KR101403799B1 - Apparatus and method of packet allocation for time division multiplexing with multiple rf channel - Google Patents

Abstract

In a system for providing a plurality of services using a plurality of RF bands, when a plurality of different service packets to be transmitted from a transmitter to a receiver are generated, Grouping the plurality of service packets, determining a shift length for each service packet group such that each service packet group generated by the grouping is transmitted at different times in each of the plurality of RF bands, Shifts each service packet group in the corresponding frame according to its length, and allocates each cyclic-shifted service packet group to each RF band

Broadcast, TDM, time-frequency division, packet assignment

Description

[0001] APPARATUS AND METHOD OF PACKET ALLOCATION FOR TIME DIVISION MULTIPLEXING WITH MULTIPLE RF CHANNEL [0002]

The present invention relates to an apparatus and method for allocating packets, and more particularly, to an apparatus and method for allocating packets in a system having a plurality of channels.

In the information society of the 21st century, broadcasting and communication services are in the era of full-scale digitalization, multi-channelization, broadband and high-quality. In particular, with the spread of high-definition digital TVs, PMPs, and mobile broadcasting devices, demand for supporting various receiving methods of digital broadcasting services is increasing.

In accordance with this demand, DVB-T2 (Digital Video Broadcasting-Terrestrial), a second-generation terrestrial digital broadcasting standard for Europe, uses a receiving method for reusing a conventional digital receiving antenna for home use, a receiving method using multiple antennas for increasing capacity, And a receiving method for a portable mobile terminal. In consideration of the fact that DVB-T / H, which is the first-generation terrestrial digital broadcasting standard, considers only two types of fixed / mobile receiving schemes, a consideration is given to a method using multiple antennas. It is an unavoidable situation. A control channel is a channel for transmitting a control message for a transmission method in a physical layer, and is transmitted through a modulation scheme, a coding rate, a cell ID (cell ID), and the like. Since each information is selected in consideration of the characteristics of the base station, the coverage, the radio channel condition, and the characteristics of the receiving terminal, flexibility and diversity are selected so that optimal control information suitable for various radio transmission / reception systems can be selected .

FIG. 1 is a diagram illustrating a transmission scheme of a conventional first generation broadcasting system. Referring to FIG. 1, a transmitting station transmits different broadcasting services for a plurality of radio frequencies (RF), and a tuning ) To detect the desired service (1).

2, in the next generation broadcasting system, a plurality of services are transmitted by sharing a plurality of RF bands without allocating RF resources unique to each service in order to efficiently use time-frequency resources. In the transmitting station, the conventional large-size packet is divided into a plurality of small-sized packets, transmitted through a plurality of RF bands, and the receiver 1 searches for an RF band including a desired service and detects a desired broadcast signal. Using this scheme has the advantage of achieving both time diversity and frequency diversity gain, and this scheme is referred to as TFS (Time-Frequency Slicing).

FIG. 3 shows a transmission frame standard of the TFS as an example. In FIG. 3, 10 types of service packets are transmitted in four RF bands. In the method of constructing such a frame, first, all service packets of 10 types are allocated to one RF band, and service packets are arranged in a cyclic-shifted form of the RF band in adjacent RF bands .

In this case, however, splitting occurs in which a packet of a specific service is simultaneously present at the beginning and end of a frame, as in the case of packet # 8 in the RF2 band of FIG. 3 splitted at the beginning and end of the frame. In this case, the UE must enter the active mode twice in order to receive the same service, which causes an increase in power consumption.

As another problem of the frame configuration, when two different frames are transmitted adjacent to each other, when a specific service is transmitted at the last position of the previous frame and then transmitted at the start position of the RF band different from the previous frame in the next frame Problems can arise. In this case, the terminal must change the reception RF band in a short time in order to receive a specific service, thereby increasing the possibility of an error in the received packet. For example, in FIG. 3, the service packet # 10 in the RF1 band is located at the start position of the RF4 band in the next frame. In the above example, a reception failure may occur because the terminal does not have enough time to tune to the next RF.

It is another object of the present invention to provide a method for effectively reducing power consumption of a receiver in a next generation wireless broadcasting system.

It is still another object of the present invention to provide a method for solving the conventional problem of reception failure by sufficiently securing an RF tuning time of a receiver in a next generation wireless broadcasting system.

In order to achieve the above objects, the following two schemes are proposed as an efficient service packet allocation scheme of the present invention. The method of allocating service packets in the first embodiment includes a process of adjusting a transmission order of service packets in order to prevent a problem that a specific service is transmitted to a different RF band with little time difference at the end and end of an adjacent frame.

In the second embodiment, the service packet allocation method adjusts the length of the cyclic shift to solve the service packet splitting problem in one frame. It should be noted that the two schemes may be used in combination with each other, but may be used independently of each other.
A first method according to an embodiment of the present invention comprises: A method for transmitting service packets in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, the method comprising: when a plurality of different service packets to be transmitted to a receiver are generated, Grouping the plurality of service packets according to the number of RF bands; shifting each service packet group generated by the grouping so that each service packet group is transmitted at a different time in each of the plurality of RF bands; And cyclically shifting each service packet group in a corresponding frame according to the determined shift length and allocating each cyclically shifted service packet group to each RF band according to the determined shift length .
A second method according to an embodiment of the present invention comprises: A method of transmitting a service packet in a system that provides a plurality of services using a plurality of radio frequency (RF) bands, the method comprising: transmitting a service packet transmitted last in each RF band of the first frame, The method comprising the steps of: assigning priority to a predetermined position of a second frame, which is a next frame of a frame, excluding a last transmitted service packet in each RF band among service packets transmitted in each RF band of the first frame; And allocating a remaining service packet to a remaining position of the second frame.
A third method according to an embodiment of the present invention comprises: A method for receiving a service packet in a system providing a plurality of services using a plurality of radio frequency (RF) bands, the method comprising the steps of: receiving a preamble signal and extracting desired service information; Receiving a first service packet in a first RF band at a specific time based on service information, acquiring information on a second RF band and a transmission time point at which a second service packet is to be transmitted based on the received first service packet, And tuning to the second RF band in the first RF band and receiving the second service packet at the transmission time.
A first apparatus according to an embodiment of the present invention includes: In a system for providing a plurality of services using a plurality of radio frequency (RF) bands, when a plurality of different service packets to be transmitted to a receiver are generated in a transmitter, Grouping a plurality of service packets, determining a shift length for each service packet group such that each service packet group generated by the grouping is transmitted at a different time in each of the plurality of RF bands, A controller for cyclically shifting each of the service packet groups in the corresponding frame according to the control information and allocating each cyclic-shifted service packet group to each of the RF bands according to control of the control unit; .
A second apparatus according to an embodiment of the present invention comprises: In a system for providing a plurality of services using a plurality of radio frequency bands (RF bands), in a transmitter, a transmitter transmits a last transmitted service packet in each RF band of a first frame to a next frame The service packets transmitted in the respective RF bands of the first frame excluding the last transmitted service packets in the respective RF bands are allocated to the second frame in a predetermined position, And a transmission unit for transmitting a service packet according to the control of the control unit.
A third apparatus according to an embodiment of the present invention includes: A receiver in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, the receiver comprising: a receiver for receiving a preamble signal; a processor for extracting desired service information from the received preamble signal, When the first service packet is received in the first RF band at a specific time based on the service information, acquires information on the second RF band and the transmission time point at which the second service packet is to be transmitted based on the received first service packet, And controlling the receiver to receive the second service packet at the transmission time after tuning from the first RF band to the second RF band.

The present invention solves the problem that specific service packets are divided at both ends in one frame in a system in which a plurality of RFs are interlinked to transmit a service in a time-frequency divisional manner, thereby reducing power consumption by reducing frequent active mode entry of the terminal It is effective. Further, the present invention eliminates the problem of sudden RF change between adjacent frames, thereby overcoming a reception failure caused by a failure of the receiver to change the RF in time.

The operation principle of the preferred embodiment 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. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification. Meanwhile, although the DVB-T2 system, which is a next generation wireless broadcasting system, is described in the present specification, the present invention can be applied to other wireless communication systems to which scheduling of a base station is applied without adding or subtracting it.

FIG. 4 is a diagram showing a frame standard in which each RF band is cyclic shifted by a predetermined length determined in a conventional manner.

In the conventional method, the entire frame length is equally divided by the number of RF bands, shifted to the same length and transmitted. In FIG. 4, when the total number of RF bands is 4, one frame is divided into 4 equal parts on the time axis, and the packets are shifted by 1/4 for each RF band. When the RF1 band and the RF2 band are compared, the transmission time of the service packet # 1 is shifted by 1/4 within the frame, and the transmission time of the service # 1 of the RF1 band and the RF3 band is shifted by 2/4 within the frame . When a service packet is transmitted in this manner, packets of the same service are splitted as in the 11th service packet of the RF2 band or the 4th service packet of the RF4 band, and thus the problem of being located at the start and end of the frame occurs. The above problem arises because the length of a different packet is not considered for each service when arranging service packets of each RF band.

≪ Embodiment 1 >

5 is a diagram illustrating a process of varying the length of a cyclic shift for each RF band according to the first embodiment of the present invention.

First, groups of packets of services 1 to 13 arranged in a similar size are created, and groups having similar lengths as shown in FIG. 5 are created. The number of the generated groups is equal to the number of RF bands. 1 to 4 in the lowest RF1 band, and then sequentially arranges the service packet groups 11 to 13 in the RF2 band as shown in the example. The RF3 and RF4 bands are also arranged in a group-by-group manner. In FIG. 5, the group decision to be placed in the start frame in each RF band is made in the order of the packet size of each group. This is because the shifted length gradually becomes smaller toward the band 1 to 4 and at the same time, Bring the effect of placing. It is needless to say that in the embodiment, the packet size is shifted in the order of a larger group, but conversely, the packet size can be shifted in the order of a smaller group. If each service packet is allocated to the entire RF in this manner, it is possible to prevent a specific service packet from being divided into both sides of the frame as shown in FIG.

6 is a diagram showing the entire operation flow at the transmitting end.

If service packets to be allocated in the frame are determined (601), a service packet order to be allocated to the lowest RF is determined (602). At this time, the determination may be performed in the order of packet arrival time, which is a conventional method, but the scheduling method of the present invention described in FIG. 8 may be used. If the allocation order is determined in step 602, service packets are allocated in the lowest RF1 band first (603), and a different shift length is determined for each RF band according to the method of the present invention described in FIG. 5 (604). The order of determining the shift length will be described in detail in Fig. In step 605, service packets are allocated in different RF bands according to the shift length determined in step 604, and a signal is transmitted according to the completed frame standard in step 606.

7 is a diagram showing the entire operation flow in the receiving end.

The receiver receives the preamble signal in the current RF band (702). The preamble signal includes information on currently transmitted service packets, and the information includes a start time and a packet length of a desired service packet, so that the mobile station knows the start time of the active mode or the start time of the reception. In step 703, the UE is in a sleep mode or in a transmission standby state until the desired reception start time of the desired service. When the desired service packet transmission starts, the UE receives the service packet in step 704, (705). In accordance with the extracted information, the receiving band is switched to the next RF band, and enters a standby mode (706). The above process is repeated to select and receive only the desired service.

≪ Embodiment 2 >

FIG. 8 is a flowchart illustrating a scheduling method according to a second embodiment of the present invention for allocating service packets at the lowest RF, and corresponds to step 602 of FIG.

The scheduling is performed such that the last service of the previous frame is continuously maintained in the current frame. Thus, not only the active mode time of the UE is sufficiently provided but also abrupt RF change is prevented, thereby overcoming the reception failure. In operation 801, a service packet to be transmitted by the transmitter is received. In operation 802, the last service packets transmitted in each RF band of the previous frame are preferentially arranged in a predetermined position 802. The determined position is determined in consideration of a shift. Then, the service packets remaining in the empty frame space are sequentially arranged to complete the scheduling (803). Through this procedure, the order of service packets to be placed in the lowest RF is determined.

9 is a flowchart illustrating a process of calculating a shift length to determine another RF frame from the lowest RF frame structure determined from the above process.

Each service is placed in the RF1 band (901), and grouping is performed so that the lowest-ranked RF services have similar lengths (902). The number of the groups is equal to the number of RF bands to be transmitted. After the grouping is performed, the length of each group is calculated (903), and the calculated values are shift magnitudes by RF band in reverse order. For example, when the total number of RFs is 4, the length of the first group is a shift value in RF 4, and the length of the second group is a shift value in RF 3.

Accordingly, the frame format of FIG. 5 is finally completed and the service signal is transmitted according to the determined frame format.

1 is a diagram showing a transmission scheme of a conventional first generation broadcasting system

2 is a diagram showing a transmission scheme considered in a next generation broadcasting system;

3 is a diagram showing a transmission frame standard of the TFS system;

4 is a diagram showing a frame standard cyclically shifted according to a predetermined length in a conventional manner

5 is a diagram illustrating a process of varying the length of a cyclic shift according to the method of the present invention.

6 is a flowchart showing the overall operation flow in the transmitting end

7 is a flowchart showing the overall operation flow at the receiving end

8 is a flowchart illustrating a scheduling method proposed by the present invention for the service packet allocation at the lowest RF

9 is a flowchart illustrating a process of calculating a shift length to determine another RF frame from the determined lowest RF frame structure

Claims (18)

A method for a transmitter to transmit a service packet in a system providing a plurality of services using a plurality of radio frequency (RF) bands, Grouping the plurality of service packets according to the number of the plurality of RF bands when a plurality of different service packets to be transmitted to the receiver are generated; Determining a shift length for each service packet group so that each service packet group generated by the grouping is transmitted at a different time in each of the plurality of RF bands; And cyclically shifting each service packet group in a corresponding frame according to the determined shift length and assigning each cyclic-shifted service packet group to each RF band. How to transfer. The method according to claim 1, The grouping of the plurality of service packets comprises: And grouping the plurality of service packets so that the same number of service packet groups as the plurality of RF bands are generated. The method according to claim 1, The step of determining the shift length comprises: Calculating a packet length for each service packet group, and determining a shift length for each service packet group based on the calculated packet length. A method for transmitting a service packet in a system providing a plurality of services using a plurality of radio frequency (RF) bands, Assigning a last transmitted service packet in each RF band of the first frame preferentially to a predetermined position of a second frame which is a next frame of the first frame; And allocating remaining service packets excluding service packets transmitted last in each RF band among service packets transmitted in the respective RF bands of the first frame to remaining positions of the second frame And transmitting the service packet. 5. The method of claim 4, Wherein a predetermined position of the second frame Wherein the service packet is a location determined considering that service packets transmitted in each RF band will be shifted. 5. The method of claim 4, Wherein the last transmitted service packet in each of the RF bands of the first frame comprises: Wherein the second frame is allocated to the same RF band as the RF band used in the first frame of the second frame. A method for a receiver to receive a service packet in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, Receiving preamble signals and extracting desired service information, Receiving a first service packet in a first RF band at a specific time point based on the extracted service information; Acquiring information on a second RF band and a transmission time point at which a second service packet is to be transmitted based on the received first service packet; Tuning from the first RF band to the second RF band, and receiving the second service packet at the transmission time point. 8. The method of claim 7, The extracted service information, Information on a transmission time of the first service packet and length information of the first service packet. 8. The method of claim 7, When the reception of the first service packet is completed, the mobile terminal enters a sleep mode. When the information about the second RF band and the transmission time point at which the second service packet is to be transmitted is acquired, the method comprising the steps of: (a) entering an active mode; 1. A transmitter in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, the transmitter comprising: A plurality of service packets are grouped according to the number of the plurality of RF bands and a group of service packets generated by grouping are grouped into a plurality of service bands in each of the plurality of RF bands A shift length for each service packet group to be transmitted at a different time, cyclically shifts each service packet group in a corresponding frame according to the determined shift length, A control unit for allocating a packet group to each RF band, And a transmitter for transmitting a service packet under the control of the controller. 11. The method of claim 10, Wherein the control unit groups the plurality of service packets so that the same number of service packet groups as the number of the plurality of RF bands are generated. 11. The method of claim 10, Wherein the control unit calculates a packet length for each service packet group and determines a shift length for each service packet group based on the calculated packet length. 1. A transmitter in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, the transmitter comprising: A service packet transmitted in each of the RF bands of the first frame is preferentially allocated to a predetermined position of a second frame that is the next frame of the first frame, A control unit for allocating remaining service packets except for the lastly transmitted service packet in each RF band to a remaining position of the second frame, And a transmitter for transmitting a service packet under the control of the controller. 14. The method of claim 13, Wherein a predetermined position of the second frame Wherein the location is determined considering that service packets transmitted in each RF band will be shifted. 14. The method of claim 13, Wherein the last transmitted service packet in each of the RF bands of the first frame comprises: And is allocated to the same RF band as the RF band used in the first frame of the second frame. A receiver in a system for providing a plurality of services using a plurality of radio frequency (RF) bands, the receiver comprising: A receiver for receiving a preamble signal, Extracting desired service information from the received preamble signal, and receiving a first service packet in a first RF band at a specific time based on the extracted service information, extracting a second service packet based on the received first service packet, Acquires information on a second RF band and a transmission time to be transmitted, tunes the first RF band to the second RF band, and controls the receiver to receive the second service packet at the transmission time And a control unit. 17. The method of claim 16, The extracted service information, And information on a transmission time of the first service packet and length information of the first service packet. 17. The method of claim 16, When the reception of the first service packet is completed, the controller enters a sleep mode. When the information on the second RF band and the transmission time to which the second service packet is to be transmitted is acquired, And to enter an active mode into the active mode.

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