which is a schematic view of a UE3. The UE3comprises a transceiver31and a processor33. It shall be noted that, other elements (e.g., elements unrelated to the present invention, such as a display module, a storage, a power supply module or the like) of the UE3are omitted from depiction in the attached drawings for simplification of the description. The transceiver31is electrically connected with the processor33. The processor33is configured to generate information, signals, and messages and make determinations or the like. The transceiver31is configured to transmit and receive information, signals, messages or the like. The UE3may be the user equipment UE1or the user equipment UE2of the aforesaid embodiments.

For the first embodiment and the second embodiment, if the UE3is the user equipment UE1, then the processor33transmits the resource request message (i.e., the first resource request message102) to the base station1via the transceiver31and receives the uplink transmission control information (i.e., the first uplink transmission control information106) from the base station1. The uplink transmission control information106indicates the unlicensed band radio resource pool (i.e., the first unlicensed band radio resource pool RP1) of the unlicensed band. Thereafter, the processor33contends for a specific subframe (e.g., the subframe CA1SF2) of the unlicensed band radio resource pool RP1via the transceiver31according to the uplink transmission control information106. If the contention for the specific subframe via the transceiver31succeeds, then transmitting a reservation signal (i.e., the first reservation signal110) and transmitting an uplink data signal (i.e., the first uplink data signal112) on the specific subframe. As described earlier, the reservation signal110is associated with the ID of the user group G1to which the user equipment UE1belongs.

On the other hand, if the UE3is the user equipment UE2, then the processor33transmits the resource request message (i.e., the second resource request message104) to the base station1via the transceiver31and receives the uplink transmission control information (i.e., the second uplink transmission control information108) from the base station1. The uplink transmission control information108indicates the unlicensed band radio resource pool (i.e., the second unlicensed band radio resource pool RP2) of the unlicensed band. Thereafter, the processor33contends for a specific subframe (e.g., the subframe CA1SF2) of the unlicensed band radio resource pool RP2via the transceiver31according to the uplink transmission control information108. If the contention for the specific subframe CA1SF2fails and another reservation signal (i.e., the first reservation signal110) is detected via the transceiver31, then it is determined whether the another reservation signal110is associated with the ID of the user group G1to which the user equipment UE2belongs. If it is determined that the another reservation signal110is associated with the ID, then the uplink data signal (i.e., the second uplink data signal114) is transmitted on the specific subframe CA1SF2.

As described earlier, referring toFIG. 3A,FIG. 3B,FIG. 4A,FIG. 4B,FIG. 5A, FIG.5B,FIG. 6AandFIG. 6Btogether, the unlicensed band radio resource pool comprises a plurality of subframes, the subframes are distributed on at least one carrier and include the specific subframe, and each of the subframes comprises a plurality of resource block sets. When the UE3is the user equipment UE1, the UE3may be configured to use the resource block set RB1among the resource block sets of the specific subframe to transmit the uplink data signal112.

Additionally, when the UE3is the user equipment UE2, the UE3may be configured to use the resource block set RB2among the resource block sets of the specific subframe to transmit the uplink data signal114. Another user equipment UE1that transmits the another reservation signal110is configured to use another resource block set RB1among the resource block sets of the specific subframe to transmit another uplink data signal112. The resource block set RB1is different from the another resource block set RB2. Because the first resource block set RBS1is different from the second resource block set RBS2, the first user equipment UE1and the second user equipment UE2can commonly use the same subframe to respectively transmit the uplink data signal thereof.

For the third embodiment, the processor33further contends for the specific subframe of the unlicensed band radio resource pool via the transceiver31according to the contention priority. For example, as shown inFIG. 7, when the UE3is the user equipment UE1, the processor33further contends for the specific subframe CA2SF2of the unlicensed band radio resource pool RP1via the transceiver31according to the contention priority; and when the UE3is the user equipment UE2, the processor33further contends for the specific subframe CA1SF1of the unlicensed band radio resource pool RP1via the transceiver31according to the contention priority.

For the fourth embodiment, when the UE is the user equipment UE2and the another UE that transmits the another reservation signal110is the user equipment UE1, the user equipment UE2selects the resource block set RBS2among the resource block sets of the specific subframe so as to use the resource block set to transmit the uplink data signal114according to the user priority, and the user equipment UE1selects the another resource block set RBS1among the resource block sets of the specific subframe so as to use the another resource block set RBS1to transmit the another uplink data signal114according to the user priority.

For the fifth embodiment, the processor33further detects via the transceiver31that at least one carrier of the unlicensed band is available, and transmits a pre-reservation signal on the at least one carrier so that the base station1generates the uplink transmission control information according to the pre-reservation signal. When the UE is the user equipment UE1, the pre-reservation signal is the pre-reservation signal902and the uplink transmission control information is106; and when the UE is the user equipment UE2, the pre-reservation signal is the pre-reservation signal904, and the uplink transmission control information is108, as shown inFIG. 9A.

An eighth embodiment of the present invention is as shown inFIG. 12, which is a flowchart diagram of a transmission control method of the present invention. The transmission control method is for use in a base station, e.g., the base station1of the aforesaid embodiments. The base station is used in a wireless communication system, e.g., the wireless communication system WCS of the aforesaid embodiments. The base station comprises a transceiver and a processor. The processor is electrically connected to the transceiver and is configured to execute the transmission control method.

First, in step S1201, first uplink transmission control information and second uplink transmission control information are generated. The first uplink transmission control information indicates a first unlicensed band radio resource pool of an unlicensed band. The second uplink transmission control information indicates a second unlicensed band radio resource pool of the unlicensed band. In step S1203, the first uplink transmission control information and the second uplink transmission control information are transmitted to a first UE and a second UE of a user group respectively via the transceiver. Accordingly, the first UE can contend for a first subframe of the first unlicensed band radio resource pool according to the first uplink transmission control information, and the second UE can contend for a second subframe of the second unlicensed band radio resource pool according to the second uplink transmission control information.

Thereafter, in step S1205, when the first UE transmits a first reservation signal after having successfully contended for the first subframe and the first subframe is the same subframe as the second subframe, a first uplink data signal and a second uplink data signal are received in the same subframe via the transceiver. The first uplink data signal is transmitted by the first UE in the same subframe. The second uplink data signal is transmitted by the second UE in the same subframe after determining that the first reservation signal is associated with an ID of the user group.

In an embodiment, the first unlicensed band radio resource pool and the second unlicensed band radio resource pool comprise a plurality of subframes, the subframes are distributed on at least one carrier and include the first subframe and the second subframe, and each of the subframes comprises a plurality of resource block sets. Moreover, in an embodiment, the transmission control method of the present invention further comprises the following steps before the step S1201: configuring a first resource block set among the resource block sets of the same subframe so that the first UE uses the first resource block set to transmit the first uplink data signal; and configuring a second resource block set among the resource block sets of the same subframe so that the second UE uses the second resource block set to transmit the second uplink data signal. The first resource block set is different from the second resource block set.

Moreover, in an embodiment, the transmission control method of the present invention further comprises the following steps before the step S1201: receiving a first resource request message from the first UE via the transceiver so as to generate the first uplink transmission control information according to the first resource request message; and receiving a second resource request message from the second UE via the transceiver so as to generate the second uplink transmission control information according to the second resource request message.

Furthermore, in an embodiment, the transmission control method of the present invention further comprises the following step before the step S1201: receiving a pre-reservation signal from the first UE via the transceiver to generate the first uplink transmission control information according to the pre-reservation signal. The pre-reservation signal is transmitted on at least one carrier of the unlicensed band after the first UE has detected that the at least one carrier is available.

In addition to the aforesaid steps, the transmission control method of the present invention can also execute all the operations and have all the corresponding functions set forth in all the aforesaid embodiments. How this embodiment executes these operations and has these functions will be readily appreciated by those of ordinary skill in the art based on the explanation of all the aforesaid embodiments, and thus will not be further described herein.

A ninth embodiment of the present invention is as shown inFIG. 13, which is a flowchart diagram of a data transmission method of the present invention. The data transmission method is for use in a UE, e.g., the UE3of the aforesaid embodiments. The UE is used in a wireless communication system, e.g., the wireless communication system WCS of the aforesaid embodiments. The UE comprises a transceiver and a processor. The processor is electrically connected to the transceiver and is configured to execute the data transmission method.

First, in step S1301, uplink transmission control information is received from a base station. The uplink transmission control information indicates an unlicensed band radio resource pool of an unlicensed band. Next, step S1303is executed to contend for a specific subframe of the unlicensed band radio resource pool according to the first uplink transmission control information. It shall be appreciated that, the unlicensed band radio resource pool comprises a plurality of subframes, the subframes are distributed on at least one carrier and include the specific subframe, and each of the subframes comprises a plurality of resource block sets.

Next, in step S1305, it is determined whether the carrier where the specific subframe is located is available. If the carrier is clean, then it is determined that the carrier is available, and step S1307is executed to transmit a reservation signal after having successfully contended for the specific subframe, and an uplink data signal is transmitted on the specific subframe. The reservation signal is associated with an ID of a user group to which the UE belongs. On the contrary, if another reservation signal is detected in the contention for the specific subframe, then it is determined that the carrier is unavailable; and then step S1309is executed to determine whether the another reservation signal is associated with the ID, and the uplink data signal is transmitted on the specific subframe if it is determined that the another reservation signal is associated with the ID. For example, the ID may be one of a group ID, a cell ID, and a UE ID.

In an embodiment, the step S1303may comprise the step of: contending for a specific subframe of the unlicensed band radio resource pool via the transceiver according to a contention priority. Moreover, in an embodiment, the data transmission method of the present invention may further comprise the following step before the step S1301: transmitting a resource request message to the base station via the transceiver so that the base station generates the uplink transmission control information according to the resource request message. Additionally, in another embodiment, the data transmission method of the present invention may further comprise the following step before the step S1301: detecting via the transceiver that at least one carrier of the unlicensed band is available, and transmitting a pre-reservation signal on the at least one carrier so that the base station generates the uplink transmission control information according to the pre-reservation signal.

In addition to the aforesaid steps, the data transmission method of the present invention can also execute all the operations and have all the corresponding functions set forth in all the aforesaid embodiments. How this embodiment executes these operations and has these functions will be readily appreciated by those of ordinary skill in the art based on the explanation of all the aforesaid embodiments, and thus will not be further described herein.

According to the above descriptions, the present invention provides an uplink transmission control mechanism to make full use of the radio resources of the unlicensed band. The base station can group UEs together and allocate each of the UEs in the group an unlicensed band radio resource pool. In a case where the unlicensed band radio resource pools of a plurality of UEs in the group have overlapped subframes therebetween, the UEs in the group can still commonly use the overlapped subframes without inter-blocking with each other. In this way, the plurality of UEs in the group can transmit uplink data signals respectively via different radio resources of the same subframe to achieve the multiplexing transmission. Accordingly, the uplink transmission control mechanism of the present invention can not only make full use of the radio resources of the unlicensed band, but also reduce the number of times of rescheduling caused by the contention failure of the UE to avoid imposing an additional burden on the base station.