WO2012095051A2

WO2012095051A2 - Resource allocation method and device

Info

Publication number: WO2012095051A2
Application number: PCT/CN2012/071732
Authority: WO
Inventors: 米哈伊尔·皮勒斯基; 唐志华
Original assignee: 华为技术有限公司
Priority date: 2012-02-28
Filing date: 2012-02-28
Publication date: 2012-07-19
Also published as: CN102754464B; WO2012095051A3; CN102754464A

Abstract

Embodiments of the present invention provide a resource allocation method and device, which relate to the field of communications, and can decrease the design difficulty of a resource allocation algorithm of a system, and enable the system to reasonably allocate system resources to a user. The method is: acquiring marginal utility of a user according to a utility value of the user; detecting the number of remaining resource blocks of a system, and when the number of remaining resource blocks is not zero, determining, according to marginal utility of the users, a user of maximum marginal utility, and adding a resource block for the user of the maximum marginal utility; and determining a data rate of the user according to the number of the resource blocks allocated to the user and maximum uplink power of the user, to allocate resources to the user. The embodiments of the present invention are applicable to system resource allocation based on a utility function.

Description

Resource allocation method and device

The present invention relates to the field of communications, and in particular, to a resource allocation method and apparatus.

Background technique

In the prior art, a resource allocation method based on utility maximization usually maps system resources (such as bandwidth, power) or performance indicators (data rate, delay) through a utility function to a corresponding user's utility value, and then according to the utility value. Optimize the system. Since the user data rate is the most important factor in determining user satisfaction, the utility function is typically modeled as a function of the user's average data rate. With this approach, each user can choose the appropriate utility function to meet specific needs, business characteristics, and even different operator preferences.

For the LTE (Long Term Evolution) system, the minimum unit of user resource allocation is RB (Resource Block). When allocating resources to users, fully consider the uplink single carrier constraint, that is, how to give each Each user allocates RBs, and each user's uplink power is limited (the uplink power limitation of each user can be understood as the uplink maximum power). In the prior art, the algorithm for allocating RBs to users is complicated and computationally intensive, which is difficult to implement, thereby increasing the design difficulty of the uplink LTE system resource allocation algorithm, and making it difficult for the system to allocate resources to users reasonably.

Summary of the invention

The embodiments of the present invention provide a resource allocation method and apparatus, which can reduce the design difficulty of the system resource allocation algorithm, and enable the system to allocate the system resources to the user.

Embodiments of the present invention adopt the following technical solutions:

In one aspect, a method for resource allocation is provided, including:

Obtaining the marginal utility of the user according to the utility value of the user;

Detecting the number of remaining resource blocks of the system, when the number of remaining resource blocks is not zero, determining a user with the largest marginal utility according to the marginal utility of the user, and adding a resource block to the user with the largest marginal utility ;

Determining a data rate of the user according to the number of resource blocks allocated by the user and the uplink maximum power of the user to allocate resources to the user.

In another aspect, a resource allocation apparatus is provided, including: An obtaining unit, configured to obtain a marginal utility of the user according to the utility value of the user; a processing unit, configured to detect a number of resource blocks remaining in the system, when the number of remaining resource blocks is not zero, according to the user The marginal utility determines the user with the greatest marginal utility and adds a resource block to the user with the greatest marginal utility;

And a determining unit, configured to determine a data rate of the user according to the number of resource blocks allocated by the user and the uplink maximum power of the user, to allocate resources to the user.

An embodiment of the present invention provides a resource allocation method and apparatus, by calculating a marginal utility of a resource block for a user according to a utility value of a user, and detecting the number of resource blocks remaining in the system, when the number of remaining resource blocks is not Zero time, determine the user with the largest marginal utility according to the user's marginal utility, and add a resource block for the user with the largest marginal utility until the number of remaining resource blocks is zero, and finally according to the number of resource blocks allocated by the user and the user The maximum uplink power determines the user's data rate to allocate resources to the user, which reduces the design difficulty of the system's resource allocation algorithm, and enables the system to allocate the system resources to the user.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set forth in the drawings Other drawings may also be obtained from these drawings without paying for creative labor. 1 is a schematic flowchart 1 of a resource allocation method according to an embodiment of the present invention;

2 is a schematic flowchart 2 of a resource allocation method according to an embodiment of the present invention; FIG. 3 is a schematic structural diagram of a resource allocation apparatus according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention. The resource allocation method provided by the embodiment of the present invention, as shown in FIG. 1 , includes:

5101. Obtain a user's marginal utility according to the user's utility value.

5102. Detect the number of resource blocks remaining in the system. When the number of remaining resource blocks is not zero, determine the user with the largest marginal utility according to the user's marginal utility, and add a resource block for the user with the largest marginal utility.

S103. Determine a data rate of the user according to the number of resource blocks allocated by the user and the maximum uplink power of the user, to allocate resources to the user. An embodiment of the present invention provides a resource allocation method, by calculating a marginal utility of a resource block for a user according to a utility value of a user, and detecting a number of resource blocks remaining in the system, when the number of remaining resource blocks is not zero. According to the user's marginal utility, determine the user with the largest marginal utility, and add a resource block for the user with the largest marginal utility until the number of remaining resource blocks is zero. Finally, according to the number of resource blocks allocated by the user and the user's uplink. The maximum power determines the user's data rate to allocate resources to the user, and reduces the design difficulty of the system's resource allocation algorithm, thereby enabling the system to allocate resources to the user reasonably.

The second embodiment of the present invention provides a resource allocation method, as shown in FIG. 2, which is specifically illustrated in the first embodiment, and includes:

S201. Calculate, according to the utility value of each user, a marginal utility of adding a resource block to each user.

In a system, the goal of resource allocation is to maximize the utility of the system. The maximum value of system utility can be formulated:

St. Μ, + Μ _Ί + · · - + Μ _ν ≤Μ Get, where K is the number of users, is the user's serial number, [ (Μ) assigns ^ to the user! The utility value of ^, ^ + ^ + ... + ^ ≤ ^ is a constraint condition, that is, the sum of the number of RBs allocated to each user is less than or equal to the total number of RBs. Therefore, it can be seen that to maximize the utility of the system, firstly, the number of RBs of the user is obtained, that is, the RB allocation is first performed, and to realize the allocation of the RB, the marginal utility of the user is first obtained. Specifically, the marginal utility of the user is:

(M _k ) = U _k (M _k )-U _k (M _k -l) (2) where Δ ₄ (Μ ₄ ) assigns the marginal utility of _3⁄4 RBs to the user, and U^M^ assigns M to the household k The utility value of _k RBs, U _k (M _k -1) is the utility value of the user to allocate M _t -1 RBs, that is, the utility value after adding one RB to the user minus the utility value before the increase. Exemplarily, it is assumed that the system has three users, and it is assumed that the maximum number of RBs that can be allocated in the system is 7, as shown in Table 1, the user utility values when the number of RBs is 0-7 are allocated for the above three users. Where is the user's serial number, M is the number of RBs allocated to the user, and U^M) is the utility value of assigning M RBs to the tenant.

Table 1. User utility values

As can be seen from Table 1, the marginal utility of User 1 from 0 RBs to 1 RB is Δ ₁ (ΐ) = [/ ₁ (ΐ)-[/ ₁ (0) = 0.104-0 = 0.104, User 1 The marginal utility of increasing one RB to two RBs is (2) two (2) - [^(1) = 0.155 -0.104 = 0.051. Similarly, the value of ~ can be calculated, and the marginal utility of user 2 can also be calculated. Δ ₂ (1) ~ Δ ₂ (7) , and the marginal utility of user 3 Δ ₃ (1) ~ Δ "7;), the results are shown in Table 2: Table 2. User marginal utility values

Where is the user's serial number, M is the number of RBs allocated to the user, and M) is the marginal utility generated by allocating M RBs to the user. Further, the utility values of the three users assigned 0-7 RBs in Table 1 are calculated according to the utility function. In the system optimization, the system parameters are usually mapped by the utility function according to different needs, and are used to describe System performance or metrics. For example, in an LTE system, system resources (such as bandwidth, power) or performance metrics (data rate, delay) are usually mapped to corresponding utility values by utility functions. Therefore, the utility values calculated according to different utility functions are also different.

Exemplarily, the utility function may be a throughput maximization criterion, a PF (Proportion Fairness) criterion or a Max-Min (maximum and minimum) criterion, and the user may select a corresponding utility function according to his own needs to cope with different The scheduling criteria to meet the different needs of the system.

5202. Determine a user with the largest marginal utility according to the marginal utility of each user, and add a resource block for the user with the largest marginal utility.

Taking Table 2 as an example, when M=l, that is, when the number of RBs of users 1~3 is increased from 0 to 1, the marginal utility of users 1~3 is 0.104, 0.141, 0.133, respectively, and the marginal utility is the largest. User, for user 2.

Then, an RB is added to User 2, and the marginal utility of User 2 becomes 0.084.

5203. Detecting the number of remaining resource blocks of the system, determining whether the number of resource blocks is zero, when Step S202 is performed when the number of remaining resource blocks is not zero; otherwise, step S207 is performed. The number of remaining RBs is detected. It is assumed that the maximum number of RBs that can be allocated in the system is 7, the user 2 is allocated one, and the remaining number of assignable RBs is 6, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.104, 0.084, and 0.133, respectively, and the user with the largest margin is selected as user 3, and then an RB is added to user 3, and the marginal utility of user 3 becomes 0.094.

The number of remaining RBs is detected, and the number of remaining RBs is 5, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.104, 0.084, and 0.094, respectively, and the user with the largest margin is selected as user 1, and then an RB is added to user 1, and the marginal utility of user 1 becomes 0.051.

The number of remaining RBs is detected, and the number of remaining RBs that can be allocated is 4, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.051, 0.084, and 0.094, respectively, and the user with the largest margin is selected as user 3, and then an RB is added to user 3, and the marginal utility of user 3 becomes 0.079.

The number of remaining RBs is detected, and the number of remaining RBs is 3, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.051, 0.084, and 0.079, respectively, and the user with the largest margin is selected as user 2, and then an RB is added to user 2, and the marginal utility of user 2 becomes 0.065.

The number of remaining RBs is detected, and the number of remaining RBs is 2, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.051, 0.065, and 0.079, respectively, and the user with the largest margin is selected as user 3, and then an RB is added to user 3, and the marginal utility of user 3 becomes 0.070.

The number of remaining RBs is detected, and the number of remaining RBs that can be allocated is 1, so step S202 is repeated. At this time, the marginal utility values of users 1 to 3 are 0.051, 0.065, and 0.070, respectively, and the user with the largest margin is selected as user 3, and then an RB is added to user 3.

The number of remaining RBs is detected, and the number of remaining assignable RBs is 0. Therefore, step S204 is performed. It can be seen that 1 RB is allocated to User 1, 2 RBs are allocated by User 2, and 4 RBs are allocated by User 3, that is, the RB allocation scheme of Users 1 to 3 is M = (1, 2, 4). In this way, the allocation problem of the RB can be solved, and it can be seen that only one marginal utility value needs to be re-estimated for each RB allocated in the above step, that is, the marginal utility of the user allocated by the RB, and the marginal utility of the remaining users is not required. Recalculation reduces the amount of computation, which reduces the complexity of the algorithm and reduces the design difficulty of the system resource allocation method. The above method is equivalent to expressing the user's marginal utility as a matrix:

Then, M _max maxima are selected in the above matrix. Where k denotes that the user's serial number M _max represents the total number of RBs. Taking Table 2 as an example, the tag utility of users 1 to 3 can be expressed as:

0.104 0.141 0.133

0.051 0.084 0.094

0.035 0.065 0.079

(5)

0.026 0.053 0.070

0.014 0.034 0.054 Then, the first seven largest values, 0.141, 0.133, 0.104, 0.094, 0.084, 0.079, 0.070, are selected from the above matrix. Among them, 0.104 is the marginal utility value of user 1, 0.141, 0.084 is the marginal utility value of user 2, 0.133, 0.094, 0.079, 0.070 is the marginal utility value of user 3, so user 1 is assigned 1 RB, user 2 is assigned 2 RB, User 3 allocates 4 RBs. After the number of RBs allocated by the user is determined, the maximum value of the system utility can be determined according to formula (1). Exemplarily, according to the RB allocation schemes of the users 1 to 3, it is known that the user 1 allocates one RB, the user 2 allocates two RBs, and the user 3 allocates three RBs, so that it is 1, M ₂ ^ 2, and 3 is 4. At this point, according to Table 1, the system utility value is:

= U, (M _l ) + U ₂ (M ₂ ) + U ₃ (M ₃ )-0.104 + 0.226 + 0.376 = 0.706 The maximum system utility of this system is 0.706. Further, after completing the allocation of the RB, the method further includes:

S204. Calculate a transmit power spectrum of each user according to the number of resource blocks allocated by each user and the uplink maximum power of each user. Specifically, since the number of RBs per user M has been calculated, and the maximum uplink power of the user is known ( _ax is usually specified in the protocol, indicating the power specifications supported by the terminal), according to the formula:

Ra +101og(M)≤ corpse leg (7) It can be concluded that the user's transmit power spectrum is PSD _TX < P _max -101og( ), and the transmit power spectrum can be obtained to control the user's transmit power, which is beneficial to system resource allocation. Optimization.

S205. Calculate a user average signal interference noise ratio according to a user's transmit power spectrum. Specifically, according to the formula:

SINR = PSD _TX -PL- IN ( 8 ) Find the range of the average SINR (Signal to Interference plus Noise Ratio) (Equation (8) does not consider factors such as multi-antenna gain), where PL is the user path loss , IN is the estimated interference noise.

S206. Calculate a data rate of the user according to the number of resource blocks allocated by the user and the average signal interference noise ratio of the user. Specifically, since the data rate R of the user is determined by the number of RBs and the SINR of the user: R^M-FE(SINR) (9) Therefore, the user's data rate can be calculated based on the number of RBs M and SINR, and the SINR is a function of 3⁄4*Z, which is a function of the number of user RBs M, so the data The rate R can be reduced to a function of the number of RBs M:

R^Mf(M) (10) In this way, as long as the number of RBs of the user is determined, the data rate R of the user can be determined, that is, the user can control the user by controlling the number of RBs of the user M when the user allocates the RB. The data rate is beneficial to the optimization of system resource allocation, which reduces the difficulty of system optimization while reducing the design difficulty of the system resource allocation method.

S207, the end. The resource allocation method provided by the embodiment of the present invention first calculates the marginal utility of the user for each additional resource block according to the utility value of the user, as shown in Table 1 in the present embodiment, the user 1 to 3 obtained according to the utility function are assigned 0~ The utility value of 7 RBs, Table 2 is the marginal utility of adding 1~7 RBs according to the users 1~3 obtained in Table 1, and then detecting the remaining RB numbers of the system, when the remaining RB numbers are not zero, according to The marginal utility of the user determines the user with the largest marginal utility, and adds one RB to the user with the largest marginal utility until the number of remaining RBs is zero, thereby obtaining the number of RBs allocated by each user. For example, in Table 2, when users 1 to 3 have only 1 RB, the user with the largest marginal utility is User 2 (0.141), then User 1 is assigned 1 RB, and the user with the largest marginal utility is changed to User 3 (0.133). And if there are 6 remaining assignable RBs, then 1 RB is allocated to User 3, and the user with the largest marginal utility after allocation becomes User 1 (for 0.104) and the remaining assignable RBs are 5, then User 1 is assigned 1 RB, the user with the largest marginal utility after allocation becomes user 3 (for 0.094) and the remaining assignable RBs are four, then user 1 is assigned 1 RB, and the user with the largest marginal utility is assigned to user 2 (0.084) And the remaining number of assignable RBs is three, then one RB is allocated to user 2, and the user with the largest marginal utility after allocation becomes user 3 (for 0.079) and the remaining assignable RBs are two, then one RB is allocated to user 3. If the user with the largest marginal utility after allocation is still user 3 (0.070) and there is one RB that can be allocated, then user 1 is allocated another RB. At this time, the remaining number of RBs that can be allocated is zero, and the allocation ends. Therefore, the number of RBs allocated by users 1 to 3 is 1, 2, and 4, respectively. Finally, the data rate of the user is determined according to the number of RBs allocated by the user and the maximum uplink power of the user, to allocate resources to the user. This reduces the design of the system's resource allocation algorithm. Difficulty, so that the system can allocate the system resources to the user, which increases the throughput of the system.

The third embodiment of the present invention, as shown in FIG. 3, includes: an obtaining unit 010, configured to acquire a marginal utility of a user according to a utility value of the user when the user adds a resource block;

The processing unit 011 is configured to detect the number of resource blocks remaining in the system, and when the number of remaining resource blocks is not zero, determine a user with the largest marginal utility according to the marginal utility of the user, and add a resource block to the user with the largest marginal utility. ;

The determining unit 012 is configured to determine a data rate of the user according to the number of resource blocks allocated by the user and the uplink maximum power of the user, to allocate resources to the user.

Further, the obtaining unit 010 is specifically configured to:

When the user adds a resource block, the user's marginal utility is obtained according to the marginal utility calculation formula;

The marginal utility calculation formula includes:

, in which the user is assigned a marginal utility of RB, (Μ^ assigns a utility value of ^^ to the user, (Μ -1) assigns a utility value of M _t -1 RB to the user.

The determining unit 012 is specifically used for:

Obtaining a transmission power spectrum of the user according to the number of resource blocks allocated by the user and the uplink maximum power of the user;

Obtaining the average signal to interference and noise ratio of the user according to the transmission power spectrum of the user; and obtaining the data rate of the user according to the number of resource blocks allocated by the user and the average signal interference noise ratio of the user.

Further, the obtaining unit 011 is further configured to: acquire a utility value of the user according to the utility function.

The marginal utility of the user is an increment of the user utility value generated by the user for each additional resource block. The apparatus provided by the embodiment of the present invention can perform the operations in the foregoing method embodiments. For example, the obtaining unit 010 can perform the action of S101, the processing unit 011 can perform the action of S102, and the determining unit 012 can perform the action of S103. An embodiment of the present invention provides a resource The source allocation method and device, by calculating the marginal utility of each resource block added by the user according to the utility value of the user, and detecting the number of remaining resource blocks of the system, when the remaining number of resource blocks is not zero, according to the marginal utility of the user Determine the user with the largest marginal utility, and add a resource block to the user with the largest marginal utility until the number of remaining resource blocks is zero. Finally, the user's data is determined according to the number of resource blocks allocated by the user and the maximum uplink power of the user. The rate, in order to allocate resources to the user, reduces the design difficulty of the system's resource allocation algorithm, thereby enabling the system to allocate resources to the user reasonably.

An embodiment of the present invention further provides a processor, configured to calculate, according to a utility value of each user, a marginal utility of adding a resource block for each user; and determining, according to the marginal utility of each user, a user with the largest marginal utility, The user with the largest marginal utility adds a resource block; detects the number of remaining resource blocks of the system, so that the user whose marginal utility is determined according to the marginal utility of each user is repeated when the number of remaining resource blocks is not zero Adding a resource block to the user with the largest marginal utility until the number of remaining resource blocks is zero. The processor can be coupled to a memory for storing information processed by the processor. For the action performed by the processor, refer to the content in the resource allocation method provided in the foregoing embodiment, and details are not described herein again. The processor may be present in the resource allocation device for reasonably allocating resources. The resource allocation device can be a base station.

The embodiment of the present invention further provides a chip for reasonably allocating resource blocks to a user, and the chip may include the foregoing processor. A person skilled in the art can clearly understand that the specific working process of the system, the device and the unit described above can be referred to the corresponding process in the foregoing method embodiments for the convenience and brevity of the description, and details are not described herein again.

In the several embodiments provided herein, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be electrical, mechanical or otherwise.

The unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, may be located in one place. Square, or it can be distributed to multiple network elements. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment. In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may be physically included separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units. The above-described integrated unit implemented in the form of a software functional unit can be stored in a computer readable storage medium. The software functional unit described above is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform portions of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, which can store program codes. Medium.

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

Claim

A resource allocation method, characterized in that it comprises:

The method according to claim 1, wherein when the user adds a resource block, acquiring the marginal utility of the user according to the utility value of the user includes: adding one resource for each user When the block is obtained, the marginal utility of the user is obtained according to the marginal utility calculation formula;

The marginal utility calculation formula includes: ( ) = [ ( )-[ ( -1) , where (M _t ) assigns a marginal utility of the RB to the user, (Μ^ assigns a user a utility value of 18, ( Μ -1) Assign the user the utility value of M _t -1 RBs.

The method according to claim 1 or 2, wherein the determining the data rate of the user according to the number of resource blocks allocated by the user and the uplink maximum power of the user comprises:

Acquiring, according to the transmit power spectrum of the user, an average signal to interference and noise ratio of the user; acquiring according to the number of resource blocks allocated by the user and the average signal interference noise ratio of the user

The data rate of the user.

The method according to any one of claims 1 to 3, wherein before the obtaining the marginal utility of the user for each resource block according to the utility value of the user, the method further comprises: acquiring each according to the utility function. User's utility value.

5. The method according to claim 4, wherein the utility function comprises: a throughput maximization criterion, a proportional fairness criterion or a maximum and minimum criterion.

The method according to any one of claims 1 to 5, characterized in that the marginal utility of the user is an increment of user utility value generated by the user for each additional resource block.

7. A resource allocation device, comprising: An obtaining unit, configured to acquire a marginal utility of the user according to the utility value of the user; a processing unit, configured to detect a number of resource blocks remaining in the system, when the number of remaining resource blocks is not zero, The marginal utility of the user determines the user with the greatest marginal utility and adds a resource block to the user with the largest marginal utility;

And a determining unit, configured to determine a data rate of the user according to the number of resource blocks allocated by the user and an uplink maximum power of the user, to allocate resources to the user.

8. The apparatus according to claim 7, wherein the obtaining unit is specifically configured to:

When the user adds a resource block, the marginal utility of the user is obtained according to a marginal utility calculation formula;

The marginal utility calculation formula includes: ( ) = [ ( )-[ ( -1), where (M _t ) assigns the marginal utility of the RB to the user, (Μ^ assigns a utility value of 18 to the user, (Μ -1) Assign the user the utility value of M _t -1 RBs.

9. Apparatus according to claim 7 or claim 8 wherein the determining unit is for:

Acquiring an average signal to interference and noise ratio of the user according to a transmit power spectrum of the user; and

The data rate of the user is obtained according to the number of resource blocks allocated by the user and the average signal interference noise ratio of the user.

The device according to any one of claims 7-9, wherein the acquiring unit is further configured to:

The utility value of the user is obtained according to a utility function.

The apparatus according to any one of claims 7 to 10, wherein the marginal utility of the user is an increment of user utility value generated by the user for each additional resource block.