Base station device and method for assigning network identifier

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a base station apparatus and a network identifier assignment method used in a digital wireless communication system.

【0002】

[Conventional technology]

In a digital wireless communication system including a plurality of base station devices that perform wireless communication with at least one communication terminal device, a communication network is identified. The identification of this communication network is performed in the following cases, for example.

【0003】

(1) When checking whether the network can be connected after turning on the power of the communication terminal and before starting communication with the base station (AP) before authentication (during so-called association).

【0004】

(2) When collating the connected company or supported services at the time of handover.

【0005】

The communication network is identified by a network identifier (for example, network ID, hereinafter abbreviated as NET-ID). A few bits of BCCH (Broadcast Control CHannel) are used for this NET-ID. This NET-ID is assigned to each communication network so that the communication network can be identified.

【0006】

Generally, 4 bits of BCCH are used for NET-ID, which enables identification of 16 types of communication networks. In addition, this NET-ID is determined by random numbers when the communication network is installed.

【0007】

[Problems to be Solved by the Invention]

However, in Japan, the frequencies assigned as the 5 GHz band for wireless communication are four frequencies. When there are many adjacent private networks such as office buildings in the city center, or when there are multiple public networks with different service types, it is assumed that there are many different communication networks in a small frequency band in a specific area. ..

【0008】

Considering these situations, it is very difficult to identify a communication network using a 4-bit NET-ID. Therefore, with the conventional method, it may be difficult to identify the communication network when a large number of communication networks coexist.

【0009】

The present invention has been made in view of such a point, and an object of the present invention is to provide a base station apparatus capable of identifying a communication network and a method for assigning a network identifier even when a large number of communication networks coexist.

【0010】

[Means for solving problems]

The gist of the present invention is to investigate the NET-ID of a surrounding base station, assign the NET-ID of the own station based on the investigation result, and even when a large number of communication networks coexist, the NET-ID can be used. It is to prevent collision.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

The base station apparatus according to the first aspect of the present invention has a search means for investigating network identifiers of existing base stations having overlapping service areas of communication networks, and own stations for unused network identifiers based on the results of the investigation. A configuration is adopted in which an allocation means to be assigned as a network identifier of is provided.

【0012】

According to this configuration, even when a large number of communication networks coexist, network identifiers can be assigned so as not to collide with network identifiers of other communication networks.

【0013】

The base station apparatus according to the second aspect of the present invention is extended when there is no unused network identifier as a result of the investigation and the investigation means for investigating the network identifier of the existing base station where the service area of the communication network overlaps. A configuration is adopted in which an identifier is set and a setting means for expanding the number of bits assigned to the network identifier and an allocation means for assigning an unused network identifier as the network identifier of the own station are provided.

【0014】

According to this configuration, even when a large number of communication networks coexist, network identifiers can be assigned so as not to collide with network identifiers of other communication networks. In addition, the number of communication networks that can be installed can be expanded.

【0015】

The base station apparatus according to the third aspect of the present invention adopts the configuration having a table in which the communication network and the network identifier are associated with each other in the first or second aspect.

【0016】

The base station apparatus according to the fourth aspect of the present invention adopts a configuration in which the investigation means conducts an investigation based on the network identifier information sent from the existing base station in any one of the first to third aspects.

【0017】

The base station apparatus according to the fifth aspect of the present invention adopts a configuration including a scrambler that scrambles the network identifier in any one of the first to fourth aspects.

【0018】

According to this configuration, an offset value can be given to the network identifier to prevent collision of network identifiers, to support more communication networks, and to increase the number of communication networks that can be installed. ..

【0019】

The communication terminal device according to the sixth aspect of the present invention is characterized in that it performs wireless communication with the base station device according to any one of the first to fifth aspects.

【0020】

The communication terminal device according to the seventh aspect of the present invention includes a receiving means for receiving a signal including information in which a communication network and a network identifier are associated with each other, and a transmitting means for periodically transmitting the information to a communication partner. And, the configuration is adopted.

【0021】

According to this configuration, even when the service areas overlap but the control channel cannot be received between the base stations, the network identifier can be efficiently assigned.

【0022】

The network identifier allocation method according to the eighth aspect of the present invention includes a step of investigating a network identifier of an existing base station having overlapping service areas of a communication network, and a self-station of an unused network identifier based on the result of the investigation. It includes a step of assigning it as a network identifier of.

【0023】

According to this method, even when a large number of communication networks coexist, the NET-ID can be assigned so as not to collide with the NET-IDs of other communication networks.

【0024】

The network identifier allocation method according to the ninth aspect of the present invention is extended when there is no unused network identifier as a result of the step of investigating the network identifier of the existing base station where the service area of the communication network overlaps and the investigation. It includes a step of setting an identifier and expanding the number of bits assigned to the network identifier, and a step of assigning an unused network identifier as a network identifier of its own station.

【0025】

According to this method, even when a large number of communication networks coexist, a network identifier can be assigned so as not to collide with the network identifier of another communication network. In addition, the number of communication networks that can be installed can be expanded.

【0026】

The network identifier allocation method according to the tenth aspect of the present invention conducts a search based on the network identifier information sent from the existing base station in the eighth or ninth aspect.

【0027】

The network identifier allocation method according to the eleventh aspect of the present invention includes a step of scrambling the network identifier in any one of the eighth to large zero aspects.

【0028】

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of a base station apparatus according to the first embodiment of the present invention. Here, a base station apparatus in a TDMA type digital wireless communication system will be described. The network identifier is a 2-bit network ID. In addition, the communication network includes an in-house LAN, various wireless communication systems, and the like.

【0029】

The signal transmitted from the communication partner is received by the wireless receiver 102 via the antenna 101. The wireless receiver 102 performs amplification (gain control), down-conversion, and A / D conversion processing on the received signal. The signal after this A / D conversion is sent to the demodulation unit 103, demodulated, and obtained as received data.

【0030】

Further, the demodulated signal is sent to the network ID assigning unit 105. The network ID assigning unit 105 assigns the NET-ID of its own station based on the NET-ID of another base station included in the signal, and updates the network ID table 104. Since the contents of the updated network ID table 104 are transmitted, they are sent to the frame configuration unit 107.

【0031】

The transmission data is sent to the frame configuration unit 107, where the frame is configured and sent to the modulation unit 106. Further, the transmission data is modulated by the modulation unit 106 and then sent to the radio transmission unit 108. The radio transmission unit 108 performs D / A conversion, up-conversion, and amplification (gain control) processing on the modulated signal. Such processed signals are transmitted via the antenna 101 as transmission signals.

【0032】

Next, the operation of the base station apparatus having the above configuration, that is, the NET-ID allocation method will be described. Here, it is assumed that TDMA communication is performed by the signal in the frame format shown in FIG. The frame format shown in FIG. 2 consists of BCCH201, FCCH (Frame Control CHannel) 202, SBCH (Slow Broadcast control CHannel) 203, DL (Down Link) 204, UL (Up Link) 205, and RA (Random Access channel) 206. Has been done.

【0033】

In the NET-ID allocation method, when a new communication network is installed, the NET-ID of a surrounding base station is investigated, and then an appropriate NET-ID is determined based on the investigation result. At this time, the determined NET-ID is updated in the NET-ID table stored in the base station.

【0034】

Specifically, when a new communication network is installed, the newly established base station first issues a communication request to the existing base station. This request is made by sending the survey instruction signal by RA206 at the frame component 107 by the survey instruction signal. This investigation instruction signal is automatically or manually transmitted when the power is turned on when a new base station is installed.

【0035】

Then, in the existing base station that has received the signal transmitted via the RA206, that is, the base station whose service area overlaps with that of the newly installed base station, the base station number is notified by BCCH201. The newly installed base station receives a signal including this base station number, demodulates it with the demodulation unit 103, and recognizes the base station number.

【0036】

Next, the frame allocation information to have the TDMA time slot allocated to the recognized base station number is sent to the frame configuration unit 107, and the frame configuration unit 107 frame-configures this frame allocation information in FCCH202. The framed signal is transmitted to the existing base station.

【0037】

After that, the existing base station notifies the contents of its own NET-ID table by BCCH201. The new base station receives this signal and sends it to the network ID assigning unit 105. The network ID assigning unit 105 determines the NET-ID based on the contents of the received NET-ID table so that the NET-IDs do not collide, and sets the received NET-ID and the determined NET-ID in the network ID table 104. Update to.

【0038】

The updated contents of the network ID table are sent to the existing base station, and the existing base station updates the contents of the received network ID table to its own network ID table.

【0039】

In this way, the NET-ID can be assigned so as not to conflict with the NET-ID of other communication networks.

【0040】

Here, the NET-ID investigation may be performed manually in advance, and an unused NET-ID may be assigned based on the information. In this case, since the unused NET-ID is manually investigated, it is not necessary to provide a special mechanism for the NET-ID investigation, and the device can be simplified.

【0041】

In addition, NET-ID allocation (setting) may be performed manually based on the NET-ID survey results. In this case, a special mechanism for setting the NET-ID becomes unnecessary, and the device can be simplified. In this case, the NET-ID allocation (setting) may be automatic, that is, the base station may independently perform the assignment (setting), or may be manual in advance.

【0042】

In addition, the NET-ID survey may be conducted regularly for a certain period of time. This allows the NET-ID table to be updated on a regular basis and more effectively assigns unused NET-IDs without conflicts. There are no particular restrictions on the survey cycle.

【0043】

Further, the NET-ID acquired by the new base station from the existing base station may be acquired by the wired communication network or the wireless communication network. For example, when at least two base stations share a communication network and the base stations are connected by a wired communication network, the NET-ID is directly transmitted from the existing base station to the new base station by wired communication. It can be sent.

【0044】

Next, the above-mentioned network identifier allocation method will be described with reference to specific examples.

【0045】

(1) Company A installs a communication network for the company LAN (see Fig. 3). First, install AP # 1-1 and set NET-ID = 1. At this time, since this system is not used in the surroundings, any value can be set without any limitation.

【0046】

Next, install AP # 1-2 and set the NET-ID. At this time, since AP # 1-2 constructs a communication network in the same system, the same NET-ID (NET-ID = 1) as AP # 1-1 is used as the NET-ID. At this time, AP # 1-2 acquires NET-ID = 1 from AP # 1-1 by wire or wirelessly by the method described above.

【0047】

(2) Company B installs a network for the company LAN (see Fig. 4). In the state of (1), Company B further installs AP # 2-1 and sets NET-ID = 2. At this time, AP # 2-1 receives BCCH data from AP # 1-1, identifies the base station number, and then requests AP # 1-1 to transmit the contents of the NET-ID table. AP # 1-1 sends the contents of its own station's NET-ID table to AP # 2-1 in response to the request of AP # 2-1.

【0048】

As a result, AP # 2-1 can recognize from the contents of the received NET-ID table that the NET-ID other than NET-ID = 1 is unused. Then, AP # 2-1 sets NET-ID = 2 other than NET-ID = 1 as its own station's NET-ID, for example, NET-ID = 2, and its own station's NET-ID set in its own station's NET-ID table. Update your ID.

【0049】

Furthermore, AP # 2-1 sends the updated contents of the NET-ID table to AP # 1-1. AP # 1-1 updates the contents of the received NET-ID table to its own station's NET-ID table, and transmits the updated contents of the NET-ID table to AP # 1-2 by wire or wirelessly. AP # 1-2 updates the contents of the received NET-ID table to its own NET-ID table.

【0050】

(3) Company C installs a network for the company LAN (see Fig. 5). In the state of (2), Company C further installs AP # 3-1 and sets NET-ID = 3. At this time, AP # 3-1 receives BCCH data from AP # 2-1, identifies the base station number, and then requests AP # 2-1 to transmit the contents of the NET-ID table. AP # 2-1 sends the contents of its own station's NET-ID table to AP # 3-1 in response to the request of AP # 3-1.

【0051】

As a result, AP # 3-1 can recognize from the contents of the received NET-ID table that the NET-ID other than NET-ID = 1,2 is unused. Then, AP # 3-1 sets NET-ID = 1, for example, NET-ID = 3 other than NET-ID = 1,2 as the NET-ID of the own station, and also sets the NET-ID table of the own station. Update your NET-ID.

【0052】

Furthermore, AP # 3-1 sends the updated contents of the NET-ID table to AP # 2-1. AP # 2-1 updates the contents of the received NET-ID table to its own station's NET-ID table, and sends the updated contents of the NET-ID table as BCCH data to AP # 1-1.

【0053】

AP # 1-1 updates the contents of the received NET-ID table to its own station's NET-ID table, and transmits the updated contents of the NET-ID table to AP # 1-2 by wire or wirelessly. AP # 1-2 updates the contents of the received NET-ID table to its own NET-ID table.

【0054】

(Embodiment 2) In the present embodiment, a case where the contents of the NET-ID table is notified via a communication terminal such as a mobile station will be described. For example, it is assumed that base stations cannot receive BCCH. In such a situation, the same NET-ID may be used. Therefore, when a communication terminal exists between the two base stations, the NET-ID is assigned using this communication terminal.

【0055】

The configuration of the base station apparatus according to the second embodiment of the present invention is the same as that of the first embodiment (FIG. 1). FIG. 7 is a block diagram showing a configuration of a communication terminal device that performs wireless communication with the base station device according to the present embodiment.

【0056】

The signal transmitted from the communication partner is received by the wireless receiver 702 via the antenna 701. In the wireless receiver 702, each process of amplification (gain control), down-conversion, and A / D conversion is performed on the received signal. The signal after this A / D conversion is sent to the demodulation unit 703, demodulated, and obtained as received data.

【0057】

After being modulated by the modulation unit 704, the transmission data is sent to the frame configuration unit 705, where the frame is configured and sent to the radio transmission unit 706. The radio transmission unit 706 performs D / A conversion, up-conversion, and amplification (gain control) processing on the spread-modulated signal. Such processed signals are transmitted via the antenna 701 as transmission signals.

【0058】

Next, the operation of the base station apparatus having the above configuration, that is, the NET-ID allocation method will be described. Here, it is assumed that a communication terminal exists between the new base station and the existing base station when BCCH cannot be received, and the communication terminal constantly or periodically displays the contents of the NET-ID table. It is assumed that the including signal is transmitted to the base station of the communication partner.

【0059】

When a new communication network is installed, the new base station can receive a signal including the contents of the NET-ID table transmitted and received between the communication terminal and the existing base station. That is, the new base station identifies the base station number, recognizes the BCCH time slot of the existing base station, and receives a signal including the contents of the NET-ID table by the same operation as in the first embodiment.

【0060】

The new base station extracts the contents of the NET-ID table of the existing base station from the received signal and sends it to the network ID allocation unit 105. The network ID assigning unit 105 determines the NET-ID based on the contents of the received NET-ID table so that the NET-IDs do not collide, and sets the received NET-ID and the determined NET-ID in the network ID table 104. Update to.

【0061】

The updated contents of the network ID table are sent to the existing base station via the communication terminal as described above, and the existing base station updates the contents of the received NET-ID to its own NET-ID table. The contents of the NET-ID table updated by this new base station are acquired by the existing base station according to the above procedure, for example, from signals transmitted by other communication terminals communicating with the new base station at all times or periodically. And update to your own NET-ID table.

【0062】

Further, in the present embodiment, when a new communication network is installed, the NET-ID table of the own station is set for the existing base station via the communication terminal in which the new base station is communicating with the own station. You may make a request to notify the contents of. At this time, when the communication terminal receives the content notification request, the communication terminal sends a network ID investigation instruction signal to the frame configuration unit 705, and the frame configuration unit 705 incorporates the network ID investigation instruction signal into the transmission frame for the existing base station.

【0063】

The communication terminal transmits a signal including this network ID investigation instruction signal to the existing base station. The existing base station notifies the communication terminal of the contents of its own NET-ID table in response to the network ID investigation instruction signal included in the received signal.

【0064】

The communication terminal sends the contents of the NET-ID table of the existing base station to the frame configuration unit 705, and the frame configuration unit 705 incorporates the contents of the NET-ID table of the existing base station into the transmission frame for the new base station. Then, the communication terminal transmits a signal incorporating the contents of the NET-ID table to the new base station.

【0065】

The new base station extracts the contents of the NET-ID table of the existing base station from the received signal and sends it to the network ID allocation unit 105. The network ID assigning unit 105 determines the NET-ID based on the contents of the received NET-ID table so that the NET-IDs do not collide, and sets the received NET-ID and the determined NET-ID in the network ID table 104. Update to.

【0066】

The updated contents of the network ID table are sent to the existing base station via the communication terminal as described above, and the existing base station updates the contents of the received network ID table to its own network ID table.

【0067】

In this way, also in this embodiment, the NET-ID can be assigned so as not to collide with the NET-ID of another communication network. Further, in the present embodiment, even when the service areas overlap but BCCH cannot be received between the base stations, the NET-ID can be efficiently assigned.

【0068】

(Embodiment 3) In the present embodiment, a case where an extension code is used when a number of communication networks exceeding the number of bits of NET-ID coexist will be described.

【0069】

Since there is a limit to the number of bits allocated for NET-ID in BCCH (for example, 4 bits or less), when the number of communication networks is set to exceed the number of bits allocated to NET-ID in BCCH. SBCH is used for.

【0070】

This SBCH is a channel used to check whether the connection destination network is contracted and whether the service to be used is supported, and is a notification channel that does not transmit every frame but transmits in a long cycle. ..

【0071】

When using this SBCH, it is necessary to use a specific NET-ID as an extension identifier. For example, let NET-ID = 0 be the extended identifier.

【0072】

As a result of investigating the used NET-ID before installing the base station, if there is no unused NET-ID value, that is, if the number of bits assigned to the NET-ID is 2 bits, NET- If all of ID = 1 to 3 are used, the field of the NET-ID value is set to "0" to notify that it is an extended identifier.

【0073】

Then, in a state where all of NET-ID = 1 to 3 are used, the NET-ID of the newly installed base station is notified using SBCH. Therefore, when the contents of the NET-ID table are acquired and only the extended identifier remains, the extended identifier becomes a mark that "NET-ID is notified by SBCH". This makes it possible to extend the number of bits in the NET-ID. As a result, the number of communication networks that can be installed can be expanded. In the above method, the investigation and setting of the NET-ID are performed in the same manner as in the first and second embodiments except that different channels are used.

【0074】

In the present embodiment, a communication network using NET-ID in BCCH and a communication network using NET-ID in SBCH may be distinguished. For example, the communication network that notifies the NET-ID by BCCH is only the private communication network, and the NET-ID of the public communication network is notified by SBCH.

【0075】

This makes it possible to simplify the operation of devices used only for private communication networks. This has great cost merit and hardware scale merit. As a result, it can be applied to household appliances.

【0076】

In addition, the communication network that notifies the NET-ID by BCCH is limited to the public communication network, and the NET-ID of the private communication network is notified by SBCH.

【0077】

As a result, it is possible to secure a sufficient number of public communication networks capable of high-speed handover. For example, if the NET-ID is 4 bits, up to 15 types of public communication networks capable of high-speed handover can be allowed. This number is considered sufficient considering roaming between public telecommunications network operators.

【0078】

In the present embodiment, when there is a communication network that exceeds the number of bits allocated to BCCH, the NET-ID used in the surrounding communication network is monitored even after the base station is installed. Then, as a result of NET-ID monitoring, if an extended identifier (for example, NET-ID = 0) is used, NET-ID (for example, NET-ID = 1 to 3) having a value other than the extended identifier is used. Even in a communication network that uses one of the values), the extended identifier is used to notify the actual NET-ID using SBCH.

【0079】

That is, when the number of installed networks exceeds the number of bits allocated to BCCH, all communication networks use SBCH to notify the NET-ID using the extended identifier.

【0080】

A communication network that continues to use NET-ID = 1 to 3 that uses BCCH for notification (early installation time) is compared to a communication network that uses SBCH, which has a long cycle, for notification (late installation time). It is not fair because high-speed handover is possible. As described above, the fairness of the handover can be maintained by having the entire communication network use the extended identifier to notify the NET-ID using the SBCH.

【0081】

Next, the above-mentioned network identifier allocation method will be described with reference to specific examples.

【0082】

Company D sets up a network for the company LAN (see Fig. 6). In the state of (3) described in the first embodiment, when Company D further installs AP # 4-1 and sets the NET-ID, AP # 4-1 is the BCCH data from AP # 3-1. After receiving and identifying the base station number, request AP # 3-1 to send the contents of the NET-ID table. AP # 3-1 sends the contents of its own station's NET-ID table to AP # 4-1 in response to the request of AP # 4-1.

【0083】

As a result, AP # 4-1 can recognize from the contents of the received NET-ID table that all NET-ID = 1 to 3 are used and only NET-ID = 0 is unused. it can. Then, AP # 4-1 sets the extended identifier NET-ID = 0 as the NET-ID of its own station, and sets its own NOP-ID (Network Operator ID) in the SBCH to identify the communication network. Set the identifier. In addition, AP # 4-1 updates the NET-ID of the own station set in the NET-ID table of the own station.

【0084】

Furthermore, AP # 4-1 sends the updated contents of the NET-ID table to AP # 3-1. AP # 3-1 updates the contents of the received NET-ID table to its own NET-ID table. As a result of the update, it is found that the NET-ID extended identifier is used, so set NET-ID = 0 (extended identifier) in the NET-ID table of your own station. Furthermore, the company's identifier is set in the NOP-ID (Network Operator ID) in SBCH. Send the updated contents of the NET-ID table to AP # 2-1.

【0085】

AP # 2-1 updates the contents of the received NET-ID table to its own NET-ID table. As a result of the update, it is found that the NET-ID extended identifier is used, so set NET-ID = 0 (extended identifier) in the NET-ID table of your own station. Furthermore, the company's identifier is set in the NOP-ID (Network Operator ID) in SBCH. Send the updated contents of the NET-ID table to AP # 1-1.

【0086】

AP # 1-1 updates the contents of the received NET-ID table to its own NET-ID table. As a result of the update, it is found that the NET-ID extended identifier is used, so set NET-ID = 0 (extended identifier) in the NET-ID table of your own station. Furthermore, the company's identifier is set in the NOP-ID (Network Operator ID) in SBCH. Send the updated contents of the NET-ID table to AP # 1-2 by wire or wirelessly. AP # 1-2 updates the contents of the received NET-ID table to its own NET-ID table. As a result of the update, it is found that the NET-ID extended identifier is used, so set NET-ID = 0 (extended identifier) in the NET-ID table of your own station. Furthermore, the company's identifier is set in the NOP-ID (Network Operator ID) in SBCH.

【0087】

(Embodiment 4) In the present embodiment, a case where an offset value is given to the NET-ID to prevent NET-ID collisions and support more communication networks will be described. As a result, the number of communication networks that can be installed can be increased.

【0088】

FIG. 8 is a block diagram showing a schematic configuration of the base station apparatus according to the fourth embodiment of the present invention. In the base station apparatus shown in FIG. 8, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.

【0089】

The base station apparatus includes a scrambler 801 for scrambling the BCCH and a scramble release unit 802 for descrambling the scrambled BCCH. As shown in FIG. 9, the scrambler 801 includes an initial value setter 901 having an adder 9011 that adds an offset value to a frame counter value, and a shift register 902 having an adder 9021 and adders 9022, 9023. Has been done. Further, the scramble release unit 802 also has the same configuration as the scrambler shown in FIG.

【0090】

In this scrambler 801, the frame counter value (the first 4 bits of BCCH in FIG. 9) + α is used as the initial value. Therefore, in the scrambler shown in FIG. 9, when the frame counter value is input to the adder 9011 of the initial value setter 901, the offset value α is added to the shift register 902 (7 bits in FIG. 9). It is output.

【0091】

In this shift register 902, the bit string is randomized due to the presence of the adder 9022. Therefore, scrambling is applied by adding this randomized bit string to the frame counter value with the adder 9023. In this way, a predetermined bit of BCCH (bit for NET-ID) is scrambled. Also in the scramble release unit 802, the scramble is released by the same operation as described above.

【0092】

In this embodiment, MOD (frame counter value + α) may be used as the initial value of the scrambler. For example, in the case of 4 bits, MOD16 (α = 0 to 15). In this case, since there are 16 α and 16 NET-ID values, it is possible to identify up to 256 types of communication networks. In particular, since α has the same number of bits as the frame counter value, no special hardware addition in the scrambler is required.

【0093】

Further, in the scrambler, the number of communication networks that can be installed can be expanded to 257 or more by setting the initial value (frame counter + β: β is an arbitrary value of 16 or more).

【0094】

In the present embodiment, the frame counter value, which is the initial value of the scrambler, may be changed for each frame to improve the confidentiality of the system. For example, the change pattern is changed for each communication network, and the frame counter value is randomly selected for scrambling. Specifically, in the communication network 1, the frame counter value is increased for each frame as in the case of "1" "2" "3", and in the communication network 2, "1" "7" "6". The frame counter value is decreased for each frame as in, and in the communication network 3, the frame counter value is increased for each frame as in 135.

【0095】

The scrambler shown in FIG. 9 performs scrambling processing based on a fixed-length polynomial (sixth-order polynomial). By changing the degree of this polynomial for each system, more communication networks can be identified.

【0096】

Considering that it facilitates roaming and handover between different operators in public services, it is desirable that the degree of the polynomial used in the scrambler is the same between the communication networks. Therefore, it is conceivable to change the degree of the polynomial between the self-employed system and the public system. For example, a self-employed system uses a 6th-order polynomial, and a public system uses a 7th-order polynomial. As a result, the number of identifiable communication networks can be appropriately increased for each system.

【0097】

In the above-described first to fourth embodiments, the case where NET-ID is used as the network identifier is described, but the present invention can be applied to all cases where a communication network can be identified. Further, the case where BCCH and SBCH are used as the channel for notifying the NET-ID has been described, but in the present invention, any channel may be used as long as the NET-ID can be notified.

【0098】

In the above-described first to fourth embodiments, the case where the NET-ID has 2 bits is described, but the number of bits of the NET-ID is not limited. Further, in the above-described first to fourth embodiments, the case where the extension code is set to NET-ID = 0 is described, but the extension code may be set to another NET-ID.

【0099】

Further, in the above-described first to fourth embodiments, the case where the digital wireless communication system is the TDMA system is described, but the present invention also describes the case where the digital wireless communication system is the TDMA system, for example, the OFDM system or the CDMA system. Can be applied.

【0100】

The present invention is not limited to the above-described first to fourth embodiments, and various modifications can be made. For example, the above-described embodiments 1 to 4 can be implemented in appropriate combinations.

【0101】

[Effect of the invention]

As described above, the base station apparatus and network identifier allocation method of the present invention investigates the NET-IDs of peripheral base stations and assigns the NET-IDs of their own stations based on the investigation results, so that a large number of communications are performed. Even when networks coexist, it is possible to prevent NET-ID conflicts.

[Simple explanation of drawings]

[Figure 1]

A block diagram showing a schematic configuration of a base station apparatus according to a first embodiment of the present invention. [Figure 2]

Diagram showing the frame format used in wireless communication [Fig. 3]

Diagram to illustrate how to assign a NET-ID to a communication network [Fig. 4]

Diagram to illustrate how to assign a NET-ID to a communication network [Fig. 5]

Diagram to illustrate how to assign a NET-ID to a communication network [Fig. 6]

Diagram to illustrate how to assign a NET-ID to a communication network [Fig. 7]

A block diagram showing a schematic configuration of a communication terminal device that performs wireless communication with a base station device according to a second embodiment of the present invention. [Fig. 8]

A block diagram showing a schematic configuration of a base station apparatus according to a fourth embodiment of the present invention. [Fig. 9]

The block diagram which shows the structure of the scrambler in the base station apparatus which concerns on Embodiment 4 above. [Explanation of symbols]

101,701 antenna 102,702 Wireless receiver 103,703 Demodulator 104 Network ID table 105 Network ID Assignant 106,704 Modulator 107,705 Frame components 108,706 Wireless transmitter 801 scrambler 802 Scramble release part