Patent ID: 12245287

DETAILED DESCRIPTION

As explained above, a particular EDT configuration is likely not optimal in all scenarios. For example, requiring use of only a large EDT-TBS may result in resource waste and increased UE power consumption if the actual sizes of transmission data in the buffers of the UEs are smaller than the EDT-TBS. As another example, requiring use of only a small EDT-TBS may result in more use of legacy random access procedure(s) and thus increased resource waste. Also using a small EDT-TBS may result in increased power consumption at UEs if the actual sizes of transmission data in the buffers of the UEs are larger than the EDT-TBS.

Accordingly, in some embodiments of this disclosure, the EDT-TBS that is optimal for a cell may be set based on any one or combination of the sizes of data actually transmitted from all UEs served by the cell, a resource efficiency, and a ratio/probability of using EDT procedure given the selected EDT-TBS.

FIG.1shows a portion of an exemplary communication system100according to some embodiments. In the system100, the network node104may serve UEs102located in an area150. The number of network node(s) and the number of UEs shown inFIG.1are just provided for illustration purpose only and do not limit the embodiments of this disclosure in any way.

The UEs102may be any device capable of connecting to a wireless network. For example, the UEs102may be a smart parking meter, a mobile phone, a tablet, a laptop, an IoT, or any other computing device. The network node104may be any network entity that may be involved in communicating with the UEs102. InFIG.1, the network node104is a base station (e.g., a 4G base station (“eNB”)).

The UEs102may use EDT for data exchange with the network node104. To optimize EDT, the system100may perform a process600shown inFIG.6according to some embodiments. In some embodiments, the network node104performs the process600. In other embodiments, any one or more network entities (including the network node104) perform the process600.

The process600may begin with step s602. In the step s602, the system100sets an initial EDT configuration. In order for the network node104to obtain information regarding the sizes of actual data that the UEs102want to transmit to the network node104, the network node104may initially allow the UEs102to use TBSs that are smaller than the EDT-TBS (e.g., allowing the UEs102to select any TBS smaller than the EDT-TBS from a non-restricted TBS set) so that the UEs102can choose the TBSs that match data size in their buffers instead of using the fixed EDT-TBS.

For example, the network node104may configure the message Msg0 shown inFIG.3to include information identifying an initial EDT-TBS and information indicating that the UEs102are allowed to select any TBS smaller than or equal to the initial EDT-TBS from a non-restricted TBS set. In some embodiments, the message Msg0 is a broadcasted message including SIB and the information is included in the SIB.

After setting the initial EDT configuration, in step s604, the system100may log data samples collected during a period T to create a TBS distribution. For example, after the UEs102receive the message Msg0 from the network node104, the UEs102may transmit actual uplink data to the network node104using any TBS that (1) is smaller than or equal to the initial EDT-TBS and that (2) is included in the non-restricted set of TBSs. The actual uplink data may be sent from the UEs102using the message Msg3 shown inFIG.3.

After the network node104receives the actual data from the UEs102, the network node104may analyze the received data to determine sizes of the received data. After the network node104collects information regarding sizes of data transmitted from the UEs for enough time, the network node104may build up a probability mass function (pmf) (or more generally a continuous probability density function (pdf) or empirical distribution function) for different TBSs included in the non-restricted set of TBSs, which will be used to calculate a resource efficiency later.FIG.7is a graph illustrating various pmf values for different TBSs.

The x-axis of the graph shown inFIG.7represents TBSs used by the UEs102for data transmission and the y-axis of the graph represents the pmf values corresponding to each TBS used by the UEs102. For example, the pmf value of 0.1 for TBS 504 may indicate that among the UEs that used EDT for data transmission to the network node104, 10% of the UEs used the TBS 504. Similarly, the pmf value of 0.3 for TBS 536 may indicate that among the UEs that used EDT for data transmission to the network node104, 30% of the UEs used the TBS 536.

Referring back toFIG.6, after creating the TBS distribution in the step s604, in step s606, the system100may determine an optimal EDT configuration based on the TBS distribution. Determining an optimal EDT configuration may comprise (1) determining an optimal EDT-TBS and/or (2) determining whether to allow the UEs102to select a TBS from a restricted set of TBSs or a non-restricted set of TBSs.

FIG.8illustrates a process800of determining an optimal EDT-TBS based on the TBS distribution according to some embodiments. The process800may begin with step s802. In the step s802, the system100calculates a resource efficiency. The resource efficiency may indicate an efficiency of EDT usage in the system100. In some embodiments, the resource efficiency is calculated as follows:

Resource⁢Efficiency=Resource⁢NeededResource⁢Allocated.
The “Resource Allocated” may be based on the initial EDT-TBS indicated in the message Msg0 shown inFIG.3. In some embodiments, the “Resource Allocated” may be equal to the initial EDT-TBS. Here, the “Resource Allocated” reflects the actual resources that are allocated from the network node104for EDT.

The “Resource Needed” may be based on the values of TBSs that the UEs102used for data transmission (e.g., using the Msg3) and the pmf value associated with each of the TBSs. For example, the “Resource Needed” may be calculated as below:

Resource Needed=Σi=0NTBS(i)*pmf(i), where N is the total number of TBSs in the non-restricted set of TBSs and pmf(i) is the probability mass function of TBS(i) included in the non-restricted set of TBSs. Here, the “Resource Needed” reflects the resources that match the actual needs of the UEs102.

Taking the pmf values shown inFIG.7as an example, the “Resource Needed” may be calculated as follows. InFIG.7, TBS(0) corresponds to 504 and pmf(0) corresponds to 0.1. Similarly, TBS(1) corresponds to 536 and pmf(1) corresponds to 0.3. Thus, in this example, Resource Needed=Σi=0NTBS(i)*pmf(i)=504*0.1+536*0.3+584*0.1+680*0.1+712*0.1+808*0.2+1000*0.1=541.76.

Assuming that the initial EDT-TBS is equal to 1000, the “Resource Allocated” may be equal to 1000. Thus, in the example above, the resource efficiency is equal to

541.761⁢0⁢0⁢0=0.54.

Referring back toFIG.8, after performing the step s802, the system100may perform step s804. Even thoughFIG.8shows that the step s804is performed after the step s802, in some embodiments, the step s804may be performed before the step s802.

In the step s804, the system100may calculate EDT procedure usage ratio. The EDT procedure usage ratio may be calculated based on a number of EDT procedures performed during a period and a number of a particular group of legacy procedures (e.g., legacy random access procedures) performed during the period. The particular group of legacy procedures may be a group of legacy procedures involving transmission of data that can be transmitted using EDT procedures. For example, assuming that EDT procedures cannot be performed for data having TBS greater than 1000 bits, legacy procedures involving transmission of data having TBS greater than 1000 bits need not be considered in calculating the EDT procedure usage ratio because it is not possible to use EDT for transmission of data having such size.

In some embodiments, the EDT procedure usage ratio may be calculated as follows:

ratio_of⁢_edt=nrof_randomaccess⁢_edtnrof_randomaccess⁢_edt+nrof_randomaccess⁢_legacy,
where the “nrof_randomaccess_edt” corresponds to the number of EDT procedures performed during a period and the “nrof_randomaccess_legacy” corresponds to the number of legacy procedures that qualify the criteria discussed in the preceding paragraph. Here, the EDT procedure usage ratio reflects the possibility that the UEs in a cell can use EDT.

In calculating the EDT procedure usage ratio, to avoid counting random access procedure initiated by R-13/R-14 UEs, it may be better to configure random access channel preamble (PRACH) resource for R-15 UEs different from the one used by R-13/R14 UEs.

After calculating the EDT procedure usage ratio, the system100may perform step s806. In the step s806, the system100may select a more optimal EDT-TBS based on the resource efficiency calculated in the step s802and the EDT procedure usage ratio calculated in the step s804.FIG.9illustrates a process of selecting a more optimal EDT-TBS according to some embodiments.

The process900may begin with step s902. In the step s902, the system100may compare the calculated resource efficiency to a first threshold TH1. After performing the step s902, in step s904, the system100may compare the calculated EDT usage ratio to a second threshold TH2. The steps902and s904may be performed in any sequence or may be performed simultaneously.

If the calculated resource efficiency is less than the first threshold TH1and the calculated EDT usage ratio is greater than the second threshold TH2, the system would know that the current EDT-TBS is a bit large. Thus, after performing the steps s902and s904, the system100may perform step s906in which the system100changes the EDT-TBS to a smaller value. The updated EDT-TBS may be indicated to the UEs102in the next SI modification period.

If the calculated resource efficiency is greater than the first threshold TH1and the calculated EDT usage ratio is less than the second threshold TH2, the system would know that the current EDT-TBS is a bit small. Thus, the system100may perform step s910in which the system100changes the EDT-TBS to a larger value. Like the step s906, the updated EDT-TBS may be indicated to the UEs102in the next SI modification period.

After performing the step s906or the step s910, the process900returns back to the step s902. The procedure may continue until that the calculated resource efficiency becomes greater than the first threshold TH1and the calculated EDT usage ratio becomes greater than the second threshold TH2.

When the calculated resource efficiency becomes greater than the first threshold TH1and the calculated EDT usage ratio becomes greater than the second threshold TH2, the system100may determine that the current EDT-TBS is optimal. In some embodiments, the process900may be performed periodically or repeatedly in a non-periodic manner. In those embodiments, after performing the step s908, the process900returns back to the step s902.

Referring back toFIG.6, in addition to determining an optimal EDT-TBS, the step s606may further comprise determining whether to allow the UEs102to select a desired TBS from a restricted set of TBSs or a non-restricted set of TBSs.

For example, in the exemplary sets of TBSs shown inFIG.4, each of the listed EDT-TBSs (except for 408) is associated with two sets of TBSs—a set of four TBSs and a set of two TBSs. The step s606may comprise determining whether to allow the UEs102to select a desired TBS from the set of four TBSs (corresponding to a non-restricted set of TBSs) or from the set of two TBSs (corresponding to a restricted set of TBSs).

Using a restricted set of TBSs may provide the benefit of reducing blind decoding at the network node104but has the drawback of causing increased power consumption at the UEs102(or at least some of the UEs102).

Accordingly, in some embodiments of this disclosure, whether to use a restricted set of TBSs or an unrestricted set of TBSs as the set of candidate TBSs from which the UEs102selects a desired TBS may be determined based on how much the power consumed at the UEs102is increased after switching from using the unrestricted set of TBSs to using the restricted set of TBSs.

FIG.10illustrates a process1000, according to some embodiments, of determining whether to use a restricted set of TBSs or an unrestricted set of TBSs as the set of TBSs from which the UEs102selects a desired TBS. The process1000may be performed by the network node104alone or by any one or more network entities (including the network node104) in the system100. The process1000may begin with step s1002.

In the step s1002, the system100may initially configure the UEs102to select a desired TBS from an unrestricted set of TBSs. For example, referring toFIG.4, the UEs102may receive from the network node104information indicating that (1) the EDT-TBS selected by the network node104is 1000 and (2) the UEs102may select a desired TBS from the unrestricted set of TBSs {328, 536, 776, 1000} associated with the selected EDT-TBS (1000).

After performing the step s1002, in step s1006, the system100may calculate how much the power consumed at the UEs102is increased after the UEs102are switched from using the non-restricted set to using the restricted set. In the example described in the preceding paragraph, the restricted set of TBSs associated with the selected EDT-TBS is {536, 1000} as shown inFIG.4.

In some embodiments, the amount of the increment of the power consumption at the UEs102is calculated as follows:

power_increase=equivaelnt⁢TBS_restrictedequivalent⁢TBS_nonrestricted.

The equivalentTBS_nonrestricted may be equal to Σi=1Ntbs(i)*pmf(i), where i is an index of TBS in the unrestricted set of TBSs and N is the total number of TBSs included in the unrestricted set of TBSs.

For example, when the EDT-TBS selected by the network node104is 1000, in the exemplary sets of TBSs shown inFIG.4, the non-restricted set of TBSs corresponding to the EDT-TBS 1000 is {328, 536, 776, 1000}. Thus, for the purpose of calculating the power increase, N would be equal to 4 and the tbs(i) would correspond to each of 328, 536, 776, and 1000.

Thus, assuming that the pmf value of the TBS 328 is 0.2, the pmf value of the TBS 536 is 0.4, the pmf value of the TBS 776 is 0.3, and the pmf value of the TBS 1000 is 0.1, the equivalentTBS_nonrestricted would be equal to 328*0.2+536*0.4+776*0.3+1000*0.1.

Like the equivalentTBS_nonrestricted, the equivalentTBS_restricted may be equal to Σi=1Ntbs(i)*pmf(i), where i is an index in the restricted set of TBSs and N is the total number of TBSs included in the restricted set of TBSs. But for the restricted set of TBSs, the pmf associated with each TBS is calculated differently.

In some embodiments, the pmf value of each TBS in the restricted TBS set is calculated as follows: for n=1 to Nr, where Nris the number of TBSs included in the restricted TBS set, pmf(n)_restricted=(Σl=1kpmf(l)_unrestricted)−pmf(n−1)_restricted, where n is the index of TBS in the restricted set, l is the index of TBS in the non-restricted set, and k is selected such that TBS(k)_unrestricted=TBS(n)_restricted.

In the example provided above, when the selected EDT-TBS is 1000, in the exemplary sets of TBSs shown inFIG.4, the restricted set of TBSs corresponding to the EDT-TBS 1000 is {536, 1000}. Then the pmfs of the TBS in the restricted set may be calculated as follows: The pmf value of the TBS 536 is the sum of the pmf value of the TBS 328 (0.2) and the pmf value of the TBS 536 (0.4). The pmf value of the TBS 1000 is the sum of the pmf value of the TBS 776 (0.3) and the pmf value of the TBS 1000 (0.1). Thus, in this example, the equivalentTBS_restricted would be equal to 536*0.6+1000*0.4.

Because (1) the power consumption at a UE is related to how much time is needed for an uplink transmission from the UE to a network node and (2) the number of resource units (RUs) and the allocated number of sub-carriers are fixed once the EDT-TBS is determined, according to 3GPP 36.213, the factors that may affect uplink transmission duration may be the repetition number and the number of resource units used through the total number of bits to be transmitted. The repetition number may be determined according to the description in 36.213 as follows: the repetition number for the message Msg3 is the smallest integer multiple of L value that is equal to or larger than

TB⁢SM⁢s⁢g⁢3TBSMsg⁢3,max.
NRepwhere the TBSMsg3is the selected TBS for the message Msg3, and the TBSMsg3, max is given by higher layer parameter EDT-TBS. That is, the repetition number is related to the selected TBS for the message MSG3. Then it is possible to calculate the equivalent MSG3 size for the non-restricted set of TBSs and the restricted set of TBSs, which can represent the power consumption at UEs to see how much power consumption is increased.

Referring back toFIG.10, after calculating the amount of the increment of the power consumption at the UEs102in the step s1006, in step s1008, the system100may compare the calculated amount of the increment of the power consumption to a threshold.

If the increment amount is lower than the threshold, in step s1010, the system100may configure the UEs102to use the restricted set of TBSs for data transmission because using the restricted set of TBSs would benefit the network node104(e.g., less blind decoding at the network node104) without negatively affecting the UEs102too much. On the other hand, if increment amount is higher than the threshold, in step s1012, the system100may configure the UEs102to use the non-restricted set of TBSs for data transmission.

In other embodiments, the power consumption at the UEs102when the UEs102selected TBSs from the non-restricted set of TBSs and the power consumption at the UEs102when the UEs102selected TBSs from the restricted set of TBSs may be compared by directly comparing TBSs in the non-restricted set and TBSs in the restricted set.

Specifically, because the amount of power consumption at the UEs102correlates to the size of possible paddings, if the network node104knows typical TBSs that the UEs102prefer to use (and thus the pmf associated with each TBS), the network node104may directly compare TBSs in the non-restricted set and TBSs in the restricted set, and determine whether configuring the UEs102to select a desired TBS from the restricted set would result in much more power consumption at the UEs102as compared to when the UEs102are configured to select a desired TBS from the non-restricted set.

The comparison of the TBSs in the non-restricted set and the TBSs in the restricted set may be performed by calculating an average overhead of each option. If the average overhead is under a threshold (e.g., when it is not expected that the restricted set would result in heavy increase of power consumption), the restricted set of TBSs may be used. On the other hand, if the average overhead is above or equal to the threshold, the non-restricted set of TBSs may be used.

For example, assuming that the network node104serves a total of four UEs102two of which have a desired TBS value of 328 and the other two of which have a desired TBS value of 1000, if the non-restricted set of TBSs is {328, 536, 776, 1000} and the restricted set of TBSs is {536, 1000}, no padding is required when the non-restricted set of TBSs is selected because all of the TBS values desired by the UEs102are already included in the selected set of TBS. On the other hand, when the restricted set of TBSs is selected, some paddings would be required for the two of the UEs102that have a desired TBS value of 328. The average overhead resulting from the required paddings may be calculated based on (1) the difference between the TBS value(s) desired by some of the UEs102, which is not included in the restricted set (e.g., 328) and the TBS value(s) included in the restricted set that is closest to the desired TBS value(s) (e.g., 536) and (2) the number of EDT procedures that used the desired TBS value(s) which is not included in the restricted set (e.g. here, two UEs used the TBS 328 which is not included in the restricted set of TBS values—{536, 1000}).

Whether to select the non-restricted set or the restricted set of TBSs may be determined based on a value reflecting the amount of padding.

In some embodiments, the above methods of determining whether to use the non-restricted set of TBSs or to use the restricted set of TBSs as the set of TBSs from which the UEs102select desired TBSs may also be used to determine whether to allow the UEs102to use a single TBS (i.e., the EDT-TBS) or to select a desired TBS from multiple candidate TBSs.

In addition to the power consumption at the UEs102, the network node104may also consider network/cell load conditions in finding optimal EDT-TBS configuration. For example, when the network node104is under heavy load, it makes sense to select EDT-TBS configuration such that the selected EDT-TBS configuration does not lead to multiple blind decoding attempts. Thus, in some embodiments, the network node104may set one or more thresholds for network/cell load condition. For example, if the current network load detected by the network node104is greater than a first threshold, the network node104may select EDT-TBS configuration that does not involve a particular number of decoding attempts (e.g., 4). On the other hand, if the current network load detected by the network node104is greater than a second threshold, the network node104may select EDT-TBS that does not involve any decoding attempts.

Referring back toFIG.6, after the system100determines an optimal EDT configuration, in step s608, the system100may notify the UEs102regarding the determined optimal EDT configuration. For example, the network node104may broadcast a message comprising SIB that includes information identifying the determined optimal EDT configuration.

As shown inFIG.6, in some embodiments, the process of determining an optimal EDT configuration may be performed periodically or repeatedly in a non-periodic manner. Thus, in some embodiments, after broadcasting the message including information identifying the determined optimal EDT configuration, the system100may perform again the step s602—logging data samples during a next time period to create updated TBS distribution. After creating the updated TBS distribution, in the step s606, the system100may determine an updated optimal EDT configuration based on the updated TBS distribution and, in the step s608, broadcast a message including the updated optimal EDT configuration.

FIG.11is a flow chart illustrating a process1100for optimizing EDT configuration. Process1100may be performed by the network node104and begin in step s1102.

Step s1102comprises transmitting, during a first period (e.g., a slot), first transport block size (TBS) information. The first TBS information may indicate a first set of one or more EDT TBSs. The first set of EDT TBSs may comprise a maximum EDT TBS.

Step s1104comprises obtaining EDT usage information.

Step s1106comprises based on the obtained EDT usage information, determining whether to transmit, during a second period, the first TBS information or second TBS information indicating a second set of one or more EDT TBSs. The first set and the second set of EDT TBSs may be different.

Step s1108comprises transmitting, during the second period (e.g., a later slot), the first TBS information or the second TBS information based on the determination.

In some embodiments, the EDT usage information comprises i) information indicating a number of EDTs performed during a time period and ii) for each EDT performed during the time period, information indicating the TBS used for the EDT.

In some embodiments, determining whether to transmit the first TBS information or the second TBS information comprises: calculating a resource efficiency based on the obtained EDT usage information, calculating an EDT usage ratio based on the obtained EDT usage information, comparing the resource efficiency to an efficiency threshold, and comparing the EDT usage ratio to a usage threshold.

In some embodiments, determining whether to transmit the first TBS information or the second TBS information comprises calculating a resource efficiency based on the obtained EDT usage information.

In some embodiments, the resource efficiency is equal to RN/RA and RA is equal to the maximum TBS. A probability value may be assigned to each EDT TBS included in the first set of EDT TBSs, and RN may be determined based on the assigned probability values.

In some embodiments, RN=Σi=1NTBS(i)*pmf(i), where N is the number of EDT TBSs in the first set of one or more EDT TBSs, TBS(i) is the ith EDT TBS included in the first set of EDT TBSs, and pmf(i) is the probability value assigned to the ith EDT TBS.

In some embodiments, determining whether to transmit the first TBS information or the second TBS information comprises comparing the resource efficiency to an efficiency threshold. The method may further comprise after determining that the resource efficiency is less than the efficiency threshold, selecting the second set of TBSs such that the second set of TBSs includes a maximum EDT TBS that is smaller than the maximum EDT TBS included in the first set of EDT TBSs.

In some embodiments, determining whether to transmit the first TBS information or the second TBS information includes calculating an EDT usage ratio based on a number of EDT procedures performed during a certain time period.

In some embodiments, the EDT usage ratio is equal to

nrof_randomaccess⁢_edtnrof_randomaccess⁢_edt+nrof_randomaccess⁢_legacy,
where the nrof_randomaccess_edt corresponds to the number of EDT procedures performed during a period and the nrof_randomaccess_legacy corresponds to the number of a particular group of legacy procedures performed during the period.

In some embodiments, determining whether to transmit the first TBS information or the second TBS information comprises comparing the EDT usage ratio to a usage threshold. The method may further comprise after determining that the EDT usage ratio is higher than the usage threshold, selecting the second set of TBSs such that the second set of TBSs includes a maximum EDT TBS that is smaller than the maximum EDT TBS included in the first set of EDT TBSs.

FIG.12is a block diagram of an apparatus1200, according to some embodiments. The apparatus1200may be used to implement the network node104. As shown inFIG.12, the network node may comprise: processing circuitry (PC)1202, which may include one or more processors (P)1255(e.g., one or more general purpose microprocessors and/or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like), which processors may be co-located in a single housing or in a single data center or may be geographically distributed (i.e., apparatus1200may be a distributed computing apparatus); a network interface1268comprising a transmitter (Tx)1265and a receiver (Rx)1267for enabling apparatus1200to transmit data to and receive data from other nodes connected to a network110(e.g., an Internet Protocol (IP) network) to which network interface1248is connected; communication circuitry1348, which is coupled to an antenna arrangement1249comprising one or more antennas and which comprises a transmitter (Tx)1245and a receiver (Rx)1247for enabling the network node to transmit data and receive data (e.g., wirelessly transmit/receive data); and a local storage unit (a.k.a., “data storage system”)1208, which may include one or more non-volatile storage devices and/or one or more volatile storage devices. In embodiments where PC1202includes a programmable processor, a computer program product (CPP)1241may be provided. CPP1241includes a computer readable medium (CRM)1242storing a computer program (CP)1243comprising computer readable instructions (CRI)1244. CRM1242may be a non-transitory computer readable medium, such as, magnetic media (e.g., a hard disk), optical media, memory devices (e.g., random access memory, flash memory), and the like. In some embodiments, the CRI1244of computer program1243is configured such that when executed by PC1202, the CRI causes the network node to perform steps described herein (e.g., steps described herein with reference to the flow charts). In other embodiments, the network node may be configured to perform steps described herein without the need for code. That is, for example, PC1202may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and/or software.

While various embodiments are described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of this disclosure should not be limited by any of the above-described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.