JP2002305490A - Packet data transmission scheme - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a packet data transmission scheme in a radio communication which has a high data transmission rate and has high immunity against frequency interference from other devices. SOLUTION: In the packet data transmission system, in which a slot segmented by a constant time width is used as a unit, one data packet exists in one slot and the direction of data transmission can be variable for each slot, a configuration is employed, in which data transmission is executed, in only one direction over a plurality continuous slots.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet data transmission system in wireless communication.

[0002]

2. Description of the Related Art Bluetooth data transmission in a short-range wireless data communication system in the 2.4 GHz band is performed in slot units separated by a width of 625 μs. In single-slot data transmission, one data packet exists in one slot. The direction of data transmission changes from slot to slot.

In an actual use environment such as file transfer, data transfer is performed only in one direction. At this time, since the data transmission direction changes for each slot, in the slot in the transmission direction opposite to the file transfer, it is determined whether or not the data packet was successfully received in the immediately preceding slot. Used to notify the side.

[0004] Further, Bluetooth employs FH (Frequency Hopping) in which the carrier frequency changes for each slot. Even if data transmission fails due to frequency interference from another device in a certain slot, data transmission can be reliably performed by re-transmitting in the next slot having a different carrier frequency.

[0005]

As described above, single-slot data transmission is resistant to frequency interference from other devices, but has a small payload size and a low data transmission speed.

To increase the data transfer rate, a data packet having a large payload size may be used. As a data packet having a large payload size, there is a multi-slot type in which one data packet extends over a plurality of slots. However, in this method, since the same carrier frequency is used in a plurality of slots in which one data packet continues, there is a high risk of receiving frequency interference from another device, and a payload lost in one frequency interference. The size increases.

That is, there has been no data transmission system that has a high data transmission speed and is resistant to frequency interference from other devices.

Accordingly, an object of the present invention is to provide a data transmission system having a high data transmission speed and being resistant to frequency interference from other devices.

[0009]

In order to achieve this object, a data transmission system according to the present invention uses a slot divided by a fixed time width as a unit, and one data packet exists in one slot. The data transmission direction is a packet type data transmission system in which the data transmission direction is variable for each slot, and the data transmission direction is a packet type data transmission system in which data transmission is performed in only one direction over a plurality of continuous slots.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, one data packet exists in one slot in units of slots divided by a fixed time width, and the direction of data transmission is as follows. In the packet data transmission method that is variable for each slot, it is a packet data transmission method in which data is transmitted only in one direction over a plurality of continuous slots, and data packets can be transmitted continuously in one direction. Therefore, the data transmission speed can be increased.

According to the second aspect of the present invention, in one slot immediately after data transmission is performed only in one direction over a plurality of continuous slots, data is transmitted in one direction over the plurality of continuous slots. Among the data packets, the packet containing the number of the packet that could not be received as data is transmitted in the opposite direction, and the first time when data transmission is performed only in the original direction over a plurality of successive slots immediately after this. This is a packet type data transmission system for transmitting again a data packet that could not be received in the above slot, and can correct a transmission error caused by data transmission.

According to a third aspect of the present invention, there is provided a packet-type data transmission system in which the number of continuous slots at the time of data transmission is variable only in one direction over a plurality of continuous slots. The data transmission speed can be adjusted.

According to a fourth aspect of the present invention, the number of continuous slots in one direction only in one direction over a plurality of continuous slots decreases when the rate of occurrence of data transmission errors is high, and This is a packet type data transmission method that increases when the error occurrence rate is low, and the data transmission speed can be adjusted according to the data transmission error.

According to the fifth aspect of the present invention, the number of consecutive slots at the time of data transmission only in one direction over a plurality of consecutive slots is equal to the RSSI (Receiver Signal Strength).
Indicator) is a packet-type data transmission method that is small when the value is small and large when the RSSI value is large, and the data transmission rate can be adjusted according to the RSSI value.

As a result, data transmission speed is high, and data transmission which is strong against frequency interference from other devices can be performed.

Hereinafter, an embodiment of the present invention will be described. In this embodiment, a conventional example will be described based on a Bluetooth system.

(Embodiment 1) In data transmission by a single slot type packet called DH1 in Bluetooth, the maximum payload of one data packet is 27
Bytes. The direction of data transmission changes for each slot (FIG. 3). When no transmission error occurred during data transmission, a 27-byte data packet was transmitted in a certain slot, and a packet containing a signal indicating that this data packet was received was returned in the immediately following slot. Net data transmission is 2
Since 27 bytes of data have been transferred in the slot, the data transfer rate is 27 * 8 / (0.625 [ms] * 2) = 172.8 [kb]
ps].

Here, according to claim 1 of the present invention, data transmission is continuously performed for 11 slots. 1 immediately after this
It was notified whether a total of 11 data packets of the previous 11 slots could be received in the slot (FIG. 1). During the experiment, no reception error occurred. Net data transmission is 297 bytes in 12 slots (27 bytes * 11
Data transmission speeds, the data transfer rate is 27 * 11 * 8 / (0.625 [ms] * 12) = 31
6.8 [kbps], and the data transfer speed could be improved as compared with the conventional example.

(Embodiment 2) The invention of claim 2 will be described. In the data transmission according to claim 1 described in the first embodiment, a case is considered where the fourth packet could not be transmitted due to a communication error in FIG. In one slot immediately after 11 consecutive packets, the receiving side requests the transmitting side to retransmit the fourth packet. The transmitting side retransmits the fourth packet with the first packet of the immediately following 11 consecutive packets. Since the net data transfer is 567 bytes (27 bytes * 21 pieces) of data transmitted in 24 slots, the data transfer rate is 27 * 21 * 8 / (0.625 [ms] * 24). = 30
The data transfer rate was 2.4 [kbps], and the data transfer rate was higher than in the conventional example, despite the retransmission of the packet.

[0020]

As described above, according to the present invention, data transmission speed is high, and data transmission resistant to frequency interference from other devices can be performed.

[Brief description of the drawings]

FIG. 1 is a time chart when data transmission is performed in only one direction during a continuous slot which is an object of the present invention.

FIG. 2 is a flowchart illustrating a case where data cannot be transmitted in one slot and data of the slot is retransmitted when data is transmitted in only one direction during a continuous slot which is an object of the present invention;

FIG. 3 is a time chart when the direction of data transmission changes for each slot in the conventional example.

[Explanation of symbols]

11 Data packet to be transmitted 12 Data packet to notify the data transmission side of the success or reception failure of the packet number 21 Data packet to be transmitted 22 Success / failure of reception of the immediately preceding data packet A packet to notify the data transmission side 31 A data packet which failed in data transmission 32 A packet which notifies the data transmission side of a packet number in which data transmission failed 33 A data packet which is retransmitted due to a failure in data transmission

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mamoru Ito 1006 Kazuma Kadoma, Kazuma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5K018 AA04 BA03 CA01 FA01 5K028 AA14 BB04 CC02 KK32 LL12 PP12 RR02 RR04 5K033 AA07 BA04 CB03 CC02 DA01 DA19 DB16 5K034 AA06 EE03 FF02 HH09 HH11 MM02 MM03 MM05 MM12 MM39 NN22

Claims (5)

[Claims] 1. In a packet data transmission system in which one data packet exists in one slot in units of slots delimited by a fixed time width and the direction of data transmission is variable for each slot. A packet-type data transmission system that performs data transmission in only one direction over a plurality of slots. 2. In one slot immediately after data transmission is performed only in one direction over a plurality of continuous slots, a data packet transmitted in one direction over a plurality of continuous slots cannot be received. A packet containing the number of the missing packet as data is transmitted in the opposite direction, and data cannot be received in the first slot when performing data transmission only in the initial direction over a plurality of successive slots immediately after this. 2. The method of claim 1, wherein the data packet is transmitted again.
2. A packet data transmission method according to item 1. 3. The packet data transmission system according to claim 1, wherein the number of continuous slots when data is transmitted in only one direction over a plurality of continuous slots is variable. 4. When the data transmission error rate is high, the number of continuous slots when data is transmitted in only one direction over a plurality of continuous slots is small, and the data transmission error rate is low. 2. The packet data transmission method according to claim 1, wherein the time increases. 5. The number of continuous slots when transmitting data in only one direction over a plurality of continuous slots is reduced when the signal strength of the received signal is weak, and is reduced when the signal strength of the received signal is strong. 2. The packet data transmission system according to claim 1, wherein the size is increased.