KR20070094319A - Broadcast signal transmission method and broadcast signal reception method - Google Patents

Abstract

The present invention relates to a broadcast signal transmission method and a broadcast signal reception method. In one aspect, the present invention provides a method comprising the steps of: (a) receiving handover related information of a second cell from a first cell receiving a broadcast signal; (b) receiving a broadcast signal of the second cell when handing over from the first cell to the second cell; (c) determining whether the received broadcast signal has a section index of a datagram subsequent to a section index of a datagram of the first cell; And (d) handing over to the second cell if there is a section index of a continuous datagram as a result of the determination, and receiving a datagram including a section having the continuous index from the second cell. A broadcast signal receiving method is provided. According to the broadcast signal transmission method and the broadcast signal reception method according to the present invention, the terminal may receive a continuous broadcast so that the broadcast is not interrupted.

Description

Broadcast signal transmission method and broadcast signal reception method {apparatus for transmitting and receiving broadcasting signal}

1 illustrates a DVB protocol hierarchy based on OSI 7 layer

2a and 2b is a conceptual diagram showing a broadcast signal transmission method of DVB-H

3 is a diagram illustrating a network information table (NIT) of a DVB-H broadcast signal

4 is a diagram illustrating a concept of handing over a neighboring cell to a DVB-H receiving terminal;

5 is a diagram illustrating an example of receiving a broadcast signal when a terminal hands over a cell;

6 is a flowchart illustrating an embodiment of a broadcast signal receiving method according to the present invention.

The present invention relates to a broadcast signal transmission method and a broadcast signal reception method, and more particularly, to a broadcast signal transmission method and a broadcast signal reception method capable of expressing a broadcast signal so that the broadcast is not interrupted during mobile reception.

Digital video broadcasting-handheld (DVB-H), which has emerged as a competitive model for terrestrial digital multimedia broadcasting (DMB), is being evaluated as a model that can converge broadcasting and communication. DVB-H is a transmission system that extends the broadcast area to the mobile portable terminal area and transmits transmission information as an IP datagram.

IP datagram refers to a signal processing method of sending a signal in a packet by using an internet protocol. DVB-H has an IP protocol for transmitting voice and video signals (audio / video) by packet unit and compressing them.

Digital video broadcasting-handheld (DVB-H) is a European digital mobile mobile terminal specification based on terrestrial digital multimedia broadcasting (terrestrial; DVB-T).

DVB-H adds a time slicing technique to reduce power consumption in the conventional DVB-T standard to improve portable mobile reception performance. In addition, DVB-H uses a multi-protocol encapsulation-forward error correction (MPE-FEC) technique to improve the carrier-to-noise (CN) ratio.

In addition, considering mobility of the receiving terminal, and using 4K mode and in-depth interleaving mode for efficiency of the transmission signal spectrum.

The orthogonal frequency division multiplexing (OFDM) technique used by the DVB-H as a transmission technique is a special form of multiple carrier transmission, and transmits one data string on a sub-carrier having a low data rate. Another reason for using the OFDM technique is that it increases the robustness against frequency selective fading or narrowband interference.

A broadcast system such as DVB-H that expands the broadcast area to the communication area has a problem in that the continuity of the broadcast is interrupted during handover when the user receives the broadcast while moving.

An object of the present invention is to provide a broadcast signal transmission method and a broadcast signal reception method capable of receiving a broadcast signal so that the terminal does not interrupt the broadcast in a multi frequency network environment.

Another object of the present invention is to provide a broadcast signal transmission method and a broadcast signal reception method capable of expressing a broadcast signal so that a terminal does not interrupt a broadcast even in a handover or handoff environment.

In order to achieve the above object, the present invention provides a method comprising the steps of: (a) receiving handover related information of a second cell from a first cell receiving a broadcast signal; (b) receiving a broadcast signal of the second cell when handing over from the first cell to the second cell; (c) determining whether the received broadcast signal has a section index of a datagram subsequent to a section index of a datagram of the first cell; And (d) receiving a datagram to which the section having the continuous index belongs from the second cell when there is a section index of the continuous datagram as a result of the determination. do.

The handover related information of step (a) is preferably included in a network information table (NIT) extracted from a broadcast signal.

The index of the continuous datagram of step (c) is preferably included in a data information table (DIT) extracted from the broadcast signal.

In another aspect, the present invention provides a method comprising the steps of (aa) compressing a broadcast signal to be transmitted into an Internet Protocol datagram; And (bb) when a cell transmits a broadcast signal, including a section index, which is continuous to an index of a section belonging to the compressed datagram, in the broadcast signal and transmitting the broadcast signal. do.

The section index of the step (bb) may belong to a data information table (DIT) when the broadcast signal is parsed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention that can specifically realize the above object will be described with reference to the accompanying drawings.

Hereinafter, the embodiment will be described by using a case of transmitting or receiving a broadcast signal of DVB-H for ease of description, but the present invention can be applied to a broadcast system capable of mobile reception.

First, the broadcast signal transmission format of DVB-H will be described.

DVB-H uses a time slicing multiplexing method, which is a multiplexing method that divides a channel's capacity into a predetermined time slot and carries a packetized broadcast signal in each time slot. .

DVB-H transmits a packetized broadcast signal in a time slot using a time slicing multiplexing method.

For example, if a DVB-H transmitter compresses a signal of 10 seconds in transmission time and transmits it with a new width of 3 seconds in transmission time, the receiver temporarily stores the compressed signal transmitted as described above in a buffer, Play the multimedia video while unzipping.

As described above, the DVB-H transmits a compressed signal using a time division multiplexing scheme and a timeslot, thereby reducing power consumption of the signal receiving terminal.

1 is a diagram illustrating a DVB protocol hierarchy based on an OSI 7 layer. Data in a transport stream packet format may be transmitted and received between a physical layer, which is a lower layer, and a data link layer, which is a lower layer. In the data link layer, data in a transport stream packet format is an elementary stream, an IP datagram format, an MPE, and a PSI / SI program related to system control. Specific Information / Service Information).

The MPE (Multi-Protocol Encapsulation) may be forward error correction (FEC) coded into a Reed-Solomon code (RS code) for improving the reception performance of a signal, which is encoded together with the RS code. The obtained MPE is hereinafter referred to as MPE-FEC.

Since the output of the physical layer is a transport stream packet (TP) format rather than an IP datagram format, a receiving terminal decodes data in a transport stream packet (TP) format to obtain data in the IP datagram format. In addition, error correction such as Reed Solomon decoding may be performed.

2A and 2B are conceptual views illustrating a broadcast signal transmission method of DVB-H. A broadcast signal transmission method of DVB-H will now be described with reference to FIGS. 2A and 2B.

2A is a conceptual diagram of a delta-t method. In the DVB-H system, the time slicing transmission method transmits a burst signal in units of frames by a delta-t method. The delta tee method is a method of notifying reception start time of a burst signal of a next frame from a section signal of a burst signal of a current frame.

Since all section signals of the current frame inform the relative difference until the start time of the burst signal of the next frame, the broadcast reception device stably stores the received signal and decodes the compressed signal until the next burst signal is received. can do.

2B shows parameters related to the transmission signal. In FIG. 2B, a burst duration means a time when one burst is transmitted, and a burst size means a bit size on a network layer through which one burst is transmitted.

Burst bandwidth refers to a bit rate when transmitting one burst, and constant bandwidth refers to an average bit rate required for transmitting an elementary stream.

Off time means a time interval in which two bursts are transmitted, respectively. Synchronization time is a time taken to demodulate a received broadcast signal from a physical layer and a data link layer to obtain an IP datagram.

The synchronization time for the DVB-H signal is about 200 to 250 ms. If the signal received through the multipath is considered, an error of about 10 ms may be generated in the delta jitter. When receiving a DVB-H signal, the time slicing method can reduce power consumption by around 90%.

In a DVB-H system, handover between heterogeneous channels of a multi frequency network (MFN) is possible.

In the DVB-H system, basic information on handover is included in a network information table (NIT) in a broadcast signal.

3 is a diagram illustrating a network information table (NIT) extracted from a signal included in a DVB-H broadcast signal. As shown in FIG. 3, the NIT includes frequency, bandwidth, constellation, hierarchy, code rate information, and the like for handover ("⇒"). Displayed).

In DVB-H, the terminal attempts to approach an adjacent cell for handover when the reception sensitivity of the current reception channel falls below the limit.

4 is a diagram illustrating a concept of handover of a DVB-H type broadcast receiving terminal to an adjacent cell. A handover concept of DVB-H will now be described with reference to FIG. 4.

In FIG. 4, it is assumed that each line represents a time axis for one cell, and the same position of each time axis represents the same time. In addition, it is assumed that cell 1, cell 2, and cell 3 are each adjacent cells. Cells 1, 2 and 3 of FIG. 4 generate a burst signal broadcast time-divided on the time axis.

The hatched portion of each burst represents the acquisition time required for the terminal receiving the signal to receive each burst. In addition, the number in each burst represents the section number or MPE section signal number of the IP datagram occurring in each cell.

For example, cell 1 sends datagram sections 1 through 5 to the first burst, section numbers 6 through 10 of the datagram to the second burst, and section number 11 of the datagram to the third burst. Send it.

In the cell environment as shown in FIG. 4, the broken line indicates that when the terminal changes a cell and receives a signal, the section numbers of the received datagram may not be consecutive.

For example, when the terminal receives a signal up to datagram 4 of the first burst in cell 2 and hands over to cell 1, the terminal receives the signal of section number 6 of the datagram of the second burst of cell 1, and thus the received signal is not continuous. .

In addition, even if the terminal attempts to handover to cell 2 again, the terminal returns to the point in time when the second burst of cell 1 is received, and thus, the third burst signal of cell 2 may be received to generate a discontinuity. Therefore, when a terminal moves to an adjacent cell, there is a possibility that broadcast signals are not continuous.

Accordingly, an embodiment of the broadcast signal transmission method according to the present invention provides an index indicating a transmission order of sections of a datagram to a signal transmitted by a cell when transmitting a burst type broadcast signal including one or more sections in a cell. index) can be included and transmitted. Herein, a cell transmitting a signal means that a broadcast station or a repeater or base station included in the cell transmits a broadcast signal.

When the terminal handovers to the neighbor cell, the terminal may use the pilot signal to determine the data state on the current channel. An embodiment of a broadcast signal transmission method according to the present invention refers to a transmission order of a datagram section in a data information table (DIT) that can be extracted from a broadcast signal so that a terminal can quickly identify a channel state. The index can be included and transmitted.

5 is a diagram illustrating a concept of a UE handover to explain an embodiment of a broadcast signal transmission and broadcast signal reception method according to the present invention. An embodiment of a broadcast signal transmission and broadcast signal reception method according to the present invention will be described with reference to FIG. 5.

Since FIG. 5 assumes a situation similar to that of FIG. 4, it is assumed that cells 1, 2, and 3 are all adjacent cells.

Cell 1 transmits the first burst signal, the second burst signal, and the third burst signal sequentially, the first burst signal is datagram section number 1 to 5, and the second burst signal is datagram section number 6 To 10, the third burst signal includes datagram section number 11, respectively.

The first burst signal in cell 2 is datagram section number 1 to 4, the second burst signal is datagram section number 5 to 8, and the third burst signal is datagram section number 9 to 11 It includes each.

The first burst signal in cell 3 is datagram section number 1 and 2, the second burst signal is datagram section number 3 and 4, and the third burst signal is datagram section number 9 and 11 It includes each.

Each cell may include the index of the datagram consecutive to the currently transmitted datagram section index and transmit the index. Preferably, each cell may transmit the index of the datagram that is included in the index of the currently transmitted datagram section by including the DIT of the broadcast signal.

When receiving a broadcast signal from each cell, the UE may receive PSI / SI and parse NIT included in the broadcast signal. The terminal may receive and store information about an adjacent cell from the NIT of the broadcast signal.

The terminal registers the candidate cells by ordering the neighbor cells from the information on the neighbor cells, and when handing over, the terminal may access the neighbor cells in the order of registration.

The process of the UE processing the information on the handover is preferably performed during the off time (off time) does not receive the burst signal.

In the example of FIG. 5, while the UE receives the first burst in cell 2, it is possible to obtain section information of a datagram to be received after the first burst from the DIT.

If the UE attempts to handover to Cell 1 immediately after receiving the first burst in Cell 2, the UE transmits information indicating that Cell 1 will transmit datagram section number 6 through the DIT to the DIT. Immediately after a low handover attempt, a handover may be attempted back to cell 3 (indicated by the dashed line).

When the UE attempts to handover to the cell 3, the terminal may receive the broadcast signal continuously because the datagram index that the datagram section number 5 is to be transmitted from the cell 3 is transmitted through the DIT.

On the other hand, if the UE attempts to handover to cell 1 after receiving the datagram section 8 in cell 3, when the terminal receives the information that the datagram section number 11 will be transmitted from the cell 1 through the DIT at the time of the attempt , Handover to cell 2 may be attempted (indicated by a two-dot chain line).

When the terminal receives the information that the datagram section number 12 will be transmitted from the cell 2 through the DIT, the terminal may try to handover after receiving the next burst signal in the cell 3 which is the current cell without handover.

Therefore, even if the UE attempts to handover to an adjacent cell, it can receive broadcast signals continuously.

6 is a flowchart illustrating an embodiment of a broadcast signal receiving method according to the present invention. An embodiment of a broadcast signal receiving method will be described with reference to FIG. 6.

First, information about a neighbor cell is stored from an NIT included in a broadcast signal from a current cell (S 10).

Wait for the off time to attempt a handover (S 20).

It is determined whether there is a cell suitable for attempting handover (S30). If there is no cell suitable for attempting handover (no in S 30), it waits to receive the next burst signal (S 90). Then, the process returns to step S20.

If there is a cell suitable for attempting handover (yes in S 30), the frequency of the cell is tuned (S 40). The datagram section information in the DIT is received from the cell to be handed over to obtain an index of the datagram to be received next (S50).

It is determined whether the datagram index received in step S50 is continuous with the index of the datagram of the current cell (S60).

If it is determined in S 60 that the cell transmits datagrams that are not contiguous with the datagram index of the current cell, the process returns to step S 30 (no in S 60).

If it is determined in S 60 that the cell attempting handover is a cell transmitting a continuous datagram to the datagram index of the current cell (S 60), a burst may be received from the cell attempting handover (S 70). The handover is terminated (S 80).

It is easy for a person skilled in the art to change or modify the present invention from the present specification. Therefore, although an embodiment of the present invention has been described above clearly, various modifications thereof should be made without departing from the spirit and the scope of the present invention.

The effects of the broadcast signal transmission method and broadcast signal reception method according to the present invention described above are as follows. According to the broadcast signal transmission method and the broadcast signal reception method according to the present invention, the terminal may receive a continuous broadcast so as not to interrupt the broadcast.

Claims (5)

(a) receiving handover related information of a second cell from a first cell receiving a broadcast signal; (b) receiving a broadcast signal of the second cell when handing over from the first cell to the second cell; (c) determining whether the received broadcast signal has a section index of a datagram subsequent to a section index of a datagram of the first cell; And and (d) receiving a datagram to which the section having the continuous index belongs from the second cell when there is a section index of the continuous datagram as a result of the determination. The method of claim 1, The handover related information of step (a) is included in a network information table (NIT) extracted from a broadcast signal. The method of claim 1, The index of the continuous datagram of step (c) is included in the data information table (DIT) extracted from the broadcast signal. (a) compressing a broadcast signal to be transmitted into an Internet Protocol datagram; And and (b) when a cell transmits a broadcast signal, including a section index in the broadcast signal, the section index being continuous to the index of a section belonging to the compressed datagram, and transmitting the broadcast signal. The method of claim 4, wherein And the section index of step (b) is included in a data information table (DIT) when the broadcast signal is received and parsed.

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