JPH04287428A - Mobile communication traffic control system - Google Patents

Abstract

PURPOSE:To adjust number of mobile stations being traffic control objects in details without incurring an increase in operating line number for a radio block by adding intentionally an error bit to a control channel. CONSTITUTION:A transmission section at a base station side is provided with a control section 1, an interface circuit 2 being a connection section with a host controller, a signal processing section 3 processing a base band section, a modulator 6 to make transmission to a radio block and n antenna 7. The signal processing section 3 is added with an error bit adding function 5 together with an error correction/detection coding function 4. Moreover, a reception section at a mobile station consists of a control section 8, a signal processing section 9, a demodulator 11 and an antenna 12, and an error correction/detection coding decoding function 10 is mounted to the signal processing section 9. Then a bit error is generated intentionally to reduce number of mobile stations receiving normally the control channel to implement traffic control thereby varying a range of a controlled radio area.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control channel traffic control method that is necessary in a mobile communication system when starting up a system and when the control channel is congested.

0002

2. Description of the Related Art FIG. 3 shows a system configuration of a mobile communication system. In the figure, 51 is a mobile station, 52 is a wireless base station connected to the mobile station via a wireless communication line, 53 is a control station that controls a plurality of wireless base stations, and 54 is a switching station that switches communication lines. , 57 represent a network. The service area 55 is composed of a plurality of wireless zones 56, and a wireless base station is installed in each wireless zone. A mobile station selects a wireless zone while moving within a service area, and performs incoming call processing and outgoing call processing using the control channel of the wireless zone.

FIG. 4 is a diagram showing an example of a typical control channel configuration. Usually, the control channel from the radio base station to the mobile station (downlink control channel) and the control channel from the mobile station to the radio base station (uplink control channel) have different configurations. As shown in the figure, the downlink control channel 58 is composed of a broadcast control channel, an incoming control channel, and a cell-specific signaling channel. On the other hand, the uplink control channel 59 is composed of only cell-specific signaling channels and is normally accessed randomly from a plurality of mobile stations. Here, the broadcast control channel and the incoming call control channel are channels for transmitting broadcast information common to all mobile stations located in the radio zone of the base station and an incoming signal for a certain mobile station, respectively. Further, the cell individual signaling channel is a channel for transmitting information regarding individual calls at the time of origination and termination.

As described above, uplink control channels in the wireless section are accessed randomly, so if mobile stations are concentrated in a certain wireless zone, collisions of uplink control signals may occur, resulting in congestion. When this congestion situation occurs,
Traffic control that limits the number of mobile stations using a control channel becomes necessary. Traffic control is also required when adding wireless zones or when starting up a system when it is down. This is because the processing at the base station suddenly increases when the system is started up, and the base station may become unable to process.

0004

Conventional traffic control has been performed by providing a traffic control bit 61 in a broadcast control channel 60, as shown in FIG. By reading this traffic control bit, the mobile station
The mobile station was determining whether or not it was possible to perform call origination and reception processing using the control channel. That is, when the control channel is congested or when the system is started up, this traffic control bit is used to instruct the mobile station that outgoing/terminating processing is not possible, thereby regulating traffic.

In the case of this conventional method, it is necessary to increase the number of traffic control bits in order to finely adjust the number of mobile stations subject to regulation.
There was a drawback that it was necessary to increase the use of lines in the wireless section. For example, one way to adjust the number of mobile stations subject to regulation is to divide mobile stations into groups, but if this method is adopted, it is necessary to add group identification information to the traffic control bits, which increases the number of bits. I have to let it happen. For example, if mobile stations are divided into 32 groups, 5 bits are required. Since these 5 bits are bits that are not normally used, they have a major disadvantage of reducing the usage efficiency of the wireless section.

In view of these conventional problems, the present invention provides a control channel that allows fine adjustment of the number of mobile stations subject to traffic control and that does not require an increase in the number of lines used in the wireless section. The aim is to provide a traffic control method for

[0007]

[Means for Solving the Problems] The present invention has a radio base station and a mobile station, and a control signal for establishing communication between the mobile station and the radio base station is provided between the radio base station and the mobile station. In a mobile communication system that transmits an error correction code using a control channel, the range of the controllable wireless area is changed by mixing error bits into the transmission control signal from the wireless base station to the mobile station. This is a mobile communication traffic control system characterized by:

[0008]

The main feature of the present invention is that traffic is controlled by intentionally generating bit errors to reduce the number of mobile stations that can normally receive a control channel. This method differs from the conventional technology in that control channel traffic can be controlled without putting a burden on the wireless section.

[0009] The mobile station selects a control channel of the radio zone in which the mobile station is located, and uses the control channel to receive and receive calls.
Performs outgoing processing. The mobile station can select the control channel of the wireless zone in which it is located by measuring and comparing the reception level of each control channel. but,
When reading the information content of the control channel in order to perform incoming and outgoing processing on the control channel, if the number of error bits in the information content is greater than the maximum error bit correction capacity, perform processing using that control channel. Therefore, the processing on the control channel is abandoned and another control channel is reselected. The traffic control method of the present invention intentionally adds error bits to the control channel to limit the number of mobile stations that can normally receive the control channel, thereby controlling the traffic on the control channel.

0010

[Embodiment] FIG. 1 is a diagram showing an embodiment of the present invention,
(a) shows the configuration of the transmitter of the base station, and (b) shows the configuration of the receiver of the mobile station. As shown in Figure (a), the base station side transmitting unit includes a control unit 1, an interface circuit 2 which is a connection unit with a higher-level control device, a signal processing unit 3 which processes a baseband unit, and a transmitter to a wireless section. Modulator 6 for
, and an antenna 7. In addition to the error correction/detection encoding function 4, the signal processing unit 3 is also provided with an error bit addition function 5 to realize the traffic control method of the present invention. Note that although error correction/detection coding and error bit addition are expressed as separate functions in this diagram,
The hardware configurations do not necessarily need to be separate, and may be configured to perform software control under one hardware configuration. On the other hand, as shown in FIG. 2(b), the mobile station receiving section is composed of a control section 8, a signal processing section 9, a demodulator 11, and an antenna 12. A detection code decoding function 10 is implemented.

[0011] Here, using FIG. 2, we will explain the layer 2 signal frame structure transmitted using the control channel and the error correction/frame structure.
An example of a detection method will be explained. As shown in the figure, the layer 2 signal frame 20 includes an address section 21, a control section 22, and an information section 23. Then, the layer 2 frame is divided into units, and signal disassembly and assembly bits W are added to each unit. After an error detection bit CRC is added to each unit, it is further divided into small blocks, and each small block is an error correction/detection code B.
Encoded with CH code. Thereafter, the units divided into small blocks and added with CRC and BCH are interleaved and sent out to the radio section. What is interleaving?
This is an operation in which the order of a data string is changed and transmitted in order to turn a burst error into a random error, and the order is restored on the receiving side.

Traffic control according to the method of the present invention is performed by intentionally generating errors in small blocks of the downlink control signal described above. Therefore, the number of error bits in a small block of downlink control signals received by the mobile station is:
It is the number of error bits that occur during transmission plus the number of error bits that are intentionally added, so if the number of errors exceeds the error correction ability, the small block will not be able to be received normally. Since the frame to which the small block belongs is also not received, the mobile station abandons the control channel and performs processing using another control channel, so traffic control of the control channel can be performed.

As mentioned above, since a frame is composed of a plurality of small blocks, by intentionally changing the number of small blocks to which error bits are added, the non-reception rate of the frame can be changed, and the control channel can be controlled. Since the number of mobile stations that can normally receive data can be changed, the number of mobile stations subject to traffic control can be finely adjusted by increasing or decreasing the number of small blocks to which error bits are added. As mentioned above, the traffic control method of the present invention controls traffic by increasing or decreasing the number of small blocks to which errors are added without using the bits of the broadcast control channel, so if fine-grained control is desired. Even in this case, desired control can be achieved without increasing the traffic control bits of the broadcast control channel.

[0014]

[Effects of the Invention] As explained above, according to the present invention,
There is an advantage that the number of mobile stations subject to traffic control can be finely adjusted without increasing the number of lines used in the wireless section.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a layer 2 signal frame configuration.

FIG. 3 is a diagram showing a system configuration of mobile communication.

FIG. 4 is a diagram showing the configuration of a control channel in a wireless section.

FIG. 5 is a diagram showing the configuration of a broadcast control channel.

[Explanation of symbols]

1, 8 Control unit 2 Interface circuit 3, 9
Signal processing unit 4 Error correction/detection encoding function 5
Error bit addition function 6
Modulators 7, 12 Antenna 10 Error correction/detection code decoding function 1
1 Demodulator 20 Layer 2 signal frame 21
Address section 22 Control section 23 Information section

Claims (1)

[Claims] Claim 1: A system comprising a radio base station and a mobile station, and transmitting a control signal for establishing communication between the mobile station and the radio base station using a control channel prepared between the radio base station and the mobile station,
Mobile communication traffic characterized by changing the range of a controllable wireless area by mixing error bits into a transmission control signal from a wireless base station to a mobile station in a mobile communication system that transmits an error correction code. control method.