JP2984588B2 - Frequency hopping pattern setting method for wireless system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting a frequency hopping pattern in a wireless system in which a plurality of wireless zones in which a master station and a slave station perform wireless communication by the frequency hopping spread spectrum method are arranged.

[0002]

2. Description of the Related Art Conventionally, a frequency hopping pattern as disclosed in Japanese Patent Application Laid-Open No. Hei 7-162393 has been used as a frequency hopping pattern when wireless communication is performed by a frequency hopping spread spectrum method. For example, hopping patterns HP1 to HP7 are set as follows: HP1 = 1,3,9,27,19,26,16,17,20,29,25,13,8,24,10,3
0,28,22,4,12,5,15,14,11,2,6,18,23,7,21 HP2 = 19,26,16,17,20,29,25,13,8,24 , 10,30,28,22,
4,12,5,15,14,11,2,6,18,23,7,21,1,3,9,27 HP3 = 20,29,25,13,8,24,10,30,28 , 22,4,12,5,15,14,
11,2,6,18,23,7,21,1,3,9,27,19,26,16,17 HP4 = 8,24,10,30,28,22,4,12,5,15 , 14,11,2,6,18,2
3,7,21,1,3,9,27,19,26,16,17,20,29,25,13 HP5 = 28,22,4,12,5,15,14,11,2,6 , 18,23,7,21,1,3,
9,27,19,26,16,17,20,29,25,13,8,24,10,30 HP6 = 5,15,14,11,2,6,18,23,7,21,1 , 3,9,27,19,26,1
6,17,20,29,25,13,8,24,10,30,28,22,4,12 HP7 = 2,6,18,23,7,21,1,3,9,27,19 , 26,16,17,20,29,
25,13,8,24,10,30,28,22,4,12,5,15,14,11. As described above, conventionally, a plurality of communications can be simultaneously performed by shifting the phase of one frequency hopping pattern.

[0003]

In setting such a frequency hopping pattern, the condition is that each frequency hopping pattern changes simultaneously. However, when a plurality of wireless zones are arranged, and wireless communication is performed independently by frequency hopping spread spectrum in each wireless zone, it is extremely difficult to simultaneously switch frequency hopping patterns between the wireless zones,
A shift occurs in the switching timing of the frequency hopping pattern between the wireless zones.

For this reason, frequency hopping is performed between adjacent wireless zones at the same time and at the same frequency,
There is a possibility that the same frequency is used for a long period of time, and in such a case, in wireless communication within each wireless zone,
There has been a problem that the communication state deteriorates such as a long transmission waiting time and a collision of communication data. Therefore, the present invention provides a method for wireless communication within a wireless zone, since even if the same frequency is used at a certain time between wireless zones that interfere with each other, the frequencies are always different from each other due to frequency hopping. The present invention provides a frequency hopping pattern setting method for a wireless system that can immediately set a good state, secure good communication as a whole system, and improve frequency use efficiency.

[0005]

According to the first aspect of the present invention,
In a wireless system in which a number of wireless zones in which a master station and slave stations perform wireless communication using a frequency hopping spread spectrum method are arranged, a plurality of frequency hopping patterns are generated from a basic frequency hopping pattern in which all frequency hopping distances are different. From the shifted frequency bands of the plurality of frequency hopping patterns and the expanded frequency bands so that the used frequency bands of the plurality of frequency hopping patterns partially overlap,
When using the same frequency, select a frequency hopping pattern that will always be different when frequency hopping,
The assignment of this frequency hopping pattern to wireless zones that interfere with each other when using the same frequency.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of an arrangement of wireless zones. For example, zone 1 is located on the first floor of a supermarket or the like.
-6, zones 7-12 on the second floor, zone 1 is adjacent to zones 2, 3 on the first floor, zone 3 is adjacent to zones 1, 4, 5, and zone 5 is zone 3, 6 and on the second floor zone 7 is adjacent to zones 8 and 9;
Zone 9 is adjacent to Zones 7, 10, 11 and Zone 11
Is adjacent to zones 9 and 12. Each of the wireless zones 1
In each of Nos. 1 to 12, one master station and a plurality of slave stations are arranged, and wireless communication is performed between the master station and each slave station by a frequency hopping spread spectrum method.

When the same frequency is used for each of the radio zones 1 to 12, when the same frequency is used between two specific zones at a certain time in a zone that interferes with each other, frequency hopping is performed. Two specific zones are assigned a frequency hopping pattern that always results in different frequencies. For example, wireless zone 1 and wireless zone 3 are adjacent zones, and using the same frequency at the same time interfere with each other. As shown in FIG. 2, when the wireless zone 1 and the wireless zone 3 use the same frequency of CH17 at a certain time, they interfere with each other. However, since the wireless zone 1 is changed to CH23 and the wireless zone 3 is changed to CH15 by frequency hopping, they do not interfere with each other.

[0008] As shown in FIG. 3, among the frequency bands usable for wireless communication, frequency band B and frequency band C are used.
And assign to each wireless zone. The frequency band B and the frequency band C have some shared frequencies, thereby improving the frequency use efficiency.

Next, setting of a frequency hopping pattern will be described. Q is a prime number or a power of a prime number, α is a primitive element, n
0,1,2,3, ..., when the Q-2 integer, the frequency hopping pattern Y ₁ the basic _{(matrix), y n = mod (α} n, Q) Y 1 = {y 0, y _1, y _2, ..., it can be generated from the y _Q-2}. Where mod (x, y)
Is the remainder of x divided by y. This is a pattern in which all the frequencies hop to different hopping distances.

A _i (matrix) represents the amount by which the frequency is shifted at offset 1, and A _i = ia _i , a _i ,
a _i ,..., a _i }, a _i = i, and i is 0, 1, 2,.
.., Q−1, the Q frequency patterns of Y ₀ , Y ₁ , Y ₂ ,..., Y _Q−1 are obtained from the formula of Y _i = mod {(Y ₁ + A _i ), Q}. Generated. This frequency hopping pattern becomes a basic frequency hopping pattern.

B (matrix) is offset 2 and B = ｛b,
.., b}, b are positive integers and YU _i (matrix)
By changing i to 0, 1, 2,..., Q−1 using = Y _i + B, the Q frequency hopping patterns in the frequency band A in FIG. A frequency hopping pattern in this band is set as one group to be used.

Further, c is a positive integer (use frequency interval),
D (matrix) = {d, d, d,..., D} is offset 3
In represents the amount of shifting the frequency, the d is 0 or an integer, with the _{YV i = Y i × c-} D, used in the frequency band C in FIG. 3. Where y
was the maximum value of the y _Q-2 from _{y 0 imax, c-d ≦} b ≦
y _imax × cd. Under this condition, a part of the frequency band can be shared as in the frequency bands B and C in FIG. As a result, frequency use efficiency can be improved.
Then, from among the frequency hopping patterns of the frequency band B and the frequency hopping pattern of the frequency band C in FIG. 3, when the same frequency is used, the frequency hopping pattern is allocated so that the same frequency is not continuously used in the zones that interfere with each other.

As an example of allocating a frequency hopping pattern to a wireless zone, as shown in FIG. 1, a microwave oven ER is provided in a wireless zone 1, and interference from the microwave oven ER is provided in a wireless zone 1 and a wireless zone 2. It is assumed that a radio is present and the other radio zones are not affected by the microwave oven ER. FIG. 4 is an example of a graph showing the relationship between the peak value of the frequency spectrum of the microwave oven ER and the frequency. Also, 2.471 GHz to 2.497
GHz is a frequency band that can be used for a medium-speed wireless LAN.

As can be seen from the graph, the microwave oven ER operates at a frequency above the frequency band usable for a medium-speed wireless LAN.
When the frequency band B is used, the interference is small because the peak of the power of the spectrum emitted from the spectrum is small. That is, the wireless zone 1 and the wireless zone 2 affected by the microwave oven ER use the frequency band B. In the other wireless zones 3 to 12, the frequency band C is used.
As a result, even if the microwave oven ER exists in the wireless system, the communication state does not deteriorate so much.

Table 1 shows that Q = 11, α = 7, b = 14, c
= 2 and d = 1, the frequency hopping patterns used in the wireless zones 1 to 12 are shown. The frequency hopping pattern of each wireless zone shown in Table 1 is switched and operated asynchronously for each wireless zone.

[0016]

[Table 1]

The center frequency of CH1 is 2.472 GHz,
The center frequency of CH25 is 2.496 GHz, and f1,
The frequencies are switched in the order of f2, f3,..., f10, f1,. That is, the wireless zone 1 is CH17, CH2
3, CH21, CH18, CH19, CH15, CH2
The frequency is switched by repeating 0, CH22, CH25, and CH24. Thereby, between adjacent zones, that is,
Even if the same frequency is used at a certain time between the wireless zone 1, the wireless zone 2, and the wireless zone 3, the frequency always becomes different if frequency hopping is performed. Therefore, even if interference occurs, wireless communication in the wireless zone can be immediately brought into a good state, and good communication can be secured as a whole system.

Further, if c = 2 and the frequency interval to be used is 2C
By setting every H, wireless zone 3 to wireless zone 12
In this case, since the adjacent channel is not used, it is possible to eliminate the interference between zones due to the use of the adjacent channel. Further, since the frequency hopping pattern does not use the same frequency and adjacent channel continuously in all adjacent zones, it is possible to reduce interference between zones and to have good communication characteristics as a wireless system. it can.

[0019]

As described above, according to the first aspect of the present invention, even if the same frequency is used at a certain time between radio zones which interfere with each other when the same frequency is used, the two always differ from each other due to frequency hopping. Since the frequency is used, the wireless communication in the wireless zone can be immediately brought into a good state, good communication can be secured as a whole system, and the frequency use efficiency can be improved.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an example of frequency hopping between adjacent wireless zones in the embodiment.

FIG. 3 is a diagram showing a used frequency band in the embodiment.

FIG. 4 is a graph showing a relationship between a used frequency band and a peak value and a frequency of a frequency spectrum of a microwave in the embodiment.

[Explanation of symbols]

 ER ... Microwave

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 1/69-1/713 H04B 7/26 H04J 13/00-13/06 H04Q 7/00-7 / 38

Claims (1)

(57) [Claims] In a wireless system in which a plurality of wireless zones in which a master station and a slave station perform wireless communication by a frequency hopping spread spectrum method are arranged, a plurality of frequencies are determined from a basic frequency hopping pattern in which frequency hopping is performed at different frequency hopping distances. Generate a hopping pattern,
From the frequency band hopping pattern shifted from the frequency band used and the frequency band hopping pattern from the frequency band expanded so that the frequency band used partially overlaps, when the same frequency is used, frequency hopping always occurs A frequency hopping pattern setting method for a wireless system, comprising selecting a frequency hopping pattern that results in a different frequency, and assigning the frequency hopping pattern to wireless zones that interfere with each other when the same frequency is used.