JPH04329725A - Radio channel designation method - Google Patents

Abstract

PURPOSE:To suppress the reception rate reduction of a radio channel designation signal by sending a radio channel designation signal through a low speed control channel and then sending it through a high speed control channel for plural number of times. CONSTITUTION:When a control section of a base station sends a radio channel designation signal, the use of a low speed channel is designated to a control circuit 306 and a transmission signal is inputted to a framing circuit 304. Then a high speed channel is designated to the control section 306 and a transmission signal is inputted to the circuit 304 for a prescribed number of times. When the radio channel designation signal is received, a mobile station selects the designated radio channel. When the signal transmission quality is excellent and the signal transmission is available through the low speed control channel, the designation signal is sent without interrupting communication and when the quality is deteriorated and the mobile station cannot receive the signal through the low speed control channel, since the radio channel designation signal is sent through the high speed control channel with high transmission reliability, the probability of disable reception of the radio channel designation signal is suppressed and the reduction in the reception rate is suppressed.

Description

[Detailed description of the invention]

0001

[Field of Application of the Invention] The present invention relates to a mobile communication system.
The present invention relates to a method for specifying a wireless channel for channel switching from a base station to a mobile station in communication.

0002

2. Description of the Related Art In mobile communications, a method is adopted in which a service area is divided into a plurality of radio zones and the same frequency is repeatedly used in geographically distant locations to improve frequency utilization. In such a small zone configuration method, if a mobile station moves across zones during communication, or due to interference from a frequency repetition zone, it becomes difficult to continue communication on the wireless channel being used for communication. In this case, so-called channel switching control is performed in which the communication is continued by switching to another wireless channel. In this channel switching control, the network that manages the wireless channel determines the wireless channel to switch to, sends a wireless channel designation signal to the mobile station via the base station, and the mobile station that receives the signal immediately switches to the wireless channel. to report the completion of channel switching. When performing such control, in consideration of the possibility that the wireless channel designation signal may be incorrect on the transmission path and not received by the mobile station, it is necessary to In this case, retransmission control is performed in which a wireless channel designation signal is repeatedly transmitted at fixed time intervals until a report of completion of channel switching is received from the switching destination base station.

[0003] Methods for transmitting and receiving control signals between a mobile station and a base station during communication include a method in which a communication channel and a low-speed control channel are multiplexed on a signal transmission channel to transmit and receive signals;
Although there is a method in which all signal transmission channels are used as high-speed control channels to transmit and receive signals, currently the mainstream method is to use both in combination. Examples of methods for transmitting signals by multiplexing communication channels and low-speed control channels include methods for multiplexing on the frequency axis and methods for multiplexing on the time axis, but since there is no essential difference between the two methods, A digital mobile communication system that multiplexes on the time axis will be explained below as an example.

FIG. 3 shows the configuration of a general communication physical channel in a digital mobile communication system. As shown in Figure 3 (B), the carrier is framed for each fixed bit, and each frame includes a frame synchronization word (FSW) to identify the beginning of the frame, and a frame synchronization word (FSW) to identify whether the control channel is slow or fast. /consists of a high-speed identifier (S/F) and a signal transmission channel. When using a low-speed control channel, the low/high-speed identifier is set to low-speed (S) as shown in Figure 3 (C), and the signal transmission channel is configured with a predetermined number of bits for the communication channel and control channel. Time division multiplexing is performed, and communication signals and control signals are transmitted and received on each channel. Furthermore, when using a high-speed control channel, the low/high-speed identifier is set to high-speed (F) as shown in FIG. 3(D), and control signals are transmitted and received using all signal transmission channels as control channels. The high-speed control channel has a larger signal transmission capacity per frame than the low-speed control channel, so when transmitting control signals of the same length, it can be transmitted and received with fewer frames, and control signals can be transmitted and received in a short time. Furthermore, under fading, which is a characteristic of electric field fluctuations unique to mobile communications, signal dropouts occur on a frame-by-frame basis, but the signal non-reception rate is lower than with a low-speed control channel that requires many frames for signal transmission. On the other hand, the slow control channel
Since control signals are sent and received along with the communication channel, it is possible to send and receive control signals while continuing communication.

[0005] In conventional systems having such a signal configuration, it is determined in advance which control channel to send and receive control signals on the physical communication channel, low or high speed, for each signal, and retransmission control Even when transmitting signals on the high-speed control channel, the signals sent on the high-speed control channel are also transmitted on the high-speed control channel when retransmitted.
In addition, signals transmitted on the low-speed control channel are also transmitted on the low-speed control channel when retransmitted. When transmitting and receiving wireless channel designation signals, it is necessary to decide in advance which control channel to transmit and receive, but when transmitting on a high-speed control channel, there is a drawback that communication is always interrupted during signal transmission. . Therefore, it is common practice to transmit the wireless channel designation signal using a low-speed control channel.

FIG. 4 shows the operation flow of the base station in this case. When the base station performs the operation shown in Figure 4, the non-reception rate will be high if the signal transmission condition in the wireless section is poor, and even if retransmission control is performed, the non-reception rate of retransmitted signals will also be high, so sufficient retransmission will not be possible. Control is not effective. Furthermore, when retransmission control is performed using a low-speed control channel, it takes a considerable amount of time to specify the wireless channel when retransmission time is taken into account. There is a risk that the channel may become unavailable and communication may be interrupted.

[0007]Also, in the digital system, a method using a TDMA system is also adopted, but even in this case, the above-mentioned frames are simply multiplexed on one carrier for each frame, and the method is essentially the same as the present system.

[0008]

[Problems to be Solved by the Invention] An object of the present invention is to minimize the probability of instantaneous communication interruption due to signal transmission and reception when specifying a wireless channel for channel switching from a base station to a mobile station in communication. It is an object of the present invention to provide a mobile communication system that can reduce the time required for signal retransmission, suppress a decrease in the reception rate of a radio channel designation signal, and shorten the time spent on signal retransmission.

[0009]

[Means for Solving the Problems] The present invention is characterized by a procedure for transmitting and receiving signals between a mobile station and a base station by multiplexing a communication channel and a low-speed control channel on a signal transmission channel of a physical communication channel. In a mobile communication system that has a procedure for transmitting and receiving signals using all transmission channels as high-speed control channels, and in which the mobile station and base station simultaneously select one of these procedures to transmit and receive signals during communication, the base station has a control It has a procedure for transmitting a signal multiple times in succession on a high-speed control channel, and transmits a radio channel designation signal on a low-speed control channel when designating a radio channel for channel switching from a base station to a communicating mobile station. Then, the wireless channel designation signal is transmitted multiple times in succession on a high-speed control channel, and the mobile station switches the wireless channel when the channel designation signal is received without error on any channel. .

0010

[Operation] When specifying a wireless channel for channel switching from a base station to a mobile station in communication, the present invention transmits a wireless channel designation signal on a low-speed control channel and then transmits it multiple times in succession on a high-speed control channel. It is characterized by the fact that it is sent by The main difference from the conventional technology is that a low-speed control channel and a high-speed control channel are used together in the same signal.

[0011]

Embodiment FIG. 2 shows the configuration of a transmitting/receiving section of a base station and a mobile station in an embodiment of the present invention. Here, also in this embodiment, the physical channel for communication in the wireless section has the configuration shown in FIG. In FIG. 2, 301 is a modulation circuit, 302 is a demodulation circuit, 303 is a clock generator for framing a signal,
304 multiplexes the communication signal from the communication unit and the control signal from the control unit according to the high-speed/low-speed control channel designation from the control circuit 306, adds a low/high-speed identifier and a frame synchronization word, and configures a frame for the wireless section. A circuit 305 detects a frame synchronization word from a signal in a wireless section and
A circuit disassembles the frame based on the high-speed identifier and outputs a control signal to the control section and a communication signal to the communication section. 306 is a circuit that specifies a high-speed/low-speed control channel to the framing circuit based on a command from the control section. .

The operation flow of the base station in the embodiment of the present invention is shown in FIG. 1, and the operations of the control sections of the mobile station and the base station will be explained below. When transmitting a wireless channel designation signal, the base station control unit first designates a low-speed channel to the control circuit 306 (14), and inputs the transmission signal to the framing circuit 303. Thereafter, a high-speed channel is designated to the control unit 306 (16), and a transmission signal is input to the framing circuit 303 a fixed number of times. On the other hand, when the mobile station receives the radio channel designation signal, it switches to the designated radio channel (28).

[0013] By performing the above control, if the signal transmission quality in the wireless section is good and signal transmission is possible using a low-speed control channel, the wireless channel designation signal can be transmitted without interrupting communication. This is possible, and the mobile station switches the wireless channel immediately after that, so there will be no instantaneous interruption of communication due to the wireless channel designation signal on the high-speed control channel that is subsequently transmitted. In addition, if the signal transmission quality in the wireless section is poor and the mobile station does not receive the signal on the low-speed control channel, the wireless channel designation is transmitted on the next high-speed control channel with higher transmission reliability.
The probability that the wireless channel designation signal is not received can be reduced,
In addition, signals can be transmitted in a shorter time than when retransmitting the wireless channel designation the same number of times.

[0014]

[Effects of the Invention] According to the method of the present invention, when transmitting a wireless channel designation signal for channel switching from a base station to a mobile station in communication, a low-speed control channel is first used to ensure good signal transmission conditions. In some cases, it is possible to minimize the probability that communication will be momentarily interrupted due to signal transmission and reception. Furthermore, by transmitting multiple times in succession on the high-speed control channel after transmitting on the low-speed control channel, it is possible to suppress the decline in the reception rate of the wireless channel designation signal and reduce the time spent retransmitting the signal. Become.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a base station operation flow in an embodiment of the present invention.

FIG. 2 is a diagram for explaining the configuration of transmitting and receiving devices of a mobile station and a base station.

FIG. 3 is a diagram for explaining the configuration of a general communication physical channel in a digital mobile communication system.

FIG. 4 is a diagram for explaining a base station operation flow in a conventional system.

[Explanation of symbols]

301 Modulation circuit 302 Demodulation circuit 303 Transmission clock 304 Framing circuit 305 Deframing circuit 306 Control circuit

Claims (1)

[Claims] Claim 1: A procedure for transmitting and receiving signals between a mobile station and a base station by multiplexing a communication channel and a low-speed control channel on a signal transmission channel of a physical communication channel, and a procedure for transmitting and receiving signals by using all signal transmission channels as high-speed control channels. In a mobile communication system in which a mobile station and a base station simultaneously select one of the procedures to transmit and receive signals during communication, the base station transmits a control signal multiple times in succession over a high-speed control channel. When specifying a wireless channel for channel switching from a base station to a communicating mobile station, after transmitting a wireless channel designation signal on a low-speed control channel, the wireless channel designation signal is controlled at high speed. A wireless channel designation method, characterized in that the wireless channel is transmitted multiple times in succession on a channel, and the mobile station switches the wireless channel when a channel designation signal is received without error on any channel.