RU2341029C2 - Method of scheduling algorithm with minimum resource parameter and calculation method - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention refers to communication systems and provides scheduling algorithm in wireless communication system scheduler including staged minimum resource parameter receiving from interface. Specified minimum resource parameter indicates minimum resources separated for interface in scheduling frame to respond to resource restriction, and allocation planners for radio access to interface in scheduling frame according to minimum resource parameter. Besides invention refers to method executed in wireless communication network interface in order to generate minimum resource parameter used in scheduling algorithm to plan allocation planners in scheduling frame for radio access to interface according to minimum resource parameter, providing stages of minimum resource parameter calculation based on evaluation of power required to process scheduling frame and transfer calculated minimum resource parameter to scheduler.

EFFECT: provided saving operation of receiver with reasonable power consumption for operation and processing.

27 cl, 8 dwg

Description

This invention relates to communication systems. It is, in particular, applicable to a wireless communication system, where the scheduling algorithm assigns channel resources to subscribers for transmitting and receiving data. More specifically, this invention relates to a method for executing a scheduling algorithm set forth in independent claim 1 and a method for calculating a minimum resource parameter for use in a scheduling algorithm set forth in independent claim 1.

In a cellular mobile communication system, a mobile station typically transmits and receives information to and from the base station using channel resources such as time slots, operating frequency range, code sequence, or combinations thereof. These resources are usually shared between the subscribers of the communication system.

In a special mobile communication system, a radio access point typically transmits and receives information to and from other radio access points within the same special network using channel resources such as time intervals, operating frequency range, code sequence, or combinations thereof. These resources are usually shared between the subscribers of the communication system. In such a special network, there can be either a dedicated main access point for managing a special network, or alternatively, one radio access point can receive the functionality of the main access point for managing a special network.

It should be clear to those skilled in the art that the cellular base station and the dedicated main access point share at least part of the responsibilities for managing resources and subscribers within their service area. Similarly, the role of a radio access point in a special network has much in common with the role of a mobile device in a cellular wireless system. For simplicity, the following description will relate to a cellular wireless network. The changes required to apply this invention to special networks are easily inferred to those skilled in the art from the description.

In the context of wireless communications, all operations involved in either transmitting or receiving data are called data processing. To process data, a mobile device must expend the processing power of its hardware. From an economic point of view, the most reasonable use of these capacities is obtained if, in return, the mobile receiver processes a lot of data using these capacities. On the other hand, such power is inappropriately consumed if at the same time the data is not processed or a little data is processed.

The distribution of data to the subscriber through a channel resource is usually carried out by a scheduling algorithm. At least for the downlink, i.e. to direct transmission from the base station to the mobile terminal, such a scheduler typically operates in the base station or other parts of non-mobile objects within the communication system. Such a scheduler usually evaluates parameters, such as data service speed, channel status, but does not take into account the economic factor described above. Even for the uplink, i.e. transfer direction from the mobile terminal to the base station, the scheduler can work in a central node (for example, a base station in cellular systems, a main station in a special network) to allocate resources. The result of such planning of the central node can then be transmitted to the mobile objects.

In wireless communication systems using dynamic channel assignment (DCA) schemes, radio interface resources are assigned dynamically to communication links between a base station (BS) and a plurality of mobile terminals (MTs). The layout of a typical communication system is shown in FIG. 1, where a BS serves several MTs in a service area. The resources of a radio interface are usually defined by a logical channel, where a logical channel corresponds, for example, to one or multiple codes in a CDMA system, to one or multiple subcarriers in an OFDM system, to one or multiple time slots in a TDMA system (e.g. GSM), or combinations thereof in an OCDMA system or MC-CDMA. DCA can be applied to the uplink and downlink.

Using adaptive modulation and coding (AMC), the data rate within the planning frame for the planned MT will be adapted to the instantaneous channel quality of the corresponding communication line by dynamically changing the modulation and coding scheme. AMC is commonly used in conjunction with DCA.

In a system using DCA and AMC, the so-called scheduler decides which resources are assigned to which MTs. A common approach is to use central planning when the scheduler is located in the BS and makes its decision on the basis of the following additional information, such as information about the quality of the channel of communication lines to MT, or the proposed traffic for specific communication lines, for example, the amount of data available for transmission to a specific MT

The general tasks of the scheduler are to achieve equal rights between subscribers, maximize system performance and / or fulfill quality of service (QoS) requirements (for example, latency, data rate, probability of loss, jitter) for services provided by planned mobile terminals. In prior art wireless communication systems, the scheduler operates on a packet basis.

The following schedulers are well-known examples in the field of wireless communications.

Circular Planner (RR).

This scheduler distributes equal resources of the air interface to all MSs regardless of channel conditions, thereby achieving an equal division of resources.

Scheduler maximum speed (MR) or maximum C / I (MC).

This scheduler selects the subscriber with the highest instantaneous data rate (carrier to interference C / I ratio). It achieves maximum system performance, but ignores the equality between subscribers.

Proportional Scheduler (PF).

This scheduler maintains the average data rate transmitted to each subscriber within a given time window, examines the ratio of instantaneous to average channel conditions (or the ratio of the instantaneous possible data rate to average data rate) experienced by different subscribers, and selects the subscriber with the maximum ratio. This scheduler increases system performance relative to RR planning while maintaining some degree of long-term equity.

More detailed information on the structure and function of the scheduler can be obtained, for example, from US 2003/0104817, which discloses a method for scheduling multiple subscribers sharing a communication resource, especially related to high-speed wireless transmission, with emphasis on the consideration of QoS.

In modern systems, the terminal can transmit signals to inform the scheduler of what data rate is needed in order to satisfy the subscriber or service. Among other parameters, this may include the average connection (or service) data rate and the maximum allowed delay. However, the scheduling in the BS cannot know whether the MT works efficiently in terms of power consumption for receiving data.

The objective of the invention is to provide a method for executing a scheduling algorithm that allows a receiver to operate sparingly with a reasonable power consumption during operation and processing.

An additional objective is to provide a method for generating the minimum resource parameter used in the planning algorithm, which enables effective frame planning.

The above problems are solved by the methods set forth in independent claims 1 and 2 of the claims.

The invention is based on the idea of transmitting signals of a minimum resource parameter from a communication unit, which can be, for example, either a mobile terminal or a base station, to supply the scheduler with information about the power consumption for data processing. The signal transmission carries information about the minimum value of the channel resource, which must be allocated by the scheduler in the planning frame for radio access to the communication unit. Radio access is understood as access of the first communication unit to at least a part of the radio resource (for example, a logical channel, a physical channel, a frequency band, a time interval, a code, etc.) for transmitting or receiving data from or to a second block or communication node (for example , base station, mobile terminal, radio access point) within a wireless communication network, for example a cellular system, its sector or a special network. Therefore, such a signal transmission can carry information about the radio access of the downlink, as well as about the uplink, either at different moments of the signals, or at the same time.

According to preferred embodiments, the minimum resource parameter can represent either a minimum number of unit blocks or a minimum number of information bits for a subscriber or service in a scheduling frame. According to one embodiment, the minimum resource parameter represents the minimum ratio of the processed information bits to the expended processing power and the work expended for its operation during radio access.

According to another preferred embodiment, the minimum resource parameter is periodically transmitted from the communication unit. Alternatively, it can be requested by the scheduler or initiated by the communication unit after fulfilling the power control conditions, for example, battery status or communication link power budget.

Additional scheduling parameters, such as channel conditions, the amount of data available for transmission, quality of service, delay, data rate, and carrier to interference ratio are considered in the scheduling algorithm, which provides additional benefits.

According to yet another preferred embodiment, determining the power spent includes considering power units for each processed bit (variable costs) and / or power units spent to process the planning frame (fixed costs). Thus, a very accurate determination of the power expended can be obtained.

The invention will be described with reference to the following preferred embodiments with reference to the accompanying drawings.

Figure 1 illustrates a cellular concept consisting of one base station and six mobile terminals.

2 shows an example of a time division frame structure, where two unit blocks form one scheduling frame.

3 shows an example of a time / frequency division frame structure, where ten unit blocks form one scheduling frame.

4 shows an example of a time / frequency / code division frame structure, where eighteen unit blocks form one scheduling frame.

Figure 5 illustrates the structural details of a receiver and a transmitter adapted to carry out the method according to the invention.

Fig.6 illustrates in more detail the transmitter shown in Fig.5.

7 illustrates a block diagram for calculating a minimum resource parameter according to an embodiment of the invention.

Fig. 8 illustrates a block diagram for calculating a minimum resource parameter according to another preferred embodiment.

FIGS. 2-4 illustrate the concept of scheduling a frame based on an arbitrary number of unit blocks, either in the time domain (FIG. 2), or in the time-frequency domain (FIG. 3), or in the time-frequency-code domain (FIG. 4) .

As mentioned above, scheduling is performed in a scheduler, typically contained in a base station or other parts of non-mobile communications system objects.

Typically, scheduling is applied to unit blocks (e.g., in the time / frequency / code domain) containing a number of information bits carried. However, for implementation purposes, it may be easier to obtain, calculate, or calculate other quantities, or they may be more representative than those expressed in bits. Such amounts include, but are not limited to, the number of modulation symbols, FEC code blocks, or Internet protocol packets.

It is usually preferable to schedule a large number of adjacent unit blocks for a single subscriber. Typically, the full frequency band is allocated to the subscriber in order to reduce the amount of signaling from the base station to the mobile terminal.

5, the transmitter is indicated by 100, and the receiver is indicated by 200. As can be seen from the figure, only the necessary details are shown to illustrate the invention. The remaining functional blocks of the transmitter and receiver are known to those skilled in the art and have been omitted for brevity.

The transmitter includes a scheduler 120 that schedules resources (unit blocks) in a scheduling frame. As mentioned above, scheduling parameters received either from a network or from a mobile receiver determine a scheduling algorithm for establishing communication for serving subscribers by transmitting data packets.

The receiver 200 includes a power control unit 210 and a calculation unit 220 for calculating a minimum resource parameter, as will be described in further detail below.

Based on the minimum resource parameter, the scheduler decides whether the currently available resources allow the execution of the minimum resource parameter, and, if so, he schedules unit blocks in the planning frame for this particular subscriber. If the scheduler, due to lack of resources, is not able to provide the requested minimum resource parameter, then unit blocks for this particular subscriber are not planned at all. This has the advantage that resources can be shared among the remaining subscribers. In addition, it is ensured that the receiver operates economically and reasonably, i.e. power consumption for receiving data having less than the minimum amount of information data is avoided.

Additional strategies for uniting single blocks into a planning frame when the minimum resource constraint is not satisfied are described in the pending international patent application entitled “A Method and Scheduler for Performing a Scheduling Algorithm with Minimum Resource Scheduling” 2004 under the name of this applicant.

6 shows an example of some structural details in the form of a block diagram of a transmitter (for example, either a base station or a mobile station) for executing a scheduling algorithm according to the invention.

As shown in the figure, the transmitter 100 includes a scheduler 120, a control unit 130, and a check and release unit 110. All other standard structural details of the transmitter have been omitted since they are not directly related to the invention. Scheduler 120, together with control unit 130, implements a scheduling algorithm. The check and release unit 4 receives the minimum resource parameter that is generated in the receiver 200 (FIG. 5) in the manner shown in FIGS. 7 and 8. The minimum resource parameter is preferably stored in the buffer memory 150, which is accessed by the control unit 130 and which may be updated after system initialization or after receiving the appropriate command from the receiver or network controller of the system.

Finally, the transmitter 100 (as well as the receiver 200) includes transmit and receive circuits 140 for sending and receiving data and control signals using its antenna over the air interface. As noted earlier, signal transmission data regarding the minimum resource parameter is transmitted or received from other communication units of the system. Again, details of a transmission and reception operation using logical data channels and control signals are known to those skilled in the art in the field of communications.

Although the above description has focused on the fact that the scheduler is implemented in a base station acting as a transmitter, the principles of the present invention can be easily applied by those skilled in the art to a mobile terminal acting as a transmitter for sending data to the base station as a receiving unit, i.e. e. on the uplink. In this case, the scheduler may be implemented in the mobile station to execute the scheduling algorithm described above.

7 shows the essential steps for calculating a minimum resource parameter according to an embodiment of the invention, where the minimum resource parameter is applicable to receiving data. The minimum resource parameter, therefore, is represented by the ratio of the received information bits relative to the power spent for their reception on the planning frame.

In order to calculate this ratio, the number of information bits per scheduling frame is first determined in step 310. In addition, the power units expended for receiving information bits, including the processing and operation power per scheduling frame, are determined at step 320. The power units can be roughly divided between those expended for receiving one scheduling frame, including signaling, active work receiver circuits, CRC checksum, etc., indicated by 322. These power units are usually called fixed costs, since they do not show a direct connection with the amount of received information at others planning.

In addition, the units of power spent for each received bit, representing the variable cost factor, are also taken into account and are indicated by 324.

Based on the results of the determination steps 310 and 320, the ratio of the received information bits to the expended processing and operation power can be determined as follows:

Obviously, the higher η, the better the mobile terminal is able to work from an economic point of view. In order to determine whether the receiver is operating economically, the resources allocated to this receiver must exceed the minimum resource threshold ρ _th , which is equivalent to a certain threshold value η _th . Because different mobile terminals will use different architectures, there will be a wide variety of terminal capabilities that cannot be foreseen when planning a communications system. Therefore, there is a need for signaling such network thresholds using a radio interface.

Typically, the variable power units expended depend mainly on the number of bits processed. However, there may be times when variable costs depend on other quantities. Such amounts include, but are not limited to, the number of processed unit blocks, modulation symbols, FEC code blocks, or Internet protocol packets.

FIG. 8 describes another embodiment for calculating a minimum number of unit blocks for a scheduling frame in excess of a threshold ratio. In order to calculate the minimum number of allocated resources ρ _th , first the threshold η _{th of the} received information bits to the consumed power for reception per scheduling frame is obtained as specified by the network (step 340). Next, in step 350, it is necessary to determine the units of power expended for reception, the processing power and operation per planning frame. Based on the results of steps 340 and 350, the minimum number ρ _{th of} unit blocks required to exceed the threshold η _th is calculated at step 360 according to equality (2) given below.

The exact relationship between the allocated resources and the received information bits will depend on the communication system. Almost always, additional signaling of some sort will occur in addition to the transmission of information data. Therefore, the costs of power units can be divided into fixed costs and variable costs.

Example.

For this example, the following assumptions apply.

1. One unit block (au) is capable of transmitting 1000 information bits.

2. CRC checksum is added for the information data of one planning frame, the size is 24 bits (= fixed costs).

3. For associated signaling, an additional overhead of 48 bits is required for transmission in each scheduling frame (= fixed costs).

4. For each received bit, the receiver must spend 1 unit of power (pu) (applicable to both fixed and variable costs).

5. For general active operation, the receiver must spend 2000 pu per planning block (= fixed costs).

Case 1

The allocated resources for the planning frame ρ _{alloc are} sufficient to transfer one unit block to the subscriber, ρ _alloc = 1 ^au / _frame .

Hence,

Case 2

The allocated resources are sufficient to transfer sixteen unit blocks to the subscriber, ρ _alloc = 16 ^au / _frame .

Hence,

Case 3

If the threshold η _th = 0.5 ^bit / _{pu is} set (for example, by a communication system), the minimum number of unit blocks required to exceed this threshold is obtained as follows:

Therefore, the minimum number of resources allocated in the planning frame, ρ _alloc ≥ ρ _th, must be three or more.

Note that the threshold value η _th can be set by the design of the communication system, i.e. transmitted from the BS (or network) to the mobile terminal, or determined autonomously by the mobile terminal, for example, depending on the state of the battery.

In addition, we note that the extension of the method to data transmission (for example, in the uplink) is obvious to specialists in this field of technology, regardless of whether the scheduler is in the base station or in the mobile terminal.

Signaling by the mobile terminal can be carried out periodically (for example, every frame, once for a certain time interval, etc.) or after a special request from the network or base station. An additional mechanism could be implemented in that after the initiation by the mobile terminal, for example, if the battery capacity drops below a certain level, the minimum resource parameter alarm is activated. Thus, an economical class value representing a range of resources or a number of bits can be determined (for example, class I can represent one to two unit blocks, class II can represent three to five unit blocks; class A can represent 1000 to 1500 bits , class B can represent from 1501 to 3800 bits; etc.).

An additional possible state, when signaling may become necessary, is during the establishment or establishment of a connection or call between the base station and the mobile terminal.

Finally, the above calculated or received threshold values may be affected by the actual state of the battery of the mobile terminal, the possible connection of power to the line network of constant power, the duration of the connection or the budget of the communication line power for communication between the base station and the mobile terminal.

Claims (27)

1. A method for scheduling radio resources in a transmitter of a wireless communication system, wherein radio resources for transmitting data are allocated by a transmitter for a planning frame and in distribution units, wherein said method is performed in a transmitter and comprises the steps of receiving a parameter from the receiver, said parameter indicating a minimum number of units distribution allocated to transmit data to the receiver in the planning frame to meet the resource constraint, distribution units are planned to transfer Aci data receiver in planning the frame, wherein the number of allocation units determined in accordance with said parameter. 2. The method according to claim 1, wherein said parameter represents a minimum number of information bits per scheduling frame for a subscriber or service. 3. The method according to claim 1, in which said parameter represents the minimum ratio of processed information bits to the spent processing power and work consumed during radio access at the receiver. 4. The method according to claim 1, wherein said parameter is a value sufficient to exceed the power efficiency threshold in a planning frame. 5. The method according to claim 1, wherein said parameter is transmitted periodically from the receiver to the scheduler. 6. The method according to claim 1, wherein said parameter is transmitted from the receiver to the scheduler after the request of the scheduler. 7. The method according to claim 1, wherein the transmission of said parameter is initiated by the receiver after the power control conditions are met. 8. The method according to claim 1, in which the planning stage includes an additional consideration of at least one of the following planning parameters: channel status, amount of data available for transmission, quality of service, delay, data rate and carrier to interference ratio. 9. The method according to claim 1, in which the planning frame has the structure of at least one of the structure of the frame with time division, frequency division or code division. 10. The method according to claim 1, wherein the distribution units comprise a number of any one of the transmitted information blocks, Internet protocol packets, code blocks, or modulation symbols. 11. The method according to claim 1, wherein said parameter is transmitted by the receiver through a separate control channel associated with the data channel through which the distribution units are transmitted. 12. The method according to claim 1, in which the calculation step further includes considering the associated transmission of signaling added to the information bits for the scheduling frame. 13. The method performed by the receiver of the wireless network to generate a parameter indicating the minimum number of distribution units used in scheduling at the transmitter, said parameter being used to determine the minimum number of distribution units for transmitting data to the receiver, said method being performed at the receiver and comprises the steps of calculating said parameter based on the determination of the power required to process the planning frame at the receiver, and transmitting said The calculated parameter in the transmitter. 14. The method of claim 13, wherein said parameter represents a minimum number of information bits per scheduling frame for a subscriber or service. 15. The method according to item 13, in which said parameter represents the minimum ratio of processed information bits to the spent processing power and work consumed during radio access at the receiver. 16. The method according to item 13, in which said parameter is a value sufficient to exceed the threshold of efficiency in power in the planning frame. 17. The method according to item 13, in which said parameter is transmitted periodically from the receiver to the scheduler. 18. The method according to item 13, in which said parameter is transmitted from the receiver to the scheduler after the request of the scheduler. 19. The method of claim 13, wherein the transmission of said parameter is initiated by the receiver after the power control conditions are met. 20. The method according to item 13, in which the planning stage includes an additional consideration of at least one of the following planning parameters: channel status, the amount of data available for transmission, quality of service, delay, data rate and carrier to interference ratio. 21. The method according to item 13, in which the planning frame has the structure of at least one of the structure of the frame with time division, frequency division or code division. 22. The method of claim 13, wherein the distribution units comprise a number of any one of the transmitted information blocks, Internet protocol packets, code blocks, or modulation symbols. 23. The method according to item 13, in which the said parameter is transmitted by the receiver on a separate control channel associated with the data channel through which the distribution units are transmitted. 24. The method according to item 13, in which the calculation step further includes considering the associated transmission service signaling added to the information bits for the scheduling frame. 25. The method according to item 13, in which the definition of the spent power includes units of power for each processed bits and / or units of power spent to process the planning frame. 26. A mobile terminal comprising means for calculating a parameter used in scheduling performed at the transmitter, the calculation of said parameter being based on determining the power spent for processing the planning frame in the mobile terminal, said parameter indicating the minimum number of distribution units to be allocated for transmitting data to a mobile terminal in a scheduling frame; and means for transmitting said parameter to a base station or network resource controller of a wireless communication system. 27. A base station of a wireless communication network comprising means for obtaining a parameter, said parameter indicating a minimum number of scheduling units allocated to transmit data to a mobile terminal in a scheduling frame to satisfy a resource constraint, and means for scheduling distribution units for at least one of of the following: transmission to the mobile terminal and reception from the mobile terminal in accordance with said parameter.

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