JPH02155335A - Radio packet transmission system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency and to relieve the possibility of repetitive transmission by sending only a final data being a required minimum data packet again from a base station if a terminal equipment does not give reply due to a line fault. CONSTITUTION:If a base station does not receive any reply regardless of transmission of P#n(ACK) for l times, the station applies the processing of P#n(RVI), sends only a final data D(n), not all relevant blocks and sends the P#n(ACK) again. If a line fault is caused due to fading or the like in the sequential reception of each data in the (m+1)th block, although the transmission mode is not selected, since the line is recovered while the base station applies l times of retransmission of the P#n(ACK), the reception mode is surely attained by a polling signal P#n(RVI) and the mode is switched into the transmission mode by the final data D(n) received afterward and an acknowledge reply (block ACK) is returned.

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention provides a base station and a plurality of terminal stations using a polling method.
The present invention relates to a wireless packet transmission system that performs heavy wireless packet communication, and particularly relates to a retransmission control technique when a terminal station does not respond to transmission from a base station.

(Prior Art) For example, the polling method shown in FIG. 2 is known as a polling method employed in a wireless packet transmission method in which a base station and a plurality of terminal stations perform half-duplex wireless packet communication using a polling method.

In FIG. 2, as shown in FIG. 2(a), transmission from the base station to all terminal stations is performed in units of slots. As shown in FIG. 2B, each slot has a polling section at the beginning, followed by a data section. The polling unit receives a polling signal (P
#O.

P#1. P#2. ---P#n), P#n in Figure 4
(ACK) and various signals shown as P#n (PVI) are inserted. These signals are one per slot.
Sent to one address. Here, the polling signal P with number #0
#0 is a signal inviting all terminal stations to make a call. Also, number #1. Same #2. ...Polling signal of #n (
PI1. PI3. ...P#n) is a signal that grants transmission rights to a specific terminal station. In addition, P#n (ACK)
, P#n (RVI) will be described later.

Then, the terminal station is in either the transmission mode or the reception mode, and when in the transmission mode, it determines the timing at which the terminal station transmits data packets etc. by looking at the polling section. For example, as shown in FIG. 2(a), in response to polling signal P#0, terminal station #i in transmission mode makes a call request in that slot, and polling signal P#1
Terminal station #1, which has been given the right to transmit, transmits a data packet in that slot. Furthermore, when in the reception mode, the data section is checked to determine whether there is data for the own station, and if it is for the own station, it is taken in.

Now, when a base station transmits data to a specific terminal station, a block transmission method is adopted. This transmission block consists of multiple data packets ((0)
~(n)), and the transmission blocks having such a configuration are transmitted sequentially from the first to a specific terminal station. At this time, the final data packet (n
) has an important meaning as a distinction between each transmission block. Hereinafter, block transmission in the conventional wireless packet transmission system will be explained with reference to FIG.

FIG. 4 shows the procedure when the terminal station #n in the reception mode takes in a data packet that is block transmitted in the data portion of the slot.

In FIG. 4, when the base station continuously transmits n pieces of data (D(0) to D(n)) of the m-th block, terminal station #n
In this way, the base station sends a request (P#n (ACK)) for an acknowledgment (block ACK) as to whether or not the m-th block was successfully received in the polling section of the slot. P#n(ACK
). On the other hand, when the terminal station #n receives the final data D(n) of the m-th block, it switches from the reception mode to the transmission mode. That is, terminal station #
n is a Bohng signal P#n transmitted by the base station in the polling part of the slot after receiving the final data D(n)
(ACK), transmits a block ACK to the base station. As a result, the base station receives P for the 1nth block.
#n (ACK) processing ends.

Next, the base station sends a polling signal P to terminal station #n.
For example, the polling section of the next slot transmits #n()eVI) to deprive the terminal station #n of the transmission right, and in the subsequent data section, n pieces of data (D() of the m+1 block are transmitted.
0) to D(n)) are continuously transmitted in the same manner as the previous time, and, for example, a polling signal P#n (ACK) of the next slot/soto polling unit C is transmitted.

On the other hand, the terminal station #n abandons the transmission right in response to the polling signal P#++ (RVI) transmitted by the base station in the polling unit, enters the 2nd reception mode, and enters the m+lth
Each block of data is received one by one.

At this time, if the final data D(n) cannot be received due to a line abnormality due to fading, etc., the terminal station #n cannot enter the transmission mode, and the confirmation response request (P#n
Block ACK cannot be returned for (ACK)).

Therefore, the base station issues an acknowledgment request (P#n (ACK)).
) once, and if the terminal station #n still does not respond, it is assumed that the terminal station #n has not been able to receive the m+1th block normally, and retransmission processing is performed. In other words, the base station
Polling signal P#n (RVI
), and again sends the 1st n) n data of 1 block (
D (0) ~ D (n)) and P#n (AC
Perform the process K).

Then, a polling signal P# which is this confirmation response request signal
n (ACK>), if there is a response (block ACK) to
CK), and thereafter all transmission blocks are transmitted using the same procedure.

(Wires to be Solved by the Invention) However, in the conventional wireless packet transmission system described above, if the terminal station does not respond, the base station retransmits the corresponding block again. The terminal station actually retransmits even data packets that have been correctly received, leading to a decrease in data transmission efficiency and an increase in the retransmission rate due to an increase in the amount of data to be retransmitted.

The present invention was developed in view of these problems, and its purpose is to enable the base station to retransmit only the minimum necessary data packets when the terminal station does not respond, thereby improving transmission efficiency. An object of the present invention is to provide a wireless packet transmission method that can reduce the repeat transmission rate.

(Means for Solving the Problems) In order to achieve the above object, the wireless packet transmission system of the present invention has the following configuration.

That is, the wireless packet transmission method of the present invention is a wireless packet transmission method in which a base station and a plurality of terminal stations perform half-duplex wireless packet communication using a polling method, and the base station transmits the "C1 transmission block" to the corresponding terminal station. After continuously transmitting a plurality of data packets that make up the transmission block, the terminal station transmits an acknowledgment request for the one transmission block, and the terminal station changes from reception mode to transmission mode in response to receiving the last data packet in one transmission block. In a wireless packet transmission system in which a VL acknowledgment is transmitted in response to the request; when the base station does not receive the acknowledgment even after making the request n times, the base station sends a message to the corresponding terminal station. On the other hand,
The present invention is characterized in that it includes means for transmitting the final packet data and requesting an acknowledgment again.

(Function) Next, the function of the wireless packet transmission system of the present invention configured as described above will be explained.

When the base station does not receive the N acknowledgment despite requesting an acknowledgment for one transmission block for which transmission has been completed n times, the base station transmits the final packet data to the corresponding terminal station, and , requests the confirmation response again.

Then, when the corresponding terminal station is receiving each data bucket 1~ of one transmission block one by one, a line abnormality occurs due to fading etc., and the terminal station is unable to receive the final data packet.
As a result, even if it is not possible to switch to transmission mode,
Since the line is restored while the base station makes one acknowledgment request, it is possible to switch to the transmission mode depending on the final packet data received thereafter, and return an i-acknowledgement.

In summary, according to the present invention, when a terminal station becomes unresponsive due to a line abnormality, the transmission/reception relationship of half-duplex wireless packet communication can be brought into a normal state by performing the minimum processing of transmitting only the final packet data. This allows for quick recovery. [7] Since there is no need to retransmit the transmission block, it is possible to improve the transmission efficiency and reduce the retransmission rate.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a procedure for transmitting downlink data in a wireless packet transmission system according to an embodiment of the present invention.

Although the configurations of the base station and terminal station are well known and are not shown in the drawings, in the present invention, as shown in FIG. In the case of a response, it processes P#n (RV I), sends only the final data D (n>) instead of all of the corresponding program block (in the illustrated example, the m+1 block), and then processes P#n again.
(ACK).

Thus, when the terminal station #n is receiving each data of the m+1 block one by one at L7, a line abnormality occurs due to fading etc., and the terminal station #n cannot receive the final data D(0), and as a result it switches to the transmission mode. Even if the polling signal P#n (RVI
) ensures that the receiving mode is activated, and then the received final data D(n) switches to the transmitting mode,
This means that an acknowledgment (block ACK) can be sent back.

(Effects of the Invention) As explained above, according to the wireless packet transmission method of the present invention, when a terminal station becomes unresponsive due to a line abnormality, the base station retransmits only the final data, which is the minimum necessary data packet. As a result, the transmission/reception relationship of half-duplex wireless packet communication can be quickly restored to a normal state with a minimum amount of processing. Further, since there is no need to retransmit the transmission block, there is an effect that the transmission efficiency can be improved and the retransmission rate can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a procedure for transmitting downlink data in a wireless packet transmission system according to an embodiment of the present invention;
FIG. 2 is an explanatory diagram of a polling method adopted in a wireless packet transmission system, FIG. 3 is a configuration diagram of downlink transmission data, and FIG. 4 is a flowchart showing the procedure of conventional downlink data transmission. D(0) to D(n)...Data within one transmission block (data packet), P#n (ACK)...
...Polling signal for confirmation response request, pro-nk A
CK... Confirmation response, P#n (RVI)...
...Polling signal for sending mytt.

Claims (1)

[Claims] A wireless packet transmission method in which a base station and multiple terminal stations perform half-duplex wireless packet communication using a polling method, in which the base station continuously transmits multiple data packets constituting one transmission block to the corresponding terminal station. After that, a request for an acknowledgment regarding the one transmission block is sent, and the terminal station switches from reception mode to transmission mode in response to receiving the final data packet in one transmission block, and sends an acknowledgment in response to the request. In the wireless packet transmission system, when the base station does not receive the acknowledgment even after making the request n times, the base station transmits the final packet data to the corresponding terminal station, and transmits the final packet data again to the corresponding terminal station. A wireless packet transmission system characterized by comprising means for requesting an acknowledgment response.