KR101336735B1 - Method and apparatus for reliable communication using ack aggregation in directional wireless communication system - Google Patents

Abstract

The present invention relates to a method and apparatus for reliable communication through Eck aggregation in a directional wireless communication system.
In a directional wireless communication system according to an embodiment of the present invention, a communication method of a receiver includes: receiving i data frames (i is an integer) multicasted in a first sector of a transmitter antenna beam; Identifying ACK aggregation scheduling information included in at least one of the i data frames; And collecting ACK information for the i data frames based on the ACK aggregation scheduling information, wherein the collection of the ACK information is performed in the first sector according to the order included in the ACK aggregation scheduling information. Receiving the ACK information of the previous receiver belonging to, or transmitting the ACK information to the next receiver in the above order.

Description

TECHNICAL AND METHOD AND DEVICE FOR RELIABLE COMMUNICATION USING ACCESS IN DIRECT WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a method and apparatus for reliable communication through Eck aggregation in a directional wireless communication system. Here, the directional wireless communication system may be a wireless local area network (WLAN) capable of high-speed data service of 1Gbps or more, such as IEEE 802.11ad.

Recently, researches on wireless local networks capable of high-speed data service of 1Gbps or more have been actively conducted. High-speed data services use high directional antennas to ensure high throughput using frequencies in the 60 GHz band.

Services using WLAN based on IEEE 802.11ad may include reliable multicasting services.

Multicasting services can be very important in many applications, such as software updates, alarm signal transmissions, and so on.

To date, there are not many studies related to reliable multicasting protocols for directional antennas, and many studies have been conducted only on wireless networks.

In the prior art associated with multicasting, the sender multicasts the frame to all receivers, and the ACKs of each of the receivers are scheduled to prevent ACK explosion problems. In this case, the transmitting end may maintain a bitmap table that records a receiver for which no ACK is received.

The transmitting end may retransmit the original multicast frame including the bitmap information, and the receiver that does not receive the frame may correct the error.

As such, since all receivers in the prior art must transmit ACK, delay may inevitably occur, and throughput of the entire communication system may be degraded. The larger the number of receivers, the lower the overall throughput of the communication system will be.

On the other hand, in the NAK-based multicasting method, proper control may not be performed when all transmission frames fail.

In a hybrid system using both ACK and NAK, a receiver and a transmitter selected as a leader may perform ACK-based multicasting, and the remaining receivers may perform NAK-based multicasting. At this time, in the case of receivers other than the receiver selected as the hybrid system, the same problem may occur as the NAK-based multicasting method.

The present invention provides a reliable communication method through Eck aggregation in a directional wireless communication system.

In addition, the present invention provides a communication system capable of avoiding delay and collision of an ACK in a directional wireless communication system.

 In a directional wireless communication system according to an embodiment of the present invention, a communication method of a receiver includes: receiving i data frames (i is an integer) multicasted in a first sector of a transmitter antenna beam; Identifying ACK aggregation scheduling information included in at least one of the i data frames; And collecting ACK information for the i data frames based on the ACK aggregation scheduling information, wherein the collection of the ACK information is performed in the first sector according to the order included in the ACK aggregation scheduling information. Receiving the ACK information of the previous receiver belonging to, or transmitting the ACK information to the next receiver in the above order.

According to an aspect of the present invention, there is provided a communication apparatus of a directional wireless communication system, comprising: a receiving unit receiving i (i is an integer) data frames multicast in a first sector of a transmitter antenna beam; A control unit which checks ACK aggregation scheduling information included in at least one of the i data frames; An ACK information collecting unit for collecting ACK information for the i data frames based on the ACK aggregation scheduling information, wherein the ACK information collecting unit includes the first sector according to an order included in the ACK aggregation scheduling information; Receive ACK information of the previous receiver belonging to, or transmits the ACK information to the next receiver in the above order.

In a directional wireless communication system according to an embodiment of the present invention, a sender communication method includes multicasting i (i is an integer) data frames in a first sector of an antenna beam; Switching the antenna beam to a second sector and multicasting the i data frames in the second sector; And switching the antenna beam to the first sector after completing the multicasting of the second sector, and receiving aggregated ACK information of receivers belonging to the first sector, wherein at least one of the i data frames Contains ACK aggregation scheduling information.

According to another aspect of the present invention, a communication apparatus of a directional wireless communication system includes: an antenna unit configured to multicast a data frame using an antenna beam; An antenna switching unit for switching the antenna beam; And a control unit for generating ACK aggregation scheduling information, wherein the antenna unit multicasts i data frames (i is an integer) to a first sector in a first period and multiplies to a second sector in a second period. Casting, wherein the antenna switching unit switches the antenna beam to the second sector after the first section and the reporting section, switches the antenna beam to the first sector after the second section, and the antenna unit After the second interval, the aggregated ACK information of the receivers belonging to the first sector is received.

According to the present invention, a reliable communication method through Eck aggregation in a directional wireless communication system is possible, and delay and collision of an ACK can be avoided in the directional wireless communication system.

The directional wireless communication system according to the present invention can avoid delay and collision of the ACK.

1 is a view for explaining an example of a network topology of K = 4 according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of scheduling according to a communication scenario of a network illustrated in FIG. 1.
3 illustrates an example of ACK aggregation using a bitmap, according to the communication scenario of FIG. 1.
4 shows an example of comparing reliability based on frame error rate (FER).
5 shows an example of comparing reliability based on frame loss rate (FLR).
6 shows an example of comparing ACK collection latency on the basis of frame error rate (FER).
7 illustrates a communication method of a receiver in a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna according to an embodiment of the present invention.
8 shows an example of the configuration of a communication device (receiver) of a directional wireless communication system according to an embodiment of the present invention.
FIG. 9 illustrates a sender communication method in a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna according to an embodiment of the present invention.
10 shows an example of the configuration of a communication device (sender) of a directional wireless communication system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the principle of spatially pipelined ACK aggregation reliable multicast (SPARM) applied to the present invention will be described. Hereinafter, a communication method and a communication device using the SPARM will be described.

Embodiments proposed herein relate to an ACK-based reliable multicast protocol in a directional wireless communication system. In this case, the directional wireless communication system refers to a wireless communication system using a directional antenna such as 60GHz technology.

An ACK based scheme may have a problem of ACK explosion and ACK collection latency. In this case, the ACK collection latency refers to a delay time for receiving the ACK.

Embodiments of the present invention can increase system performance by solving the problems of ACK explosion and ACK collection latency. The problem of ACK explosion and ACK collection latency can be solved or alleviated by "spatial reuse" and "pipelining of ACK aggregation" of directional antennas. Here, "aggregation" may mean a series of processes of merging ACKs and transmitting the merged ACKs to the transmitter S without interference. Of course, the term "aggregation" may in some cases mean merging ACK itself.

<SPARM>

In the present specification, a directional wireless communication system is assumed to be an antenna beam switching system in which K (K is an integer) beam patterns are non-overlapping. Here, the antenna beam switching system may be, for example, a system conforming to the IEEE 802.11 MAC standard. Also, for example, a 60 GHz wireless communication system may switch antenna beams and may be implemented such that the plurality of beams do not overlap. Here, the switching of the antenna beam may be to spatially move the beam radiated through the antenna.

In directional communication, when one beam is transmitted or received, the remaining beams are blocked. Thus, embodiments of the present invention do not consider the case where all K beams are multicast simultaneously. That is, the antenna beam may be sequentially multicasted from 0 to K-1 th.

의 앵글(angle)

를 저장하고, 저장된

를 이용하여 빔포밍(beamforming)을 수행할 수 있다. 이때, j는 리시버들을 구분하는 인덱스이고, i는 송신기 S의 빔에 대한 인덱스이다. 즉,

는 송신기 S의 i번째 안테나 빔을 수신할 수 있는 영역 내의 j번째 리시버를 의미한다.

는

의 등록 프레임(registration frame)을 이용한 AOA(angle of arrival) 추정(estimation)에 의해 획득될 수 있다. As shown in Fig. 1, the transmitter S is a receiver.

Angle

Save it, and

Beamforming may be performed using. In this case, j is an index for distinguishing the receivers, and i is an index for the beam of the transmitter S. In other words,

Denotes the j-th receiver in the region capable of receiving the i-th antenna beam of the transmitter S.

The

It may be obtained by an angle of arrival (AOA) estimation using a registration frame of.

까지의 상대적인 거리(relative distance)

를 추정할 수 있다. 이때, 상대적인 거리

는 예를 들어 리시버의 전송 전력(transmit power) 정보를 포함하는 등록 프레임의 수신 전력을 측정(measuring)함으로써 획득될 수 있다. Transmitter S

Relative distance to

Can be estimated. At this time, the relative distance

Can be obtained, for example, by measuring the received power of a registration frame that includes the transmit power information of the receiver.

와 같이 표현할 수 있고, 이때 n_i는 R _i 의 리시버들의 개수이다. 멀티캐스트 그룹은 "안테나 빔의 섹터"로 도 표현될 수 있다. 예를 들어, 도 1에서 송신기 S는 4개의 안테나 빔 섹터들(R ₀ , R ₁ , R ₂ , R ₃ ) 각각에 멀티캐스팅할 수 있다.
As shown in FIG. 1, the multicast group of the transmitter S may be defined as R _i for the antenna beam (which may be referred to as 'beam' for short) i. In other words,

N _i is the number of receivers of R _i . Multicast groups can also be represented as "sectors of antenna beams". For example, in FIG. 1, the transmitter S may multicast to each of four antenna beam sectors R ₀ , R ₁ , R ₂ , and R ₃ .

<SPARM Scheduling>

In SPARM technique according to an embodiment of the present invention, the sender S may multicasting the data frame in a rotational manner (circular fashion) from the R ₀ to R _K-1. That is, in FIG. 1, the transmitter S may perform beamforming on R ₀ and then perform beamforming on R ₁ .

After multicasting the data frames, the transmitter S needs to receive an ACK.

In this case, it may be an important issue when to set an optimal time for transmission of ACKs by each of the receivers. The ACK transmission may be performed after data multicasting up to R _K-1 is completed. However, from the receiver's point of view, sending an ACK while transmitter S performs multicasting may be more efficient in reducing the overall communication delay, as long as it does not interfere with transmitter S performing multicasting.

In the SPARM technique according to an embodiment of the present invention, ACKs of receivers belonging to R _i are aggregated to reduce the ACK collection latency time. In this case, the collection of ACKs means that the transmitter S multicasts the data frame in the beam (i + 1)% K (i = {0, 1, ..., K-1 and% means modulo operation}). May be collected. The aggregation concept of the ACKs and the aggregation schedule are described in more detail with reference to FIG. 2.

FIG. 2 is a diagram illustrating an example of scheduling according to a communication scenario of a network illustrated in FIG. 1.

In FIG. 2, T ₀ and T ₁ represent the multicasting periods of beam 0 and beam 1, respectively, and T _r represents the reporting duration of the collected ACKs.

Referring to FIG. 2, the transmitter S multicasts a data frame with R ₀ in a T _{0 period} . After completing multicasting for R ₀ , the transmitter S switches the beam to 1 and multicasts the data frame to R ₁ in the T _{1 period} . ACK of the receivers belonging to R ₀ in the T ₁ interval is collected.

Since there may be multiple multicast frames for which no ACK has been identified, the transmitter S may track and maintain whether an ACK is received for each of the frames.

Each of the receivers maintains a bitmap for the multicast frame. In this case, the bitmap may be used to indicate whether the i-th frame has been successfully received. For example, "1" in the bitmap indicates that the frame has been successfully received. By logically ANDing the bitmaps, the final receiver can know which frame was successfully received for each of all receivers. In this case, the final receiver may be a receiver that collects the ACK and reports it to the transmitter S. The logical AND operation may be performed in units of bits of the bitmap.

3 illustrates an example of ACK aggregation using a bitmap, according to the communication scenario of FIG. 1.

로부터

으로, 그리고

으로부터

로의 순서로 스케줄링 되었다고 가정한다. In FIG. 3, the first sequence number of the bitmap is 0, and the ACK aggregation is

from

And then

From

Assume that they are scheduled in the order of.

Referring to FIG. 3, the bitmap frame includes a bitmap header H. H may include a first sequence number (SN) of the bitmap and a frame number of a frame targeted for ACK. The i th bit of the bitmap may indicate whether the i th frame has been successfully received.

는

로부터 수신된 비트맵과 자기 자신의 비트맵을 AND 연산 함으로써, 첫 번째 데이타 프레임이 유실(missing)되었다는 것을 알 수 있다. 마찬가지로,

는

로부터 수신된 비트맵과 자기 자신의 비트맵을 AND 연산 함으로써, 첫 번째(SN (1)), 세번째(SN (3)) 및 네번째(SN (4)) 데이타 프레임들이 유실(missing) 되었다는 것을 알 수 있다. 도 3의 step 2에서

는 시퀀스 넘버가 1인 데이타 프레임이 수신되지 않은 상태에서 시퀀스 넘버가 2인 데이타 프레임이 수신되면 자신의 ACK 비트맵의 두번째 비트를 "0"으로 명시할 수 있다. Referring to Figure 3, the receiver

The

By ANDing the bitmap received from it and its own bitmap, it can be seen that the first data frame has been missed. Likewise,

The

By ANDing the bitmap received from its own bitmap, we know that the first (SN (1)), third (SN (3)) and fourth (SN (4)) data frames are missing. Can be. In step 2 of FIG.

If a data frame with a sequence number of 2 is received while a data frame with a sequence number of 1 is not received, may designate a second bit of its ACK bitmap as "0".

Unlike the prior art, in the SPARM technique according to the embodiment of the present invention, the transmitter S does not necessarily maintain a bitmap for each of the receivers. That is, in the SPARM technique according to the embodiment of the present invention, the bitmap table indicates whether reception of each data frame is successful. Accordingly, according to the SPARM technique according to the embodiment of the present invention, the bitmap table has a feature that is independent of the number of receivers and is scalable. In the present specification, the bitmap table may be a lookup table that records the bitmap reported to the transmitter S by the final receiver.

로부터

로 ACK가 전송되는 것으로 가정하면,

의 ACK 전송을 위한 빔은 송신기 S가 R ₁ 에 멀티캐스팅하는 동안 R ₁ 에 속해 있는

에 간섭을 일으킬 수 있다. 따라서, ACK 취합 또는 취합 스케줄링은 주의 깊게 설계될 필요가 있다. 1,

from

Assuming an ACK is sent to

Beam for transmission of the ACK is that belong to R ₁ while the transmitter S multicasting to R ₁

May cause interference. Thus, ACK aggregation or aggregation scheduling needs to be carefully designed.

로부터

으로, 그리고

으로부터

로의 순서로 스케줄링 된다. 물론,

로부터 송신기 S로의 리포트는 R ₁ 의 멀티캐스팅이 종료될 때까지 지연된다. 1 to 3, ACK aggregation for R ₀ may be performed to prevent interference with R ₁ .

from

And then

From

It is scheduled in order. sure,

The report from the transmitter to the transmitter S is delayed until the multicasting of R ₁ ends.

,

및

는 ACK들을 취합한다. Referring back to FIG. 2, in the interval where the transmitter S multicasts the data frame to R ₁ .

,

And

Collects ACKs.

는 R ₁ 의 멀티캐스팅이 종료될 때까지 기다린 후, 취합된 ACK를 송신기 S로 보고한다. 즉,

는 도 2의 step 3에서 생성된 "aggregated ACK to be transmitted"에 해당하는 비트맵을 송신기 S로 전송한다. Final receiver

Waits for the multicasting of R ₁ to end and reports the aggregated ACK to transmitter S. In other words,

Transmits a bitmap corresponding to "aggregated ACK to be transmitted" generated in step 3 of FIG. 2 to the transmitter S. FIG.

As can be seen in the example described in FIGS. 1-3, transmitter S receives only one ACK report for R ₀ . Therefore, the SPARM technique according to the embodiment of the present invention can solve the problem of ACK explosion (implosion) regardless of the number of transmitters.

In an embodiment of the invention, the ACK aggregation scheduling may be determined by the transmitter S. The transmitter S may determine an ACK collection order according to the following two policies (hereinafter, referred to as an 'collecting scheduling policy').

가 작아지는 순서로 소팅(sorting) 되어야 한다. 즉,

이면,

는

의 ACK를 취합한다. 이때, a 및 b는 각각 리시버를 구분하는 인덱스이다. 도 1의 예에서,

로부터

의 순서로 취합되면 R ₁ 에 대한 간섭은 일어나지 않지만,

로부터

의 순서로 취합되면 R ₁ 에 속해 있는

에 간섭을 일으킬 수 있음을 알 수 있다. Policy 1 : The ACK Collection Schedule is Angled with Transmitter S

Should be sorted in order of decreasing. In other words,

If so,

The

ACK is collected. In this case, a and b are indices for distinguishing receivers, respectively. In the example of FIG. 1,

from

If collected in the order of, no interference to R ₁ occurs,

from

In the order of, belonging to R ₁

It can be seen that it can cause interference.

Here, an angle formed with the transmitter S refers to an angle formed by the connection line between s and the receiver with respect to the start line of R _i as shown in FIG. 1. In this case, it is assumed that the transmitter S knows the location information of each of the receivers.

이면, ACK 취합 스케줄은 송신기 S로부터의 거리

가 커지는 순서로 소팅(sorting) 되어야 한다. 도 1에 도시된 바와 같이,

및

는 송신기 S와 이루는 앵글이 동일하고,

이다. 이때,

로부터

로의 ACK 취합(즉, 지향성 안테나를 이용한 ACK 전송)은 송신기 S 및 R ₁ 에 간섭을 일으키지 않지만,

로부터

으로의 ACK 취합은 간섭이 발생할 수 있다.
Policy 2 :

If ACK collection schedule is the distance from transmitter S

Should be sorted in increasing order. As shown in Figure 1,

And

Is the same angle as the transmitter S,

to be. At this time,

from

ACK aggregation (i.e., ACK transmission using a directional antenna) to a channel does not interfere with transmitters S and R ₁

from

ACK aggregation to the interference may occur.

< Sender and Receiver Behavior >

The following pseudo code shows an example of an algorithm for the behavior of a transmitter.

Pseudo Code-The SPARM algorithm at the sender

는 전송 버퍼

에서의 미확인 프레임(unacknowledged frame)의 개수를 나타낸다. 이때,

는 빔 i를 위한 전송 버퍼 어레이를 의미한다. 즉, 위한 전송 버퍼 어레이는 멀티캐스팅의 대상이 되는 데이타 프레임을 저장하고 있는 메모리일 수 있다. Here, SN _i is the last sequence number of the frame to be ACK in the beam i,

Transfer buffer

This indicates the number of unacknowledged frames in. At this time,

Denotes a transmission buffer array for beam i. That is, the transmit buffer array may be a memory that stores a data frame that is a target of multicasting.

When the transmitter S is turned on, the transmitter S collects information of the receivers from the registration frame, where the registration frame is received from each of the receivers. In this case, the receiver information includes an AOA value, transmission power information, and the like. Subsequently, the transmitter S performs ACK aggregation scheduling in consideration of the aggregation scheduling policy described above, and sets SN _i of each beam to zero. Upon completion of the ACK aggregation scheduling, the transmitter S prepares for multicasting of the data frame.

및

를 계산한다. 도 2를 참조하면,

및

는 각각 "R _i 에 내의 첫번째 리시버에 대한 ACK 취합의 스타트 타임(start time)" 및 " R _i 에 내의 최종 리시버에 대한 리포트 타임(report time)"이다. 리포트 타임은 최종 리시버가 비트맵 프레임(즉, 도 2의 step 3에서 생성된 "aggregated ACK to be transmitted")를 송신기 S로 전송하는 시간을 의미한다. Before the transmitter S transmits multicast frames, i.e., a data frame subject to multicasting,

And

. 2,

And

Is the "time report (report time) of the final receiver in the R _i", "start time (start time) of the ACK for the first collected in the receiver R _i" and respectively. The report time refers to the time when the last receiver transmits a bitmap frame (ie, “aggregated ACK to be transmitted” generated in step 3 of FIG. 2) to the transmitter S.

및

는 각각 수학식 1 및 수학식 2와 같이 표현될 수 있다.

And

May be expressed as Equation 1 and Equation 2, respectively.

[Equation 1]

&Quot; (2) &quot;

및

와 더불어 ACK 취합의 순서에 대한 정보(즉, 리시버들의 순서 리스트)는 멀티캐스트 프레임에 포함된다. In this case, T _data is a frame transmission time, T _ack is an ACK transmission time, and T _C is the current system time. sure,

And

In addition, information on the order of ACK aggregation (ie, the order list of receivers) is included in the multicast frame.

>0이면, 즉 ACK가 수신되지 않은 어떤 프레임이 존재하는 경우, 송시기 s는

및

에 기초하여 해당 데이타 프레임을 멀티캐스트한다. 또한, 새로운 데이타 프레임이 발생하면(즉,

), 송신기 S는 새로운 데이타 프레임을

및

에 기초하여 전송하고, SN_i의 값을 증가시킨다. 송신기 S가 R_i에 대한 멀티캐스팅을 종료하면, 취합 과정에서 에러가 발생하지 않는 한,

에서의 ACK 취합은 완료된다. 송신기 S는 빔

로 스위칭하고, T_ack구간에서

내의 최종 리시버로부터 비트맵 프레임을 수신한다. if,

> 0, i.e. if there is any frame for which no ACK has been received, the transmitter s

And

Multicast the corresponding data frame based on. Also, when a new data frame occurs (that is,

), The transmitter S sends a new data frame

And

Transmit based on the value of SN _i . If transmitter S ends multicasting for R _i , unless an error occurs in the aggregation process,

The ACK collection at is complete. Transmitter s beam

In the T _ack interval

Receive a bitmap frame from the last receiver in the.

로부터 해당 데이타 프레임을 삭제할 수 있다. The transmitter checks the received bitmap frame to confirm that the data frame has been successfully received.

You can delete the data frame from it.

When the receiver is turned on, it is associated with the transmitter S through transmission of a registration frame. When the receiver successfully receives a multicast frame, i.e., a frame that is multicasted from the transmitter, it marks the SN _i- th bit of the bitmap as 1, as shown in FIG. Each receiver can know its collection order through a multicast frame. That is, since the multicast frame includes an order list of receivers, each of the receivers can know its own collection order.

As shown in FIG. 3, the first receiver of the ACK aggregation schedule relays its bitmap to the next receiver at Ts (i). The final receiver of the ACK aggregation schedule aggregates (ie, ANDs) the bitmap relayed (ie received from the previous receiver) with its bitmap and sends the aggregated bitmap to the transmitter at T _E (i). do. The receiver, which is not the first receiver or the last receiver, aggregates the received bitmap with its bitmap and sends the aggregated bitmap to the next receiver on the ACK aggregation schedule.

<Example of PERFORMANCE EVALUATION>

4 shows an example of comparing reliability based on frame error rate (FER).

5 shows an example of comparing reliability based on frame loss rate (FLR).

6 shows an example of comparing ACK collection latency on the basis of frame error rate (FER).

4 to 6 show a case where the data frame has a length of 1024 bytes and the ACK frame has a length of 2 bytes. 4 to 6, n denotes the number of nodes (receivers).

In this case, the reliability is a value obtained by dividing the number of transmission success frames by the number of transmission frames including a retransmission frame, and the ACK collection latency is a value obtained by measuring an average delay from transmission of a data frame to reception of an ACK.

Also through the performance measurement example, it can be seen that the SPARM technique according to the embodiment of the present invention reduces the problems of ACK explosion (implosion) and ACK collection latency (latency) compared to the prior art.

Hereinafter, specific embodiments of the "communication method and communication device using SPARM" will be described based on the principle of spatially pipelined ACK aggregation reliable multicast (SPARM). 1 to 3 may be applied to both the communication method and the description of the communication device to be described later.

7 illustrates a communication method of a receiver in a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna according to an embodiment of the present invention.

The method shown in FIG. 7 may be performed by each of the receivers of FIG. 1.

In step 710, the receiver receives i data frames (i is an integer) multicasted in the first sector of the transmitter antenna beam. For example, the first receiver r ₀ ⁰ of FIG. 1 may receive five data frames in the first duration T ₀ of FIG. 2. In this case, the five data frames may be data frames corresponding to SN (0) to SN (4) in FIG. 3. In FIG. 3, it is assumed that a data frame corresponding to SN (0) includes “ACK aggregation scheduling information”, and SN (1) is the first frame targeted for ACK.

In step 720, the receiver checks ACK collection scheduling information included in at least one of the i data frames. The ACK aggregation scheduling information may include information on a sector-by-sector multicasting time, a report time of aggregated ACK information, and an aggregation order of ACK information.

That is, the ACK aggregation scheduling information may include "sector-specific multicasting time information" such as start and end times of each of T ₀ and T ₁ shown in FIG. 3.

In addition, the ACK aggregation scheduling information may include "report time information of aggregated ACK information" such as a start and end time of the Tr of FIG. 3.

In addition, the ACK collection scheduling information may include "information on the collection order of ACK information" such as "aggregation scheduling" described in <SPARM scheduling>.

In step 730, the receiver collects ACK information for the i data frames based on the ACK collection scheduling information.

In this case, "collecting ACK information" means generating a bitmap described in <SPARM> and <SPARM scheduling> and performing a series of processes of transmitting and receiving bitmaps.

Accordingly, the collection of ACK information receives ACK information of a previous receiver belonging to the first sector (eg, R _{0 in} FIG. 1) according to the order included in the ACK collection scheduling information, or the next receiver according to the order. And transmitting ACK information.

In this case, when the receiver for performing the method of FIG. 7 is r ₀ ¹ of FIG. 1, the “previous receiver belonging to the first sector” may be r ₀ ^{1 of} FIG. ¹ . Of course, when the receiver performing the method of FIG. 7 is r ₀ ² of FIG. ¹ , the "previous receiver belonging to the first sector" may be r ₀ ¹ .

In this case, when the receiver performing the method of FIG. 7 is r ₀ ⁰ of FIG. 1, the "next receiver" may be r ₀ ¹ .

As described with reference to FIG. 3, the aggregation of ACK information may be performed in a period T ₁ in which the transmitter antenna multicasts to a second sector (eg, FIG. R ₁ ).

The ACK information includes a bitmap that specifies whether to receive each of the i data frames. That is, the ACK information generated by each of the receivers and transmitted / received between the receivers is " Own ACK bitmap (or referred to as " magnetic bitmap ") " , 320, 330). The ACK information also includes "aggregated bitmaps" 311, 321, 331 generated by an AND operation.

The process of collecting the ACK information includes "generating a bitmap indicating whether to receive each of the i data frames" and "sending the bitmap to the next receiver".

For example, assuming that a receiver performing the method of FIG. 7 is r ₀ ⁰ , r ₀ ⁰ generates a bitmap 310 specifying whether to receive each of i data frames. Since r ₀ ⁰ is the receiver having the fastest aggregation order in the first sector, the AND operation is not performed. Thus, the "aggregated ACK Bitmap" of 311 r ₀ ⁰ is the same as 310 and, r ₀ ⁰ transmits an ACK frame 311 to ₀ r ¹ of the next receiver.

Assuming that the receiver performing the method of FIG. 7 is r ₀ ¹ , r ₀ ¹ generates an "own bitmap" 320 that specifies whether to receive each of the i data frames. r ₀ ¹ receives the bitmap 311 of the previous receiver r ₀ ⁰ . r ₀ ¹ performs an AND operation on the bitmap 311 of the previous receiver r ₀ ⁰ and the magnetic bitmap 320 to generate an “aggregated bitmap 321”. r ₀ ¹ transmits the "aggregated bitmap 321" to r ₀ ² .

Assuming that the receiver performing the method of FIG. 7 is r ₀ ² , r ₀ ² generates an “own bitmap” 330 that specifies whether to receive each of the i data frames. r ₀ ² receives the bitmap 321 collected from the previous receiver r ₀ ¹ . r ₀ ² performs an AND operation on the aggregated bitmap 321 and the magnetic bitmap 330 to generate an “aggregated bitmap 331”. r ₀ ² sends an “aggregated bitmap 331” to the transmitter.

At this time, r ₀ ² is the second sector after the multi-cast on (for example, R ₁ in Fig. 1) complete reporting period (for example, T _r in Fig. 2), aggregate the ACK information of the transmitter " Aggregated Bitmap 331 "

Referring to the "aggregated bitmap 331" illustrated in FIG. 3, it can be seen that the first 301, third 303, and fourth 305 data frames have failed to be transmitted.

8 shows an example of the configuration of a communication device (receiver) of a directional wireless communication system according to an embodiment of the present invention.

The structure shown in FIG. 8 may be a structure of each of the receivers of FIG. 1. Thus, the receiver shown in FIG. 8 may perform the method shown in FIG. 7.

Referring to FIG. 8, the receiver includes a receiver 810, a controller 820, and an ACK information collector 830.

The receiver 810 receives i data frames (i is an integer) multicasted in the first sector of the transmitter antenna beam. The receiver 810 may include a directional antenna (not shown) that is switchable for each preset sector.

The controller 820 checks ACK aggregation scheduling information included in at least one of i data frames. The controller 820 may include at least one processor. In this case, the at least one processor may be configured to control the overall operation of the receiver.

The ACK information collecting unit 830 collects ACK information for the i data frames based on ACK aggregation scheduling information.

The ACK information collecting unit 830 may receive ACK information of a previous receiver belonging to the first sector according to the order included in the ACK collection scheduling information, or may transmit ACK information to the next receiver according to the order.

The ACK information collector 830 may include a bitmap generator 831, an AND operator 833, and a transmitter 835.

The bitmap generator 831 generates an "own bitmap" that specifies whether to receive each of the i data frames.

The AND operator 833 receives the bitmap of the previous receiver and ANDs the bitmap and the magnetic bitmap of the previous receiver. Of course, the AND operator 833 may receive the bitmap 321 collected from the previous receiver. Here, the bitmap 311 of the previous receiver or the bitmap 321 collected from the previous receiver is received through the antenna of the receiver 810.

The transmitter 835 transmits an "aggregated bitmap" reflecting the result of the AND operation to the transmitter. Of course, the transmitter 835 may transmit the "aggregated bitmap" reflecting the result of the AND operation to the next receiver.

FIG. 9 illustrates a sender communication method in a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna according to an embodiment of the present invention.

The method shown in FIG. 9 may be performed by transmitter S of FIG.

In step 910, the transmitter multicasts i (i is an integer) data frames in the first sector (eg, R ₀ ) 110 of the antenna beam. At least one of the i data frames includes ACK aggregation scheduling information. As illustrated in FIG. 7, "ACK aggregation scheduling information" may be included in a data frame corresponding to SN (0) of FIG. 3.

In step 920, the transmitter switches the antenna beam to the second sector (eg, R _{1 of} FIG. ₁ ) 120.

In step 930, the transmitter multicasts the i data frames in the second sector.

In step 940, after the multicasting of the second sector is completed, the transmitter switches the antenna beam to the first sector and receives aggregated ACK information of receivers belonging to the first sector. As illustrated in FIG. 3 and FIG. 7, the collected ACK information 331 includes a bitmap that specifies whether reception is successful for each of i data frames. Each of the i bits included in the bitmap represents a result of performing an AND operation on whether the i th data frame of each of the receivers belonging to the first sector is successfully received.

As described in "Policy 1" of <SPARM Scheduling>, the order of collecting ACK information may be determined in order of receivers having the angle with the sender in the receiver having the angle with the sender being large.

은

보다 크기 때문에, , ACK 정보의 취합 순서는

으로부터

로의 순서로 스케줄링된다. That is, the angle formed by the connecting line 102 of the reference axis 101 and the first receiver (r ₀ ¹ ) 111 in FIG.

silver

Since it is larger, the collection order of ACK information is

From

Are scheduled in order.

In addition, as described in &quot; Policy 2 &quot; of &lt; SPARM Scheduling &gt;, the order of collecting ACK information is determined in order of receivers having a long distance from the sender in receivers having a short distance from the sender.

10 shows an example of the configuration of a communication device (sender) of a directional wireless communication system according to an embodiment of the present invention.

The structure shown in FIG. 10 may be the structure of the transmitter S of FIG. 1. Accordingly, the communication device shown in FIG. 10 may perform the method shown in FIG. 9.

Referring to FIG. 10, the transmitter includes an antenna unit 1010, an antenna switching unit 1020, and a controller 1030.

The antenna unit 1010 multicasts a data frame using an antenna beam.

The antenna unit 1010 multiplies i (i is an integer) data frame into a first sector (for example, 110 in FIG. 1) in a first duration (for example, T ₀ of FIG. 2). Casting is performed to multicast to the second sector (120 in FIG. 1) in the second section (T _{1 in} FIG. 2).

The antenna unit 1010 receives the collected ACK information of the receivers belonging to the first sector after the second interval.

The antenna switching unit 1020 switches the antenna beam.

The antenna switching unit 1020 switches the antenna beam to the second sector after the first period and the reporting period T _r , and switches the antenna beam to the first sector after the second period.

The controller 1030 generates ACK aggregation scheduling information. Of course, the controller 1030 may include at least one processor designed to control the overall operation of the transmitter.

The controller 1030 may determine an order in which the ACK information is collected in the order of the receivers having the angle with the sender having the smallest angle with the sender.

The controller 1030 may determine the collection order of the ACK information in the order of the receiver having the short distance to the sender from the receiver having the short distance to the sender.

The methods according to embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (20)

In the directional wireless communication system for transmitting and receiving data through the beam of the directional antenna, in the communication method of the receiver,
Receiving i data frames (i is an integer) multicasted in the first sector of the transmitter antenna beam;
Identifying ACK aggregation scheduling information included in at least one of the i data frames; And
Collecting ACK information for the i data frames based on the ACK aggregation scheduling information;
The collection of the ACK information includes receiving ACK information of a previous receiver belonging to the first sector according to an order included in the ACK aggregation scheduling information, or transmitting ACK information to a next receiver according to the order.
Communication method of a receiver in a directional wireless communication system. The method of claim 1,
The collection of the ACK information is performed in a section in which the transmitter antenna multicasts to a second sector,
Communication method of a receiver in a directional wireless communication system. The method of claim 1,
The ACK aggregation scheduling information,
Including information on the sector-by-sector multicasting time of the transmitter, the reporting time of collected ACK information, and the collection order of ACK information.
Communication method of a receiver in a directional wireless communication system. The method of claim 1,
The ACK information includes a bitmap that specifies whether to receive each of the i data frames.
Collecting the ACK information,
generating a bitmap indicating whether to receive each of the i data frames; And
Transmitting the bitmap to the next receiver,
Communication method of a receiver in a directional wireless communication system. The method of claim 1,
The ACK information includes a bitmap that specifies whether to receive each of the i data frames.
Collecting the ACK information,
generating an "own bitmap" specifying whether to receive each of the i data frames;
Receiving a bitmap of the previous receiver; And
And ANDing the bitmap of the previous receiver and the magnetic bitmap;
Communication method of a receiver in a directional wireless communication system. The method of claim 1,
The ACK information includes a bitmap that specifies whether to receive each of the i data frames.
Collecting the ACK information,
generating an "own bitmap" specifying whether to receive each of the i data frames;
Receiving an aggregated bitmap from the previous receiver;
ANDing the "collected bitmap" and the "magnetic bitmap" received from the previous receiver; And
Transmitting the "collected bitmap" reflecting the result of the AND operation to the transmitter,
Communication method of a receiver in a directional wireless communication system. The method of claim 5,
The step of transmitting to the transmitter,
Performed after multicasting for the second sector of the transmitter is completed,
Communication method of a receiver in a directional wireless communication system. A communication apparatus of a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna,
A receiver for receiving i (i is an integer) data frames multicast in the first sector of the transmitter antenna beam;
A control unit which checks ACK aggregation scheduling information included in at least one of the i data frames;
And an ACK information collecting unit for collecting ACK information for the i data frames based on the ACK aggregation scheduling information.
The ACK information collecting unit receives the ACK information of the previous receiver belonging to the first sector according to the order included in the ACK collection scheduling information, or transmits the ACK information to the next receiver in the order,
Communication device in a directional wireless communication system. 9. The method of claim 8,
The ACK information collecting unit,
a bitmap generator for generating an "own bitmap" that specifies whether to receive each of the i data frames; And
And an AND operator configured to receive a bitmap of the previous receiver and AND the bitmap of the previous receiver and the magnetic bitmap.
Communication device in a directional wireless communication system. 10. The method of claim 9,
The ACK information collecting unit,
Further comprising a transmitter for transmitting to the transmitter "aggregated bitmap" reflecting the result of the AND operation,
Communication device in a directional wireless communication system. In a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna, in a sender communication method,
Multicasting i (i is an integer) data frames in a first sector of the antenna beam;
Switching the antenna beam to a second sector and multicasting the i data frames in the second sector; And
Switching the antenna beam to the first sector after completing the multicasting of the second sector, receiving aggregated ACK information of receivers belonging to the first sector,
At least one of the i data frames includes ACK aggregation scheduling information,
Sender communication method in directional wireless communication system. 12. The method of claim 11,
The ACK aggregation scheduling information,
It includes information about the multicasting time for each sector of the sender, the reporting time of the collected ACK information and the order of collecting the ACK information,
Sender communication method in directional wireless communication system. The method of claim 12,
The collection order of the ACK information,
In the receiver having the largest angle with the sender, the angle with the sender is determined in order of the smallest receiver,
Sender communication method in directional wireless communication system. The method of claim 12,
The collection order of the ACK information,
In the receiver having a shorter distance to the sender is determined in order of the longest distance with the sender,
Sender communication method in directional wireless communication system. 12. The method of claim 11,
The collected ACK information includes a bitmap indicating whether reception is successful for each of i data frames.
Each of the i bits included in the bitmap is a result of performing an AND operation on whether the i th data frame of each of the receivers belonging to the first sector is successfully received.
Sender communication method in directional wireless communication system. A communication apparatus of a directional wireless communication system for transmitting and receiving data through a beam of a directional antenna,
An antenna unit for multicasting a data frame using an antenna beam;
An antenna switching unit for switching the antenna beam; And
A control unit for generating ACK aggregation scheduling information;
The antenna unit multicasts i data frames (i is an integer) to a first sector in a first duration and performs multicasting to a second sector in a second interval.
The antenna switching unit switches the antenna beam to the second sector after the first period and the reporting period, and switches the antenna beam to the first sector after the second period,
The antenna unit receives the collected ACK information of the receivers belonging to the first sector after the second interval,
Communication device in a directional wireless communication system. 17. The method of claim 16,
The ACK aggregation scheduling information,
Including information on a sector-by-sector multicasting time of the communication device, a report time of collected ACK information, and a collection order of ACK information.
Communication device in a directional wireless communication system. 18. The method of claim 17,
The control unit,
Determining a collection order of the ACK information in a receiver having a large angle with the communication device in order of a receiver having a small angle with the communication device,
Communication device in a directional wireless communication system. 18. The method of claim 17,
The control unit,
Determining a collection order of the ACK information in order of a receiver having a short distance from the communication device in a receiver having a short distance from the communication device,
Communication device in a directional wireless communication system. 17. The method of claim 16,
The collected ACK information includes a bitmap indicating whether reception is successful for each of i data frames.
Each of the i bits included in the bitmap is a result of performing an AND operation on whether the i th data frame of each of the receivers belonging to the first sector is successfully received.
Communication device in a directional wireless communication system.

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