JP3246718B2 - Frequency Hopping Pattern Selection Method in Frequency Hopping Spread Spectrum Communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a frequency hopping pattern selection method in frequency hopping spread spectrum communication used in a wireless system such as a wireless LAN system.

[0002]

2. Description of the Related Art For example, a spread spectrum radio using the 2.4 GHz band includes a frequency hopping method and a direct spread method. In the direct spreading method, since a given frequency range is used at the same time, there is no channel separation. On the other hand, the frequency hopping method is a method in which, for example, in Japan, a frequency obtained by dividing a 26 MHz band in units of 1 MHz is used in a time division manner by 10 or more waves by a specific algorithm. Many kinds of frequency hopping patterns can be created by this algorithm. Therefore, one frequency hopping pattern is used in one wireless zone including one wireless master station and one or more wireless slave stations, and another frequency hopping pattern is used in other wireless zones. In this way, by using different frequency hopping patterns for each wireless zone, simultaneous communication can be performed in each wireless zone even if there is an overlapping portion between adjacent wireless zones.

[0003] Therefore, it is necessary to determine which frequency hopping pattern to use in each wireless zone. As a method of this determination, a method of transmitting frequency hopping pattern data from an upper server to a wireless master station of each wireless zone and determining one of the wireless master stations of each wireless zone.
There is a method in which a maintenance tool is connected to each table, and a frequency hopping pattern is transmitted from the maintenance tool to determine the frequency hopping pattern. In addition, since the radio base station in each radio zone starts the frequency hopping operation from that point when the frequency hopping pattern to be used is determined, the frequency hopping timing is asynchronous between the radio base stations.

[0004]

In a method of determining a frequency hopping pattern of each wireless master station using a server,
The server requires setting software for the wireless master station, and it is necessary to prepare the setting software for each server model. There is also a problem that management becomes complicated. Also,
In the method of determining the frequency hopping pattern using the maintenance tool, it is not necessary to use the setting software, but it is troublesome to go to the installation location of each wireless master station and connect and set the maintenance tool.
In particular, there has been a problem that when installed in a new place, it is very inconvenient due to inadequate power supply and the like.

If the frequency hopping operation is performed asynchronously, two or more wireless master stations may use the same frequency at some timing. For example, when the wireless zones using the hopping patterns f2, f6,... F8, f14 and the wireless zones using the hopping patterns f24, f4,. If hopping is performed, the same frequency is not used at the same time among the wireless master stations. However, when the hopping timing is shifted when asynchronous, each wireless master station uses the same frequency f6 when, for example, two hops are shifted. There are cases. In this case, if adjacent wireless zones overlap, simultaneous communication cannot be performed at this frequency, and the communication efficiency is reduced accordingly.

Therefore, according to the present invention, the frequency hopping pattern used by the wireless master station can be automatically selected without using a server or a maintenance tool.
In addition, the present invention provides a frequency hopping pattern selection method in frequency hopping spread spectrum communication that can prevent the use of the same frequency between adjacent wireless zones and improve communication efficiency.

[0007]

According to the first aspect of the present invention,
When a plurality of wireless zones are provided, each wireless zone includes one wireless master station and one or more wireless slave stations, and each wireless zone performs frequency hopping spread spectrum communication between the wireless master station and the wireless slave station. , N frequency hopping patterns are set in advance by assigning pattern numbers of 1 to n, and when starting operation, the wireless master station determines which frequency hopping pattern is used by the wireless master station in the surrounding wireless zone. To detect
When the wireless master station in the surrounding wireless zone does not use any frequency hopping pattern, the frequency hopping pattern having the pattern number 1 is selected from the set n frequency hopping patterns and the frequency hopping spread spectrum communication is started. If the number of frequency hopping patterns used by the wireless master stations in the surrounding wireless zones is less than n, the frequency of the next pattern number after the largest pattern number among the used frequency hopping pattern numbers When a hopping pattern is selected and frequency hopping spread spectrum communication is started, and the number of frequency hopping patterns used by the wireless master stations in the surrounding wireless zones is n or more, the least used and the least Select the frequency hopping pattern with the smaller pattern number and It is to initiate Tsu ping spread spectrum communications.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an arrangement relationship of the wireless zones Z1 to Z5, wherein the wireless zone Z1 is a wireless zone Z2, Z3.
, Z4 and partially overlap with each other. The wireless zone Z2 is adjacent to the wireless zones Z1 and Z3,
And they partially overlap. Also, the wireless zone Z3
Are adjacent to the radio zones Z1, Z2, Z4, Z5 and partially overlap. The wireless zone Z4 is adjacent to the wireless zones Z1, Z3, Z5 and partially overlaps.

FIG. 2 is a block diagram showing the configuration of the wireless LAN system, in which a server 2 is connected to a LAN (local area network) 1 and each wireless zone Z1 is connected.
, Z2, Z3,... Are connected. The wireless master station 31 in the wireless zone Z1 is composed of m wireless slave stations 41, 42,...
And frequency hopping spread spectrum communication. The wireless master station 32 in the wireless zone Z2 performs frequency hopping spread spectrum communication with p wireless slave stations 51, 52,... 5p arranged in the same zone. The wireless master station 33 in the wireless zone Z3 performs frequency hopping spread spectrum communication with q wireless slave stations 61, 62,... 6q arranged in the same zone.

The wireless master stations 31, 32, 33,... Of the wireless zones Z1, Z2, Z3,... Are respectively wireless slave stations 41, 42,... 4m, 51, 52,.
,... 6q and frequency hopping spread spectrum communication in the 2.4 GHz radio frequency band.
As shown in Table 1, the frequency f1 (= 2.471) obtained by dividing the 26 MHz width of Hz to 2.497 GHz into 1 MHz units.
GHZ), f2 (= 2.472GHZ), f3 (= 2.
473GHZ),..., F24 (= 2.494GHZ), f2
5 (= 2.495 GHz), f26 (= 2.496 GHz)
) Is used as the hopping frequency.

[0011]

[Table 1]

[0012] Of the 26 waves, 23 frequencies f2 to f24 are used and n frequency hopping patterns are set with pattern numbers 1 to n as shown in Table 2. n is 23 or less.

[0013]

[Table 2]

For example, for pattern number 1, HOP (hopping frequency) 1 is f2, HOP2 is f6,
.., The pattern is set with HOP22 being f8 and HOP23 being f14. The pattern number 2 is HO
P1 is f24, HOP2 is f4, ..., HOP22
Are set as f10 and the HOP 23 is set as f6. The feature of the algorithm of this pattern is that when two frequency hopping patterns are selected, the same frequency does not appear if there is synchronization, and if the frequency is asynchronous, the same frequency may appear but 1 Only 22 times and the other 22 times have different frequencies.

The wireless master stations 31, 32, 33,... Of the respective wireless zones Z 1, Z 2, Z 3,... Are set to perform a frequency hopping pattern selection control shown in FIG. are doing.

First, in S1, a control signal transmitted by each of the other wireless master stations at each hopping frequency is detected as a reception state at a specific frequency of f2 to f24. This is for detecting which frequency hopping pattern is being used if there is a master station already operating around.

Then, in S2, a timer for about 10 seconds is started. That is, the control signal is transmitted from the wireless master station to the .0 signal.
A radio wave periodically emitted within 4 seconds, including a master station number, a frequency hopping pattern number, a current hop number (hopping frequency number), and the like. Synchronizes frequency hopping. 0.4 seconds is the maximum time allowed to stay at one frequency specified by the Radio Law. Since one frequency hopping pattern is composed of 23 waves, 0.4 × 23 = 9.2 seconds. Therefore, all control signals transmitted by other wireless master stations can be detected by searching for 9.2 seconds or more. Become.

When the control signal is received, the frequency hopping pattern number of the received control signal is stored in the memory at S3. This control signal reception is repeated until the timer expires. If there is no frequency hopping pattern number received when the timer expires, frequency hopping pattern number 1 is selected in S4, and this selection is performed in S5. HOP of pattern number 1
Start frequency hopping from 1. Thus, the frequency hopping spread spectrum communication is started.

If there is a frequency hopping pattern number received when the timer expires, then it is checked whether all n frequency hopping pattern numbers are used, and if all n pattern hopping pattern numbers are used, If not, in S6, the frequency hopping pattern of the pattern number next to the largest pattern number among the received frequency hopping pattern numbers is selected. Then, in S7, the reception state is established at the frequency of HOP1 of the frequency hopping pattern of the largest pattern number.

In this state, when the control signal of the HOP1 of the frequency hopping pattern of the largest pattern number is received, in S5, the frequency hopping pattern number already selected (the pattern number next to the largest pattern number)
Hopping is started from HOP1 of and synchronization is established.
Thus, the frequency hopping spread spectrum communication is started.

When the timer expires, n
When it is detected that all of the frequency hopping pattern numbers are used, in S8, the frequency hopping pattern number that is the least used and the youngest among the frequency hopping pattern numbers, ie, the frequency of the smallest pattern number, Select a hopping pattern. Then, in S9, the selected frequency hopping pattern number HOP2
Is set to the receiving state.

In this state, when the control signal of HOP2 of the selected frequency hopping pattern number is received, in S5, the HO of the selected frequency hopping pattern number is received.
Frequency hopping is started from P1, and synchronization is shifted by one HOP in the same hopping pattern. Thus, the frequency hopping spread spectrum communication is started.

In such a configuration, when the power of the radio base station in a certain radio zone is turned on and the radio base stations in the surrounding radio zones are not operating at all, the control signal is transmitted while the timer expires. In this case, the wireless master station does not receive the frequency hopping pattern number 1
Hopping is started from HOP1 of and synchronization is established.
Thus, the wireless master station and each wireless slave station in a certain wireless zone start frequency hopping spread spectrum communication.

When the power of the radio base station in a certain radio zone is turned on and the radio base stations in the surrounding radio zones are operating, the radio base station operates while the timer expires. And stores the frequency hopping pattern number in the memory. And
At this time, if the stored frequency hopping pattern number is less than n, the frequency hopping pattern of the pattern number next to the largest pattern number among the received frequency hopping pattern numbers is selected. And
A standby state is established at the frequency of HOP1 of the frequency hopping pattern having the largest pattern number. When a corresponding control signal is received in this state, frequency hopping is started from HOP1 of the frequency hopping pattern number that has already been selected and synchronization is established. Thus, the wireless master station and each wireless slave station in a certain wireless zone start frequency hopping spread spectrum communication.

When the radio base station in a certain radio zone is turned on and the radio base stations in the surrounding radio zones are operating, the radio base station operates while the timer times out. And stores the frequency hopping pattern number in the memory. And
At this time, if the stored frequency hopping pattern numbers are n or more, it is determined that all the frequency hopping patterns are used, and among the frequency hopping pattern numbers, the frequency of the least used and the youngest pattern number is determined. Select a hopping pattern. Then, a standby state is established at the selected frequency hopping pattern number HOP2, and when a corresponding control signal is received in this state,
HOP1 of the selected frequency hopping pattern number
Start frequency hopping from and start synchronization. Thus, the wireless master station and each wireless slave station in a certain wireless zone start frequency hopping spread spectrum communication.

As described above, the wireless master station can automatically select a frequency hopping pattern to be used without using a server or a maintenance tool. In addition, the frequency hopping pattern selected in this way changes the frequency in synchronization with the frequency hopping pattern used by the wireless master station in the surrounding wireless zone, so that the frequency used in the surrounding wireless zone can be prevented from matching. Thus, simultaneous communication is always possible, and communication efficiency can be improved.

It is needless to say that the number and arrangement of the wireless zones are not limited to this embodiment.

[0028]

As described above in detail, according to the first aspect of the present invention, the frequency hopping pattern used by the wireless master station can be automatically selected without using a server or a maintenance tool. It is possible to provide a frequency hopping pattern selection method in frequency hopping spread spectrum communication that can prevent the use of the same frequency between wireless zones and improve communication efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement relationship of wireless zones according to an embodiment of the present invention.

FIG. 2 is an exemplary block diagram showing a configuration of a wireless LAN system used in the embodiment;

FIG. 3 is a flowchart showing frequency hopping pattern selection control of a wireless master station in each wireless zone according to the embodiment;

[Explanation of symbols]

 Z1 to Z5: wireless zone 31 to 33: wireless master station 41 to 4m, 51 to 5p, 61 to 6q: wireless slave station

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04J 13/00-13/06 H04B 1/69-1/713 H04B 7/24-7/26 H04Q 7 / 00-7/38 H04L 12/28

Claims (1)

(57) [Claims] 1. A wireless hopping spectrum comprising a plurality of wireless zones, each wireless zone having one wireless master station and one or more wireless slave stations, wherein each wireless zone has a frequency hopping spectrum between the wireless master station and the wireless slave station. When performing spread communication, n frequency hopping patterns are set in advance by assigning pattern numbers of 1 to n, and when starting operation, the wireless master station in the surrounding wireless zone determines which frequency hopping pattern If the wireless master station in the surrounding wireless zone does not use any frequency hopping pattern, a frequency hopping pattern having a pattern number of 1 is set from the set n frequency hopping patterns. Select to start frequency hopping spread spectrum communication and use less than n frequency hopping patterns used by wireless master stations in surrounding wireless zones. In this case, the frequency hopping pattern of the pattern number next to the largest one among the frequency hopping pattern numbers being used is selected and the frequency hopping spread spectrum communication is started, and the wireless master station in the surrounding wireless zone is started. When n or more frequency hopping patterns are used, the frequency hopping pattern of the least used and the smallest pattern number is selected to start frequency hopping spread spectrum communication. Frequency hopping pattern selection method in frequency hopping spread spectrum communication.