JPH01227534A - Mobile communication control system - Google Patents

Abstract

PURPOSE:To dispense with a synchronization between stations with a high accuracy and to execute an extendability, a profitability, a high speed, and a power saving by providing a transmission power fluctuating means to fluctuate a communication power form each base station by means of a combination pattern, in which a random pattern is added to a prescribed pattern, to the base station. CONSTITUTION:In the transmission system of the base station, an adder 5 adds a specific pattern supplied from a specific pattern preparing pattern 6 and the random pattern supplied from a random pattern preparing device 7, and a combination pattern signal is supplied to a power amplifier 2. The power amplifier 2 amplifies a radio frequency signal supplied from a modulator 3 to a transmission power to be fluctuated according to the combination pattern signal supplied from the adder 5. The radio frequency signal, in which the transmission power is changed by the combination pattern, is transmitted through an antenna 1 to a mobile station. Thus, the synchronization between the stations with a high accuracy can be made unnecessary, an application to a high-speed signal transmission can be facilitated, simultaneously, the profitability can be made excellent, and the extension of a system can be also facilitated.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a system for transmitting signals from a plurality of base stations to a mobile station in a mobile communication system with a small zone configuration in which a service area is covered by a plurality of base stations. This invention relates to a mobile communication control method for transmitting and calling a specific mobile station or transmitting information.

(Prior Art) A typical example of this type of mobile communication control system is a call termination control system in a car telephone system.

FIG. 6 is a diagram explaining the zone configuration of a mobile communication system including such a car telephone system, in which 11 is a call receiving control area, 12 is a wireless zone, 21°, 22, 23 is a base station, and 24 is a mobile station. It is. Moreover, FIG. 7 is a block diagram showing the configuration of a mobile communication system, in which 21 to 23 are base stations, 24 to 26 are mobile stations, and 27 is an upper station. In this mobile communication system, C manages the incoming call control area 11 where mobile stations exist on the base station side using a home memory or the like. This is achieved by, for example, registering the location with the base station each time the mobile station moves through the incoming call control area 11, which is comprised of a plurality of wireless zones 12. What is incoming call control?
When a mobile station receives a call from the general network connected to the upper station 27 via the upper station 27, the upper station 27 accesses the home memory that manages the location of the mobile station and determines whether the mobile station exists. In this control, incoming call information is transmitted to the base stations that make up the incoming call control area 11, and signals are transmitted from all of the base stations to the radio section to call the mobile station that received the incoming call.

This incoming call control method ensures highly accurate synchronization, which is smaller than the length of 1 bit of the digital signal that transmits information between all base stations, and allows multiple stations to transmit signals at the same frequency at the same time. It is used. According to this method, a frequency for incoming call control is determined for each control zone, and one mobile station uses different frequencies in the control area 11 only near the boundary of the incoming call control area 11, which is composed of a plurality of wireless zones 12. All you have to do is search, and normally it is sufficient to receive one incoming call on the 111 October frequency.

□ However, this method is based on highly accurate synchronization between base stations, and for this purpose, it is necessary to receive incoming control channels from surrounding base stations and correct the timing difference in the transmission of digital signals with the own base station. tII to monitor and adjust deviations
It is necessary to do ill. Therefore, a receiver and a control device for timing adjustment are required, which is disadvantageous in terms of system economy.

In particular, when applied to systems in which the transmission speed of digital signals is increased, highly accurate synchronization is required, and in areas where the propagation time in the wireless section becomes an issue, This method has the disadvantage that it is almost impossible to achieve accurate synchronization and is therefore not applicable.

Furthermore, since the system is operated on the premise of inter-station synchronization, failures in synchronization can cause major damage to the entire system, which is disadvantageous in terms of system reliability. Furthermore, in order to cope with the increase in the number of subscribers after the start of operation, the wireless zone may be divided and new base stations added, directional antennas may be used (sectorization), or the service area may be expanded. When adding a new base station to a new base station, it is necessary to take into account the inter-station synchronization control of the already installed base stations, making the design difficult and lacking in expandability.

Another incoming call control method is a multi-different frequency transmission method in which base stations within a control zone transmit at different frequencies to avoid co-channel interference. In this method, signals are transmitted simultaneously from each base station, but there is no interference from signals transmitted on the same frequency, so there is no need for a cycle between stations, and the high-precision synchronization mentioned above is required. There are no drawbacks that arise.

However, since the frequency of the incoming call control channel differs in each wireless zone, it is necessary to search and switch the frequency of the incoming call control channel each time the wireless zone is changed. In particular, in a system in which the wireless zone is made very small in order to improve the frequency utilization rate, the frequency of searching for this channel becomes extremely high. Since the mobile station cannot receive incoming signals while searching for a new channel, the mobile station is unable to receive calls, reducing the reliability of incoming call control, or in specific areas near the wireless zone border where it is difficult to receive incoming calls due to channel searching. It had the disadvantage of being able to

When the mobile station is a portable device, power saving is an important issue, and an intermittent reception method is an effective means for achieving this goal. This is done by dividing mobile stations into groups in advance.
A time slot for transmitting an incoming signal is determined for each group, and the mobile station performs reception operation only during the time slot of its own group, and saves money by turning off the power of unnecessary parts during other periods. By using electricity, the amount of time available for carrying the vehicle will be greatly increased. For mobile stations to which this intermittent reception is applied, it is possible to eliminate the inability to receive calls due to channel search by searching for an incoming control channel during a period other than the own time slot, but the reception operation is turned on during the channel search period. Therefore, in the case of a minimal zone configuration in which the channel search frequency is high, there is a drawback that the power saving effect due to intermittent reception becomes small. Broadly speaking, this method requires a large amount of frequency resources because each base station transmits the same information using a different frequency, and has the drawback of being inferior in terms of frequency utilization.

Furthermore, as another method for controlling incoming calls, there is a multi-station sequential transmission method in which the transmission frequency from each base station is the same and the same information is transmitted sequentially in time slots determined by each base station to prevent interference. be. FIG. 8 is a diagram showing an example of transmission signals from each base station in this multi-station sequential method. In this method, there is no need for channel search since the frequencies are the same.

However, since one signal is transmitted sequentially from each base station, if the inter-station synchronization accuracy for controlling the transmission timing is poor, many guard pits are required between the transmission time slots of each base station, which reduces throughput. There is a problem with doing so. Furthermore, in order to avoid this, highly accurate synchronization less than the bit length is not required, but inter-station synchronization accuracy within a sufficiently short time compared to the signal length is required. Furthermore,
Since the same information is unconditionally repeatedly transmitted to the intermediate number of zones that are sequentially transmitted, the throughput is low and the number of subscribers that can be accommodated in one channel is low.

(Problems to be Solved by the Invention) As mentioned above, in each conventional mobile communication control system, the need for highly accurate base station r1 synchronization, the monitoring and adjustment of synchronization deviations, etc. are uneconomical, and synchronization failures, etc. Decreased reliability and poor scalability, difficulty in receiving calls and decreased reliability due to frequency search in multi-station sequential transmission, decreased power saving effect and frequency usage due to channel search frequency in intermittent reception method There are problems such as a decrease in rate and a decrease in throughput in multi-station sequential transmission.

The present invention has been made in view of the above, and aims to eliminate the need for highly accurate inter-station synchronization, provide scalability,
The purpose of the present invention is to provide a mobile communication control method that is economical, reliable, and capable of increasing speed and saving power.

[Structure of the Invention] (Means for Solving the Problem) The mobile communication control method of the present invention transmits signals from a plurality of base stations to a mobile station in a mobile communication system with a small zone configuration in which a service area is covered by a plurality of base stations. Mobile communication IT a that transmits and calls a specific mobile station or transmits information.
This is a method in which the communication power from each base station is randomly distributed.
Alternatively, a transmission power variation means that varies the transmission power according to a predetermined pattern determined by the base station or a combination pattern of the predetermined pattern and a random pattern, and If the information is not returned to the base station within a predetermined time, the information is retransmitted from the base station. □ Furthermore, the mobile communication control method of the present invention can transmit signals from a plurality of base stations to a mobile station to call a specific mobile station in a mobile communication system with a small zone configuration in which a service area is covered by a plurality of base stations. A mobile communication control system for transmitting information, comprising: an allocation means for allocating to each base station different combinations each consisting of one each of a plurality of types of transmission power fluctuation patterns and a plurality of types of transmission frequencies allocated to a service area; The transmission power allocated to each base station is varied by the transmission power fluctuation pattern assigned to each base station by this allocation means, or by a combination pattern of adding a random pattern to the fluctuation pattern. The present invention includes a transmission means for transmitting information at a transmission frequency, and a retransmission means for retransmitting information from the base station if a response from the mobile station to the information transmission from the base station is not returned to the base station within a predetermined time. This is the summary.

(Function) In the mobile communication control system of the present invention, the transmission power from each base station is varied randomly, in a predetermined pattern determined by the base station, or in a combination pattern that is a predetermined pattern plus a random pattern. I'm letting you do it.

Furthermore, in the mobile communication control system of the present invention, different combinations of multiple types of transmission power fluctuation patterns and multiple types of transmission frequencies are assigned to each base station, and each base station uses this assigned transmission frequency. Information is received at the assigned transmission frequency while varying the transmission power according to a power fluctuation pattern or a combination pattern obtained by adding a random pattern to the fluctuation pattern.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit block diagram of a transmission system of a base station used in a mobile communication control system according to an embodiment of the present invention. In the figure, 1 is an antenna, 2 is a power amplifier that can variably control the transmission power, 3 is a modulator, 4 is an encoder, and 5 is an output signal to the power amplifier 2 so as to vary the transmission power of the power amplifier 2. 6 is a specific pattern generator, 7 is a random pattern generator, 8 is a timing control device, and 9 is an information input terminal from the upper station.

In the transmission system of the base station configured as described above, when incoming call information etc. to a specific mobile station is input from the upper station via the input terminal 9, this information is encoded by the encoder 4, and then It is modulated by the variable WA device 3 and converted into a radio frequency signal,
It is supplied to power amplifier 2. On the other hand, the adder 5 adds the specific pattern supplied from the specific pattern generator 6 and the random pattern supplied from the random pattern generator 7, and sends the combined pattern signal, which is the specific pattern plus the random pattern, to the power amplifier 2. supply

As a result, the power amplifier 2 amplifies the radio frequency signal supplied from the modulator 3 while changing the transmission power according to the combination pattern supplied from the adder 5. That is, the power amplifier 2 amplifies the radio frequency signal supplied from the modulator 3 to a transmission power that varies according to the combination pattern signal supplied from the adder 5. The radio frequency signal whose transmission power from the power amplifier 2 changes according to the combination pattern is transmitted to the mobile station via the antenna 1. In addition, the timing controller 8
is the control of the transmission power supplied from the specific pattern generator 6 and the random pattern generator 7 to the power amplifier 2 via the adder 5, and the radio frequency supplied from the encoder 4 to the power amplifier 2 via the modulator 3. It controls the signal and thereby controls the timing of the signal that is framed.

The radio frequency signal output as described above is transmitted from the antenna 1 while the transmission power fluctuates according to the combination pattern of the specific pattern output from the specific pattern generator 6 and the random pattern output from the random pattern generator 7. Fluctuations in the transmission power, which will be transmitted to the mobile station, will be further explained with reference to FIG. 2.

FIG. 2(a) shows an example of the structure of a signal to be transmitted. In the figure, B is a frame for broadcast information, and may include partially different information for each base station. pi (
i-1, 2, . . . ) represents incoming call information for the mobile station with number i. Pi and B are composed of a frame synchronization signal and an error correction code in which check bits are added to information bits.

The dotted arrow indicates that if a response to this incoming call information is not received by the base station within a certain period of time, the response is retransmitted. This retransmission control is performed by the upper station 27 shown in FIG. 7 mentioned above. Note that if at least one of B and Pl includes information indicating the order in the cycle of the group for intermittent reception, at the time when one signal containing that information is received,
Since the own time slot is known, intermittent reception operation is possible.

FIG. 2(b) shows an example of a variation pattern of the transmission power of each base station 1, 2.3. In this example, the waveform changes stepwise in signal frame units, but the waveform may change continuously. Further, in this example, the transmission timings between the respective base stations are the same, but there is no particular need to use inter-station synchronization, and in general, there may be some difference in the transmission timings.

FIG. 3 is a diagram illustrating the operation of this embodiment.

In the figure, 1 to 3 are base stations, 4 is an area where the ratio of the signal received power from the most strongly received base station to other signal power phases is small among signals from a plurality of base stations at a certain point in time, and 5 further indicates an area where the ratio of the signal received power from the most strongly received base station to the other signal power phases is small among the signals from multiple base stations at other times when the transmission power from each base station changes. ing.

In Figure 3, the radio wave propagation characteristics of land mobile communication are considered to be distance characteristics that are inversely proportional to the α power of distance and short-term average value fluctuations that follow a logarithmic occurrence distribution.
3, this is the area where the ratio of the signal received power from the most strongly received base station and other signal power phases is small at the time when the transmission power of only base station 1 is 10 dB higher, and the area 5 is the area where a certain amount of time has elapsed. This shows an area where the ratio of the signal received power from the base station that is most strongly received and the other signal power phases is small at the time when only base station 2 becomes 10 dB higher.

If there is no synchronization between base stations and the signal transmission timing from each base station is shifted by one bit or more, the signals from other base stations become interference waves, and the probability of receiving the signals depends on their level ratio. If this level ratio is small, the signal non-reception rate is large, making it difficult to transmit the incoming signal, and the shaded area 4 shown in FIG. 3 can be considered to indicate an area in which it is extremely difficult to transmit the incoming signal. If the mobile station moves and crosses the shaded area while incoming call control is performed, that is, before the incoming signal is retransmitted a predetermined number of times, it is easy to improve the reliability of incoming calls by retransmission. The area indicates the evaluation based on the average value for one interval, and is usually considered to be several tens of meters in size.It is the number of retransmissions possible within the allowable connection delay time, or the allowable number of retransmissions in terms of throughput. It cannot be expected that the mobile station will cross the shaded area within the required number of retransmissions. Therefore, in the conventional system where the transmission power is constant, the shaded area becomes a specific area where it is difficult to receive calls, or an insensitive area, and the service is not effective. This is a big problem.To avoid this, in the conventional method,
The system uses highly accurate inter-station synchronization and uses different transmission frequencies and time slots to avoid interference caused by delayed waves, and as mentioned above, this has resulted in drawbacks. In this embodiment, even if the mobile station under call termination control is not expected to shift, as the transmission power fluctuates from moment to moment, the call reception dead area will also move accordingly.
This reduces the probability that a call cannot be received because the ratio of desired waves to interference waves is small in a specific location due to the influence of shadowing caused by buildings, etc., and it is possible to ensure the quality of call reception control reliability in the entire service area.

In this case, the reliability of an average single signal transmission deteriorates depending on the location, so the number of retransmissions increases and the throughput decreases. If the incoming call response is not received by the base station within a certain period of time, the incoming signal is retransmitted, so if the maximum number of transmissions N is 8, the incomplete transmission rate of the incoming signal is P''= 0.0007, which is less than 0.1%, and the average number of transmissions is (1-P)/(1-P)=1.67
times, the throughput decrease is not even 1/2,
When the one-time transmission incomplete rate P is even smaller, there is almost no decrease (for example, in the case of po, i, the average number of transmissions is 1.1 times).

If a large drop in throughput due to unreliable signal transmission against interference cannot be tolerated, an effective method is to use different transmission frequencies depending on the base station. Furthermore, if the pattern for varying the transmission power is set so that the correlation between the variation patterns of each base station has a negative value, reliability can be greatly improved due to the above-mentioned incoming call dead area moving rapidly and retransmission.

The description of another embodiment of the present invention that effectively utilizes this is given in the fourth section.
As shown in the figure. Figure 4(a) shows the transmission patterns of each base station, with A and B depending on the base station.

Three types of transmission patterns are set. This transmission pattern is set by a two-step change of maximum transmission power, minute transmission power, or complete transmission off, and the timing is different for each type of A, B, and C. A card time is provided so that even if the transmission timings of the three types of base stations A, B, and C are shifted, the transmission time slots do not overlap. Further, some sections may be set as sections in which all patterns are transmitted, and since the combined power from the base station of each pattern can be known by receiving this section, it can be used for zone selection.

FIG. 4(b) shows the intermittent reception operation of a mobile station whose transmission pattern type is A among the grouped mobile stations. After selecting a zone, the intermittent reception mobile station operates to turn on reception in the transmission time slot for its own group and in the selected zone. In order to check the transition of zones, reception and reception level measurements of transmission time slots in other zones shown by dotted lines are performed periodically or when the reception level of the time slot being received falls below a certain value. Furthermore, other frequencies are searched in long cycles. A mobile station that does not require power saving, that is, a mobile station that does not perform intermittent reception, will receive the time slot with the lowest reception level even if it receives all the transmission time slots.
Alternatively, it is divided into two groups and operates to search for other frequencies in the time slot that is not in the own group.

FIG. 4(C) shows the signal format in section T of maximum transmission power. Time slots for incoming signals for mobile stations grouped within section T are determined,
A plurality of broadcast information B1 incoming signals P are included in the time slot. Furthermore, broadcast information B and incoming signal P are composed of a frame synchronization signal and an error correction code in which check pits are added to information bits. Unlike conventional multi-station sequential transmission, one transmission time slot includes multiple signal frames, and repeated signal transmission is treated as retransmission control. That is, - it is transmitted again only when the base station cannot receive a response within a certain period of time. Therefore,
The same incoming signal is not necessarily transmitted repeatedly in each transmission time slot.

FIG. 5 is an explanatory diagram of still another embodiment of the present invention, in which transmission frequencies and transmission time slots (i.e., types A, B, and C in FIG. 4<a>) are combined for each base station. An example of assignment is shown below. That is, in the figure, ft indicates that the frequency f1 is the transmission time slot of type A. In this example, r”L
m f 2. , f 3° f4 are used. In addition, in Figure 5 (1)), zones covering the same frequency are arranged adjacent to each other in the arrangement of transmission frequencies and time slots, thereby reducing the frequency at which it is necessary to switch frequencies as the mobile station moves. It is something that exists. Therefore, frequency searches need to be performed less frequently, and a decrease in the intermittent reception ON rate due to frequency searches can be reduced.

In each of the embodiments configured and operated as described above, if the frequency to be used is Nt waves and the type of transmission pattern, that is, the type of transmission time slot is Nt, the base station transmits in the same time slot and at the same frequency. The distance between them can be N fXN t. Therefore, by appropriately setting the type of transmission time slot Nt while increasing the distance between base stations where co-channel interference occurs, the number of channels used, that is, the number of channels that need to be searched during zone transition, can be reduced compared to the conventional method. For frequency transmission, N
What was previously required can be reduced to NC/Nt, and it is possible to reduce the deterioration of the intermittent reception rate and the inability to receive calls due to channel search. In addition, in the conventional multi-station sequential transmission,
In order to avoid co-channel interference, the same information is unconditionally repeated NC times and transmitted sequentially on one frequency, so the throughput will definitely drop to 1/NC or less, but in this example, in the worst case 1/Nt, and the decrease in throughput can be reduced depending on the setting of Nt.

As described above, this embodiment has a large degree of freedom in design, and can be set so as to realize the best system by considering the trade-off between throughput and the number of search channels.

Furthermore, regarding throughput, since it is treated as retransmission control instead of unconditionally repeating transmission Nt times, the number of types of transmission time slots, the average number of transmissions is (Nt+1>/2), assuming that each transmission time slot is transmitted once. Yes, and the drop in throughput is even smaller.Also, in the case of a mobile station that does not receive intermittent reception or a mobile station that receives intermittent reception but receives multiple time slots, the transmission frequency and time slot arrangement are particularly similar to that shown in Figure 5(b). In the configuration shown, signal transmission is successful in most cases with one transmission, so there is almost no reduction in throughput.

Furthermore, as shown in FIG. 4(C), one section T is composed of a plurality of signal frames, and the length of section T is set to be long enough to cause no problem in terms of connection delay. It is possible to reduce the rate of throughput reduction due to guard time, which needs to be set in anticipation of transmission timing shifts between base stations. Even if the transmission timing shift exceeds the guard time, the signals at different positions within section T, that is, at the end of the time slot, overlap when being retransmitted, so by retransmitting at other parts, Reliability can be ensured. In the example shown in Figure 4(b), each signal occupies the same position in each transmission time slot every fourth time, but it is also possible to create a signal configuration in which this position is sequentially shifted to different positions. Groups can avoid being unable to receive calls due to transmission timing shifts,
Furthermore, when retransmitting data across transmission time slots, it is always transmitted at a different position. Therefore, an increase in transmission timing deviation does not immediately cause a system failure, and there is no need to set a guard time larger than necessary to reduce throughput. If inter-station synchronization is provided within the economical range, the guard time can be further reduced, so a configuration including an inter-station synchronization device with a simple configuration is also conceivable. If the interval T is assumed to be about 0.5 to 1 second and the synchronization accuracy is several milliseconds or less, the drop in throughput due to the guard time can be almost ignored, so severe accuracy is not required. For example, the configuration may be such that each base station controls the transmission timing using a sufficiently accurate clock as a reference, and occasionally checks the clock for discrepancies.

Regarding signal transmission reliability, in the case of a mobile station that does not receive intermittent reception or a mobile station that receives multiple time slots, especially when the transmission frequency and time slot arrangement are as shown in FIG. 5(b), If the transmission fails in one transmission, retransmission is performed, so the same information is transmitted multiple times at the same frequency. At this time, since signals are received from multiple base stations, a site diversity effect is obtained, which is effective as a countermeasure against the influence of shadowing from buildings surrounding the mobile station, and improves transmission reliability. There are advantages.

Furthermore, as explained in FIG. 4(C), after selecting a zone, that is, after determining the nearest base station, the intermittent reception mobile station learns the type of transmission pattern of that one base station from broadcast information etc. Therefore, it is only necessary to turn on reception in the transmission time slot of that base station and the time slot of its own group.

Normally, in the case of No grouping, the intermittent reception on rate excluding the reception on time required for frequency search and startup is 17NQ, but in this embodiment, by taking advantage of sequential transmission, the intermittent reception on rate is 1/(NO・Nt). In this embodiment, there are 8 groups, but it is possible to divide them into 1/24.

In the embodiments described above, it is more effective if the transmission power is set according to information regarding the mobile station when changing the transmission power of the base station. For example, if a mobile station memorizes and manages the base station to which it connected most recently, or performs W11 registration for each incoming call control area, if there is enough channel space for location registration, it is possible to The wireless zone in which the mobile station is located can be predicted by performing location registration, etc., and the transmission power of the base station covering that wireless zone can be increased first, or By transmitting the incoming signal, the average number of transmissions can be reduced and throughput can be improved.

Moreover, it can be made even more effective by changing the transmission power according to the number of retransmissions. For example, if the base station does not receive a response even if it transmits an incoming signal multiple times with a constant transmit power, the mobile station that is the target of the call will receive the desired signal versus the interference signal at that constant transmit power. Since it is expected that the transmission power exists in an area where the ratio is small, it is effective to change the transmission power only at that time, that is, only when the number of retransmissions exceeds a certain value.

[Effects of the Invention] As explained above, according to the present invention, the transmission power from each base station can be adjusted randomly, in a predetermined pattern determined by the base station, or by adding a random pattern to a predetermined pattern. By assigning different combinations of multiple types of transmission power fluctuation patterns and multiple types of transmission frequencies to each base station, each base station uses this assigned transmission power fluctuation pattern. , or a combination pattern in which a random pattern is added to the fluctuation pattern to transmit information at the assigned transmission frequency while varying the transmission power, which eliminates the need for high-precision inter-station synchronization, resulting in high-speed signal transmission. It is easy to apply to
The system is easy to expand, and also has excellent reliability and power savings.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a transmission system of a base station used in a mobile communication control system according to an embodiment of the present invention;
The figure is a diagram for explaining the transmission power fluctuation used in the embodiment of FIG. 1, FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention, and FIG. 4 is a diagram for explaining another embodiment of the present invention. A diagram for explaining the operation of the example, FIG. 5 is a diagram for explaining still another embodiment of the present invention,
FIG. 6 is a diagram explaining the zone configuration of a mobile communication system;
FIG. 7 is a block diagram showing the configuration of a mobile communication system, and FIG. 8 is an explanatory diagram of an example of a transmission signal in a conventional multi-station sequential transmission system. 1... Antenna 2... Power amplifier 3... Modulator 4... Encoder 5... Adder 6... Specific pattern generator 7... Random pattern generator 8... Timing Controller agent Patent attorney Yasuo Miyoshi Figure 1 Figure 5 (a) Figure 5 (b)

Claims (2)

[Claims] (1) A mobile communication control method that transmits signals from multiple base stations to mobile stations to call a specific mobile station or transmit information in a small zone mobile communication system that covers a service area with multiple base stations. a transmission power varying means for varying communication power from each base station randomly, in a predetermined pattern determined by the base station, or in a combination pattern of a predetermined pattern plus a random pattern; 1. A mobile communication control system comprising: retransmission means for retransmitting information from a base station if a response from a mobile station to an information transmission from a mobile station is not returned to the base station within a predetermined time. (2) A mobile communication control method that transmits signals from multiple base stations to mobile stations to call a specific mobile station or transmit information in a mobile communication system with a small zone configuration that covers a service area with multiple base stations. an allocation means for allocating to each base station a different combination consisting of one each of a plurality of types of transmission power fluctuation patterns and a plurality of types of transmission frequencies allocated to a service area; The information is transmitted at the transmission frequency assigned to each base station while varying the transmission power from each base station using the transmission power variation pattern assigned to the base station or a combination pattern of adding a random pattern to the variation pattern. A mobile communication control comprising a transmitting means and a retransmitting means for retransmitting information from the base station if a response from a mobile station to the information transmission from the base station is not returned to the base station within a predetermined time cycle. method.