KR20130118465A - Method for forwarding sync signal and reusing frequency in picocast based wireless communication system, and the picocast based wireless communication system - Google Patents

Abstract

The present invention relates to a PicoCast-based wireless communication system or an Internet telephone system, comprising a plurality of wireless communication bases using a single synchronization signal, and applying the concept of infinitely extending the service area based on PicoCast. In the PicoCast wireless communication system using the method of retransmitting synchronization between a plurality of wireless communication bases and reusing a limited frequency in the plurality of wireless communication bases, the first wireless communication base may be a method of retransmission and frequency reuse. Generating grade information, use frequency offset information, and general information for wireless communication based on the system time of the mobile terminal and transmitting the generated information on a synchronization signal; If the second wireless communication base receives the synchronization signal transmitted by the first wireless communication base and compares its own rating with that of the wireless communication base transmitting the synchronization signal, the second wireless communication base adjusts its system time to achieve synchronization. Acquiring the general information for wireless communication included in the synchronization signal, marking the frequency offset information of the first wireless communication base on the frequency band, and selecting an unmarked frequency offset from the frequency band. Setting to a frequency offset; Transmitting a synchronization signal by carrying the information on its own grade, frequency of use frequency offset, and general information necessary for wireless communication based on the time when the second wireless communication base is adjusted to the synchronization signal of the first wireless communication base; The third wireless communication base receives the synchronization signal transmitted from the first wireless communication base and the second wireless communication base, marks the frequency offset information of each wireless communication base in the frequency band, and then unmarks the frequency in the frequency band. Select the frequency offset and set it to its own frequency offset, and compare one's received signal with one's received signal by comparing the received signal strength of the synchronization signal and the class of the wireless communication base that sent the sync signal with its own. Adjusting a system time of the apparatus and acquiring general information included in the synchronization signal for wireless communication; Transmitting, by the third wireless communication base, a synchronization signal by carrying its own grade information, use frequency offset information, and general information necessary for wireless communication based on the time adjusted by the selected synchronization signal; And repeating the retransmission of the synchronization signal according to the classes of the plurality of wireless communication bases to form a single synchronous wireless communication service area by covering a wide area while reusing the limited use frequency.

Description

Method for forwarding SYNC signal and reusing frequency in PicoCast based wireless communication system, and the PicoCast based wireless communication system}

The present invention relates to a wireless communication system, and more particularly, to a picocast-based wireless communication system or an Internet telephone system.

PicoCast, short for Pico-cell Broadcast, is a one-to-one communication (Unicast), group communication (Multicast), broadcast, and secure communication functions among information devices in a pico cell space centered on users ranging from several tens of meters in radius. It is a wireless personal area network (WPAN) technology. This technology is released to the world market in various product forms, and with the development of these technologies and products, domestic and international standardization activities are actively performed. In December 2009, the TTA picocast standard was announced in Korea, and in May 2010, it was confirmed as the ISO / IEC 29157 standard.

Picocast is a technology that operates in the same frequency domain as the more well-known Bluetooth (IEEE 802.15.1) and ZigBee (802.15.4). Picocast 1.0, which is reflected in the current ISO / IEC standard, has a transmission rate of 1 Mbps through a 1 MHz bandwidth channel in a 2.4 GHz ISM band and a piconet of about 30 m. In picocast 2.0, a transmission rate of 4 Mbps is possible. In addition, it is possible to apply in the white space band, which is a surplus band of digital TV, which is attracting attention as an unlicensed frequency sharing band beyond the 2.4 GHz band.

The present invention provides a method for retransmitting synchronization between a plurality of PicoCast-based wireless communication bases, reusing a limited frequency in a plurality of wireless communication base systems, and also applies a PicoCast wireless communication to which the method is applied. To provide a system for that purpose.

In order to achieve the above object, it consists of a plurality of wireless communication base using a single synchronization signal, by applying the concept of infinitely extending the service area to retransmit synchronization between a plurality of PicoCast-based wireless communication base, Synchronous retransmission and frequency reuse method according to the present invention in the PicoCast wireless communication system applying the method of reusing the limited frequency in the wireless communication base, the first wireless communication base based on the system time of the class information and the use frequency offset information And generating general information for wireless communication and carrying it on a synchronization signal. If the second wireless communication base receives the synchronization signal transmitted by the first wireless communication base and compares its own rating with that of the wireless communication base transmitting the synchronization signal, the second wireless communication base adjusts its system time to achieve synchronization. Acquiring the general information for wireless communication included in the synchronization signal, marking the frequency offset information of the first wireless communication base on the frequency band, and selecting an unmarked frequency offset from the frequency band. Setting to a frequency offset; Transmitting a synchronization signal by carrying the information on its own grade, frequency of use frequency offset, and general information necessary for wireless communication based on the time when the second wireless communication base is adjusted to the synchronization signal of the first wireless communication base; The third wireless communication base receives the synchronization signal transmitted from the first wireless communication base and the second wireless communication base, marks the frequency offset information of each wireless communication base in the frequency band, and then unmarks the frequency in the frequency band. Select the frequency offset and set it to its own frequency offset, and compare one's received signal with one's received signal by comparing the received signal strength of the synchronization signal and the class of the wireless communication base that sent the sync signal with its own. Adjusting a system time of the apparatus and acquiring general information included in the synchronization signal for wireless communication; Transmitting, by the third wireless communication base, a synchronization signal by carrying its own grade information, use frequency offset information, and general information necessary for wireless communication based on the time adjusted by the selected synchronization signal; And repeating the retransmission of the synchronization signal according to the classes of the plurality of wireless communication bases to form a single synchronous wireless communication service area by covering a wide area while reusing the limited use frequency.

According to the present invention, it is possible to retransmit synchronization between a plurality of wireless communication bases in a PicoCast wireless communication system composed of a plurality of PicoCast-based wireless communication bases, and reuse a limited frequency in a plurality of wireless communication base systems. .

1 is a configuration diagram of a synchronous relay,
2 illustrates exemplary synchronization information of each AP in a synchronization relay;
3 shows an exemplary synchronization table of submaster 6 after a certain time,
4 shows an exemplary synchronization table of submaster 6 after a certain time after transmitting the synchronization signal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The configuration of the system according to the present invention consists of a plurality of wireless communication bases using a single synchronization signal, and applies a concept of infinitely extending the service area to retransmit synchronization between a plurality of PicoCast-based wireless communication bases, The PicoCast wireless communication system adopts a method of reusing a limited frequency in a wireless communication base system. The PicoCast wireless communication system is composed of a master base system that initially generates a synchronization signal and a server-master system that retransmits synchronization.

The control method of the system according to the present invention is as follows.

The first wireless communication base generates class information, use frequency offset information, and general information for wireless communication based on its system time, and loads it on a synchronization signal.

In the next step, when the second wireless communication base receives the synchronization signal transmitted by the first wireless communication base and compares its own rating with that of the wireless communication base transmitting the synchronization signal, the second wireless communication base receives its own system time. Adjust to synchronize, obtain various information for wireless communication included in the synchronization signal, and mark the frequency of use frequency offset information of the first wireless communication base in the frequency of use table, and unmarked frequency offset in the frequency of use table. Select and set it to your frequency offset.

In the next step, the second wireless communication base transmits the synchronization signal with its own class information, frequency offset information, and all the necessary information for wireless communication based on the time adjusted by the synchronization signal of the first wireless communication base. do.

In a next step, the third wireless communication base receives the synchronization signal transmitted from the first wireless communication base and the second wireless communication base, marks the use frequency offset information of each wireless communication base in the use frequency table, and then uses the use frequency table. Select a frequency offset that is not marked and set it as its own frequency offset, and compare the received intensity of the sync signal and the class of the wireless communication base that sent the sync signal with its class to synchronize one of the received sync signals. Select to adjust its own system time and obtain all the information for wireless communication included in the synchronization signal.

In the next step, the third wireless communication base transmits the synchronization signal by carrying its own grade information, frequency of use frequency offset information, and general information necessary for wireless communication based on the time adjusted by the selected synchronization signal.

The above steps are repeated according to the classes of the plurality of wireless communication bases to form a single synchronous wireless communication service area covering a wide area while reusing the limited use frequency.

The synchronization relay process will be described in more detail with reference to FIG. 1 as follows.

The Master AP (hereinafter referred to as Master) carries its sync information (id, freq.-offset, depth) on the sync signal and transmits it.

The master sends a sync signal but does not receive it (the first sync source). Instead, the SubMaster AP (hereinafter referred to as subMaster) transmits while receiving a sync signal (synchronous relay).

SubMaster receives a sync signal from another sync source (AP transmitting a sync signal), reads sync information, and stores sync information and RSSI values of the corresponding sync source in its sync information table. At this time, the key of the sync information table is FO (Freq offset).

SubMaster adjusts its own synchronization by selecting one sync source based on the information in the sync information table generated for a certain time, and then periodically adjusts its own synchronization with the sync signal of the selected sync source.

At this time, it sets its own sync information from the set sync information table information and the information of the sync source, and transmits synchronization.

In this case, the sync information includes a format of id = 0 ~ 255, FO (Freq.Offset) = 0 ~ 15, depth = 0 ~ 255, SSID (Sync Source ID) = 0 ~ 255, RFOL (Receive Freq.Offset List) The maximum number of FOs available is 16, and the number of submasters that can be installed in close proximity for frequency reuse is limited to 16.

FIG. 2 shows exemplary synchronization information of each AP during a synchronous relay. An AP operating before execution of a subMaster6 is assumed to be a master, a subMaster1, a subMaster2, a subMaster5, and a subMaster9, and a subMaster6 receives a sync signal from all operating APs. Receive.

After a certain time, the synchronization table of the sub master 6 is shown in FIG. 3.

SSID setting and sync adjustment: Select sync source from Sync information table (optional condition: RSSI, Depth)-> select subMaster5 with ID 5 as sync source and adjust self sync

FO setting: Select FO of Sync information table and FO which is not used in RFOLx-> lowest 5 times among unavailable (0,1,2,3,4) and available (5 ~ 15)

Detpth setting: Set to Depth + 1 when the SSID of the Sync information table matches

RFOL Settings: all values of the FO in the Sync Info table

Determined sync information: ID = 6, FO = 5, Depth = 2, SSID = 5, RFOL = 0,1,4,2,3 (in descending order of depth)

It sends the sync signal to the set FO by carrying the determined sync information.

When the subMaster 6 checks the sync information table after a predetermined time after transmitting the sync signal, its FO (= 5) is added to the RFOL as shown in FIG. 4.

The sync source is determined as follows.

Decision criteria are determined by (RSSI, Depth).

Specifically, the AP with the highest Depth (or RSSI in the case of duplicate) is selected among the IDs having the best RSSI and the IDs within the comparison range (approximately 5 dB).

In the current sync information table, the best APs and values for RSSI are ID = 2, RSSI = -46dB, ID, Depth, RSSI for RSSI comparison range (> -51dB), and 2/2 / -46, 5 / respectively. Since it is 1 / -48, the sync source selects subMaster5 with ID 5, and the sync depth is 2.

So far I looked at the center of the preferred embodiment for the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (2)

It consists of a plurality of wireless communication bases using a single synchronization signal, and applies the concept of infinitely extending its service area to retransmit synchronization between a plurality of PicoCast-based wireless communication bases, and reuses limited frequencies in the plurality of wireless communication bases. In the method of synchronous retransmission and frequency reuse in PicoCast wireless communication system applying
Generating, by the first wireless communication base, grade information, frequency of use frequency offset information, and general information for wireless communication based on its system time and loaded on a synchronization signal;
If the second wireless communication base receives the synchronization signal transmitted by the first wireless communication base and compares its own rating with that of the wireless communication base transmitting the synchronization signal, the second wireless communication base adjusts its system time to achieve synchronization. Acquiring the general information for wireless communication included in the synchronization signal, marking the frequency offset information of the first wireless communication base on the frequency band, and selecting an unmarked frequency offset from the frequency band. Setting to a frequency offset;
Transmitting a synchronization signal by carrying the information on its own grade, frequency of use frequency offset, and general information necessary for wireless communication based on the time when the second wireless communication base is adjusted to the synchronization signal of the first wireless communication base;
The third wireless communication base receives the synchronization signal transmitted from the first wireless communication base and the second wireless communication base, marks the frequency offset information of each wireless communication base in the frequency band, and then unmarks the frequency in the frequency band. Select the frequency offset and set it to its own frequency offset, and compare one's received signal with one's received signal by comparing the received signal strength of the synchronization signal and the class of the wireless communication base that sent the sync signal with its own. Adjusting a system time of the apparatus and acquiring general information included in the synchronization signal for wireless communication;
Transmitting, by the third wireless communication base, a synchronization signal by carrying its own grade information, use frequency offset information, and general information necessary for wireless communication based on the time adjusted by the selected synchronization signal; And
And repeating the retransmission of the synchronization signal according to the classes of the plurality of wireless communication bases to form a single synchronous wireless communication service area covering a large area while reusing the limited use frequency. Synchronous retransmission and frequency reuse in wireless communication systems. PicoCast wireless communication system to which the method of claim 1 is applied.

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