JP2012186792A - Method of executing uplink frequency selectivity scheduling in wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of executing an uplink frequency selectivity scheduling of a plurality of user devices in a communication network.SOLUTION: The method includes a step for setting the number of targets of a resource block for each user device out of a plurality of user units, a step for determining the spare capacity of a sub-frame based on the total number of targets of resource blocks available in the sub-frame and resource blocks of the plurality of user units, a step for resetting the number of targets of resource blocks of the first user device out of the plurality of user units, based on the resource block allocation reference and the spare capacity of the sub-frame, a step for determining a fragmentation reference for the sub-frame, and a step for allocating a reset number of targets of resource blocks to the first user device based on the fragmentation reference.

Description

  The present disclosure relates generally to resource block allocation to user equipment in a wireless communication system, and more specifically, single carrier frequency division multiple access (SC-FDMA) based wireless communication. The present invention relates to a method for performing uplink frequency selective scheduling for a system.

  The uplinks of some of the currently popular wireless communication systems, and in particular Long Term Evolution (LTE) communication systems, are allocated to different user equipment (UE) during each subframe ( It consists of individual frequency chunks (also called resource blocks or RBs). The UE channel quality for each of these frequency blocks may vary depending on the coherent bandwidth of the UE channel. A Frequency Selective Scheduling (FSS) scheme in the uplink can assign RBs to UEs in an opportunistic manner based on the quality of RBs assigned to different UEs. However, FSS needs to work within some constraints.

  For the uplink LTE channel, the UE can be assigned only RBs with continuous frequency. Inefficient RB allocation can lead to wasted RB due to fragmentation. By trying all possible RB allocations for all UEs because the computational complexity is too high for the 1 msec (ms) allocation deadline (ie LTE subframe duration) The brute force mechanism for assigning RBs is inappropriate.

  Therefore, there is a need for a method for performing uplink frequency selective scheduling for LTE communication systems.

  A method for performing uplink frequency selective scheduling for a plurality of user equipments in a communication network is disclosed. The method determines a target number of resource blocks for each user device of a plurality of user devices based on resource block allocation criteria including signal quality criteria and proportional fairness criteria, and further based on a set of resource block parameters. Including setting. Further, the method determines the spare capacity of the subframe based on the available resource blocks in the subframe and the total number of targets of the resource blocks of the plurality of user apparatuses. Next, the method resets the target number of resource blocks of the first user equipment among the plurality of user equipments based on the resource block allocation criterion and the spare capacity of the subframe, and the subframe Determine fragmentation criteria for. Further, the method assigns the reconfigured target number of resource blocks to the first user equipment based on the fragmentation criteria.

1 is a block diagram of a wireless communication system according to various embodiments of the invention. FIG. FIG. 3 is a block diagram of a user equipment (UE) according to various embodiments of the invention. FIG. 4 is a block diagram of an access point according to various embodiments of the invention. FIG. 6 is a logic flow diagram illustrating a method for performing uplink frequency selective scheduling (FSS) for multiple user equipments in a communication network according to various embodiments of the invention. FIG. 6 is a logic flow diagram illustrating a method for performing uplink frequency selective scheduling (FSS) for multiple user equipments in a communication network according to various embodiments of the invention. FIG. 4 is a logic flow diagram illustrating a method for allocating resource blocks in a subframe to one user equipment of a plurality of user equipments selected for uplink transmission according to various embodiments of the invention. . FIG. 4 is a logic flow diagram illustrating a method for allocating resource blocks in a subframe to one user equipment of a plurality of user equipments selected for uplink transmission according to various embodiments of the invention. . FIG. 5 is a logic flow diagram illustrating a method for ranking user equipment before FSS, according to an embodiment of the present invention. FIG. 6 is a logic flow diagram illustrating a method for determining whether a UE is a UE that is not receiving sufficient service according to an embodiment of the present invention. FIG. 5 is a logic flow diagram illustrating a method for determining the type of fragmentation form according to an embodiment of the present invention. FIG. 4 is a logic flow diagram illustrating a method for RB allocation in a highly fragmented form according to an embodiment of the present invention. FIG. 4 is a logic flow diagram illustrating a method for RB allocation in a low fragmentation form according to an embodiment of the present invention.

  The accompanying drawings, in which like reference characters refer to the same or functionally similar elements in the different figures, together with the following detailed description, are incorporated into and constitute a part of this specification, It also serves to further describe embodiments of the claimed inventive concept and to explain various principles and effects of those embodiments.

  Those skilled in the art will appreciate that elements in the drawings are illustrated for simplicity and clarity and need not be drawn to scale. For example, some dimensions of elements in the drawings can be exaggerated relative to other elements to help improve understanding of embodiments of the invention.

  The components of the apparatus and method are indicated by the previously indicated symbols in the figures where appropriate and have disclosures with details that will be readily understood by those skilled in the art having the benefit of the description herein. For the purpose of clarity, only certain details relevant to an understanding of embodiments of the invention are shown.

  Before describing in detail a specific method for performing uplink frequency scheduling according to embodiments of the present disclosure, the present disclosure provides uplink frequency selective scheduling for multiple user equipments in a communication network. It should be noted that mainly exists in a combination of method steps for performing. Accordingly, those method steps are indicated by the preceding symbols in the figures where appropriate and have disclosures with details that will be readily understood by those skilled in the art having the benefit of the description herein. To avoid obscuring, only certain details relevant to understanding the present disclosure are shown.

  FIG. 1 is a block diagram of a wireless communication system 100 in accordance with some embodiments of the invention. The wireless communication system 100 includes an access point 102 and a number of user equipments (UEs) 104-106 (three shown) each communicating with the access point via a corresponding wireless link 110-112. Including. It should be noted that there may be any number of access points and UEs within the wireless communication system 100, and the present invention is not limited to the devices 102 and 104-106 illustrated in FIG. .

  Access point 102 is preferably a long term evolution (LTE) access point that can perform a wireless connection to a UE served by the access point, such as UEs 104-106. In various embodiments of the present invention, the LTE access point may be referred to as an eNodeB (sometimes abbreviated as eNB) or an LTE base station. The UEs 104-106 may be any device used by end users communicating on the wireless communication system 100. Examples of UEs include portable radios, cell phones, PDAs for wireless devices, personal computers or laptop computers for wireless devices, cognitive radios, and the like.

  2 and 3, block diagrams of UE 202 and access point 102, such as UEs 104-106, according to one embodiment of the present invention are illustrated. Each of the UE 202 and access point 102 has a respective processor 204, such as one or more microprocessors, microcontrollers, digital signal processors (DSPs), combinations thereof, or other such devices known to those skilled in the art. 304, each processor is configured to perform the functions described herein as executed by UE 202 and access point 102, respectively. Each of UE 202 and access point 102 may be performed by an associated processor, respectively, and data that enables UE 202 and access point 102 to perform all functions necessary to operate within communication system 100. And at least one storage device 206, 306, which may include random access memory (RAM) holding programs, dynamic random access memory (DRAM) and read only memory (ROM), or the like, or the equivalent thereof. Further included. Each of the UE 202 and the access point 102 also has a respective radio frequency (RF) transmitter 208, 308 for transmitting signals over the corresponding radio interface and a respective RF receiver for receiving signals over the corresponding radio interface. 210, 310.

  The access point 102, and more specifically, the processor 310 of the access point, performs the scheduling function described herein based on a program held by at least one storage device 306 of the access point. A scheduler 302 to be executed is implemented. Unless otherwise specified herein, the functionality described herein as performed by access point 102 is performed by scheduler 302, and further, each at least associated with that access point Implemented by or implemented in software programs and instructions stored in one storage device 306 and executed by processor 304 associated with the access point. However, in other embodiments of the invention, the scheduler 302 is independent of that access point and that access point while performing the functionality described herein as performed by the access point 102. There is a possibility that it becomes an element combined with. In such a case, the functions described herein as performed by the access point 102 are performed by the scheduler processor based on a program held by at least one storage device of the scheduler. Alternatively, such functionality can be exchanged between the access point (at least one storage device and processor thereof) and the scheduler. For example, determination of signal quality criteria (metric) can be performed by the access point and communicated to the scheduler during selection of a UE for scheduling and allocation of resource blocks to the selected UE The criteria can be executed by the scheduler.

  Also, the functionality described herein as performed by each of the UEs 104-106 is stored in each at least one storage device 122 associated with that UE and by the processor 204 associated with that UE. Implemented by or implemented within software programs and instructions that are executed. However, one of ordinary skill in the art will recognize embodiments of the present invention in hardware, eg, an integrated circuit (IC), and an application specific integrated circuit (such as an ASIC implemented in one or more of its scheduler, BS and UE). Clearly understand that ASIC) can be implemented alternatively. One of ordinary skill in the art will readily be able to make and implement such software and / or hardware without undue experimentation based on the present disclosure.

  The communication system 100 employs a single carrier frequency division multiple access (SC-FDMA) modulation scheme for transmitting data over the radio interfaces 110-112, where the frequency bandwidth used by the communication system is: During a predetermined period, it is divided into a number of frequency subbands or resource blocks (RBs). Each subband includes a number of orthogonal frequency subcarriers associated with a predetermined number of OFDM symbols, through which information and signal channels are physical layer channels that are transmitted in a TDM or TDM / FDM scheme. The channel bandwidth may also be subdivided into one or more subband groups or resource block groups (RBGs), where each subband group includes one or more consecutive subbands, The subband groups may or may not be the same size. A communication session can assign one or more subbands or groups of subbands for bearer information exchange, which allows multiple users to transmit so that each user's transmission is orthogonal to other users' transmissions. It is possible to transmit simultaneously in different subbands.

  Preferably, the communication system 100 is a 3GPP (Third Generation Partnership Project) LTE (Long Term Evolution) communication system. However, those skilled in the art will recognize that the communication system 100 employs any wireless communication technology that employs a single carrier frequency division multiple access (SC-FDMA) modulation scheme and frequency selective scheduling (FSS), such as, but not limited to, 3GPP. A clear understanding that it can function in accordance with a communication system evolved from LTE.

  Further, it should be understood that FIG. 1 is provided merely to illustrate the principles of the present invention. FIG. 1 is not intended to be a comprehensive block diagram of all the components of such a communication system. As such, the wireless communication system 100 can include a variety of other configurations and still be within the scope of the present disclosure.

  According to various embodiments of the present invention, the access point 102 calculates signal strength parameters associated with each UE 104-106. Based on the signal strength parameters, quality of service requirements, and throughput achieved so far, the access point 102 determines a scheduling criterion for each UE of the multiple UEs 104-106. The access point 102 then ranks based on the determined scheduling criteria, i.e. assigns a rank to each of the UEs 104-106. In one embodiment, the access point 102 may perform physical downlink control channel (PDCCH) allocation using the rankings of the UEs 104-106.

  The access point 102 is then selected for uplink transmission during the next scheduling period, and any UE has a physical downlink control channel (PDCCH) assignment for the allowed uplink. Determine the target number of resource blocks (RBs) for each UE, such as existing UEs 104-106. The RB allocation is processed by the scheduler 302 at the access point 102. Further, the access point 102 determines an RB assignment for each UE 104-106 selected for uplink transmission based on various factors, ie, an RB assignment in terms of time and frequency.

  One or more RBs assigned to the next uplink transmission, i.e. transmission during the next scheduling period, e.g. one UE out of a number of UEs 104-106 scheduled for a subframe, e.g. UE 104 Later, the access point 102 determines whether one or more RBs have already been assigned to all of the multiple UEs 104-106 scheduled for the next uplink transmission. If one or more UEs, e.g., UEs 105 and 106, have not yet been scheduled for the next uplink transmission, the access point 102 will be in the rank associated with each UE of the multiple UEs 104-106. Based on this, the UE for the next scheduling, eg, UE 105 is selected. The access point 102 then assigns one or more RBs to this next UE 105 and there are no RBs available for scheduling until RBs are assigned to all UEs scheduled for the next uplink transmission. Until this process continues, assigning RBs to UEs that have not yet been scheduled based on the rank associated with each of the multiple UEs 104-106. If the access point 102 determines that RBs are assigned to all UEs 104-106 scheduled for the next uplink transmission, the access point is still assigned some RBs in the subframe. It is determined whether it is available for allocation. If one or more RBs in the subframe are available for assignment, the access point 102 assigns each unassigned RB in the subframe to at least one assigned adjacent to the unassigned RB. For the next uplink transmission with a higher rank than the other UEs of the multiple UEs 104-106 having a number of RBs and having at least one assigned RB adjacent to an unassigned RB Assign to one of a number of scheduled UEs 104-106. As a result, the RBs in that subframe are continuously assigned to each UE 104-106 selected for uplink transmission.

  FIG. 4 is a logic flow diagram 400 illustrating a method performed by the access point 102 when performing uplink frequency selective scheduling according to various embodiments of the invention. The logic flow diagram 400 begins when the access point 102 ranks UEs 104-106 that are scheduled for uplink transmission during the next scheduling period (step 402).

  Referring now to FIG. 6, a method for ranking UEs 104-106 by access point 102 according to an embodiment of the present invention is described. The logic flow diagram 600 calculates one or more received signal quality criteria associated with each UE 104-106 that the access point will be scheduled for uplink transmission during the next scheduling period (step 604). (Step 602). For example, the signal quality criteria include wideband signal-to-interference-plus-noise ratio (SINR), narrowband SINR for up to N consecutive resource blocks (RBs) for each UE 104-106, reception Signal strength parameters (eg, RSSI) and / or quality of service (QoS) based parameters for each UE 104-106 may be included. The access point then calculates a scheduling criterion based on the above signal quality criterion (step 606). The access point then ranks each UE 104-106 according to the calculated scheduling criteria associated with the UE (step 608) and the logic flow diagram ends (step 610).

  Returning to FIG. 4, in addition to ranking each UE 104-106, the access point 102 may determine that the RBs for each user equipment 104-106 that are scheduled for uplink transmission during the next scheduling period ( N) sets the number of targets (step 404). In the present specification, the scheduling period is referred to as a subframe. However, those skilled in the art can apply the present invention to any scheduling period known in the technical field, and the duration of the scheduling period is: It is clearly understood that it is not important to the present invention. The number of RB targets represents the number of RB targets set by the access point 102 for each UE 104-106 in the subframe, and is based on the resource block allocation criteria and the set of resource block parameters. Also, the resource block allocation criterion and the set of RBs are calculated based on the broadband channel quality.

  The resource block allocation criteria include one or more of signal quality criteria and proportional fairness criteria. Proportional fairness criteria maintain a balance between two competing benefits, eg, all UEs scheduled for uplink transmission in the next subframe while maximizing overall radio network throughput. Means a scheduling algorithm that is based on enabling at least a minimum level of service for.

Further, the set of resource block parameters includes parameters such as N _MCS , N _TBS and N _Q. The parameter N _MCS is assigned to the UE so that the modulation coding scheme (MCS) of the UE does not drop below the maximum MCS that can be realized when only one resource block is assigned to the UE. Indicates the number of resource blocks (RB) that can be used. In other words, N _MCS is the threshold power level required to maintain the same MCS as the maximum realizable MCS for the UE when the transmit power per RB is assigned only one RB to that UE. Indicates the minimum number of RBs transmitted until: In this specification, the threshold power level is a predetermined power level. N _TBS indicates the number of RBs that maximizes the transport block size (TBS). In this specification, TBS is defined as the number of bits in one transport block. Furthermore, N _Q indicates the number of RBs required to be transmitted in a particular subframe in order to empty the queue or empty the buffer.

Also, according to an embodiment of the present invention, the access point 102 determines whether the UEs 104 to 106 scheduled for uplink transmission in the next subframe are underserved UEs (underserved UEs). Is determined (step 406). If the UE is not able to get enough past average throughput, the UEs 104-106 are called UEs that are not receiving enough service. In other words, a UE that is not receiving sufficient service is a UE that has a scheduling criterion that causes it to be repeatedly scheduled in most subframes, even though it is scheduled in most subframes. For UEs that are not fully serviced, the target number of RBs is
Number of RB targets (N) = min (N _TBS , N _Q )
Set as

However, if it is determined that the UEs 104-106 are not UEs not receiving sufficient service, the target number of RBs is given by the following equation:
Number of RB targets (N) = min (N _MCS , N _Q )
Is determined.

The access point 102 then determines the reserved capacity of the subframe, ie, the unassigned portion of the subframe, based on the assignable RB capacity and the presented RB load (step 408). The allocatable RB capacity is defined as the total amount of RBs available for allocation to a number of UEs 104-106 scheduled for uplink transmission in that subframe. The presented RB load is defined as the sum of the target number of each resource block of the plurality of UEs 104 to 106. The reserve capacity (Δ) is the following equation:
Δ = Max {(allocable RB capacity−presented RB load), 0}
You may calculate using.

  Further, the access point 102 resets the target number of the resource block of the first UE among the plurality of UEs 104 to 106, for example, the UE 104, based on the resource block allocation criterion and the reserve capacity of the subframe. (Step 410). More specifically, as described above, the access point 102 calculates the load status based on the reserved capacity based on the presented RB load and the assignable RB capacity. When the allocatable RB capacity is equal to or greater than the presented RB load, the load status is determined to be low. Otherwise, the load situation is determined as a high load.

Further, if the load situation is low load and the UEs 104-106 under consideration are not UEs that are not fully serviced, the access point 102 may have the following equation:
N = min {(N _MCS + Δ), N _TBS , N _Q }
The number of RB targets is reset as follows. This is done to increase the data transmission rate for that UE.

Next, the access point 102 determines a fragmentation criterion (F) for the subframe (step 412). The fragmentation criterion (F) determines whether the fragmented form is a low fragmented form or a highly fragmented form. The fragmentation criterion (F) is the following equation:
F = F ₀ + number of fragments (J) -number of UEs with packet data control channel (PDCCH) allocation waiting for PUSCH allocation (K)
Is determined. However, _{F 0} is a constant. In the present specification, the number of fragments means the number of intervals generated by fragmentation by assigned RBs.

  If the value of F is determined to be less than zero, the type of fragmentation form is determined to be a low fragmentation form. However, if the value of F is greater than zero, the type of fragmentation form is determined to be a highly fragmented form.

  The access point 102 then assigns the reconfigured target number of RBs to the first UE 104 based on its fragmentation criteria (step 414). According to one embodiment, the access point 102 then schedules multiple UEs 104-106 to be scheduled for uplink transmission in the next subframe for RB allocation based on ranking for the multiple UEs 104-106. The next UE, for example, UE 105 is determined (step 416). And the target number of RB is allocated for the next UE105. Further, the access point 102 determines whether each UE of a number of UEs 104-106 scheduled for uplink transmission in the next subframe has already been assigned one or more RBs for that subframe. (Step 418). If access point 102 determines that one or more RBs are assigned to each of UEs 104-106, access point 102 determines whether some RBs in the subframe remain unassigned. That is, it is determined whether it can be used for allocation (step 420). If the RB in the subframe is available for assignment, the access point 102 has an unassigned RB for the subframe with at least one assigned RB adjacent to the unassigned RB, and the unassigned Assign to one UE, eg, UE 104, of multiple UEs 104-106 having a higher rank than other UEs 104-106 that also have at least one RB assigned adjacent to that RB (step 422). If the RB in the subframe is not available for allocation, the logic flow diagram ends (step 426). Therefore, the RBs can be assigned to the UEs 104 to 106 until all the RBs of the subframe are assigned. In addition, when the access point determines that RBs are not assigned to all the UEs 104 to 106 (step 418), the access point 102 selects the next UE among the many UEs 104 to 106. (Step 424), Steps 406 to 416 of the logic flow diagram 400 are repeated.

Referring now to FIG. 5, performed by the access point 102 in allocating RBs in a subframe to UEs selected for uplink transmission, eg, UEs 104-106, according to one embodiment of the present invention. A logic flow diagram 500 illustrating the method is described. The logic flow diagram 500 shows parameters for each UE 104-106 under consideration for which the access point is scheduled to schedule on an uplink channel, eg, a physical uplink shared channel (PUSCH), eg, , N _MCS , N _TBS and N _Q (step 502). As described above, the parameter N _MCS is equal to or less than the maximum MCS that can be realized for the UE when only one resource block is allocated to the UE. This represents the number of resource blocks (RB) that can be allocated to the UE so as not to decrease. In other words, the N _MCS is required for the transmission power per RB to maintain the same MCS as the maximum MCS achievable for the UE when only one resource block is allocated to the UE. Represents the minimum number of RBs transmitted before falling below a certain threshold power level. In this specification, the threshold power level is a predetermined power level. _{Furthermore, N TBS} represents the number of RB to maximize transport block size (TBS). In this specification, TBS is defined as the number of bits in one transport block. Further, N _Q represents the number of RBs in a particular subframe that are needed to free up the queue or to empty the buffer. Also, the access point 102 determines, for each UE 104-106 scheduled for uplink transmission in that subframe, whether the UE is a UE that is not receiving sufficient service (steps). 504). If a UE cannot get enough past average throughput, it is called a UE that is not receiving enough service. Alternatively, a UE that is not receiving sufficient service may be a UE that has a scheduling criterion that causes it to be repeatedly scheduled in most subframes even though it is scheduled in most subframes.

FIG. 7 is a logic flow diagram 700 that describes a method by which an access point 102 determines whether a UE is not fully serviced, according to one embodiment of the invention. The logic flow diagram 700 determines a UE with the minimum proportional fairness criterion (PF _min (t)) from among all of the UEs 104-106 whose access point is scheduled for uplink transmission in a subframe. (Step 702). As used herein, a proportional fairness standard maintains a balance between two competing benefits, for example, maximizing overall radio network throughput, while at least providing a minimum level of service to all UEs. Derived from a proportional fairness scheduling algorithm that is based on enabling. Further, the access point determines the UE with the maximum proportional fairness criterion (PF _max (t)) among all of the UEs 104-106 scheduled for uplink transmission in the subframe (step 706). ). The access point then determines a proportional fairness criterion (PF (t)) for the UE under consideration as to whether it is a UE that is not receiving sufficient service (step 708). The access point 102 then determines the UE's (PF (t)) proportional fairness criterion, the UE's proportional fairness criterion (PF _min (t)), and the maximum proportional fairness criterion (PF _max (t)). It is determined whether or not the UE under consideration is a UE that does not receive sufficient service based on the proportional fairness criteria of the UE having (step 710). That is, the access point 102 determines whether or not PF (t)> PF _min (t−1) + e (PF _max (t−1) −PF _min (t−1)), where e is These are constant values that can be set by the designer of the communication system 100. If this condition is repeatedly satisfied for the UE despite the UE being scheduled for transmission, the UE under consideration as to whether or not it is an under-served UE is sufficient It is determined that the UE is not receiving a special service. The logic flow diagram 700 then ends (step 712).

Referring again to FIG. 5, for each UE 104-106, if the access point 102 determines that the UE is not fully serviced (step 504), the access point preferably That is,
Number of RB targets (N) = min (N _TBS , N _Q )
_With, based on the _{N TBS} and _{N Q,} sets the target number of RB for the UE (step 506). However, if the access point 102 determines that the UE is not a poorly serviced UE (step 504), the access point preferably preferably has the following equation:
Number of RB targets (N) = min (N _MCS , N _Q )
_Is used to set the target number of RBs for that UE based on N _MCS and N _Q (step 508).

After setting the target number of RBs for each UE 104-106 to which RBs of subframes are allocated for uplink transmission (step 506, step 508), the access point 102 determines the presented RB load, assignable RB capacity, And reserve capacity for the subframe is determined (step 510). The presented RB load is defined as the sum of the target number of RBs for each UE in the multiple UEs 104-106 under consideration. The allocatable RB capacity is defined as the total amount of RBs available for allocation to the UEs 104 to 106 in the subframe. And the reserve capacity (Δ) is the following equation:
Δ = Max {(allocable RB capacity−presented RB load), 0}
Defined by

  After determining the presented RB load, allocatable RB capacity and reserve capacity (step 510), the access point 102 determines whether or not the load status is low (step 512). The load situation is calculated based on the presented RB load and the assignable RB capacity. When the allocatable RB capacity is equal to or greater than the presented RB load, the load status is determined to be low. Otherwise, it is determined that the load status is a high load.

If the load situation is low load and the UEs 104-106 under consideration for RB allocation are not UEs that are not fully serviced, the access point 102 may have the following equation:
N = min {(N _MCS + Δ), N _TBS , N _Q }
To recalculate the target number of RBs for that UE (step 514), ie reconfigure. This is done to increase the data transmission rate for that UE. If the load status is not low load, ie, the load status is high load, or after recalculating the target number of RBs in case of low load (step 514), the access point 102 It is determined whether or not the conversion form is advanced (step 516).

Referring now to FIG. 8, a logic flow diagram 800 describing a method performed by the access point 102 in determining the type of fragmentation form according to one embodiment of the present invention is described. The logic flow diagram 800 begins when the access point determines the number of fragments in a subframe (step 804) (step 802). Next, the access point 102 has the following equation:
F = F ₀ + number of fragments (J) -number of UEs with packet data control channel (PDCCH) assignments waiting for PUSCH assignment (K)
Is used to calculate the fragmentation criterion (F) (step 806). However, _{F 0} is a constant. In the present specification, the number of fragments means the number of intervals generated by fragmentation by assigned RBs.

  After calculating the fragmentation criteria (step 806), the access point 102 determines whether the value of F is less than zero (0) (step 808). If it is determined that the value of F is smaller than 0, it is determined that the type of fragmentation form is a low fragmentation form (step 810). However, if the value of F is greater than zero, it is determined that the type of fragmentation form is a highly fragmented form (step 812).

  Returning to FIG. 5, if it is determined that the fragmentation form is a highly fragmented form (step 516), the access point 102 determines the next UE 104-106 to be scheduled for uplink transmission. Select (step 518) and determine a target RB assignment for the next UE based on its highly fragmented form. On the other hand, if the fragmentation form is a low fragmentation form, the access point 102 selects the next UE 104-106 to be scheduled for uplink transmission, and based on the low fragmentation form, the next Determine target RB assignments for the UEs.

9 and 10 are logic flow diagrams 900 and 1000 illustrating methods of RB allocation by the access point 102 in a highly fragmented form and a low fragmented form, respectively, according to embodiments of the present invention. Referring to FIG. 9, a logic flow diagram 900 illustrating a method for selecting a next UE and target RB assignment for the next UE based on high fragmentation is described. The logic flow diagram 900 begins when the access point 102 selects a UE 104-106 that has the maximum scheduling criteria used for PDCCH allocation (step 904) (step 902). As described above, the scheduling criteria are calculated based on signal quality criteria, throughput criteria and quality of service (QoS) criteria. The access point then determines the fragment size (F _j ) for each fragment in the subframe (step 906), and for each fragment, the fragment size (F _j ) is the RB of the selected UE. It is determined whether or not the number of targets is less than or equal to (step 908). If the fragment size (F _j ) is less than or equal to the target number of RBs for the selected UE, the access point designates the entire fragment as a candidate for target RB allocation (step 910). However, if the fragment size (F _j ) is greater than the number of RB targets for the selected UE, the access point may be of a size equal to the number of RB targets for the selected UE at the end of the fragment. All subintervals are considered as candidates for target RB allocation (step 912). In any case, after determining whether the entire fragment or sub-interval of the fragment is a candidate for target RB allocation, the access point 102 may contact the UE under consideration for target RB allocation. The candidate with the largest TBS is selected (step 914) and the logic flow diagram 900 ends (step 916). In this specification, TBS is calculated using frequency selective SINR information per RB. In another embodiment, instead of assigning RBs to one UE at a time, eg, UE 104, all UEs 104-106 can be considered together, and the best set for RBs is UE 104- Determined for each of 106. And the following equation:
(Maximum TBS size among all RB allocation candidates) / (TBS corresponding to wideband SINR in case of N (ie number of targets) RBs)
The UE with the maximum value for is selected, eg, UE 106, and a corresponding set of RBs is assigned to UE 106. The same procedure is then performed for the remaining set of UEs and RB fragments.

Referring now to FIG. 1000, a method is described by the access point 102 to select a next UE and a target RB assignment for the next UE based on low fragmentation. The logical flow diagram 1000 shows that the access point 102 has already been assigned a maximum target number of RBs for uplink transmission in scheduled subframes, ie, UEs 104-106 having a maximum value of N. Is started (step 1002). The access point 102 then determines the fragment size (F _j ) of each fragment in the subframe (step 1006), and for each fragment, the fragment size (F _j ) is set to the maximum value of N (N It is determined whether or not it is equal to or less than the target number (N) of RBs for the UE (having) (step 1008). If the fragment size (F _j ) is equal to or smaller than the target number (N) of RBs, the access point 102 designates the entire fragment as a candidate for target RB allocation (step 1012). However, if the fragment size (F _j ) is larger than the target number (N) of the RB, the access point 102 assigns all sub-intervals of size N in the fragment to candidates for target RB allocation. (Step 1010). In any case, after determining whether the entire fragment or the sub-interval of the fragment is a candidate for target RB allocation, the access point 102 is the candidate with the maximum TBS for the UEs 104-106 under consideration. Is selected (step 1014), and the logic flow diagram 800 ends (step 1016). In another embodiment, instead of assigning RBs to one UE at a time, all UEs can be considered together and the best set of PRBs is determined for each UE. And the following equation:
(N × maximum TBS size among all RB allocation candidates) / (TBS corresponding to wideband SINR for N (ie, number of targets) RBs)
The UE with the largest value for is selected and the corresponding set of RBs is assigned to that UE. The same procedure is performed for the remaining set of UEs and RB fragments.

  Referring back to FIG. 5, after selecting a target RB assignment for the UE and the next UE based on either the high fragmentation or low fragmentation method, the access point 102 has reconfigured the RB. The TBS corresponding to the target number is greater than the minimum number of RBs needed to empty the queue of data waiting for transmission by the UE (and held in at least one storage device 206 of the UE) Whether or not (step 522). If the TBS size corresponding to the reconfigured target number of that RB is larger than the minimum number of RBs required to empty such a queue, the access point 102 may , Reduce the size of the target RB allocation by at least one RB (step 524). More specifically, the size of the target RB allocation is lower in the low fragmentation form until the number of RBs is greater than the minimum number required to empty the queue. Reduced by at least one RB from the end of the target RB assignment with the worst signal quality criterion (eg, Signal to Interference Noise Ratio (SINR)) compared to the signal quality criterion associated with the other end . In addition, the size of the target RB allocation is such that in the highly fragmented form, the reconfigured target number of RBs is high until the number of RBs is greater than the minimum number required to empty the queue. In order not to increase the number of fragments, it is reduced from target RB allocations that are adjacent to unassigned RBs.

  The access point 102 determines whether or not RBs are assigned to all UEs 104 to 106 under consideration (step 526). Otherwise, the access point 102 selects the next UE 104-106 (step 528) and returns to step 510 to determine the presented RB load, assignable RB capacity and reserve capacity. However, if the access point 102 determines that RBs have been assigned to all UEs 104-106 under consideration (step 526), the access point determines whether all RBs have been used up. That is, it is determined that all RBs are allocated (step 530). If all RBs have been assigned, the logic flow diagram 300 ends (step 532). However, if all RBs are not used up, that is, RBs can be assigned to each unassigned RB adjacent to an existing target RB assignment that has not used up the corresponding UE queue length. The access point 102 assigns its unassigned RB to the UE with the neighboring RB assignment and with the highest scheduling criteria (step 534), resulting in the UE's TBS size. Will increase. The logic flow diagram 500 then returns to determining whether all RBs are exhausted (step 530) until all RBs are exhausted.

  Thus, the method described above guarantees high system performance at both high and low loads. Furthermore, the benefits of FSS are realized without incurring the disadvantage of inefficient use of RBs due to fragmentation.

  In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below.

Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive, and all such modifications are intended to be included within the scope of the present teachings.
Benefits, effects, solutions to problems and any elements that may produce or make any benefit, effect or solution significant, essential or essential for some or all claims Should not be construed as specific features or elements. The invention is defined solely by the appended claims including any amendments made during the pendency and all equivalents of those claims that have been published.

  Also, in this document, related terms such as first and second, top and bottom, are not necessarily required to imply or imply any actual relationship or order between components or operations, An element or action can be used to distinguish it from another component or action. The terms “comprising”, “comprising”, “having”, “having”, “including”, “including”, “including”, “including”, or other Any variation comprising, including, including, including, and including a list of components, a process, method, article or device is not explicitly described or includes only those components It is intended to include non-exclusive inclusions so that other components unique to the process, method, article or apparatus may be included. A component following “comprising”, “having”, “including”, “including” includes, without, more restrictive, includes, includes, includes, includes, includes, or includes that component. It does not exclude the presence of identical additional components in the device. The term “one” is defined as one or more unless otherwise specified herein. The terms “substantially”, “essentially”, “abbreviated”, “about”, or some other version thereof, are defined as close to those understood by those of ordinary skill in the art and are not limited to one In embodiments, the term is defined to be within 10%, within 5% in another embodiment, within 1% in another embodiment, and within 0.5% in another embodiment. Is defined as being. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a way is configured in at least that way, but may be configured in ways not described.

  Some embodiments include one or more general purpose or special purpose processors (or “processors”) such as microprocessors, digital signal processors, custom processors, field programmable gate arrays (FPGAs), and some non-processor circuits. And control one or more processors (both software and firmware) to perform some, most or all of the functions and / or devices described herein. It will be appreciated that it can consist of (including) uniquely stored program instructions. Alternatively, some or all functions may be performed by a state machine in which no program instructions are stored, or in one or more application specific integrated circuits (ASICs), where each A function, or some combination of several groups of functions, is implemented as custom logic. Of course, a combination of these two approaches can also be used.

  Embodiments also include a computer readable storage medium storing computer readable code for programming a computer (eg, including a processor) to perform the methods described herein and claimed herein. Can be implemented as Examples of such computer-readable storage media include, but are not limited to, hard disks, CD-ROMs, optical storage devices, magnetic storage devices, ROM (read only memory), PROM (programmable ROM), EPROM (erasable) PROM), EEPROM (electrically erasable PROM) and flash memory. In addition, many of those skilled in the art are potentially motivated by considerable effort and, for example, available time, current technology and economic considerations, when taught by the concepts and principles disclosed herein. It is anticipated that it would be readily possible to generate such software instructions and programs and ICs with minimal experimentation, despite the design choices.

  This summary of the disclosure is provided so that the reader can quickly ascertain the nature of the technical disclosure. This specification is filed with the understanding that it will not be used to interpret or limit the scope or spirit of the claims. Moreover, in the form for implementing said invention, it can be seen that various functions are grouped together in various embodiments for the purpose of rationalizing the present disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, the gist of the invention is by no means within all the functions of a single disclosed embodiment. Accordingly, the following claims are incorporated in the embodiments for carrying out the invention, with each claim as it is, and in the state where it is independently claimed.

Claims (22)

A method for performing uplink frequency selectivity scheduling for a plurality of user equipments in a communication network, comprising:
Setting a target number of resource blocks for each user equipment of the plurality of user equipments based on resource block allocation criteria including signal quality criteria, and further based on a set of resource block parameters;
Determining a reserve capacity of the subframe based on an available resource block in a subframe and a total number of targets of resource blocks of the plurality of user equipments;
Resetting the target number of resource blocks of the first user equipment among the plurality of user equipments based on the resource block allocation criteria and the spare capacity of the subframe;
Determining a fragmentation criterion for the subframe;
Allocating a reconfigured target number of resource blocks to the first user equipment based on the fragmentation criteria.   Setting the target number of resource blocks for each user device of the plurality of user devices based on a resource block allocation criterion and a set of resource block parameters is a resource block allocation for each user device. The method of claim 1, comprising determining a criterion and a set of resource block parameters calculated based on the broadband channel quality.   The method of claim 1, wherein for each user equipment, determining the signal quality criteria comprises determining one or more of proportional fairness criteria and throughput for each user equipment. The set of resource block parameters is
The maximum number of resource blocks transmitted before the transmit power per resource block falls below the threshold power level,
The number of resource blocks to maximize the transport block size,
The method of claim 1, comprising one or more of a minimum number of resource blocks required to free a queue.   The method of claim 1, further comprising assigning to each user device of the plurality of user devices one of a plurality of ranks based on a scheduling criterion associated with the user device. Determining a next user device based on a plurality of ranks associated with each user device of the plurality of user devices;
6. The method of claim 5, further comprising: assigning a target number of resource blocks to a next user equipment. Assigning to each user device of the plurality of user devices one of a plurality of ranks based on a scheduling criterion associated with the user device;
Determining a signal strength parameter associated with each user equipment;
6. The method of claim 5, comprising, for each user equipment, calculating a scheduling criterion based on a signal strength parameter determined for that user equipment.   The method of claim 1, further comprising reducing a size of a resource block allocation by at least one resource block based on the fragmentation criterion. Reducing the size by the at least one resource block,
If the transport block size corresponding to the reconfigured target number of the resource block is larger than the estimated amount of data in the queue, and if the fragmentation criterion is larger than a predetermined value, an unassigned resource block The method of claim 8, further comprising: reducing the size of at least one resource block from resource block assignments adjacent to. Reducing the size by the at least one resource block,
When the fragmentation criterion is smaller than a predetermined value and the transport block size corresponding to the reconfigured target number of the resource block is larger than the estimated amount of data in the queue, the other resource block allocation 9. The method of claim 8, further comprising: reducing the size by at least one resource block from an end of the resource block allocation having the worst signal interference to noise ratio as compared to a signal interference to noise ratio associated with the edge. The method described. Determining that a resource block is allocated to each of the plurality of user devices;
Determining that resource blocks in the subframe are available for allocation;
An unassigned resource block of the subframe has at least one resource block assigned adjacent to the unassigned resource block and is assigned adjacent to the unassigned resource block The method of claim 1, further comprising: assigning to one user device of the plurality of user devices having a higher rank than other user devices of the plurality of user devices having at least one resource block. Method. Determining a fragmentation criterion for the subframe includes
Determining the number of fragments in one subframe;
Based on the number of fragments in the subframe, the fragmentation parameters, and the number of user equipment having packet data control channel assignment and waiting for physical uplink shared channel assignment, The method of claim 1, comprising determining. Selecting a next user device among the plurality of user devices based on the fragmentation criteria;
The method of claim 1, further comprising: assigning a target number of the resource block to a next user equipment based on the fragmentation criterion. Assigning the reconfigured target number of the resource block to a first user equipment based on the fragmentation criteria,
Selecting one user device of the plurality of user devices having the highest target number of resource blocks when the fragmentation criterion is a low fragmentation criterion;
Determining the fragment size of each fragment in the subframe;
Determining one or more candidates for resource block allocation, wherein the candidate resource block allocation is a fragment having a fragment size smaller than the highest target number of resource blocks, or the highest target of said resource block Determining the one or more candidates including a sub-interval of fragments having a fragment size greater than a number, wherein the size of the sub-interval is equal to a target number of the resource block;
Determining a transport block size for each of said resource block allocation candidates;
The method of claim 1, comprising: assigning a candidate having a maximum transport block size to a selected user equipment. Allocating the target number of the reconfigured resource blocks to the first user equipment based on the fragmentation criteria,
Selecting one user device of the plurality of user devices having a highest scheduling criterion if the fragmentation criterion indicates a high degree of fragmentation;
Determining the fragment size of each fragment in the subframe;
Determining one or more candidates for resource block allocation, wherein the resource block allocation candidate is a fragment having a fragment size that is smaller than a target number of resource blocks for the selected user equipment; Sub-intervals at both ends of a fragment having a fragment size larger than the target number of resource blocks for the selected user equipment, the size of the sub-interval being the target number of resource blocks for the selected user device Determining the one or more candidates equal to
Determining a transport block size for each of said resource block allocation candidates;
The method of claim 1, comprising assigning a candidate having a maximum transport block size to the selected user equipment. An access point that performs uplink frequency selective scheduling for a plurality of user equipments in a communication network comprising:
Setting a target number of resource blocks for each user equipment of the plurality of user equipments based on resource block allocation criteria including signal quality criteria, and further based on a set of resource block parameters;
Determining a spare capacity of the subframe based on an available resource block in a subframe and a total number of target resource blocks of the plurality of user equipments;
Based on the resource block allocation criterion and the reserve capacity of the subframe, reset the target number of resource blocks of the first user equipment among the plurality of user equipments,
Determine a fragmentation criterion for the subframe,
An access point comprising a scheduler configured to allocate a reconfigured target number of resource blocks to the first user equipment based on the fragmentation criteria. A method for allocating a resource block in a subframe to one user equipment among a plurality of user equipments selected for uplink transmission, comprising:
Determining a resource block allocation criterion including one or more of a signal quality criterion and a performance criterion for each user device of the plurality of user devices;
Determining a set of resource block parameters for each user device of the plurality of user devices;
Setting a target number of resource blocks for each user equipment of the plurality of user equipments based on the resource block allocation criteria determined for the user equipment and a set of resource block parameters;
Determining a fragmentation criterion for the subframe including resource blocks to be allocated;
Allocating a target number of the resource block to the user equipment based on the fragmentation criterion.   The method of claim 17, wherein determining the resource block allocation criterion comprises determining a signal quality criterion.   The method of claim 18, wherein determining the signal quality includes determining one or more of a proportional fairness criterion and throughput. Determining the set of resource block parameters includes
Determining the maximum number of resource blocks transmitted before the transmit power per resource block falls below a threshold power level;
Determining the number of resource blocks that maximizes the transport block size;
18. The method of claim 17, comprising one or more of: determining a minimum number of resource blocks required to empty a queue. Determining a fragmentation criterion for the subframe to which the resource block is to be allocated,
Determining the number of fragments in the subframe;
Determining the fragmentation criteria based on the number of fragments, fragmentation parameters, and the number of user equipment with packet data control channel assignments waiting for physical uplink shared channel assignments. Item 18. The method according to Item 17. An access point that allocates a resource block in a subframe to one user equipment among a plurality of user equipments selected for uplink transmission,
Determining a resource block allocation criterion including one or more of a signal quality criterion and a performance criterion for each user device of the plurality of user devices;
Determining a set of resource block parameters for each user device of the plurality of user devices;
Setting a target number of resource blocks for each user device of the plurality of user devices based on the resource block allocation criteria determined for the user device and a set of resource block parameters;
Determining a fragmentation criterion for the subframe including the resource block to be allocated;
An access point comprising a scheduler configured to allocate a target number of the resource block to the user equipment based on the fragmentation criterion.