KR20130133463A - Data transmission method and apparatus using slot reservation random access scheme adjusting transmission of packet replicas - Google Patents

Abstract

The present invention relates to a data transmission method using a random access scheme in a communication network and, more specifically, to a method and an apparatus for performing random access in a communication network using a slot reservation scheme of a satellite network controlling the number of replicated data packets. In order to achieve the above objective, the data transmission method using a random access scheme according to one embodiment of the present invention comprises the following steps: receiving a communication channel for one frame period and identifying the occupancy of a slot; selecting at least one empty slot, replicating data packets in each empty slot, and transmitting the replicated data packets; distinguishing the slots, which receive the data packet which does not collide with other data packets, from the replicated data packets; and determining a reservation slot among the distinguished slots. [Reference numerals] (AA) Start;(BB) End;(S210) Receive a satellite channel for one frame period and identify the occupancy of slots;(S220) Select at least one empty slot, replicate data packets in each empty slot, and transmit the replicated data packets;(S230) Distinguish the slots, which receive the data packet which does not collide with other packets, from the replicated data packets;(S240) Determine a reservation slot among the distinguished slots

Description

Data transmission method using slot reservation random access scheme controlling replication packet transmission {Data Transmission Method and Apparatus using Slot Reservation Random Access Scheme Adjusting Transmission of Packet Replicas}

The present invention relates to a data transmission method using a random access scheme in a communication network, and more particularly, to implement random access in a communication network by utilizing a slot reservation scheme of a communication network that controls the number of replicated data packets. A method and apparatus are disclosed.

The present invention is derived from the research conducted as part of the support project for mid-sized researchers of the Ministry of Education, Science and Technology and the Korea Research Foundation, and the support program for the development of university IT research centers of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunication Industry Promotion. Name: A Study on High Efficiency / Reliability Random Access Technology for Next Generation Satellite Communication Service, Assignment No .: ITAC1090112100100001000100100, Title: Defense IT Tactical Communication Technology Research].

Satellite networks have the advantage that they can be shared by end stations located in a wide area, while the cost of using the network is high. Therefore, a highly efficient communication technique has been used in satellite networks where the amount of data to be transmitted is high and low.

In general, in a satellite network, a demand assign technique and a random access technique are used in parallel. Since the random access scheme is very low in system throughput, it is limited in the case of a small amount of transmission traffic in a satellite network.

Slotted ALOHA in the 1970s, one of the random access schemes, is known to have a maximum system throughput of 37%. Therefore, it is not used when there is a large amount of transmission traffic such as data traffic of an application program. However, it is used only when the traffic amount is small, such as network control data and system management messages.

A technique mainly used as a request allocation technique used in the case of a large amount of traffic is demand assign multiple access (DAMA). However, in DAMA, when traffic is generated less than the required quota, the network is wasted as much as the difference between the actual traffic and the required default quota. To overcome this, CF-DAMA (combined-free DAMA) technology has emerged. CF-DAMA includes a technique for distributing wasted capacity between terminals.

However, CF-DAMA has a problem that the efficiency decreases as traffic has intermittent characteristics. As the traffic has intermittent characteristics, the traffic capacity changes drastically because the CF-DAMA technique cannot cope with such a sudden change rapidly. In particular, since the propagation delay time is very long in a satellite network, a request allocation scheme is not suitable for traffic having intermittent characteristics.

In order to cope with traffic having intermittent characteristics, the random access scheme is superior to the request allocation scheme. However, as mentioned earlier, the low system throughput makes it difficult to use random access techniques in satellite networks.

Although many methods have been proposed to improve the system throughput of the random access scheme, a diversity slotted ALOHA (DSA) technique is a representative technique for increasing the system throughput to be used in a geostationary satellite system. PRMA (packet reservation multiple access) may be used in the mid / low orbit. This is because mid / low orbit satellites have a shorter propagation delay time than stationary orbits, and thus packet reservation is possible.

Currently, the most advanced random access technique available in geostationary orbit satellite systems is content resolution diversity slotted ALOHA (CRDSA). CRDSA has been reported to improve system throughput to 52%. CRDSA uses interference cancellation technology. In addition, to transmit one packet, a duplicate data packet containing the same information is used. Each of the duplicated data packets contains slot information of each other, so that when one of the duplicated packets is recovered, the location of its own duplicated data packet can be known. The technique of removing interference packets using this information is an interference cancellation technique, which is a core technology of CRDSA.

As an example of using the CRDSA technology, US Patent Publication No. 20100124222 "METHOD OF TRANSMITTING DATA" has been proposed a method in which a terminal station and a user simultaneously transmits data packets according to a transmission channel using a CRDSA.

However, since the prior patent, that is, CRDSA technology still uses duplicate packets, it is necessary to control the traffic input amount to the network to ensure maximum system throughput. In addition, in all cases, data packets were duplicated and transmitted, thereby limiting the efficiency of the channel.

United States Patent Application Publication No. 20100124222

"Contention Resolution Diversity Slotted ALOHA (CRDSA): An Enhanced Random Access Scheme for Satellite Access Packet Networks", Casini, E .; De Gaudenzi, R .; Herrero, Od. R .; Eur. Space & Technol. Center, Eur. Space Agency, Noordwijk, Wireless Communications, IEEE Transactions on, April 2007

CRDSA technology yields very good results, including increased system throughput. IRSA and CSA techniques with modified CRDSA have also been proposed by the same investigator group. However, they all have two problems because they use replicated data packets. The first problem is using duplicated data packets, so to ensure maximum system throughput, you must control the amount of traffic input. Otherwise, system throughput is reduced. The second problem is that channel efficiency is reduced because of the use of replicated data packets. It is necessary to transmit two or more identical packets in order to transmit one packet.

In addition, the service to be used in the next generation satellite network is expected to increase the message size, the number of packets to be transmitted will vary. In addition, the increase in the number of users will be a factor to deepen the intermittent characteristics of the traffic.

Therefore, in order to solve the technical problem, the present invention proposes a random access scheme that controls whether data packets are duplicated and applies a reservation scheme to slots.

In order to achieve the above object, the present invention is configured to determine a reserved slot by receiving a communication channel for a role in the terminal station and transmitting a duplicated data packet to an empty slot. The terminal station is a terminal or mobile terminal located on the ground. A reserved slot is a slot that is allocated exclusively to one terminal station so that packet transmission is always successful. An empty slot is when there is no terminal station using the slot or two or more terminal stations are connected and a packet collision is detected in this slot.

At the terminal station, the action begins with the arrival of a message that must occur and be transmitted in the service. A message consists of a number of packets, each packet being transmitted in order. Since there is no reserved slot in the first packet transmission, a communication channel is received for one frame period to determine an empty slot.

When the terminal station uses an empty slot, an arbitrary slot is selected from the empty slots and the packet is transmitted. At this time, the slot is selected as many times as the number of duplicate data packets received from the terminal station, and one duplicate data packet is transmitted in one slot. After transmitting the duplicated data packet, the terminal station receives the communication channel and determines whether the transmission of the packet in the corresponding slot was successful. If there is a successful packet among the duplicated data packets, one of the slots to which the successful packet is allocated is selected and determined as a reserved slot.

According to an embodiment of the present invention, the slot with the lowest number among the slots to which a successful packet is allocated is determined as a reserved slot. According to another embodiment of the present invention, the slot with the highest number among the slots to which a successful packet is allocated may be determined as a reserved slot. Once the reserved slot is determined, the terminal station will use the reserved slot exclusively until all duplicate data packets have been transmitted.

Since the packet is transmitted exclusively using the reserved slot in the communication network, the terminal station does not need to use the duplicated data packet when using the reserved slot in the communication network.

According to an embodiment of the present invention, when the packet transmitted from the terminal station is the last packet, at least one other terminal station except for the terminal station transmitting and transmitting by specifying the slot reservation cancellation indicates the state of the empty slot and communicates. In the network, it should be an empty slot so that it can be used from the next frame.

According to another embodiment of the present invention, even if a separate slot reservation cancellation is not specified and transmitted, when the corresponding slot is empty in the next frame, other terminal stations grasp the empty state of the slot and transmit to the corresponding empty slot in the next frame. You can try to make a reservation.

The present invention relates to a protocol for applying a random access scheme to a communication network. When a plurality of short messages are transmitted through the communication network, the random access scheme may be more effective than the request allocation scheme.

The present invention can reduce the amount of packet interference by controlling the data packet transmission replicated in the random access scheme of the communication network, and can improve the system throughput and channel efficiency compared to the conventional CRDSA scheme. In particular, by using the slot reservation scheme, it is more effective in communication network services using multi-packet messages, for example, satellite network services. Therefore, it is possible to effectively implement a satellite / terrestrial integrated service using a next generation satellite network service, a voice call service based on a random access scheme, and an emergency messaging service.

The present invention can be applied to not only satellite networks but also cellular networks and Ad-Hoc environments according to system configuration. For example, the method of the present invention can be applied to a star-type or mesh-type satellite network composed only of terminal stations, and includes a star-type network control center (NCC) that provides slot information for each terminal station. When configuring a communication network, it can be applied not only to satellite networks but also to cellular networks and Ad-Hoc environments.

1 shows a data transmission structure of a random access method according to an embodiment of the present invention.
2 is a flowchart illustrating a random access data transmission method according to an embodiment of the present invention.
Figure 3 shows a flow chart for using exclusively reserved slots according to an embodiment of the present invention.
4 is a flowchart illustrating a reservation cancellation of a reservation slot according to an embodiment of the present invention.
5 shows a flowchart for the determined reservation slot according to an embodiment of the present invention.
6 is a flowchart illustrating the number of data packets copied according to the traffic input amount received from the satellite network according to an embodiment of the present invention.
7 is a flowchart illustrating determining a reserved slot among several slots according to an embodiment of the present invention.
8 shows a conceptual configuration of a terminal station according to an embodiment of the present invention.
9 shows a conceptual configuration of a terminal station capable of data transmission according to an embodiment of the present invention.
10 shows a structure of a frame and a slot of a satellite network according to an embodiment of the present invention.
11 illustrates a data transmission structure of a random access method of a terminal station according to traffic input amount according to an embodiment of the present invention.
12 is a diagram illustrating an example of slots allocated for each terminal station in the random access data transmission method according to the present invention.
FIG. 13 illustrates a method of reserving slots for each terminal station when slots are allocated as shown in FIG. 12.
FIG. 14 illustrates a method of another embodiment of reserving slots for each terminal station when slots are allocated as shown in FIG. 12.
15 is a flowchart illustrating a random access data transmission method according to another embodiment of the present invention.
16 shows a conceptual configuration of a terminal station capable of data transmission according to another embodiment of the present invention.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

However, the present invention is not limited to or limited by the embodiments. Like reference symbols in the drawings denote like elements.

The present invention relates to a data transmission method using a random access scheme in a communication network, and more particularly, by implementing a random access in a communication network by utilizing a slot reservation scheme of a communication network that controls the number of replicated data packets. In addition, it is proposed to reduce packet interference and to improve system throughput and channel efficiency compared to CRDSA.

Conventional CF-DAMA has a problem that the efficiency decreases as traffic has an intermittent characteristic. As the traffic has an intermittent characteristic, the traffic capacity changes drastically, because the demand allocation technique cannot respond quickly to such a sudden change in traffic. Since the propagation delay time is very long in a communication network, a request allocation scheme is not suitable for traffic having intermittent characteristics.

The present invention provides a random access method data transmission method and apparatus that controls the transmission of the duplicated data packet, and applies the reservation method for the slot to solve this technical problem.

The present invention is applicable to a satellite network composed only of terminal stations, a satellite network composed of terminal stations and a network control center (NCC), a cellular network, and an Ad-Hoc environment.

Here, the satellite network composed only of the terminal stations may include a star satellite network and a mesh satellite network, and the star satellite network is an environment in which transmission data packet results of all terminal stations can be observed in the central terminal station. Since there is no control center, each terminal station must observe the transmission data packet result, and mesh type satellite network is an environment in which each terminal station can observe its transmission data packet result after the physical delay time. In this case, only the terminal stations can be applied to the satellite network.

On the other hand, when the network control center (NCC) is included, it can be applied not only to satellite networks, but also to cellular networks and ad-hoc environments, and the network control center is composed of a star network that plays its role in the center. Its use may be higher. Of course, the network control center may be any one of the terminal stations, and in this case, even when the communication network is composed of only the terminal stations, the network control center can be applied to not only satellite networks but also cellular networks and Ad-Hoc environments.

As described above, the present invention is applicable to a satellite network, a cellular network, and an Ad-Hoc environment. For convenience of description, the detailed description of the present invention will be given using satellite networks as an example.

1 shows a data transmission structure of a satellite network of a random access method according to an embodiment of the present invention.

As shown in FIG. 1, the satellite network 100 according to the present invention includes at least one or more terminal stations 110 and 120, a satellite body 130, and a network control center 140.

Here, the terminal stations 110 and 120 represent a concept including at least one of a communication terminal / communication device such as a mobile phone, a transmission / reception device installed in a ship or a car, or a satellite signal reception device.

Each communication link constituting the satellite network 100 is named as follows.

In a relationship between the terminal stations 110 and 120 and the Network Control Center 140 (NCC), the link forwarding of the terminal stations 110 and 120 to receive data from the NCC 140 is forwarded. link, the link through which the terminal stations 110, 120 transmit data is called a return link.

When the link is divided based on the satellite body 130, the direction transmitted from the ground to the satellite 130 is uplink, and conversely, the direction transmitted from the satellite 130 to the ground is downlinked. It is called. In the classification of the uplink and the downlink, the terminal stations 110 and 120 and the NCC 140 are classified as communication entities on the ground, and the satellite body 130 serves as a standard for classifying the link.

The terminal stations 110 and 120 receive the satellite channel for one frame period from the satellite network 100 to determine whether the slot of the satellite network 100 is an empty slot or a slot in which data packets are stored. If there are empty slots in the satellite network 100, the terminal stations 110 and 120 select at least one or more empty slots of the satellite network 100, and duplicate data packets in each of the at least one or more empty slots. The satellite 130 transmits.

Here, the terminal station may include information on the slot in which the same data packet is transmitted, such as a data packet header, and unique information for distinguishing the terminal station.

Subsequently, the terminal stations 110 and 120 receive data from respective slots of the satellite network 100 and receive a packet that is not collided with another data packet among the data packets transmitted and transmitted to the satellite network 100. The identified slots are identified, and any one of the identified slots is determined as a reserved slot.

The satellite body 130 is a concept including one or more of a geostationary communication satellite, a satellite having a forwarding / communication function, or an aircraft having a forwarding / communication function, and the satellite body 130 in the random access data transmission method of the present invention. ) May be fixed, but need not necessarily be fixed.

Network Control Center 140 (Network Control Center, NCC) is the operation management of network resources to respond to data demands, the operation management of network resources to eliminate failure factors and temporarily maintain the service, events, status, measurement data Statistics collection, processing, reporting, centralized maintenance testing and control activities, administrative data storage and access, network performance and resource use to collect, report, and generate necessary analysis and actions and use them for engineering and management purposes. Can be viewed as a network resource that provides one or more of the following: modeling and analysis, network modification, software, and hardware generation.

10 shows a structure of a frame and a slot of a satellite network according to an embodiment of the present invention.

1 and 10, the packet 1010 is a data packet including a message of information of letters or numbers transmitted between the terminal stations 110 and 120, the satellite body 130, and the network control center 140. The maximum length of the packet 1010 is determined in each system, and a message longer than the predetermined size can be divided into several packets and transmitted.

The frame 1020 refers to a unit time interval in which data is transmitted in the satellite network 100. One frame 1020 includes a finite number of slots 1030, and the length of the frame 1020 is a satellite. Specified longer than the propagation delay time at. Thus, each terminal station (110, 120) can check whether the transmission of the already transmitted packet is successful, and then can transmit the next packet.

2 is a flowchart illustrating a random access data transmission method according to an embodiment of the present invention. 8 is a block diagram conceptually illustrating each module of the terminal stations 110 and 120 in which the random access data transmission method of FIG. 2 is executed.

2 and 8, the slot occupancy determining unit 111 receives a satellite channel during one frame period of the satellite network 100 to determine a slot occupancy state (S210). The duplicate packet transmitter 112 selects at least one or more empty slots of the satellite network 100, and duplicates and transmits a data packet to each selected empty slot (S220).

The packet collision determination unit 113 identifies a slot in which a packet which does not collide with another data packet among the duplicate data packets transmitted to the empty slot of the satellite network 100 is received (S230).

The reserved slot determination unit 114 determines at least one of the identified slots as a reserved slot (S240).

Figure 3 shows a flow chart for using exclusively reserved slots according to an embodiment of the present invention. 8 is a block diagram conceptually illustrating each module of the terminal stations 110 and 120 in which the random access data transmission method of FIG. 3 is executed.

FIG. 9 is a block diagram conceptually illustrating each module for the terminal stations 110 and 120 in which the random access data transmission method of FIG. 3 is executed. 3, 8, and 9, the data transmitter 115 exclusively uses a reserved slot that receives a data packet (S310). At this time, it is determined whether all data packets to be transmitted from the terminal stations 110 and 120 are transmitted (S320). If all the duplicated data packets have not been transmitted, the data packet continues to use the reserved slot exclusively (S310), and if all the data packets have been transmitted (S320), the reserved reserved slot is terminated and terminated. At this time, the termination of the reserved slot may explicitly include the cancellation message of the reserved slot in the final data packet, or, conversely, the termination of the reserved slot may be naturally detected by monitoring the occupancy status of the slot in other terminal stations.

4 is a flowchart illustrating a case where a reservation cancellation of a reservation slot is specified according to an embodiment of the present invention.

The data transmitter 115 transmits to the satellite network 130 by indicating the reservation cancellation of the reserved slot in the data packet last transmitted among the data packets related to the duplicated data packet received from the terminal station A 110 (S410). ). At this time, another terminal station B 120 receives the reservation cancellation from the satellite network path 130 and recognizes the reservation cancellation of the reservation slot (S420).

5 shows a flowchart for the determined reservation slot according to an embodiment of the present invention. FIG. 8 is a block diagram conceptually illustrating each module of the terminal stations 110 and 120 in which the random access data transmission method of FIG. 5 is executed.

The duplicate packet transmitter 114 determines whether a reserved slot has been determined (S510). In this case, if the reserved slot is not determined, the data packet copied from the terminal stations 110 and 120 is allocated to the empty slot of the satellite network 100 and transmitted. If the reserved slot is determined, the duplicate packet transmitter 112 transmits the data packet. The replication for the packet is stopped (S520).

6 is a flowchart illustrating the number of data packets copied according to the traffic input amount received from the satellite network according to an embodiment of the present invention. 8 is a block diagram conceptually illustrating each module of the terminal stations 110 and 120 in which the random access data transmission method of FIG. 6 is executed.

When executing the random access data transmission method, the terminal stations 110 and 120 receive the traffic input amount from the satellite network 130 (S610). In addition, the terminal stations 110 and 120, in particular, the duplicate packet transmitter 112 determine the number of duplicate data packets according to the received traffic input amount (S620).

7 is a flowchart illustrating determining a reserved slot among several slots according to an embodiment of the present invention. 8 is a block diagram conceptually illustrating each module of the terminal stations 110 and 120 in which the random access data transmission method of FIG. 7 is executed.

The packet collision determination unit 113 identifies a slot in which a data packet in which no collision has occurred has been received, and the reservation slot determination unit 114 determines any one of the identified slots as a reserved slot.

At this time, if there are two or more identified slots, the reserved slot determination unit 114 may determine a slot having a lower number as a reserved slot (S710). According to another embodiment, when there are two or more identified slots, the reserved slot determination unit 114 may determine a slot having a higher number as a reserved slot (S710). If a plurality of slots are available, the reserved slot determination unit 114 selects one slot as a reserved slot, and the selection criteria may be shared between the terminal stations 110 and 120.

After the reserved slot is determined, the terminal stations 110 and 120, in particular, the data transmitter 115 transmits the data packet using the determined reserved slot (S720).

8 shows a conceptual configuration of the terminal stations (110, 120) according to an embodiment of the present invention.

The data transmission apparatus of the random access system illustrated in FIG. 8 includes a slot occupancy determining unit 111, a duplicate packet transmission unit 112, a packet collision determination unit 113, and a reserved slot determination unit 114.

The slot occupancy determining unit 111 receives a satellite channel for one frame period of the satellite network 130 and determines the occupancy state of the slot (S210).

The duplicate packet transmitter 112 selects at least one or more empty slots of the satellite network 130, and duplicates and transmits a data packet to each empty slot (S220).

The packet collision determination unit 113 identifies a slot in which a packet that does not collide with another data packet except the duplicated data is received among the duplicated data packets received from the satellite network 130 (S230).

The reservation slot determination unit 114 determines any one of the identified slots as a reserved slot (S240).

For a detailed description of each device and how to use it, refer to the description of the device according to the flowchart of FIGS. 1 to 7.

9 illustrates a conceptual configuration of terminal stations 110 and 120 capable of data transmission according to an embodiment of the present invention.

The data transmitter 115 transmits the data packet by indicating the reserved cancellation of the slot designated as the reserved slot in the last data packet transmitted among the data packets related to the data packet transmitted to the satellite network 130. At this time, at least one terminal station B (120) except for the terminal station A (110) which transmits the data packet indicating the reservation cancellation is canceled when the reservation slot is canceled by the reservation slot from the satellite network (130). Recognize reserved slots.

11 illustrates a data transmission structure of a random access method of a terminal station according to traffic input amount according to an embodiment of the present invention.

As shown in FIG. 11, the satellite network includes at least one or more terminal stations 1110, 1120, a satellite body 1130, and a network control center 1140.

The terminal stations 1110 and 1120 use the occupancy information of the slot observed by receiving the satellite channel during one frame period of the satellite network to determine the traffic volume of the latest frame of the satellite network. Then, the amount of data transmitted from the terminal stations 1110 and 1120 to the satellite network is controlled based on the determined traffic volume. At this time, traffic information of the satellite network may be periodically received from the satellite body 1130, and the traffic volume of the latest frame is corrected based on the received traffic information of the satellite network.

In order to stably operate the random access scheme, it is necessary to keep the traffic amount of data input to the channel of the network at an appropriate level. In the conventional random access scheme, the amount of traffic input to the channel is determined from the latest frame information and fed back to adjust the data transmission amount of the terminal stations 1110 and 1120 according to the result. According to the conventional traffic information feedback method, a closed loop scheme for determining the total traffic amount at the network control center 1140 and informing each terminal station 1110 or 1120 is used. According to this, as shown in FIG. 11, a time of 1 round trip delay (2-hop) was taken.

In the random access scheme of the present invention, since each terminal station 1110, 1120 checks the state in units of frames in order to monitor the occupancy state of the slot, it is necessary to determine the amount of traffic input to the channel from the latest frame information. It takes the time of / 2 round trip delay (RTD) (1-hop), and there is an advantage that it is possible to quickly update the latest frame information in real time.

However, when the terminal stations 1110 and 1120 determine the state of the channel, 'recent frame information' may be differently recognized according to the channel state of each terminal station 1110 and 1120. Therefore, in order to correct this, the network control center 1140 periodically transmits traffic information to the terminal stations 1110 and 1120, and each terminal station 1110 and 1120 periodically receives the traffic information from the network control center 1140. Receive and correct 'recent frame information'. Such 'recent frame information' may be obtained from the state information (used or unused) of the slot observed in units of frames, and the state information of the slot may be referred to as 'snapshot information'.

On the other hand, the information used to grasp the traffic information may be a 'state value of the frame', only the 'final packet tag' included in the case of transmitting the 'final packet' from any terminal station 1110, 1120 Upon reception and detection, the occurrence of unused reserved slots in each terminal station 1110 and 1120 can be reduced.

In the detailed description of the present invention with reference to FIGS. 1 to 11, the terminal station is configured to include at least one of slots to which the duplicated data packet transmitted by the terminal station is allocated and which does not collide with the data packet transmitted by another terminal station. Although it has been described that one is determined as a reserved slot, the present invention is not limited thereto, and even if a collision occurs in all assigned slots, at least one slot may be allocated using a relationship with another terminal station, that is, interference cancellation. Can be. This will be described with reference to FIGS. 12 to 14.

12 to 14, it is assumed that one frame 1210 includes four slots 1211.

12 is a diagram illustrating an example of slots allocated for each terminal station in the random access data transmission method according to the present invention.

As shown in FIG. 12, the terminal station A 1220 allocates the first slot and the fourth slot to transmit the duplicated data A1 and A2, and the terminal station B 1230 allocates the second slot and the fourth slot to replicate. The data B1 and B2 are transmitted, and the terminal station C 1240 allocates the second slot and the third slot to transmit the duplicated data C1 and C2. Of course, the information on the slot allocated by the corresponding terminal station is included in each header of the duplicated data transmitted through each slot. It contains information that the duplicate data is transmitted through the first slot and the fourth slot.

Each of the terminal stations 1220-1240 receives all duplicate data received through the respective slots. For example, each of the terminal stations 1220-1240 receives the A1 duplicate data through the first slot, receives the overlapped data of B1 and C1 through the second slot, receives the C2 duplicate data through the third slot, and the fourth slot. A1 and B2 receive the overlapped data through the slot.

Thus, in each of the terminal stations, terminal station A 1220 may know that no collision occurs in the first slot, and terminal station C 1240 may know that collision does not occur in the third slot. B 1230 may know that collisions occur in all assigned slots.

Since a collision occurs in all slots to which the duplicate data of the terminal station B 1230 is allocated, the duplicate data of the terminal station B 1230 must be restored in the terminal station A 1220 and the terminal station C 1240. For example, the terminal station A 1220 may know that the duplicate data of the terminal station C 1240 is transmitted to the second slot through the header of the duplicate data C2, and thus, the terminal station A 1220 knows the duplicate data B1 of the terminal station B 1230. Can be. Similarly, the terminal station C 1240 knows that the duplicate data of the terminal station A 1220 has been transmitted to the fourth slot through the header of the duplicate data A1, and thus, knows the duplicate data B2 of the terminal station B 1230. Can be.

FIG. 13 is a view illustrating an embodiment of reserving slots for each terminal station when slots are allocated as shown in FIG. 12. FIG. 13 illustrates a slot for a terminal station having a collision after first reserving a slot for a terminal station for which there is no collision. It's about how to make a reservation.

Referring to FIG. 13, the terminal station A 1220 reserves the first slot in which no collision occurs among the allocated first slot and the fourth slot, and the terminal station C 1240 encounters a collision among the allocated second slot and the third slot. Reserve a third slot you haven't.

In addition, the terminal B1230 collides with the allocated second slot and the fourth slot, and since the other terminal stations 1220 and 1240 do not reserve both slots, one of the two slots is allocated. Make a reservation. In FIG. 13, the terminal B1230 reserves the second slot, but may reserve the fourth slot and may reserve both the second slot and the fourth slot.

Since three terminal stations have been described in FIG. 13 and a case where there is one terminal station with which all assigned slots collide with each other, terminal B may reserve two slots, but more terminal stations are used and assigned. There may be cases where there are two or more terminal stations where all slots collide. In such a case, the terminal stations with which all assigned slots collide may use a method of sequentially reserving one slot, and the method of reserving a slot may also reserve the earliest slot among the allocated slots or the slowest slot. You can also reserve a sequence of slots.

FIG. 14 illustrates a method of reserving a slot for each terminal station when slots are allocated as shown in FIG. 12. FIG. 14 illustrates a method of reserving a slot using slot reservation priority for each terminal station.

Referring to FIG. 14, a method of sequentially reserving slots from a terminal station A 1220 to a terminal station C 1240 is used.

That is, the terminal station A 1220 reserves the first slot in which no collision has occurred among the allocated slots, and the terminal station B 1230 reserves the fourth slot in which no collision has occurred with the terminal station C among the allocated slots. Terminal station C 1240 reserves all of the remaining slots, the second and third slots.

Of course, terminal station C 1240 may reserve only one of the two slots, and terminal station B may also reserve a second slot in which there is no collision with terminal station A.

As described with reference to FIGS. 12 to 14, the present invention relates to terminal stations having slots in which no collisions occur among the assigned slots among the plurality of terminal stations. A slot station may use a scheme of reserving slots and may sequentially reserve slots for each of the terminal stations irrespective of whether there is a collision in the allocated slots. Of course, when the slots are sequentially booked, it is preferable to reserve the slots in which collisions do not occur among the allocated slots when the slots have slots that do not cause collisions.

15 is a flowchart illustrating a random access data transmission method according to another embodiment of the present invention.

FIG. 15 shows that step S230 is changed to steps S1530 and S1540 in the step shown in FIG. Each terminal station can know the information on each slot through the received communication channel, that is, frame information. In this case, each slot can be roughly divided into a used slot and an unused slot. In addition, each slot may be subdivided as follows by an interference cancellation (IC) technique. The usage slot may be subdivided into a single accessed slot and a successively decoded slot. Unused slots can be subdivided into no accessed slots and unsuccessfully decoded slots. Each terminal station monitors the frame information and can segment and identify all four pieces of information for each slot. Since the details of steps S1510, S1520, and S1550 of FIG. 15 are the same as those of steps S210, S220, and S240 of FIG. 2, repeated descriptions thereof will be omitted.

Referring to FIG. 15, the present invention selects at least one or more empty slots in step S1520, duplicates the data packet in each selected empty slot, and transmits all slots constituting each slot of the satellite network, that is, one frame. Receive data from the terminal, and identify at least one slot that can be reserved among the empty slots selected in step S1520 using interference cancellation of the received data (S1530, S1540).

Here, the scheme of identifying at least one slot that can be reserved through interference cancellation has been described in detail with reference to FIGS. 13 and 14, and the slots that can be reserved can be identified or determined by applying the schemes of FIGS. 13 and 14.

16 shows a conceptual configuration of a terminal station capable of data transmission according to another embodiment of the present invention.

Referring to FIG. 16, the random access data transmission method includes a slot occupancy determination unit 1610, a duplicate packet transmission unit 1620, a reserved slot determination unit 1630, a reserved slot determination unit 1640, and a data transmission unit ( 1650).

Here, the slot occupancy determining unit 1610, the duplicate packet transmission unit 1620, the reserved slot determination unit 1640, and the data transmission unit 1650 are the slot occupancy determination unit 111 and the clone shown in FIGS. 8 and 9. Since the functions of the packet transmitter 112, the reserved slot determiner 114, and the data transmitter 115 are the same, their description is omitted.

When data is received from each slot of the satellite network, that is, all of the slots constituting one frame, the reserved slot determination unit 1630 uses the interference cancellation of the received data in the duplicate packet transmitter 1620. Identifies at least one reserved slot among the selected empty slots.

Here, the scheme of identifying at least one slot that can be reserved through interference cancellation has been described in detail with reference to FIGS. 13 and 14, and the slots that can be reserved can be identified or determined by applying the schemes of FIGS. 13 and 14.

Random data transmission method according to an embodiment of the present invention is implemented in the form of program instructions that can be executed by various computer means may be recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. 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. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art, various modifications and variations are possible from these descriptions.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

100: Link diagram of satellite network
110: terminal station A
120: terminal station B
130: satellite
140: network central control unit

Claims (18)

In the data transmission method of the random access method to the communication network,
Receiving, at a terminal station, a communication channel during one frame period of the communication network to determine the occupancy state of the slot;
Selecting at least one empty slot in the terminal station, and duplicating a data packet to each of the at least one empty slot and transmitting it to the communication network;
Receiving, at the terminal station, data from each slot of the communication network, identifying a slot in which the duplicated data packet is received in which the duplicated data packet has not collided with another data packet of the duplicated data packet; And
Determining, at the terminal station, any one of the identified slots as a reserved slot;
Random access data transmission method comprising a. In the data transmission method of the random access method to the communication network,
Receiving, at a terminal station, a communication channel during one frame period of the communication network to determine the occupancy state of the slot;
Selecting at least one empty slot in the terminal station, and duplicating a data packet to each of the at least one empty slot and transmitting it to the communication network;
Receiving data from each slot of the communication network at the terminal station and identifying at least one slot that can be reserved among the selected empty slots using interference cancellation of the received data; And
Determining, at the terminal station, at least one of the identified slots as a reserved slot;
Random access data transmission method comprising a. The method according to any one of claims 1 and 2,
Exclusively using the reserved slot of the communication network until the terminal station transmits all data packets related to the received data packet;
The random access data transmission method further comprising. The method according to any one of claims 1 and 2,
Indicating, by the terminal station, indicating that the reserved slot is to be canceled in the last data packet transmitted among the data packets related to the received data packet; And
Receiving the reservation cancellation at at least one second terminal station excluding the terminal station, and recognizing the reservation cancellation of the reservation slot;
The random access data transmission method further comprising. The method according to any one of claims 1 and 2,
And the terminal station stops copying the data packet when the reserved slot is determined. The method according to any one of claims 1 and 2,
Replicating the data packet and transmitting the data packet to the communication network
And random slot information of each of the duplicated data packets is included in each of the duplicated data packets and transmitted. The method according to any one of claims 1 and 2,
Determining, at the terminal station, the replicated number of data packets according to the amount of traffic received from the communication network;
The random access data transmission method further comprising. The method according to any one of claims 1 and 2,
Determining the traffic amount of the latest frame of the satellite network using the occupancy information of the slot observed by receiving the communication channel during one frame period of the communication network; And
Controlling the amount of data to be transmitted at the terminal station based on the determined traffic amount;
The random access data transmission method further comprising. 9. The method of claim 8,
Correcting the traffic amount of the latest frame based on traffic information of the communication network periodically received from a communication control station;
The random access data transmission method further comprising. The method according to any one of claims 1 and 2,
Determining the reservation slot is
And the lowest numbered slot or the highest numbered slot among the identified slots as the reserved slot. In the data transmission method of the random access method to the communication network,
Receiving, at a terminal station, a communication channel during one frame period of the communication network to determine the occupancy state of the slot;
Checking whether a specific slot is reserved for a data packet to be transmitted from the terminal station;
Determining whether to duplicate the data packet according to whether to reserve the data packet;
If a specific slot is not reserved for the data packet, selecting one or more empty slots from the terminal station, duplicating a data packet to each of the one or more empty slots, and transmitting the data packet to the communication network; And
If the specific slot is reserved for the data packet, transmitting the data packet to the communication network using the specific slot;
Random access data transmission method comprising a. A computer-readable recording medium having recorded thereon a program for executing at least one of the methods of claim 1. A random access data transmission apparatus for a communication network,
A slot occupancy determining unit which receives a communication channel for one frame period of the communication network and determines a occupancy state of the slot;
A duplicate packet transmitter which selects one or more empty slots, and duplicates a data packet in each of the one or more empty slots and transmits the data packet to the communication network;
A packet collision determination unit that receives data from each slot of the communication network and identifies a slot in which the data packet does not collide with another data packet of the duplicated data packet; And
A reservation slot determination unit which determines any one of the identified slots as a reservation slot;
Random access data transmission apparatus comprising a. A random access data transmission apparatus for a communication network,
A slot occupancy determining unit which receives a communication channel for one frame period of the communication network and determines a occupancy state of the slot;
A duplicate packet transmitter which selects one or more empty slots, and duplicates a data packet in each of the one or more empty slots and transmits the data packet to the communication network;
A reservation slot determination unit which receives data from each slot of the communication network and identifies at least one slot that can be reserved among the selected empty slots by using interference cancellation of the received data; And
A reservation slot determination unit which determines any one of the identified slots as a reservation slot;
Random access data transmission apparatus comprising a. 15. The method according to any one of claims 13 to 14,
A data transmission unit for displaying a reservation cancellation of the reserved slot and transmitting the last data packet transmitted among the data packets related to the received data packet;
Random access data transmission device further comprising. 15. The method according to any one of claims 13 to 14,
The duplicate packet transmission unit
And a copy of the data packet is stopped when the reserved slot is determined. 15. The method according to any one of claims 13 to 14,
The duplicate packet transmission unit
And random slot information of each of the duplicated data packets is included in each of the duplicated data packets and transmitted. 15. The method according to any one of claims 13 to 14,
The duplicate packet transmission unit
And the duplicated number of the data packets is determined according to a traffic input amount received from the communication network.

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