JP2551911B2 - Line control method for random access wireless communication system - Google Patents

Abstract

PURPOSE:To reduce the collision probability between a random incidence signal and other signals without switching a radio frequency by grouping a control signal sent from a radio terminal equipment to a base station into a random incidence signal use and other use and allocating a transmission slot corresponding to them. CONSTITUTION:Transmission slots are grouped into a random incident signal slot group 11 at each radio terminal equipment and a reply signal slot group 12 with respect to a base station transmission signal, and N-sets of the random incidence signal slots 11 and one reply signal slot 12 form one multi-slot. Or the transmission slot is divided further, the random incidence signal slot 11 is divided into a call slot 11s, an end of call slot 11e and the reply signal slot 12 is divided into an incoming call reply slot 12a and an interruption reply slot 12c, they are grouped in the unit of signal class and allocated to avoid collision between different kind signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a random access radio communication system in which a plurality of radio terminals access the same base station, and more particularly to a line control method for performing line setting / disconnection suitable for satellite communication systems. Is.

[0002]

2. Description of the Related Art In a random access radio communication system in which a large number of radio terminals each having a relatively small amount of traffic access the same base station, an Aloha or slotted Aloha system is effective as a line control system. . However, when this method is used, collisions between control signals will always occur on the transmission path regardless of the signal type, so that the connection quality is greatly affected. As a method of improving this, a method of preparing a plurality of control radio channels and allocating the radio channels according to the control signal type is performed. This makes it possible to reduce the probability of collision between control signals on the transmission path.

[0003]

In the above-mentioned conventional system, a plurality of control radio channels are used, so that it is not desirable from the viewpoint of frequency utilization when the traffic is small. Further, in each wireless terminal, it is necessary to switch the wireless frequency according to the transmission control signal, which complicates the hardware operation. An object of the present invention is to provide a line control method that solves the above points.

[0004]

According to the present invention, a multi-slot used for a control signal transmitted from a wireless terminal to a base station is used as a slot group for transmitting a call signal and an end signal, an incoming response signal, and Group into slot groups for transmitting disconnection response signals, and transmit the incoming signal and disconnection signal to be transmitted from the base station to the wireless terminal in slots having intervals such that the corresponding incoming response signal and disconnection response signal do not collide. To do.

The probability of collision between the random occurrence signal and a signal such as another response signal is reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a basic connection procedure in line control between a base station and a wireless terminal. In the line setting process, as shown in FIG. 1A, a calling signal from the calling terminal randomly occurs, and this calling signal reaches the called terminal as a called signal via the base station through the control channel. The incoming call response signal from the called terminal arrives at the base station, the base station sends a channel designation signal to the calling terminal and the called terminal, and the calling terminal and the called terminal use the call channel designated by the received channel designation signal. Switch from the control channel , ring the ringing ring at the receiving terminal, and the called party turns off
Hook into each other's calls.

In the line disconnection processing, as shown in FIG. 1B, one of the calling terminal and the called terminal in a call, for example, the calling channel being used by the calling terminal is switched to the control channel, and a call-end signal is transmitted to the base station. . The base station transmits a disconnection signal to the originating terminal and the terminating terminal, and the receiving terminal which receives the disconnection signal switches from the call channel to the control channel and transmits the disconnection response signal to the base station.

The control signal (uplink control signal) through the control channel to the base station is a signal randomly generated by the user such as a calling signal and an end signal, and a base station such as an incoming call response signal and a disconnection response signal. It is roughly divided into a response signal to a signal from. In the present invention, the time slots to be transmitted from the wireless terminal to the base station are divided into groups for random occurrence signals and other signals and assigned correspondingly.

FIG. 2 shows an example of the structure of a sending slot in the first embodiment of the present invention. Here, it is assumed that the relative delay time difference between the wireless terminals is sufficiently smaller than the guard time in the slot. As shown in FIG. 2A, the transmission slot is a slot 1 for random occurrence signal in each wireless terminal.
1 and a response signal slot 12 for a base station transmission signal are divided into two groups, and N random occurrence signal slots 11 and one response signal slot 12 form one multi-slot. This makes it possible to avoid collisions between the random occurrence signal and the response signal.

Further, as shown in FIG. 2B, the transmission slot is further subdivided, the random occurrence signal slot 11 is subdivided into a calling slot 11s and an end call slot 11e, and the response signal slot 12 is subdivided. Can be subdivided into the incoming response slot 12a and the disconnect response slot 12c and assigned by grouping in signal type units to avoid collision between different types of signals. As a result, the collision between the call origination signal and the call termination signal positioned as a random occurrence signal is eliminated, and even if the number of calls from the wireless terminal increases, the line disconnection time does not increase. Effective use of equipment can be achieved.

FIG. 3 shows the control signal transmission timing in the base station and the wireless terminal according to the second embodiment of the present invention. As shown in FIG. 3A, a base station transmission signal 13i (i
, 1, 2, ..., N) is transmitted to the wireless terminal i as a control signal, and the wireless terminal receives the base station transmission signal 13i as shown in FIG. , And transmits the terminal transmission response signal 14i to the base station using the response signal slot. Here, the types of base station transmission signals include incoming signals and disconnection signals, and the terminal transmission response signals include incoming response signals and disconnection response signals. As shown in FIG. 3, by controlling the transmission timing of the base station transmission signal in the base station and transmitting the base station transmission signal 13i at the same interval as the response signal transmission slot in the wireless terminal, the transmission from the corresponding wireless terminal is performed. It is possible to avoid collision between response signals that are
It is possible to further improve the transmission efficiency and the connection quality as compared with the first embodiment. That is, the incoming call sent from the base station
The signal and disconnection signal are the incoming response signal and disconnection response signal.
It is sent in slots with intervals that prevent collision.

FIG. 4 shows the control signal transmission timing in the base station and the wireless terminal according to the third embodiment of the present invention.
Here, the signal 13i transmitted from the base station is transmitted to the wireless terminal at a constant transmission interval in consideration of the response signal slot allocation in the wireless terminal, as in the second embodiment. It is assumed that the signals transmitted from the base station are simultaneously received by all the wireless terminals within the same control zone.

In FIG. 4A, when there is no signal to be transmitted at the base station, it is determined that all terminals in the control zone have not transmitted from the base station, and the corresponding response signal slot 12p is randomized. A random occurrence signal can be sent by switching to the occurrence signal slot. Further, in FIG. 4B, when there is no base station transmission signal, a random generation signal transmission permission signal 15 which permits transmission of a random generation signal in the wireless terminal is transmitted. After receiving this signal 15, all terminals within the same control zone can switch the corresponding response signal slot 12p to the random occurrence signal slot to send a random occurrence signal such as a calling signal or an end signal. To do. Depending on the information content of the random occurrence signal transmission permission signal 15, the transmission possible terminal group, the transmission possible signal type (calling,
It is also possible to specify such as (end call). If the call processing capacity at the base station exceeds the threshold, the permission signal 15
Is not sent.

As a result, it is possible to avoid the collision between the random occurrence signal and the response signal and the collision between the response signals and to reduce the probability of collision between the random occurrence signals by effectively utilizing the transmission slot. Become.

[0015]

As described above, according to the present invention, the slots for the control channels transmitted from the wireless terminal are assigned to the random occurrence signals and those for the other groups in a grouped manner, whereby the conventional Aloha or slotted slots are allocated. It is possible to improve the transmission efficiency and connection quality as compared with the method using Aloha. Therefore, the present invention is effective when applied to the channel control method of the satellite communication system in which the propagation delay time is as long as 250 msec and the number of retransmissions greatly affects the connection quality.

Further, according to the present invention, since the collision probability between the control signals transmitted from the wireless terminals can be reduced by the control radio channel of one frequency, the conventional method using the radio channels of a plurality of frequencies is used. The frequency can be used more efficiently than in the above, and since it is not necessary for the wireless terminal to perform the switching operation of the wireless channel according to the control signal type, the hardware can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic connection procedure of a line setting process and a line disconnection process in a wireless terminal and a base station.

FIG. 2 is a diagram showing a sending slot configuration in an embodiment of the present invention.

FIG. 3 is a diagram showing a control signal transmission timing in a base station and a wireless terminal in another embodiment of the present invention.

FIG. 4 is a diagram showing a control signal transmission timing in a base station and a wireless terminal in still another embodiment of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-90221 (JP, A) JP-A-4-252526 (JP, A) JP-A-63-99628 (JP, A)

Claims (1)

(57) [Claims] 1. In line control for performing line setting / disconnection in a random access wireless communication system in which a plurality of wireless terminals randomly access the same base station in a time division manner, the wireless terminal transmits to the base station. the multi-slot to be used for control signals, and the slot groups for sending a call signal and a call end signal, grouped into a slot groups for delivering the incoming call response signal and disconnection response signal, the wireless terminal from the base station A line control method for a random access wireless communication system, wherein an incoming signal and a disconnection signal to be transmitted are transmitted in slots having an interval such that the corresponding incoming response signal and disconnection response signal do not collide with each other.