KR20090029142A - Apparatus and method of packet allocation for time division multiplexing with multiple rf channel - Google Patents

Abstract

A packet allocation apparatus in a time division multiplexing system interlocked with multiple rf channels and a method thereof are provided to solve a receiving disable problem by fully obtaining an RF tuning time of a receiver. If different service packets to be transmitted to a user terminal are generated, service packets are grouped according to the number of RF bands(902). Shift length per a group is determined so that a plurality of services are transmitted at different time at each RF band(903,904). A service packet is arranged in each RF band through cyclic shift according to the determined shift length. The number of generated groups is the same as the number of RF bands to be transmitted.

Description

A packet allocation apparatus and method in a TMD system in which a plurality of channels are interlocked {APPARATUS AND METHOD OF PACKET ALLOCATION FOR TIME DIVISION MULTIPLEXING WITH MULTIPLE RF CHANNEL}

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 entering the age of full-fledged digitalization, multi-channelization, broadband, and high quality. In particular, with the recent expansion of high-definition digital TVs, PMPs, and mobile broadcasting devices, the demand for digital broadcasting services has also increased.

In response to these demands, DVB-T2 (Digital Video Broadcasting-Terrestrial), the second-generation terrestrial digital broadcasting standard for Europe, uses a reception method that recycles conventional home digital reception antennas and a reception method that uses multiple antennas to increase capacity. In addition, each standard for the three types of reception methods for the portable mobile terminal is in progress. This is because DVB-T / H, the first-generation terrestrial digital broadcasting standard, considers only two types of fixed / mobile reception methods, and considers the method of using multiple antennas, and the modification of the physical layer structure and control information accordingly is added. This is an inevitable situation. The control channel is a channel for transmitting a control message for a transmission scheme in the physical layer, and a modulation scheme, a code rate, a cell ID, and the like are transmitted therethrough. Each piece of information is selected in consideration of the characteristics of the base station and the coverage, the wireless channel situation and the characteristics of the receiving terminal, so that the optimum control information suitable for various wireless transmission / reception systems can be selected. You have to.

1 is a diagram illustrating a transmission method of a conventional first generation broadcasting system, in which a transmitting station transmits a different broadcasting service for each RF in a memorandum, and tunes to an RF containing a desired service in a receiver (1). ) Is detected.

FIG. 2 transmits a plurality of services by sharing a plurality of RF bands without allocating a unique RF resource for each service in order to efficiently use time-frequency resources in a next generation broadcasting system. A transmitting station divides a conventional large sized packet into a plurality of small sized packets and transmits them through a plurality of RF bands, and the receiver 1 searches for an RF band including a desired service to detect a desired broadcast signal. Using the above scheme has the advantage that both time diversity and frequency diversity gain can be obtained at the same time, and the scheme is called TFS (Time-Frequency Slicing).

FIG. 3 is a diagram illustrating an example of a TFS transmission frame standard, and illustrates a structure in which ten types of service packets are transmitted in four RF bands. The method of configuring such a frame is a method of allocating all ten types of service packets to one RF band and arranging service packets in a cyclic shifted form of the RF band in adjacent RF bands. .

However, in this case, in the RF2 band of FIG. 3, splitting occurs in which packets of a specific service are simultaneously present at the beginning and the end of a frame, as packets 8 and 8 are splitting at the beginning and the end of a frame. In this case, the terminal must enter the active mode twice in order to receive the same service, which causes a problem in that power consumption is increased.

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

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

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

The following two methods are proposed as an efficient service packet allocation scheme of the present invention for achieving the above objects. In the first embodiment, the method of allocating a service packet includes adjusting a transmission order of service packets to prevent a specific service from being transmitted to another RF band with little time difference at the end and end of an adjacent frame.

In the second embodiment, the method of allocating a service packet is a method of adjusting a length of a cyclic shift to solve a service packet splitting problem in one frame. Note that the two methods may be used in combination with each other, but may be used independently of each other.

The present invention solves the problem that specific service packets are split at both ends in one frame in a system for transmitting a time-frequency division service by interworking a plurality of RFs, thereby reducing power consumption by reducing frequent active mode entry of a terminal. It works. In addition, the present invention eliminates the problem that the sudden RF change between adjacent frames, it is effective to overcome the reception failure caused by the receiver does not change the RF in time.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification. In the present specification, the DVB-T2 system, which is a next generation wireless broadcasting system, has been described as an example, but the present invention can be applied to other wireless communication systems to which the scheduling of the base station is applied.

4 is a diagram illustrating a frame specification in which each RF band is cyclically shifted by a predetermined length 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, the total number of RF bands is four. One frame is divided into four equal parts on the time axis, and a packet is shifted by one quarter for each RF band. Comparing the RF1 band and the RF2 band, it can be seen that the transmission time of the service packet 1 is shifted 1/4 in the frame, and the transmission time of the service 1 in the RF1 band and the RF3 band is shifted 2/4 in the frame. . When the service packet is transmitted in this manner, packets of the same service are splitting such as service packet 11 of the RF2 band or service packet 4 of the RF4 band, thereby causing a problem of starting and ending the frame. The problem occurs when the service packet of each RF band is arranged without considering different packet lengths for each service.

<First embodiment>

FIG. 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, the packets of the services 1 to 13 arranged in the same size are grouped together to form a group having a similar length as shown in FIG. The number of generated groups is equal to the number of RF bands. In the lowest RF1 band, the service packets are sequentially arranged in groups 1 to 4, and then in the RF2 band, the service packets are sequentially arranged in groups 11 to 13 as shown in the example. The RF3 and RF4 bands are similarly arranged in group units. In FIG. 5, the group decision to be placed in the start frame in each RF band is determined in the order of packet size of each group, so that the shifted length becomes smaller as bands 1 to 4 become smaller, and at the same time, no service packets are splitting in each band. Has the effect of placing. In the exemplary embodiment, the packet sizes are shifted in order of the larger group, but conversely, the packet sizes may be shifted in order of the smaller group. If each service packet is allocated to the entire RF in this manner, it is possible to prevent a particular service packet from being split into both sides of the frame as shown in FIG. 5.

6 is a diagram illustrating an overall operation flow in a transmitting end.

If service packets to be allocated in the frame are determined (601), the service packet order to be placed in the lowest RF is determined (602). At this time, the determination method may use arrangement in order of packet arrival time, which is a conventional method, but may use the scheduling method of the present invention described with reference to FIG. 8. When the arrangement order is determined in step 602, service packets are first allocated in the lowest RF1 band (603), and different shift lengths are determined for each RF band according to the method of the present invention described with reference to FIG. The order of determining this shift length will be described in detail with reference to FIG. 9. According to the shift length determined in step 604, service packet allocation is performed in another RF band (605), and a signal is transmitted (606) according to the completed frame standard.

7 is a view showing the overall operation flow at the receiving end.

The receiver receives 702 a preamble signal in the current RF band. The preamble signal includes information on service packets currently being transmitted, and the information includes a start time and a packet length of a desired service packet, so that the UE knows an active mode start time or a reception start time. The terminal is in the sleep mode or the transmission standby state until the reception start time of the desired service (703), the terminal receives the service packet (704) at the start of the transmission of the desired service packet (704), in the next RF through the received service packet The service information of is extracted again (705). In operation 706, the reception band is switched to the next RF band according to the extracted information. By repeating the above process, only the desired service is selected and received.

Second Embodiment

FIG. 8 is a flowchart illustrating a scheduling scheme according to a second embodiment of the present invention for service packet placement in the lowest RF and corresponds to step 602 of FIG. 6.

By scheduling the last service of the previous frame to continue in the current frame, not only the active mode time of the terminal is sufficiently provided, but also a sudden RF change is prevented, thereby overcoming a reception failure. The process of receiving a service packet to be transmitted by the transmitter 801 and preferentially arranges the last service packet transmitted in each RF band in a previous frame (802). The predetermined position is determined in consideration of shift. Subsequently, scheduling is completed by sequentially placing the remaining service packets in the empty frame space (step 803). This procedure determines the order of service packets to be placed in the lowest RF.

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 arranged in the RF1 band (901), and the services of the lowest deployed RF are grouped to have a similar length, respectively (902). The number of groups is equal to the number of RF bands to transmit. After performing the grouping, the length of each group is calculated (903), and the calculated values are shift size values for each RF band in reverse order. For example, when the total number of RF 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.

Therefore, through the above process, the frame specification of the form as shown in FIG. 5 is finally completed, and the service signal is transmitted according to the determined frame specification.

1 is a diagram illustrating a transmission method of a conventional first generation broadcasting system.

2 is a diagram illustrating a transmission scheme considered in a next generation broadcasting system.

3 is a diagram illustrating a transmission frame standard of a TFS system

4 is a diagram illustrating a frame size of a cyclic shift according to a length determined in a conventional manner.

5 illustrates a process of varying the length of a cyclic shift in the manner of the present invention.

6 is a flowchart showing the overall operation flow at the transmitting end;

7 is a flowchart illustrating an overall operation flow at a receiving end.

8 is a flow chart illustrating the scheduling scheme presented in the present invention for service packet placement in 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 (8)

In the method for transmitting a service packet in a system for transmitting a plurality of services by interworking a plurality of RF frequency bands, When a plurality of different service packets to be transmitted to a user terminal are generated, grouping the service packets according to the number of the RF bands; Determining a length shifted for each group such that the plurality of services are transmitted at different times in each RF band; And placing a service packet in each RF band through a cyclic shift according to the determined shift length. The method of claim 1, The process of grouping service packets is made to have as similar size as possible for each group, and the number of generated groups is equal to the number of transmitted RF bands. The method of claim 1, wherein the method of calculating a length to shift for each group comprises: The length of each group is calculated, and the shift length for each RF band in the reverse order of the calculated length value. In the method for transmitting a service packet in a system for transmitting a plurality of services by interworking a plurality of RF frequency bands, Placing the last transmitted service packets in each RF band of the previous frame at a predetermined position in the next frame; And arranging the corresponding packet at the predetermined position, and then disposing a service packet remaining in the empty space of the frame. The method of claim 4, wherein And the predetermined position in the next frame is determined in consideration of the shift of the service packet. The method of claim 4, wherein When arranging service packets between adjacent frames, scheduling the last service of a previous frame to be transmitted in the same RF band in the next frame. The method of claim 4, wherein When arranging the service packet between the adjacent frames, the method characterized in that the service packet is arranged in a position that the terminal has enough RF tuning time. In the method for receiving a service packet in a system for transmitting a plurality of services by interworking a plurality of RF frequency bands, Extracting desired service information through a preamble by a receiver, Receiving a service in a current RF band at a specific starting point through the extracted information; Acquiring information on a next RF band and transmission time point through which the desired service packet is to be transmitted through the received service packet; And tuning to the next RF band, entering the active mode at the time of transmission and receiving the desired service data.

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