Patent Application
20190150197
The disclosure relates to a user equipment (UE) and a resource sensing and selection method thereof.
In the third generation partnership project (3GPP) long term evolution (LTE) Release 14, a cellular vehicle-to-everything (C-V2X) standard has been proposed. The LTE-based C-V2X standard focuses on communication between vehicles and other objects, e.g., vehicle to vehicle, vehicle to infrastructure, vehicle to pedestrian, and so on. Besides, the C-V2X communication is a device-to-device (D2D) communication based on proximity-based services (ProSe). The vehicle-to-vehicle (V2V) communication is an extension of the D2D communication, which uses a PC5 interface to enhance direct connection and communication between vehicles.
In the Study Items and Work Items of 3GPP V2X phase 2 of Release 15, two topics for PC5 functionalities, which are carrier aggregation (CA) and reduce the maximum time between packet arrival at layer 1 (i.e., physical layer) and resource selected for transmission, have been proposed as objectives. The two topics can be co-existed in the same resource pools and use the same scheduling assignment (SA) format defined in Release 14. Here, to reduce the latency in physical layer, it has been concluded to an agreement related to the reduction of the resource selection window (i.e., to reduce the parameter T2) in 3GPP standard RAN1 meeting.
The disclosure provides a user equipment (UE) and a resource sensing and selection method thereof.
In an embodiment of the disclosure, the resource sensing and selection method is adapted to a UE with no assistance of any base station, and the resource sensing and selection method includes following steps. Channel statuses for all component carriers (CCs) are measured and obtained. Several candidate component carriers (CCs) are determined from all the CCs according to the measurement values of the channel statuses for all the CCs and a proximity-based service per-packet priority (ProSe per-packet priority, PPPP) corresponding to the UE. At least one of the candidate CCs is selected as at least one selected usable CC, and a resource sensing and selection process is performed on the at least one selected usable CC.
In an embodiment of the disclosure, a UE at least includes, but not limited to, a receiver, a transmitter, and a processor. The receiver receives a signal. The transmitter transmits the signal. The processor is coupled to the receiver and the transmitter. Besides, the processor is configured to perform following steps. Channel statuses for all CCs are measured and obtained through the receiver. Several candidate CCs are determined from all the CCs according to the measurement values of the channel statuses for all the CCs and a PPPP corresponding to the UE. At least one of the candidate CCs is selected as at least one selected usable CC, and a resource sensing and selection process is performed on the at least one selected usable CC through the receiver.
Several exemplary embodiments accompanied with figure are described in detail below to further describe the disclosure in details.
The accompanying drawing is included to provide further understanding, and is incorporated in and constitutes a part of this specification. The drawing illustrates exemplary embodiments and, together with the description, serves to explain the principles of the disclosure.
The UE 100 at least includes, but not limited to, one or more antennas 110, a receiver 120, a transmitter 130, an analog-to-digital (A/D) and digital-to-analog (D/A) converter 140, a memory 150, and a processor 160.
The receiver 120 and the transmitter 130 are respectively configured to receive and transmit a signal through the antenna 110 wirelessly. Besides, the receiver 120 and the transmitter 130 can perform analog signal processing operations, such as low noise amplification, impedance matching, frequency mixing, frequency up-conversion or down-conversion, filtering, amplification, and the like. The A/D and D/A converter 140 is configured to convert an analog signal to a digital signal and convert a digital signal to an analog signal.
The memory 150 may be any type of fixed or movable random access memory (RAM), read-only memory (ROM), flash memory, any other similar component, or a combination of said components. The memory 150 is configured to store programming codes, device configuration, codebook, buffered or permanent data, e.g., a channel status threshold value-proximity-based service per-packet priority (PPPP) mapping table, measurement values of channel statuses, information of UE capability, resource occupancy information, energy threshold values, previous information, and so on, which will be elaborated hereinafter. The memory 150 is also configured to record a physical layer, a media access control (MAC) layer, a logical link control (LLC) layer, a network service layer, an upper layer, or any other communication protocol related software module.
The processor 160 is configured to process a digital signal and execute procedure according to the exemplary embodiments of the disclosure and is able to access or load information and software modules recorded in the memory 150. The functions of the processor 160 may be achieved by a central processing unit (CPU), a microprocessor, a micro-controller, a digital signal processing (DSP) chip, a field programmable gate array (FPGA), or another programmable unit. Alternatively, the functions of the processor 160 may also be implemented by an individual electronic apparatus, an integrated circuit (IC), or software.
In order to facilitate the understanding of the operation flow provided in the embodiments of the disclosure, several embodiments are provided below to elaborate the operation flow of the UE 100.
The processor 160 measures and obtains channel statuses for all component carriers (CCs) through the receiver 120 (step S310). Specifically, according to the CA technology, two or more CCs with continuous or discontinuous certain bandwidths (for example, 10, 20, or 50 MHz) can be simultaneously combined to increase the total bandwidth for data transmission, thereby increasing the transmission rate. If the number of CCs which can be selected by the UE 100 increases (e.g., 3GPP V2X phase 2 study item/work item has defined that the CA can use up to eight CCs), available (radio) resources can also increase. If the selection of resources by the UE 100 can be effectively scheduled, the transmission efficiency of one single UE or even the entire system may be improved. Here, the channel status can be applied to evaluate whether resources are occupied, busy, idle, and/or interfered, and a measurement value of the channel status may be a channel busy ratio (CBR), a channel occupancy ratio (CR), a received signal strength indication (RSSI), a reference signal received quality (RSRQ), a reference signal received power (RSRP), a signal-to-noise ratio, or any other value associated with channel usage.
In an embodiment, a time for resource sensing in each CC relates to a specific period (e.g., the duration of the sensing window shown in
With reference to
Note that the length of the measurement periods MP1, MP2, MP3, and MP4 and the channel statuses adopted with reference to
The processor 160 can determine several candidate CCs from all the CCs according to the measurement values of the channel statuses for all the CCs and the PPPP corresponding to the UE 100 (step S330). Specifically, a transmission between two UEs 100 in the V2X mode 4 is via a PC5 interface. According to the 3GPP TS 23.303 and TS 36.300 standards, when a ProSe upper layer performs the transmission of protocol data unit through the PC5 interface, the ProSe upper layer provides PPPP information for such transmission (selected from 8 possible numeral ranges). The PPPP information is a quantitative value associated with the protocol data unit, and it gives priority to the transmission of the protocol data unit. Each UE 100 is assigned a specific PPPP value, so as to give priority to the PC5-S message or other protocol data units transmitted by each UE 100 (e.g., the transmission with higher priority is processed first, and the transmission with lower priority is processed later).
In an embodiment, the processor 160 compares the measurement value of the channel status for each of the CCs with a channel status threshold value corresponding to the PPPP granted to the UE 100 and to each of the CCs, so as to determine whether each of the CCs is a busy CC or an idle CC. The channel status threshold value is, for instance, a CBR threshold value, a CR threshold value, a signal-to-noise threshold ratio, and so on, and the channel status threshold value corresponds to the type of the channel statuses. Data transmission will be seriously interfered if the CC is a busy CC, thus resulting in transmission failure or excessive failure. On the other hand, the idle CC may serve as the candidate CC, and the interference of data transmission on the idle CC is lower than the interference of data transmission on the busy CC. In response to the measurement value of the channel status for a certain CC being smaller than the corresponding channel status threshold value, this CC is considered by the processor 160 as a candidate CC. In response to the measurement value of the channel status for this CC being greater than or equal to the corresponding channel status threshold value, the processor 160 does not consider (or prohibit/stop considering) this CC as a candidate CC. In light of the above, the determination of the channel status threshold value may affect the determination of the candidate CCs.
In an embodiment, the processor 160 obtains a channel status threshold value-PPPP mapping table (which is defined in advance or is received from instructions of other apparatuses). The channel status threshold value-PPPP mapping table records all channel status threshold values corresponding to all of the corresponding PPPPs and to all of the CCs. The processor 160 may then compare the measurement value of the channel status corresponding to the PPPP of the user equipment and to each of the CCs with the channel status threshold value corresponding to the same PPPP and to the same one of the CCs in the channel status threshold value-PPPP mapping table. The channel status threshold value can be between an upper limit and a lower limit, and the upper and lower limits may be of a fixed value or may be adjusted. For instance, the upper limit of the CBR threshold value is 0.8, and the lower limit is 0.35.
In an embodiment, all of the PPPPs recorded by the channel status threshold value-PPPP mapping table include corresponding indexes that may be arranged according to a priority order. For instance, the channel status threshold value—PPPP mapping table records a first PPPP—an mth PPPP (i.e., PPPP1-PPPPm, wherein the index i of PPPPi is a positive integer ranging from 1 to m). The first PPPP has the highest priority, the second PPPP has the second highest priority, and the others can be deduced therefrom, i.e., the mth PPPP has the lowest priority in the priority order. Each PPPP corresponds to at least one service type, and the priority of these services types is the same.
Besides, each PPPP is assigned a certain number of CCs. In an embodiment, as to the numbers of the CCs corresponding to all PPPPs recorded in the channel status threshold value-PPPP mapping table, the number of the CCs corresponding to a PPPP with higher priority in the priority order is greater than or equal to the number of the CCs corresponding to a PPPP with lower priority in the priority order, which is mathematically expressed as follows:
n
1
≥n
2
≥ . . . ≥n
m (1),
wherein n1 represents the number of CCs corresponding to the first PPPP, and the others can be deduced therefrom. That is, the higher the priority of the PPPPs, the more the CCs assigned to the PPPPs, so as to reduce the possibility of resource selection collisions and improve reliability for the PPPP with higher priority.
In an embodiment, all CCs corresponding to each of the PPPPs recoded in the channel status threshold value-PPPP mapping table include corresponding indexes arranged according to a second priority order. As to the second priority order of the CCs corresponding to the PPPPs, an index of a CC with higher priority in the second priority order is smaller than or equal to an index of another CC with lower priority in the second priority order. For instance, the channel status threshold value—PPPP mapping table records that PPPP1 corresponds to M CCs, including the first CC—the Mth CC (i.e., CC1-CCM, wherein the index i of the CCi is a positive integer from 1 to M), and the second priority order is CC1≥, CC2≥, . . . , ≥CCM. Besides, as to indexes with a foremost order arranged in the second priority order among the indexes of the CCs corresponding to all of the PPPPs, the index with the foremost order in the CCs corresponding to a PPPP with higher priority in the priority order is smaller than or equal to the index with the foremost order in the CCs corresponding to a PPPP with lower priority in the priority order. The relationship is mathematically expressed as follows:
l
1
≥l
2
≥ . . . ≥l
m (2),
wherein l1 represents an index offset of the CC corresponding to the first PPPP (the index with the foremost order may be obtained by adding one to said index offset), and the rest may be deduced therefrom. The index of the CC corresponding to the ith PPPP (the index i is a positive integer from 1 to m) is l1+k, wherein kϵ{1, . . . , ni}. For instance, the number of the CCs corresponding to the first PPPP is eight, i.e., the first CC to the eighth CC, wherein n1=8 and l1=0 (the index with the foremost order is l1+1=1). The number of the CCs corresponding to the eighth PPPP is one, i.e., the eighth CC, wherein n8=1 and l8=7 (the index with the foremost order is l8+1=8). That is, a PPPP having higher priority in the priority order is more likely to be assigned to a CC having the smaller index. In view of the above, by using the assignment to the PPPP with higher priority for CC having the smaller index and the priority order of the CCs corresponding to each PPPP, the CCs corresponding to each PPPP can be separated as much as possible, and each PPPP would be corresponding to different component carriers (CCs) selected as the candidate CCs. Therefore, the possibility of resource selection collisions can be reduced and the reliability can be improved.
In different embodiments, in each of the CCs, the channel status threshold value corresponding to each of the PPPPs recorded in the channel status threshold value-PPPP mapping table may differ from each other. In an embodiment, as to the channel status threshold values corresponding to all the CCs in each of the PPPPs, the channel status threshold value corresponding to the front CC (i.e., with the smaller index) is greater than the channel status threshold values corresponding to the rear CC (i.e., with the greater index), which may be mathematically expressed as follows:
δi,1>δi,2> . . . >δi,n
wherein δi,n
The number of PPPPs corresponding to one CC may be more than one, and one single CC may corresponds to a PPPP group including one or more PPPPs. In the same PPPP group, the number of the CCs corresponding to all PPPPs and the index offset of the CCs are the same. In an embodiment, in each of the CCs, the corresponding channel status threshold values corresponding to all the PPPPs recorded in the channel status threshold value-PPPP mapping table may differ from each other. For instance, in the third CC, the corresponding channel status threshold value of the first PPPP is 0.65, and the corresponding channel status threshold value of the second PPPP is 0.7.
Besides, the channel status threshold values recorded in the channel status threshold value-PPPP mapping table corresponding to the resource selection window at different time lengths (i.e., the parameter T2 as shown in
For easy understanding, examples of CBR-PPPP-service type mapping table are provided with reference to Table (1)-Table (10). The parameter m of the number of PPPPs and the parameter M of the number of CCs are both 8 in Table (1)-Table (6). Here, the PPPP groups indicated in Table (1), Table (3), and Table (5) respectively include one, two, and three PPPPs, and the parameter T2 of the resource selection window is 20 ms. The groups indicated in Table (2), Table (4), and Table (6) respectively include one, two, and three PPPPs, and the parameter T2 of the resource selection window is 10 ms. The PPPP groups indicated in Table (7)-Table (10) all include two PPPPs. Here, the (m, M) parameter combinations, in which the number of PPPPs is the parameter m and the number of CCs is the parameter M, in Table (7) and Table (9) are (8,4) and (4,8), respectively, and the parameter T2 of the resource selection window is 20 ms. The (m, M) parameter combinations, in which the number of PPPPs is the parameter m and the number of CCs is the parameter M, in Table (8) and Table (10) are (8,4) and (4,8) as well, and the parameter T2 of the resource selection window is 10 ms. Table (1) to Table (10) all include two service types, i.e., #1 and #2.
In Table (1), the PPPP group corresponding to one CC includes one PPPP, a parameter T2 of a resource selection window is 20 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(8, 7, 6, 5, 4, 3, 2, 1), and an index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 1, 2, 3, 4, 5, 6, 7).
In Table (2), the PPPP group corresponding to one CC includes one PPPP, the parameter T2 of the resource selection window is 10 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(8, 7, 6, 5, 4, 3, 2, 1), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 1, 2, 3, 4, 5, 6, 7).
In Table (3), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 20 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4 n5, n6, n7, n8)=(8, 8, 6, 6, 4, 4, 2, 2), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 2, 2, 4, 4, 6, 6).
In Table (4), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 10 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(8, 8, 6, 6, 4, 4, 2, 2), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 2, 2, 4, 4, 6, 6).
In Table (5), the PPPP group corresponding to one CC includes three PPPPs, the parameter T2 of the resource selection window is 20 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(8, 8, 8, 5, 5, 5, 2, 2), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 0, 3, 3, 3, 6, 6).
In Table (6), the PPPP group corresponding to one CC includes three PPPPs, the parameter T2 of the resource selection window is 10 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(8, 8, 8, 5, 5, 5, 2, 2), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 0, 3, 3, 3, 6, 6).
In Table (7), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 20 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n3, n4, n5, n6, n7, n8)=(4, 4, 3, 3, 2, 2, 1, 1), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 1, 1, 2, 2, 3, 3).
In Table (8), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 10 ms, the number of CCs corresponding to PPPP1-PPPP8 is (n1, n2, n4, n4, n5, n6, n7, n8)=(4, 4, 3, 3, 2, 2, 1, 1), and the index offset of the CCs corresponding to PPPP1-PPPP8 is (l1, l2, l3, l4, l5, l6, l7, l8)=(0, 0, 1, 1, 2, 2, 3, 3).
In Table (9), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 20 ms, the number of CCs corresponding to PPPP1-PPPP4 is (n1, n2, n3, n4)=(8, 8, 4, 4), and the index offset of the CCs corresponding to PPPP1-PPPP4 is (l1, l2, l3, l4)=(0, 0, 4, 4).
In Table (10), the PPPP group corresponding to one CC includes two PPPPs, the parameter T2 of the resource selection window is 10 ms, the number of CCs corresponding to PPPP1-PPPP4 is (n1, n2, n3, n4)=(8, 8, 4, 4), and the index offset of the CCs corresponding to PPPP1-PPPP4 is (l1, l2, l3, l4)=(0, 0, 4, 4).
Table (10) is taken as an example, and it is assumed that the UE 100 is set to correspond to the fourth PPPP (i.e., PPPP4), and the measurement values of the channel statuses (referring to the CBRs in this example) calculated by the processor 160 for all the CCs are 0.68. It can be learned from Table (10) that the fourth PPPP corresponds to the fifth, the sixth, the seventh, and the eighth CCs, and the corresponding CBR threshold values are 0.75, 0.7, 0.65, and 0.6, respectively. Since the measurement values of the channel statuses (0.68 and 0.68, respectively) for the fifth CC and the sixth CC corresponding to PPPP4 are both less than the corresponding CBR threshold values (0.75 and 0.7, respectively), the fifth CC and the sixth CC can be determined as the candidate CCs of the UE 100. The measurement values of the channel statuses (0.68 and 0.68, respectively) for the seventh CC and the eighth CC corresponding to PPPP4 are both greater than the corresponding CBR threshold values (0.65 and 0.6, respectively), and thus the seventh CC and the eighth CC cannot be determined as the candidate CCs of the UE 100.
The processor 160 then selects at least one of the candidate CCs as at least one selected usable CC and performs a resource sensing and selection process on the at least one selected usable CC through the receiver 120 (step S350). In an embodiment, the processor 160 can determine at least one selected usable CC from all the CCs according to the priority order of the candidate CCs and a capability of the UE 100. According to the present embodiment, the smaller the index of the CC corresponding to each PPPP, the higher the priority of the CC. For instance, the priority of the first CC is higher than the priority of the second CC. The capability of the UE 100 are associated with the number of the CCs which can be supported by the UE 100 (including the transmitting end, the receiving end, or both) at the same time, the supported frequency band, whether CA is supported, allowable bandwidth, and/or other parameters.
In another embodiment, if the UE 100 is capable of transmitting data with use of a certain number of CCs at the same time, and the certain number of CCs is greater than or equal to the number of the candidate CCs obtained after the step S330, the processor 160 directly determines all of the candidate CCs as the selected usable CCs.
After the selected usable CCs are determined, please refer to
If the resource location of the SA region and the data region shown in
On the other hand, if the resource location of the SA region and the data region shown in
In another embodiment, the resource sensing process is divided into two stages: the first stage is based on a subchannel resource, and the second stage is based on a resource block group (RBG). As to the first-sage resource sensing process based on the subchannel resource, a resource of each selected usable CC is divided into multiple subchannel resources according to time and/or frequency, wherein the size of the subchannel resources is determined by the upper layer, and each subchannel resource includes at least one RBG. The processor 160 receives signals through the receiver 120 and measures the strength of the signals of all subchannel resources in each selected usable CC. According to a first energy threshold value (which may be determined in advance or dynamically adjusted according to the average power of background noise), the processor 160 determines statuses of all subchannel resources in each selected usable CC. In response to the energy (average or in certain segment) obtained by measuring a certain subchannel resource in a certain selected usable CC being smaller than or equal to the first energy threshold value, the processor 160 determines that the subchannel resource is an idle subchannel resource, and the idle subchannel resource is a candidate resource configured for resource selection. In response to the energy obtained by measuring the subchannel resource being greater than the first energy threshold value, the processor 160 determines that the subchannel resource is not the idle subchannel resource but a busy subchannel resource. As shown in
As to the second-stage resource sensing process based on the RBG, for accuracy, the processor 160 further divides the busy subchannel resources (e.g., the busy resources shown in
As exemplarily shown in
In an embodiment, as to the busy resources, the processor 160 may further determine whether the BRBGs are decodable resource regions or collision resource regions according to a third energy threshold (which may be determined in advance or dynamically adjusted according to the energy threshold value used in the SA decoding process). In response to the energy (average or in certain segment) obtained by measuring a certain BRBG being smaller than or equal to the third energy threshold value, the processor 160 determines that the BRBG is a decodable resource region. In response to the energy obtained by measuring the BRBG being greater than the third energy threshold value, the processor 160 determines that the BRBG is a collision resource region.
In still another embodiment of resource sensing, the processor 160 may combine the resource occupancy information-based resource sensing method and the two-stage energy measurement resource sensing method as described above and compare the resource status indications (including whether the resource is occupied, decodable, or idle) obtained by applying said two methods in conjunction with weight coefficients (e.g., determine whether the results obtained by applying the two methods are the same), so as to obtain a more reliable and accurate hybrid resource indication. For instance, if the resource location of the SA region and the data region is pre-configured, the resource status indication obtained by applying the resource occupancy information-based resource sensing method will give higher weight coefficients to the decodable resource region and the collision resource region. If the resource location of the SA region and the data region is not pre-configured, the resource status indication obtained by applying the resource occupancy information-based resource sensing method will give higher weight coefficients to the decodable resource region.
A resource pool (RP) corresponding to each selected usable CC may be determined based on the corresponding PPPP. In an embodiment, the processor 160 may equally or unequally divide the RP (e.g., the resource R shown in
In another embodiment, the processor 160 may unequally divide the resource pool (e.g., the resource R shown in
As to resource selection, the processor 160 may sequentially assign a corresponding location number to each RU in the selected usable CC, wherein the size of the RU is determined by the upper layer, and each RU includes at least one RB.
The processor 160 randomly performs the initial resource selection process or the resource reselection process on one of the IRBs (e.g., the IRBs shown in
If the selected resource collides, the processor 160 determines to perform the next resource reselection process on all idle resources or all collided resources sensed in the next resource sensing process according to the value of the location number corresponding to the corresponding resource selected in the initial resource selection process or the resource reselection process. The collision of the selected resource indicates that the resource is simultaneously selected by at least two UEs 100 during resource selection or reselection process. As exemplarily shown in
As exemplarily shown in
Note that the determination of the value of the location number is based on the threshold value of the location number which is associated with the number of all IRBs or CRBs. For example, in the previous embodiment, the threshold value of the location number is half the number of all CRBs and is thus two, and the two UEs 100 encountering the collision issue and selecting the smallest location number would select any one of the four CRBs corresponding to the location numbers 17, 19, 27, and 29 randomly. Besides, in other embodiments, the UEs 100 selecting the smaller location numbers may randomly select the idle resources, and the UEs 100 selecting the larger location numbers may randomly select the collided resources.
In addition to the resource reselection process performed on the same selected usable CCs, in response to the number of times of collisions exceeding a threshold value (e.g., the number of times is 3, 5, or 7) when the resource selection process is performed on a first selected usable CC, the processor 160 performs a resource sensing and selection process on another newly selected usable component carrier (CC) different from the first selected usable CC (step S750), and the resource sensing and selection process on the first selected usable CC is stopped. Here, the newly selected usable CC is selected from one of the other candidate CCs having the highest priority. As exemplarily shown in
To sum up, improvement of V2X mode 4 is described according to the UE and the resource sensing and selection method provided in one or more embodiments of the disclosure. Based on its PPPP, the UE obtains the channel status threshold value corresponding to each of the CCs and to its PPPP through looking up the channel usage threshold-PPPP mapping table set by the upper layer, and the measurement value of the channel status for the corresponding CC is compared with the corresponding channel status threshold value, so as to determine the candidate CC. Next, according to the capability of the UE and the priority order of the CCs, at least one of the candidate CCs is selected as at least one selected usable CC on which the resource sensing and selection process is simultaneously performed. As to resource sensing, the location information of the busy resources and the idle resources may be obtained according to the resource occupancy information, energy measurement, or the combination thereof. As to resource selection, if the selected resource encounters collision, the resource reselection is performed on all idle resources or all collided resources sensed in the next resource sensing process according to the location number corresponding to the corresponding resource selected in the initial resource selection process or the resource reselection process.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 107138692 | Oct 2018 | TW | national |
This application claims the priority benefits of U.S. provisional application Ser. No. 62/587,423, filed on Nov. 16, 2017, U.S. provisional application Ser. No. 62/629,151, filed on Feb. 12, 2018, and Taiwan application serial no. 107138692, filed on Oct. 31, 2018. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of specification.
| Number | Date | Country | |
|---|---|---|---|
| 62587423 | Nov 2017 | US | |
| 62629151 | Feb 2018 | US |
