KR20100118450A - Apparatus and method for resource management in relay based cellular networks - Google Patents

Abstract

PURPOSE: A device and a method for managing resource in a relay-based mobile communication network are provided to control the size of the dedicated resource about a relay-base station link, thereby reducing the signaling overhead and delay in every frame. CONSTITUTION: A repeater receives an initial resource allocation and window time from a base station(S121). If it is a window time cycle, the repeater feeds back average virtual required band information which is estimated by every frame time within current window time(S122,S123). If the repeater receives band allocation information from the base station through R-MAP, the repeater allocates real-time traffic preferentially. The repeater allocates the rest of the resources to non real-time traffic(S126).

Description

Apparatus and Method for Resource Management in Relay Based Cellular Networks}

The present invention relates to radio communication resource management, and more particularly, to radio resource management in uplink data transmission between a repeater and a base station.

Many wireless communication technologies have been proposed for high speed mobile communication.

As such, the cells are becoming smaller and smaller in order to accommodate high-speed communication and higher call volume. In this case, it is expected that a centralized design using the current wireless network design method is not possible. Therefore, the next generation communication system should be able to actively cope with environmental changes such as the addition of a new base station while being distributedly controlled and constructed.

For this purpose, the addition of repeaters in cellular networks has been proposed.

1 shows a repeater in a cellular network.

As shown in FIG. 1, the terminal 11 included in the area of the base station 30 is directly connected to the base station 30 by a link, and is located outside the area of the base station 30 so that the channel state from the base station 30 is changed. The poor terminal 12 is connected to the base station 30 through the repeater 20.

At this time, the repeater 20 is located on the building roof relatively higher than the terminal 10, and is fixedly installed and operated. Therefore, the channel environment between the repeater and the base station is smaller in variation than the channel between the terminal and the repeater and has a high channel gain on average.

In this way, since the signal is relayed between the base station and the terminal using the repeater, a base station-terminal link, a base station-relay station link, and a relay station-terminal link are configured. That is, when the terminal is located at the cell boundary of the base station or in a shaded area where the shielding phenomenon is severe due to a building, the terminal communicates with the base station through the repeater. As described above, a repeater technique may be applied in a cell boundary region having a poor channel state to provide a high speed data channel and expand the cell service region.

The environment in which the repeater has been introduced is being discussed in the WiMAX standard, which is a next generation mobile communication system.

The Wimax standard adopts the IEEE 802.16j standard introduced by the repeater, and the IEEE 802.16j standard mainly proposes two types, a dedicated channel allocation method and a scheduling-based multiple access method.

First, a brief description of the first method, that is, the dedicated channel resource allocation method, the repeater may allocate, change, or return a fixed size resource from the base station using the dedicated channel allocation request message.

Specifically, according to the dedicated channel allocation method, the repeater transmits a signaling message for resource allocation to the base station, and the base station determines the size of the resource allocated to the dedicated. At this time, the base station allocates an appropriate size according to the traffic demand of the repeater. Resource allocation can be changed or terminated through signaling.

Next, referring to the second scheme, the scheduling-based multiple access scheme, the terminal requests and allocates resources before transmitting uplink data.

According to the IEEE 802.16j standard, the scheduling-based multiple access method includes a central scheduling-based multiple access method in which a base station directly schedules according to the type and capability of a repeater, and a distributed type in which the base station and the repeater are individually distributed. Scheduling-based multiple access schemes, and delayed scheduling for reducing scheduling (Multi-Access) based multiple access schemes exist.

Such three scheduling-based multiple access schemes will be described in more detail with reference to FIGS. 2 to 4.

2 is a flowchart illustrating centralized scheduling based multiple access according to the prior art.

As shown in FIG. 2, according to the conventional centralized scheduling scheme, when there is data to be transmitted, the mobile station (MS) 10 transmits a resource allocation request (BW REQ: Bandwidth Request) to the relay RS. : Relay Station (20), and the repeater 20 transmits the request to the base station (BS) (30). Then, the base station 30 determines the resource allocation for the terminal 10 and transmits it (CDMA Allocation Information Element).

That is, according to the centralized scheduling scheme, the base station manages all resource allocation for the terminal and the repeater.

3 is a flowchart illustrating distributed scheduling based multiple access according to the prior art.

As shown in FIG. 3, according to the conventional distributed scheduling scheme, in order to reduce the overhead that the repeater 20 has to transmit a request of the terminal to the base station 30, the repeater 20 has a radio given to it. By using the resources, the channel link between the terminal 10 and the repeater 20, that is, manages radio resources. That is, the repeater 20 appropriately allocates radio resources to the terminal 10 by using the radio resources given to it. The base station 30 manages a channel link, that is, a radio resource, between itself and the repeater 20. That is, the base station 30 allocates resources to the repeater 20. The channel link is configured in units of frames. The channel link frame includes an Initial Maintenance Opportunities area for initial ranging, a Request Contention Opportunities area for maintenance ranging, that is, periodic ranging and bandwidth request ranging, and an SS including uplink data of the terminal and repeaters. Contains scheduled data areas.

The repeater 20 manages only the terminals included therein without transmitting the resource request of the terminal to the base station 30, and the base station 30 manages only the repeater 20 connected to the base station 30.

4 is a flowchart illustrating a delayed distributed scheduling based multiple access scheme according to the prior art.

As shown in FIG. 4, according to the conventional delay reduction distributed scheduling scheme, before the relay 20 receives data from the terminal 10 in order to reduce the delay of the aforementioned distributed scheduling scheme, The repeater 20 requests the base station the resources between the repeater and the base station in advance so that the repeater 20 can transfer the data from the terminal 10 to the base station 30 immediately.

Therefore, the delay reduction distributed scheduling scheme may reduce delay compared to the distributed scheduling scheme that requests the base station after the relay successfully receives data from the terminal.

In the above, the scheduling-based multiple access method according to the IEEE 802.16j standard has been described.

In addition, as mentioned previously, the IEEE 802.16j standard has described that there are two types of multiple access schemes for a relay-base station link, that is, a scheduling scheme and a dedicated channel allocation scheme.

However, while the scheduling scheme is adaptive to the channel to efficiently use resources, the overhead and delay may be increased due to the resource request and allocation process.

In addition, according to the scheduling method, since the terminal needs to go through a resource request and allocation process in advance before transmitting data to the uplink, that is, the base station, the access delay and signaling overhead are large. In addition, if the existing scheduling scheme is applied not only to the terminal-relay link but also to the relay-base station link, since the resource request and allocation process must be repeatedly performed by the relay and the base station, connection delay and signaling overhead are much more serious. do.

In addition, in the above-described centralized scheduling method and delayed-reduced distributed scheduling method, aggregation of individual traffics is not considered in the repeater, so that resource allocation and data transmission to the base station for each request of the terminal are separately performed. It is made of. These individual transmissions are less efficient than aggregation transmissions at the repeater and increase signaling overhead.

In addition, since the traffic of the repeater is the traffic volume of the terminals belonging to each repeater is merged, the amount of traffic is larger than the terminal and the change is relatively small, the existing scheduling method is characterized by the characteristics of the repeater-base station channel This is not reflected, and despite the small variation in the amount of channel and traffic of the relay-base station link, since the scheduling is repeatedly performed at the repeater and the base station, the signaling overhead and connection delay as described above are increased. .

On the other hand, the dedicated channel allocation method reduces overhead and delay because data can be sent immediately without additional signaling by using dedicated resources, but it is inefficient in resource usage because it cannot be adaptively applied to the channel every time. It can be enemy.

In addition, the dedicated channel allocation scheme, like the aforementioned scheduling scheme, does not allocate resources based on the entire repeaters included in the base station, but rather allocates them according to resource requests of individual repeaters. Since the characteristics are not considered separately, there is a disadvantage in that resource use is inefficient.

Accordingly, an object of the present invention is to solve the above problems. That is, an object of the present invention is to solve the inefficiency due to overhead and delay, which are problems of the conventional scheduling-based multiple access scheme and the dedicated channel allocation scheme-based multiple access scheme.

In other words, the present invention is to increase the efficiency in the link between the base station and the repeater.

In order to achieve the above object, the present invention periodically allocates a dedicated resource for each specific window time Tw in consideration of channel conditions and traffic conditions for the link between the relay station and the base station.

As such, the reason why the present invention allocates dedicated resources for each specific window time Tw is that the relay-base station link transmits aggregation traffic summed with traffics (or data) received from terminals. This is because, as a channel used, merge traffic of a relatively large size is transmitted as compared with the terminal-relay link, so that the size of transmitted data is large and the amount of change is small. And, another reason is that if the repeater is a fixed repeater, it is a line condition of LOS (Line-Of-Sight) or a relatively good channel situation than the terminal-relay link because it has a relatively low channel characteristics, MCS higher than the terminal-relay link Because you can use

In view of these characteristics, the present invention provides a window-based virtual bandwidth multiple access for allocating and managing resources based on the bandwidth required by the relay, which is updated at a specific window time for the relay-base station link. ; W-VBMA) method.

Specifically, the present invention provides a method for managing resources in a repeater. The method includes receiving information about a window time Tw from a base station; Requesting allocation of a band required by the base station within the window time; Allocating the allocated band to data received from at least one terminal based on the allocated band; Requesting reallocation of a band from the base station if additional bandwidth is needed, even before the window time arrives.

On the other hand, the present invention provides a method for the base station to allocate resources to the repeater. The method includes receiving a band allocation request from one or more repeaters; Allocating a band to the one or more repeaters within a predetermined window period; Reallocating a band reassignment request from the one or more repeaters before the predetermined window period arrives.

The present invention considers the channel and traffic characteristics generated by the introduction of the repeater, and controls the size of the dedicated resource based on the amount of traffic of each repeater for a specific window time for the repeater-base station link, thereby signaling for transmission in every frame. Reduce overhead and delay

In addition, the present invention divides the real-time traffic from the non-real-time traffic and handles the real-time traffic preferentially, thereby reducing signaling overhead and delay for the real-time traffic, and when the amount of the real-time traffic is small, allocated resources are allocated. By allocating most non-real time traffic, dedicated resources can be managed more efficiently for non-real time traffic.

In addition, since the present invention can change and change the MCS level for each window time, it is possible to increase the efficiency of resource use for channel change over the existing dedicated channel allocation method that uses the MCS level fixedly.

Finally, the present invention allows the repeater to immediately receive reallocation of resources by sending a reassignment request message to the base station when the traffic suddenly requires much more resources due to a sudden increase in traffic. This can overcome the inefficiency of the dedicated channel allocation method even in the case of a sudden increase in traffic in a specific repeater, and more evenly use the resources between the repeaters.

The present invention applies to IEEE 802.16. However, the present invention is not limited thereto, and may be applied to all communication systems to which the technical idea of the present invention can be applied, such as 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and methods.

It should be noted that the technical terms used herein are merely used to describe particular embodiments, and are not intended to limit the present invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. In addition, when the technical terms used herein are incorrect technical terms that do not accurately express the spirit of the present invention, they should be replaced with technical terms that can be understood correctly by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced sense.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In the present application, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various components, or various steps described in the specification, wherein some of the components or some of the steps It should be construed that it may not be included or may further include additional components or steps.

In addition, terms including ordinal numbers, such as first and second, as used herein may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In addition, in describing the present invention, when it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easily understanding the spirit of the present invention and should not be construed as limiting the spirit of the present invention by the accompanying drawings. The spirit of the present invention should be construed to extend to all changes, equivalents, and substitutes in addition to the accompanying drawings.

Hereinafter, the term “terminal” is used, but the terminal may be referred to as a user equipment (UE), a mobile equipment (ME), or a mobile station (MS). In addition, the terminal may be a portable device such as a mobile phone, a PDA, a smart phone, a laptop, or the like, or may be a non-portable device such as a PC or a vehicle-mounted device.

5 is an exemplary view showing a concept of resource allocation and management of the present invention.

As shown in FIG. 5, the present invention allocates dedicated resources periodically for a specific window time Tw in consideration of channel conditions and traffic conditions, i.e., amount of data transmission, for the relay-base station uplink. To this end, in the present invention, the resource allocation message transmitted from the base station to the repeater is set to be valid for a specific window time (Tw), and the repeater does not receive a separate resource allocation message at every frame time (Tf) during the validity period. Allows you to leverage existing resources.

According to the present invention, the window-based virtual band multiple access method feeds back to the base station the band information required for the entire real-time and non-real-time traffic (data) for each specific window time (Tw) defined between the base station and the repeater. Assigns the virtual bands maintained within the specific window time Tw to the repeaters as the required band ratios of the feedback relays.

The specific window time Tw may be set based on various data, for example, the frequency of reassignment requests, traffic time zone information, and the like. The specific window time Tw includes a predetermined number of frames Tw = kx T _f , as shown in FIG. 5. The frame consists of a plurality of time slots, a plurality of transmission time intervals (TTIs), or a plurality of sub-frames.

Within the specific window time Tw, since the repeater transmits using resources allocated to the virtual band, there is no delay or signaling overhead for the repeater to access the base station unlike the prior art. However, feedback and resource reallocation of required bandwidth information updated for each specific window time are required.

When the repeater is allocated a resource that can be used exclusively within the specific window time (Tw), first allocates the real-time traffic (data) as much as the required bandwidth estimated for the real-time traffic (data), and allocates the remaining resources Allocated and used for non-real time traffic (data).

This is to satisfy the quality of service of the real-time traffic (or data) by first processing the real-time traffic (or data) so that it is hardly accumulated in the queue.

As described above, the window-based virtual band multiple access scheme of the present invention can achieve the same effect as using the allocated virtual band exclusively within the window time, thereby reducing signaling overhead and delay for data transmission. have.

Hereinafter, various embodiments of applying a window-based virtual band multiple access (W-VBMA) scheme to a relay-base station link will be described.

6 is a block diagram conceptually illustrating a configuration of a repeater and a base station according to the present invention.

As shown in FIG. 6, the repeater 200 may include a virtual request band estimator 210, a resource allocation requester 220, a resource adjuster 230, a traffic spike determination unit 240, and a reallocation requester 250. ).

The virtual required band estimator 210 estimates the amount of traffic of the repeater for each type of traffic. The resource allocation request unit 220 requests the base station 220 to allocate a resource based on the estimated virtual request band, and receives the resource.

The resource adjusting unit 230 divides the allocated resources by types of traffic and allocates them to each terminal.

The traffic spike determination unit 240 suddenly increases the amount of traffic so as to determine whether additional resources are needed immediately.

If it is determined that the additional resources are necessary, the reassignment requester 250 requests reassignment to the base station.

The base station 300 includes a window setting unit 300 and a resource allocation and reassignment unit 320.

The window setting unit 310 sets the specific window time Tw. In this case, in order to set the specific window time, various data, for example, the frequency of reassignment request, traffic over time information, and the like may be used.

The resource allocation and reassignment unit 320 receives a resource allocation request and a reallocation request from the relay 200 and allocates resources accordingly.

In the above, the conceptual configuration of the repeater 200 and the base station 300 is shown. However, the conceptual configuration of the repeater 200 and the base station 300 may be physically implemented by a combination of a processor (for example, a CPU), a storage unit (for example, a memory, a hard disk, and a solid state disk (SSD)). . That is, the conceptual configuration of the repeater 200 may be implemented as a program, stored in a storage means, and executed by the processor.

7 is a flowchart illustrating an operation at a base station according to the present invention.

As shown in FIG. 7, the base station 300 searches for a repeater, sets a window time Tw, and allocates initial resources to each relay station 200 evenly (S111). The base station 300 informs each relay of resource allocation information and the window time through a map for a relay, that is, a relay-MAP (R-MAP).

The R-MAP includes the allocated resource region information and coding information of a signal. Herein, the frame of the base station 300 is divided into a downlink (DL) subframe and an uplink (UL) subframe, and each subframe is divided into a terminal section and a relay section. The relay-FCH and the relay map are located at the beginning of the relay section.

Subsequently, the base station 300 receives virtual request band information Qi from each repeater 200 at every window time Tw (S112 to S113). In this case, the repeater 200 transmits the virtual request band information Qi to the base station 300 by using a resource previously allocated to the repeater 200.

The base station 300 divides the resource by the ratio of the received virtual request band Qi and allocates it to each repeater (S114). Information on the allocated resources is informed to each relay through the relay-MAP (R-MAP).

On the other hand, if the base station 300 receives the reassignment message even if the window time period (Tw) (S115), the virtual request band information of the requested repeater to the virtual request band information received from the repeaters in the previous window time Thus, the resource is divided and reallocated again (S116). The base station 300 informs each repeater of this using the R-MAP. In this case, in order to prevent the window time from being changed, the reallocated resource is applied only for the remaining time until the next window period, and when the window time period Tw comes again, the virtual request band information received from all the repeaters is received. Allocate resources.

After allocating and reallocating resources as described above, the base station 300 receives data from the resource area allocated from each repeater (S117).

8 is a flowchart illustrating an operation in a repeater according to the present invention.

As shown in FIG. 8, the repeater 200 selects a base station to be serviced by itself, and receives an initial resource allocation and window time Tw from the base station (S121). This can be received via R-MAP.

When the window time period Tw is reached, the repeater 200 feeds back the average virtual request band information Qi estimated at every frame time within the current window time to the base station 300 (S213).

Then, when the relay 200 receives the band allocation information from the base station 300 through the R-MAP (S124), the real-time traffic (RT: Real-time) of the resources allocated by them at the current frame time The traffic is divided again using the occupancy of the queue and the occupancy of the non-real-time traffic (NRT) queue. At this time, the resources are allocated to the real-time traffic (RT) preferentially (S125), and the rest are allocated to the non-real-time traffic (NRT) (S126). Through this, the repeater 200 reduces the delay of the real-time traffic.

On the other hand, although not corresponding to the window time period (Tw) (S122), unlike the base station 300, if the repeater 200 corresponds to every frame time period (Tf) (S127), real-time traffic and non-real-time The virtual demand band Qi for the traffic is estimated and the change amount ΔQi is calculated (S128).

If the amount of change compared to the current virtual demand band exceeds a predetermined threshold value (ΔQi / Q _i (t-1)> Q _th ) (S129), it is determined that the traffic amount has surged, and the current virtual to the base station 300 The reassignment request message containing the request band information is transmitted (S130).

When the band reallocation information is received through the R-MAP in response to the reassignment request message from the base station 300 (S131), resources are allocated to the occupancy information of the real-time traffic and the non-real-time traffic queue between the current frames. Distribute again (S125 ~ S126).

On the other hand, even if the amount of change in the virtual request band is smaller than the threshold (S129), the resources for real-time and non-real time are redistributed by reflecting the occupancy information of the real-time traffic and the non-real time traffic queue at the current frame time (S125). ~ S126).

In addition to the window time and the frame time period, data is transmitted to the base station using the allocated resources (S132).

9 shows an uplink subframe structure of a base station according to the present invention, and FIG. 10 shows an uplink subframe structure of a repeater according to the present invention.

9 and 10, resources of an uplink subframe are divided into a UL access zone and a UL relay zone.

In FIG. 9, the UL Access Zone is used by a terminal directly serviced by a base station, and the UL Relay Zone is used by a repeater included in the base station. The UL Access Zone corresponding to the terminal-relay link is used in a conventional scheduling scheme. In contrast, the repeater-base station link represents the use of a window-based virtual band multiple access scheme (W-VBMA).

In FIG. 10, the UL Access Zone is used by a terminal serviced by the repeater, and the UL Relay Zone is used when each repeater transmits uplink data to the base station. In the UL Access Zone, the repeater allocates resources to the terminal on a scheduling basis.

The terms used in FIGS. 9 and 10 are as follows.

Ranging Subchannel represents a resource for a purpose such as synchronization and BW request, UL burst (Uplink burst) means an uplink resource block allocated by a scheduling method, R-UL W-VBMA burst is a W-VBMA method The relay-base station uplink resource block is used, UL subframe means the uplink subframe.

Hereinafter, a window-based virtual band multiple access method (W-VBMA) according to the present invention described so far will be described in more detail with reference to FIG. 11 and an equation.

11 is an exemplary diagram showing a chart based on a window-based virtual band multiple access method according to the present invention. In FIG. 11, in order to understand the window-based virtual band multiple access (W-VBMA) scheme, it is shown in two phases.

First, in a first step (shown as BS allocation), the base station 300 receives feedback of the size of the required band for the real-time and non-real-time traffic from the repeaters 200 as a ratio of the required band size of each repeater. As shown in the drawing, resources of the UL relay zone are allocated within the window period Tw.

: 중계기i 의 전체 요구 대역)는 실시간성 트래픽에 대한 요구 대역 추정치(

)와 비실시간성 트래픽에 대한 큐 점유량 추정치(

)의 합

으로 구성된다. 따라서 중계기i에 할당되는 자원은

로 결정된다. 여기서 R은 기지국이 중계기들에 대해 할당하는 전체 자원의 크기이고, Q는 중계기들의 전체 요구 대역 크기의 합(

)이다. The size of the total required band (

Is the total required bandwidth of the repeater i).

) And queue occupancy estimates for non-real time traffic (

Sum of)

It consists of. Thus, the resources allocated to repeater i

Is determined. Where R is the total size of resources allocated by the base station for the repeaters, and Q is the sum of the total required bandwidth sizes of the repeaters (

)to be.

An example of a request band estimate (Q _i ^RT ) for real-time traffic in a repeater and a request band estimate (Q _i ^NRT ) based on queue occupancy for non-real-time traffic will be described in detail.

In order to process the real-time traffic so that it hardly accumulates in the queue, the estimated bandwidth estimate at the next window time is determined by the traffic amount estimates of the repeaters every window time. The estimated bandwidth demand for real-time traffic of repeater i at window time t is expressed by the following equation.

이며, 여기서 K는 실시간성 트래픽 클래스의 집합, n_k(t)는 t에서 중계기에 연결되어 있는 실시간성 트래픽 클래스 k의 단말 개수, V_K는 실시간성 트래픽 클래스 k의 활성도(activity) 등을 고려한 인자 (

),r _k 는 실시간성 트래픽 클래스 k의 최대 전송률(peak data rate), T_f는 프레임 시간을 나타낸다. 결국, α_i ^RT(t)는 윈도우 시간 t에 프레임 시간 동안 전송 해야할 중계기i에서 단말들에 의해서 발생할 것으로 추정되는 실시간성 트래픽의 양을 나타낸다. 여기서 V_K가 1이면 최대 전송률로써 예측이 되고, 트래픽 클래스의 평균 활성도 값이면 평균 전송률로써 예측이 된다실시간성 트래픽 양의 추정치는 시간에 따라서 변하고, 정확한 값이 아니기 때문에 그의 변화량을 이용하여 추가 조정이 가능하다. 위의 수학식에서 αΔα _i ^RT (t)가 이에 해당하며, α를 이용하여 변화량에 대한 민감도를 조절할 수 있다. 이를 위해서 중계기는 윈도우 시간 내에서 프레임 시간 단위로 트래픽을 모니터링 할 필요가 있다. The estimate of the band required for the next window time t + 1 at the window time t consists of two terms. Two terms are the estimation of the occurrence of real-time traffic at t ( Q _i ^RT (t)) and the amount of change of the estimation of the occurrence of real-time traffic at Δα _i ^RT (t). α _i ^RT (t) can be estimated from terminals with real-time traffic connected to the repeater. As in the equation above

Where k is the set of real-time traffic classes, n _k (t) is the number of terminals of real-time traffic class k connected to the repeater at t, and V _K is the activity of real-time traffic class k. factor (

) , r _k represents the peak data rate of the real-time traffic class k, T _f represents the frame time. After all, α _i ^RT (t) represents the amount of real-time traffic estimated to be generated by the terminals in the relay i to be transmitted during the frame time at the window time t. If V _K is 1, it is predicted as the maximum data rate, and if the average activity value of the traffic class is predicted as the average data rate, the estimate of the amount of real-time traffic varies over time and is not an exact value. This is possible. In the above equation, αΔα _i ^RT (t) corresponds to this, and the sensitivity can be adjusted to the change amount using α. For this purpose, the repeater needs to monitor traffic in frame time units within window time.

 Non-real-time traffic uses the estimate of the demand band based on queue occupancy at the current window time to determine the required band size at the next window time. The bandwidth required for the non-real time traffic of the relay i at the window time t is determined by the following equation.

Where q _i ^NRT (t + 1) is the occupancy of the non-real-time traffic queue at the t + 1 starting point, A _i ^NRT (t + 1) is the traffic arrival estimate of the non-real-time traffic queue per frame time at t + 1, [T _w / T _f ] is the number of frames in the window time. Therefore, Q _i ^NRT (t + 1) represents the required band estimate for transmitting non-real-time traffic in bits per frame at t + 1. Where q _i ^NRT (t = 1) = (q _i ^NRT (t) + α _i ^NRT (t) -d _i ^NRT (t)) ⁺ , where q _i ^NRT (t) is non-real time at the beginning of t The traffic queue occupancy, α _i ^NRT (t) represents the traffic arrival amount of the non-real time traffic queue during window time at t, and d _i ^NRT (t) represents the amount of service of the non-real time traffic queue during window time at t. The A _i ^NRT (t + 1) value can be estimated from the value obtained by monitoring the value at every frame time by the repeater within the previous window time, and can be expressed as the average value and the change amount as shown in the following equation.

는 윈도우 시간 t에서 프레임 당 비실시간성 트래픽 큐의 도착량 의 평균값이고, ΔA_i ^NRT(t)는 변화량에 해당한다. 그리고, α를 이용하여 변화량에 대한 민감도를 조절할 수 있다.here

Is the average of the arrivals of the non-real-time traffic queues per frame at window time t, and ΔA _i ^NRT (t) corresponds to the variation. And, the sensitivity to the amount of change can be adjusted using α .

)만큼 할당하고, 나머지를 비실시간성 트래픽에 대해서 할당하여 기지국으로 각각의 실제 데이터를 전송한다. 이는 실시간성 트래픽을 우선적으로 전송하여, 큐에 거의 쌓이지 않도록 함으로써 실시간성 트래픽의 서비스 품질을 만족시키기 위함이다. 여기서

의 결정은 아래의 수학식으로 정해진다.On the other hand, in the second stage (shown as RS adjustment), the relay first allocates the resources allocated from the base station to the size of the required resources determined by the queue occupancy rate for its real-time traffic at the current frame time.

), And the rest for non-real-time traffic to transmit each actual data to the base station. This is to satisfy the quality of service of the real-time traffic by transmitting the real-time traffic preferentially, so that it rarely accumulates in the queue. here

Is determined by the following equation.

는 비트 단위의 큐 점유량을 채널에 따른 MCS(Modulation and Coding Scheme)를 고려하여 자원의 최소 단위(i.g. PUSC slot)로 변환하는 함수이 고,

는 현재 프레임에서의 비트 단위의 실시간성 트래픽 큐의 점유량을 나타내고, R_i,max ^RT=βR_i이고, R _i,max ^RT 는 릴레이i의 실시간성 트래픽에 대한 최대 자원 할당 크기를 나타낸다. 그리고 이 값은 β∈[0,1]에 따라서 조정이 가능하다. 따라서 이 수학식에서 R_i, R_i ^RT, R_i,max ^RT는 자원의 최소 단위인 슬롯의 개수로 정해진다. 실시간성 트래픽에 대한 자원의 크기(R _i ^RT )가 결정되면 릴레이가 할당 받은 전체 자원(R _i )에서 나머지를 비실시간성 트래픽에 대한 자원의 크기(R _i,max ^RT )로 결정한다. 따라서 비실시간성 트래픽에 대한 자원의 크기는

가 된다. 다음으로 릴레이는 1, 2단계에 따라 나누어진 자원을 이용하여 실시간성, 비실시간성 병합 트래픽을 기지국으로 전송한다. 1단계는 기지국에 의해서 정해진 윈도우 시간마다 수행 되고, 2단계는 릴레이에 의해서 프레임 시간마다 수행된다. 윈도우 시간은 채널, 트래픽 상황에 따라 기지국이 조정 가능하다.here

Is a function that converts the queue occupancy in bits to the minimum unit of resource (ig PUSC slot) in consideration of Modulation and Coding Scheme (MCS) according to channels.

Denotes the occupancy of the real-time traffic queue in bits in the current frame, R _{i, max} ^RT = βR _i , and R _{i, max} ^RT indicate the maximum resource allocation size for the real-time traffic of relay i. This value can be adjusted according to β∈ [0,1]. Therefore, in this equation, R _i , R _i ^RT , R _{i, max} ^RT is determined by the number of slots which are the minimum units of resources. When the resource size ( R _i ^RT ) for the real-time traffic is determined, the rest of the total resources ( R _i ) allocated by the relay determines the rest as the resource size ( R _{i, max} ^RT ) for the non-real time traffic. Therefore, the size of resources for non-real time traffic

Becomes Next, the relay transmits real-time and non-real-time merged traffic to the base station by using the resources divided according to steps 1 and 2. Step 1 is performed every window time determined by the base station, and step 2 is performed every frame time by the relay. The window time can be adjusted by the base station according to the channel and traffic conditions.

 If the traffic spikes on each repeater and cannot wait until the next window time, immediate resource reallocation is required. To support this, each repeater calculates the amount of change in parallel with estimating the virtual demand band every frame time. The change amount of the virtual required band is calculated by the following equation.

). 따라서 ΔQ(t,n)는 이전 윈도우시간 (t-1)에서의 가상요구대역(

)으로부터 현재 프레임에서 가상요구대역이 얼마나 증가했는지를 나타내는 수치이다.Where i is the repeater index, t is the current window time, and n is the nth frame within the current window time (

) . Therefore, ΔQ (t, n) is the virtual demand band at the previous window time (t-1)

) Shows how much the virtual requirement band has increased in the current frame.

It is determined by the following equation whether the amount of change in the virtual demand band has soared.

를 조정하여 변화량 판단의 민감도를 조절할 수 있다. 트래픽이 급증한 것으로 판단되면, 중계기는 윈도우시간 t의 n번째 프레임에서 추정된 현재 가상요구대역 Q _i (t;n)을 포함하여 재할당 요청 메시지를 기지국에 전송한다. 기지국은 재할당 요청 메시지를 수신하면, 이전 윈도우시간에서 중계기들로부터 수신한 가상대역정보에 재할당 요청 메시지로부터 수신한 해당 중계기의 가상대 역정보를 업데이트하여 자원을 재할당하고, R-MAP(Relay-MAP)을 이용하여 각 중계기에 알려준다. 이러한 과정을 통해서 특정 중계기에서 갑자기 트래픽이 급증할 경우에도 즉각적으로 대처할 수 있다.Here, T _i (t; n) is a change test value in the nth frame of the window time t, and when this value is larger than Q _{th, which} is a real number ( ⁺ ) factor larger than 0, it is determined that the traffic has surged. therefore

You can adjust the sensitivity of the change judgment by adjusting. If it is determined that the traffic has surged, the repeater transmits a reassignment request message to the base station including the current virtual demand band Q _i (t; n) estimated at the nth frame of the window time t. When the base station receives the reassignment request message, the base station updates the virtual band information of the corresponding repeater received from the reassignment request message to the virtual band information received from the repeaters at the previous window time, and reallocates resources. Relay-MAP) is used to inform each repeater. Through this process, even if the traffic suddenly increases in a specific repeater, it can respond immediately.

In the above description, the window-based virtual band multiple access scheme of the present invention is applied to the relay-base station link. However, the window-based virtual band multiple access scheme of the present invention may be applied to the link between the base station and the terminal. That is, the base station may allocate resources of the terminal in a window-based virtual band multiple access scheme.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, May be modified, modified, or improved.

1 shows a repeater in a cellular network.

2 is a flowchart illustrating centralized scheduling based multiple access according to the prior art.

3 is a flowchart illustrating distributed scheduling based multiple access according to the prior art.

4 is a flowchart illustrating a delayed distributed scheduling based multiple access scheme according to the prior art.

5 is an exemplary view showing a concept of resource allocation and management of the present invention.

6 is a block diagram conceptually illustrating a configuration of a repeater and a base station according to the present invention.

7 is a flowchart illustrating an operation at a base station according to the present invention.

8 is a flowchart illustrating an operation in a repeater according to the present invention.

9 shows an uplink subframe structure of a base station according to the present invention.

10 shows an uplink subframe structure of a repeater according to the present invention.

11 is an exemplary diagram showing a chart based on a window-based virtual band multiple access method according to the present invention.

Claims (16)

As a method of managing resources in a relay, Receiving information about the window time Tw from the base station; Requesting allocation of a band required by the base station within the window time; Allocating the allocated band to at least one terminal based on the allocated band; Requesting reallocation of a band from the base station if additional bandwidth is needed, even before the window time arrives. The method of claim 1, wherein And resource request information is transmitted to the base station. The method of claim 2, wherein the virtual required band is Resource allocation method comprising real-time band information (Q _i ^RT ) and non-real time band information (Q _i ^NRT ). The method of claim 3, The real time band information (Q _i ^RT ) is

Calculated by Where d _i ^RT (t) is an estimate of the occurrence of real-time traffic, i is a repeater index,

Is the change in real-time traffic occurrence estimates, The non-real time band information (Q _i ^NRT ) is

Calculated by Where q _i ^NRT (t + 1) is the occupancy of the non-real time traffic queue at the start of window time (t + 1), and A _i ^NRT (t + 1) is the non-real time traffic per frame at window time (t + 1) A predicted value of the traffic arrival amount of the queue, T _f represents a frame period, and T _w is a window period characterized by the window period. The method of claim 4, wherein The real-time traffic occurrence estimate (

)

Calculated by here

Is a set of real-time traffic classes,

Is the number of terminals of real-time traffic class k connected to the relay at t, and v _k ∈ [0,1] is a factor considering the activity of the real-time traffic class k (

),

Is the average peak data rate (peak data rate) of the real-time traffic class k, T _f represents the frame time. The method of claim 1, wherein the reassignment request step Estimating a required band every frame Tf; And calculating a change amount of the required band in each frame. The method of claim 6, wherein the amount of change Equation

Calculated by Where i is the repeater index, t is the current window time, and n is the nth frame within the current window time (

), Tf denotes a frame period, Tw denotes a window period, and ΔQ _{i (} t, n) denotes how much the virtual requirement band is increased in the current frame from the virtual requirement band at the previous window time (t-1). Resource allocation method, characterized in that the sensitivity of the decision can be adjusted by adjusting Q _th . 7. The method of claim 6 wherein the reassignment request step is And determining whether the change amount exceeds a preset threshold. The method of claim 1, And distributing the allocated and reassigned bandwidth to one or more terminals. 10. The method of claim 9, wherein in the dispensing step Allocating a band for real-time traffic to the at least one terminal among the allocated and reallocated bands; And allocating the remaining bands to the one or more terminals as bands for non-real-time traffic. The method of claim 1, wherein the window time (Tw) is Resource allocation method comprising a plurality of sub-frames. As the base station allocates resources to the repeater, Receiving a band allocation request from one or more repeaters; Allocating a band to the one or more repeaters within a predetermined window period; And reallocating a band to the one or more repeaters upon receiving a band reallocation request from the one or more repeaters before the predetermined window period arrives. 13. The method of claim 12, wherein when the predetermined window period arrives Receiving a new band allocation request from the one or more repeaters; And allocating a band according to the new band allocation request. The method of claim 12, wherein the band allocation step And resource allocation method based on the virtual request band information received from the repeater. 15. The method of claim 14, wherein the virtual request band information is Resource allocation method comprising real-time band information (Q _i ^RT ) and non-real-time band information (Q _i ^NRT ). 13. The method of claim 12, wherein the window time Tw is Resource allocation method comprising a plurality of sub-frames.

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