JP2008245141A - Base station device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To flexibly adapt to a plurality of kinds of communication rates which a plurality of terminal devices request respectively. <P>SOLUTION: An allocation unit 22 multiplexes a plurality of narrow-band channels and a plurality of wide-band channels having wider bands than the narrow-band channels, and allocates a combination of a narrow-band channel and a wide-band channel or the narrow and channel to a terminal device. A communication unit 20 communicates with a terminal device to which the combination of the narrow-band channel and wide-band channel or the narrow-band channel is allocated. The allocation unit 22 generates respective wide-band channels with an OFDM signal, and each narrow-band channel has nearly the same bandwidth with a subchannel of the OFDM signal, a peak interval between adjacent narrow-band channels being an integral multiple of and more than twice as large as an peak interval between adjacent subchannels of the OFDM signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication technique, and more particularly to a base station apparatus that performs communication by assigning a communication channel.

  In recent years, the advancement of mobile communication has been desired against the background of the development of wireless communication technology, network technology, and information technology. Such mobile communication enables real-time information provision and is expected to greatly improve convenience. As a priority control method in such mobile communication, for example, a technique has been proposed in which an uplink communication line from a terminal device to a base station device is secured by reservation. A plurality of reserved channels are prepared in advance according to the required service quality, and a terminal device that intends to use the uplink communication line accesses the specified reserved channel based on the required quality of traffic, thereby obtaining the uplink communication line. Secure. Since the base station apparatus can directly recognize the priority based on the accessed reserved channel, the efficiency of scheduling can be improved (see, for example, Patent Document 1).

Another technique defines priorities in a mobile communication environment in order to realize reliable and high-speed communication (see, for example, Patent Document 2). Here, a wireless communication system is configured by a control station and a plurality of terminal devices. The wireless communication system sets a communication channel to a high frequency band, and sets a plurality of control channels according to priority to a low frequency band. Set. For example, before the terminal device transmits user information using a communication channel, the terminal device executes a bandwidth request to the control station using a predetermined control channel corresponding to the priority of the user information. Subsequently, the control station recognizes the priority of the user information that is the target of the bandwidth request based on the received signal on the predetermined control channel, and executes bandwidth allocation according to the priority. Through the above processing, scheduling of the uplink communication line and scheduling of the downlink communication line are performed.
Japanese Patent Laid-Open No. 8-1554097 JP 2006-352191 A

  It is desirable that the wireless communication system can flexibly cope with the case where the communication speed required from each terminal device is different. For example, as in the above technique, if a reserved channel is specified in advance or a control channel corresponding to a priority is specified, useless communication bandwidth is generated due to the presence of terminal devices of various communication speeds, It becomes difficult to change the communication speed. As a result, transmission efficiency is reduced and processing is complicated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication technique that can flexibly cope with a plurality of types of communication speeds required from each of a plurality of terminal devices. is there.

  In order to solve the above problems, a base station apparatus according to an aspect of the present invention frequency-division-multiplexes a plurality of narrowband channels and a plurality of wideband channels wider than the narrowband channel, An allocation unit that allocates a combination with a wideband channel or a narrowband channel to a terminal device, and a communication unit that executes communication with a terminal device that has allocated the combination of the narrowband channel and the wideband channel or the narrowband channel in the allocation unit . In the allocation unit, each wideband channel is formed by an OFDM signal, each narrowband channel has a bandwidth equivalent to a subchannel of the OFDM signal, and the peak interval between adjacent narrowband channels is the OFDM signal. Is an integer multiple of 2 or more of the peak interval of adjacent subchannels.

  According to this aspect, each wideband channel is formed by an OFDM signal, and each narrowband channel has a bandwidth equivalent to that of a subchannel of the OFDM signal, so that communication required from each of a plurality of terminal apparatuses is required. Even if there are a plurality of speeds, the communication speed can be easily switched.

  When a narrowband channel is assigned to execute communication with the terminal device, the communication unit includes data in the narrowband channel, and when a wideband channel is assigned to execute communication with the terminal device, While including data in the channel, information about the wideband channel to be used is included in the narrowband channel. In this case, even if a wideband channel is allocated, the narrowband channel is used while including information on the wideband channel to be used in the narrowband channel. Even if there are a plurality of types of communication speeds required from the above, it is possible to easily switch the communication speeds.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if there exist multiple types of communication speed requested | required from each of several terminal device, it can respond flexibly.

  Before describing the present invention in detail, an outline will be described. Embodiments described herein relate generally to a wireless communication system including a base station apparatus and a plurality of terminal apparatuses. Here, each of the plurality of terminal devices performs various types of data communication, and the bandwidth and priority required for the data communication are different from each other. On the other hand, in the conventional wireless communication systems, a plurality of control channels are provided while the control channels correspond to the priority of the user information, and the base station apparatus determines the target of the bandwidth request based on the received signal on each control channel. The priority of the user information is recognized, and band allocation according to the priority is executed. As a result, because there is a control channel that is associated with priorities in advance, even if the bandwidths of the entire wireless communication system are gathered together, there is a wasteful bandwidth and a wasteful channel, which reduces transmission efficiency. End up. In order to cope with this, the communication system according to the present embodiment executes the following processing.

  The base station apparatus broadcasts broadcast information to an area under the jurisdiction of the base station apparatus using a downlink communication line. The broadcast information includes information that may be useful for communication between the base station device and the terminal device, such as attributes of the base station device, channel information, and line status, and this is one of the control channels. It is prescribed. A terminal device existing in a service area which is a jurisdiction area of a base station device transmits a communication request using a random access channel, and notifies that it is in the area using a control channel or a communication channel. The in-zone information of the notified terminal device is recorded together with the ID of the terminal device in the in-zone area list on the network connected to the plurality of base station devices so as to be shared by the plurality of base station devices.

  Such location information is used when connecting a downlink communication line from the base station apparatus to the terminal apparatus. Note that the above-described communication request includes information on the necessary priority of communication and the necessary bandwidth. The necessary bandwidth depends on the transmission speed, communication reliability, and the like, and includes the entire indicated value converted into the frequency band in consideration of the occupation time. The base station apparatus prioritizes communication with high priority based on the necessary priority and necessary bandwidth from the terminal apparatus. Further, when the bandwidth is insufficient as a whole, the bandwidth is limited from a terminal device with a low priority. The channel information and bandwidth are notified from the base station apparatus to the terminal apparatus through the control channel, and communication is performed with the bandwidth set in the communication channel.

  For connection from the downlink communication line, the base station device calls a specific terminal device on the paging channel, which is one of the control channels, based on the network area list on the network, and randomly receives from the terminal device. A communication request on the access channel is made. The base station apparatus performs communication after notifying the communication channel and the bandwidth setting by the control channel. Here, an FDMA system, an OFDMA system, a TDMA system, a CDMA system, or the like is used for the random access channel, the control channel, the communication channel, and the paging channel.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a base station device 10, a first terminal device 12a, a second terminal device 12b, and a network 14 collectively referred to as a terminal device 12.

  The base station apparatus 10 has an interface with a wired network at one end and an interface with a wireless network at the other end. The base station apparatus 10 is connected to the network 14 via an interface with a wired network. The base station apparatus 10 is connected to the terminal apparatus 12 via an interface with a wireless network. Here, the base station apparatus 10 prescribes | regulates a bandwidth with respect to a radio | wireless network, and performs communication with the some terminal device 12 by dividing a bandwidth with respect to the some terminal device 12. FIG. . The bandwidth dividing method by the base station apparatus 10 and the procedure for establishing a wireless network between the terminal apparatus 12 and the base station apparatus 10 will be described later. In addition, after establishing the wireless network between the terminal device 12 and the base station device 10, a signal from the terminal device 12 is transmitted to the network 14 via the base station device 10, and the signal from the network 14 is transmitted to the base station It is transmitted to the terminal device 12 via the device 10.

  FIG. 2 shows the configuration of the base station apparatus 10. The base station device 10 includes a communication unit 20, an allocation unit 22, a storage unit 24, an IF unit 26, and a control unit 28.

  The communication unit 20 performs communication with a terminal device 12 (not shown) via a wireless network. Here, a process for establishing a wireless network with the terminal device 12 will be described. The communication unit 20 broadcasts broadcast information via a broadcast channel. That is, the communication unit 20 outputs broadcast information to an area under the jurisdiction of the base station apparatus 10 using a downlink communication line. The broadcast information is composed of information that is considered useful for communication between the base station apparatus 10 and the terminal apparatus 12, such as attributes of the base station apparatus 10, channel information, and line conditions. Also, the broadcast channel for placing broadcast information is defined as one of the control channels, and is defined as a channel for the downlink communication line. Note that this broadcast channel may be shared with other control channels, or may be provided alone, but here the latter is assumed to simplify the description. In order to simplify the description, it is assumed that the broadcast channel is frequency division multiplexed with a random access channel, a control channel, and a communication channel, which are other channels described later. The area where the terminal apparatus 12 capable of receiving the broadcast information is present is the jurisdiction area of the base station apparatus 10, that is, the service area.

  The communication unit 20 receives a communication start request including information on communication priority and necessary bandwidth from the terminal device 12 that has received the notified notification information via a random access channel. That is, the terminal device 12 existing in the service area transmits a communication start request using the random access channel. Moreover, you may notify that the terminal device 12 exists in this area with a control channel or a telephone call channel. The communication unit 20 records the terminal area 12 on the network 14 together with the terminal apparatus identification number so that the area information of the received terminal apparatus 12 can be shared among a plurality of base station apparatuses 10 (not shown). The area list may be stored in a server (not shown) connected to the network 14. This located area list is used when an incoming call to the terminal device 12 is output when an incoming call addressed to the terminal device 12 is received.

  Here, the random access channel is a channel on the uplink communication line defined for outputting a communication start request from the terminal device 12 toward the base station device 10, and is shared by the plurality of terminal devices 12. In the random access channel, traffic is not controlled between the plurality of terminal devices 12, so that collision occurs when requests for communication start from the plurality of terminal devices 12 are transmitted at the same timing. However, it is assumed that the terminal device 12 includes a collision avoidance measure such as outputting a re-request after waiting for a random time. Further, as described above, when the terminal device 12 transmits a communication start request, the communication start request includes the necessary priority of communication and the necessary bandwidth as information. Here, the required bandwidth information is determined depending on the transmission speed, communication reliability, and the like, but includes an indication value of the information amount obtained by integrating the bandwidth and occupation time, and an overall indication value converted into a frequency band. . The communication unit 20 stores information on the received communication priority and necessary bandwidth in the storage unit 24.

  FIG. 3 shows information related to the terminal device stored in the storage unit 24. As shown, a terminal device name column 200, a priority column 202, a required bandwidth column 204, and an allocated bandwidth column 206 are included. In the terminal device name column 200, the terminal device 12 that has transmitted a communication start request to the base station device 10 is shown. The priority column 202 and the required bandwidth column 204 include information on the priority and required bandwidth included in the communication start request from the terminal device 12 indicated in the terminal device name column 200. Note that the priority order included in the priority order column 202 may be a value reassigned by the assignment unit 22 described later based on the priority order included in the communication start request. The allocated bandwidth column 206 will be described later. Returning to FIG.

  The allocating unit 22 compares the priority included in the communication start request received in the communication unit 20 with the priority of another terminal device 12 that is already performing communication with reference to the storage unit 24. Thus, the bandwidth to be allocated to the terminal device 12 is determined while dividing the bandwidth of the communication channel according to the required bandwidth. That is, the allocating unit 22 combines the necessary priority from the new terminal device 12, the necessary bandwidth, and the necessary priority and the necessary bandwidth in each of the plurality of terminal devices 12 already communicating, Communication is preferentially established from a high terminal device 12. For example, the allocation unit 22 allocates necessary bandwidths in order from the terminal device 12 with the highest priority, and ends the allocation when there is no bandwidth that can be allocated. Therefore, when the bandwidth is insufficient as a whole, the bandwidth is limited from the lowest priority. As a result, the terminal device 12 with a low priority is disconnected, the communication speed is reduced, or the communication quality is lowered.

  FIGS. 4A to 4B show the configuration of channels to be allocated by the base station apparatus 10. FIG. 4A shows a spectrum when communication channels are assigned to the first terminal apparatus 12a and the second terminal apparatus 12b. For simplification of the figure, one communication channel of the downlink communication line and the uplink communication line is shown here, but the other communication channel is defined by time division duplex or frequency division duplex. Also good. A broadcast channel, a random access channel, a control channel, and a paging channel are arranged on the low frequency side, and a communication channel is arranged on the high frequency side. Further, the communication channel is divided into two according to the priority and required bandwidth in the two terminal devices 12. Here, it is assumed that the sum of the required bandwidths in the two terminal devices 12 is smaller than the bandwidth of the communication channel.

  FIG. 4B shows a spectrum when the third terminal apparatus 12c is newly added to the state of FIG. Since the low frequency side is the same as that in FIG. 4A, the description is omitted here. As shown in the priority column 202 of FIG. 3, the priority order of the third terminal device 12c is higher than the priority order of the second terminal device 12b. Therefore, the allocating unit 22 allocates bandwidth to the third terminal device 12c preferentially over the second terminal device 12b. As a result, as shown in FIG. 4B, the necessary bandwidth of the third terminal apparatus 12c is allocated, and the second terminal apparatus 12b is allocated to the rest. Compared to FIG. 4A, the bandwidth allocated to the second terminal apparatus 12b becomes narrower. The allocated bandwidth is shown in the allocated bandwidth column 206 in FIG. Returning to FIG.

  The communication unit 20 notifies the terminal device 12 of the bandwidth determined by the allocating unit 22 via the control channel. That is, the allocated channel information and bandwidth are notified to the terminal device 12 through the control channel. At that time, information about the frequency and time that can identify the allocated band is shown. The communication unit 20 performs communication with the terminal device 12 in the communication channel with the notified bandwidth. At that time, the IF unit 26 outputs a signal from the communication unit 20 to the network 14 and outputs a signal from the network 14 to the communication unit 20. When the communication is completed, control information added to each communication channel is notified to the communication unit 20, and the allocating unit 22 releases the used communication channel and bandwidth based on the information.

  On the other hand, when the IF unit 26 receives an incoming call addressed to the terminal device 12 from the network 14, the allocation unit 22 refers to the area list on the network 14 via the IF unit 26. The in-zone area list is configured in the same manner as in FIG. The communication unit 20 calls the terminal device 12 through a paging channel that is one of the control channels. Thereafter, the communication unit 20 receives a request to start communication on the random access channel from the corresponding terminal device 12. Since the subsequent processing is the same as before, description thereof is omitted here. When the terminal apparatus 12 moves across a plurality of service areas, the terminal apparatus 12 performs a handover process between the plurality of base station apparatuses 10. The terminal device 12 measures the CINR (carrier-to-interference and noise ratio) of the received signal, and compares it with the CINR of the signal from the adjacent handover destination base station device 10. When the latter CNIR becomes better with a certain level difference, the terminal device 12 connects to the handover destination base station device. At that time, a communication start request is output via the random access channel. Further, the control unit 28 controls the operation of the base station device 10.

  In addition, although illustration is abbreviate | omitted, the terminal device 12 performs the process corresponding to the operation | movement demonstrated above. The communication unit of the terminal device 12 receives broadcast information from the base station device 10 through the broadcast channel. A communication part outputs the request | requirement of a communication start containing the information regarding the priority and required bandwidth of a communication via the random access channel with respect to the base station apparatus 10 which transmitted the alerting | reporting information received. In addition, the communication unit receives the determined bandwidth and the determined communication channel from the base station device 10 via the control channel. The communication unit executes communication with the base station apparatus 10 in the communication channel with a bandwidth.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The operation of the communication system 100 configured as above will be described. FIG. 5 is a sequence diagram illustrating a communication procedure when connection is made from a terminal device in the communication system 100. The base station apparatus 10 broadcasts broadcast information through a broadcast channel (S10). The first terminal apparatus 12a transmits a communication start request to the base station apparatus 10 through a random access channel (S12). After allocating a channel to the first terminal apparatus 12a, the base station apparatus 10 transmits the result as an allocation notification on the control channel (S14). Thereafter, the first terminal apparatus 12a and the base station apparatus 10 perform communication through a communication channel (S16).

  FIG. 6 is a sequence diagram showing a communication procedure when connection is made from the base station apparatus 10 in the communication system 100. The base station apparatus 10 transmits a call on the paging channel (S30). The first terminal apparatus 12a transmits a communication start request to the base station apparatus 10 through a random access channel (S32). After allocating a channel to the first terminal apparatus 12a, the base station apparatus 10 transmits the result as an allocation notification on the control channel (S34). Thereafter, the first terminal apparatus 12a and the base station apparatus 10 perform communication through a communication channel (S36).

  FIG. 7 is a flowchart showing a communication channel assignment procedure in the base station apparatus 10. The communication unit 20 receives a request to start communication (S50). The allocation unit 22 extracts the priority and the necessary bandwidth from the received communication start request (S52). The allocating unit 22 selects the terminal device 12 having the highest priority while referring to the priorities and necessary bandwidths of the other terminal devices 12 stored in the storage unit 24 (S54). If the necessary bandwidth cannot be allocated (N in S56), the allocation unit 22 allocates as much as possible (S58). On the other hand, if the necessary bandwidth can be allocated (Y in S56), the allocation unit 22 allocates the necessary bandwidth to the terminal device 12 (S60). If the terminal device 12 to be allocated remains, that is, if the allocation has not ended (N in S62), the priority order of the terminal device 12 to be allocated is lowered (S64), and the process returns to step 56. On the other hand, if the assignment is completed (Y in S62) or after the end of step 58, the assignment unit 22 assigns a communication channel to the terminal device 12 (Y in S66), the communication unit 20 determines the assigned communication channel. The terminal device 12 is notified (S68). When the communication channel is not assigned to the terminal device 12 (N in S66), the communication unit 20 notifies the terminal device 12 of assignment refusal (S70).

  Next, a modified example of the present invention will be described. The modification of this invention is related with the radio | wireless communications system comprised by a base station apparatus and a some terminal device similarly to an Example. On the other hand, in the conventional wireless communication systems, as described above, there are useless bandwidths and useless channels, so that transmission efficiency is lowered. In addition, when multiple types of communication speeds are specified and the range of communication speeds is equivalent to that of reserved channels in low-speed transmission, the communication speed cannot be increased without complicating the communication connection process. The overhead for increases. In order to cope with this, the communication system according to the present embodiment executes the following processing.

  The base station apparatus broadcasts broadcast information to an area under the jurisdiction of the base station apparatus using a downlink communication line. The broadcast information includes information that may be useful for communication between the base station device and the terminal device, such as attributes of the base station device, channel information, and line status, and this is one of the control channels. It is prescribed. A terminal device existing in a service area which is a jurisdiction area of a base station device transmits a communication request using a random access channel, and notifies that it is in the area using a control channel or a communication channel. The in-zone information of the notified terminal device is recorded together with the ID of the terminal device in the in-zone area list on the network connected to the plurality of base station devices so as to be shared by the plurality of base station devices.

  Such location information is used when connecting a downlink communication line to the terminal device. Note that the above-described communication request includes information on the necessary priority of communication and the necessary bandwidth. The necessary bandwidth depends on the transmission speed, communication reliability, and the like, and includes the entire indicated value converted into the frequency band in consideration of the occupation time. When the required bandwidth is equal to or less than that of the broadcast channel and the control channel, the base station apparatus allocates a narrowband channel provided along with the broadcast channel, the control channel, and the paging channel to the terminal apparatus. When the necessary bandwidth is wider than the narrowband channel, the base station apparatus allocates a wideband channel, which is separately defined from the narrowband channel, to the terminal apparatus. At this time, information on the wideband channel is arranged in the narrowband channel.

  The communication system 100 according to the modification is the same type as that in FIG. 1, and the base station apparatus 10 according to the modification is the same type as that in FIG. Here, the description will focus on the case of the embodiment. The allocation unit 22 allocates a communication channel to at least one terminal device in response to the communication start request received by the communication unit 20. Here, a narrowband channel and a wideband channel that is wider than the narrowband channel are defined as communication channels. FIG. 8 shows a channel configuration according to a modification of the present invention. As in FIGS. 4 (a)-(b), a broadcast channel, a random access channel, a control channel, and a paging channel are arranged on the low frequency side. A first narrowband channel, a second narrowband channel, and an Nth narrowband channel (hereinafter collectively referred to as “narrowband channel”) are arranged. Further, a first wideband channel, a second wideband channel, and an Mth wideband channel (hereinafter collectively referred to as “broadband channel”) are arranged on the high frequency side.

  The assigning unit 22 assigns communication channels to the terminal device 12 while comparing priorities in the same manner as in the embodiment. The narrowband channel and the wideband channel of the communication channels are assigned as follows. In order to clarify the explanation, it is assumed here that the communication channel is free enough to allocate the necessary bandwidth. When the required bandwidth is equal to or less than the threshold value, the allocating unit 22 allocates a narrowband channel provided alongside the control channel for voice communication or the like. Note that the threshold is set to the bandwidth of the broadcast channel and the control channel. In addition, the allocating unit 22 executes a known end process while using the narrowband channel even after a call.

  On the other hand, when the necessary bandwidth is larger than the threshold value, the allocating unit 22 includes the channel information of the wideband channel in the narrowband channel. The terminal device 12 can establish communication in the narrowband channel or a new communication process in the wideband channel by confirming the information of the narrowband channel. That is, the assigning unit 22 always assigns a narrowband channel first when assigning a communication channel to the terminal device 12. Further, when a wideband channel is allocated to the terminal device 12, the allocated wideband channel is notified to the terminal device 12 by including information on the allocated wideband channel in the already allocated narrowband channel. Further, the allocating unit 22 uses the notified broadband channel for communication with the terminal device 12. As a result, when communication using the wideband channel is performed with the terminal device 12, the allocating unit 22 uses the narrowband channel in which the control signal is arranged and the wideband channel in which the data signal is arranged. On the other hand, when communication using a narrowband channel is executed with the terminal device 12, the allocation unit 22 uses a narrowband channel in which a control signal, voice data, and the like are arranged.

  FIGS. 9 (a)-(b) show the format of signals arranged in the narrowband channel. FIG. 9A shows a format when only a narrowband channel is used. Preamble, audio data, and narrowband channel information are periodically arranged. Here, the preamble is a known signal, audio data is an example of data to be communicated, and narrowband channel information is control information. FIG. 9 (b) shows a format when a broadband channel is also used. A preamble, a broadband channel number, a priority, and broadband channel information are periodically arranged. The wideband channel number corresponds to an identification number for specifying the wideband channel assigned by the assigning unit 22, for example, the second wideband channel in FIG. Return to the description of the configuration.

  The communication unit 20 executes communication with the terminal device 12 to which the communication unit is assigned by the assignment unit 22. As described above, when a narrowband channel is assigned to perform communication with the terminal device 12, the communication unit 20 includes data in the narrowband channel and performs broadband communication to execute communication with the terminal device 12. Is assigned, the communication unit 20 includes information on the wideband channel to be used in the narrowband channel while including the data signal in the wideband channel.

  The operation of the communication system 100 configured as above will be described. FIG. 10 is a flowchart showing a communication procedure in the base station apparatus 10 according to the modification of the present invention. When the allocation unit 22 allocates a wideband channel (Y in S80), the communication unit 20 notifies information on the allocated narrowband channel through the control channel (S82). Further, the communication unit 20 notifies information on the allocated wideband channel in the narrowband channel (S84), and performs communication in the wideband channel (S86). When the allocating unit 22 does not allocate the wideband channel (N in S80), that is, when the narrowband channel is allocated, the communication unit 20 notifies the information on the allocated narrowband channel through the control channel (S88). Further, the communication unit 20 performs communication in the narrow band channel (S90).

  Next, another modification of the present invention will be described. Another modified example of the present invention also relates to a wireless communication system including a base station device and a plurality of terminal devices, as in the embodiment. On the other hand, in the conventional wireless communication systems, as described above, there are useless bandwidths and useless channels, so that transmission efficiency is lowered. In addition, when multiple types of communication speeds are specified and the range of communication speeds is equivalent to that of reserved channels in low-speed transmission, the communication speed cannot be increased without complicating the communication connection process. The overhead for increases. In a wireless communication system, when narrowband signals such as broadcast channels, control channels, narrowband channels, etc. are arranged on the frequency axis, an independent demodulation period is required to demodulate each channel, and In addition, it is necessary to perform demodulation of a wideband channel at high speed, which complicates the circuit configuration. In order to cope with this, the communication system according to the present embodiment executes the following processing.

  The base station apparatus broadcasts broadcast information to an area under the jurisdiction of the base station apparatus using a downlink communication line. The broadcast information includes information that may be useful for communication between the base station device and the terminal device, such as attributes of the base station device, channel information, and line status, and this is one of the control channels. It is prescribed. A terminal device existing in a service area which is a jurisdiction area of a base station device transmits a communication request using a random access channel, and notifies that it is in the area using a control channel or a communication channel. The in-zone information of the notified terminal device is recorded together with the ID of the terminal device in the in-zone area list on the network connected to the plurality of base station devices so as to be shared by the plurality of base station devices.

  Such location information is used when connecting a downlink communication line to the terminal device. Note that the above-described communication request includes information on the necessary priority of communication and the necessary bandwidth. The necessary bandwidth depends on the transmission speed, communication reliability, and the like, and includes the entire indicated value converted into the frequency band in consideration of the occupation time. When the required bandwidth is equal to or less than that of the broadcast channel and the control channel, the base station apparatus allocates a narrowband channel provided along with the broadcast channel, the control channel, and the paging channel to the terminal apparatus. When the necessary bandwidth is wider than the narrowband channel, the base station apparatus allocates a wideband channel, which is separately defined from the narrowband channel, to the terminal apparatus. At this time, information on the wideband channel is arranged in the narrowband channel. Here, the wideband channel is defined by an OFDM signal having a plurality of subcarriers, and the broadcast channel, the control channel, and the narrowband channel are integers of 2 or more of the frequency intervals of the subcarriers of the OFDM signal of the wideband channel. It is arranged twice.

  A communication system 100 according to another modification is the same type as that in FIG. 1, and a base station apparatus 10 according to another modification is the same type as that in FIG. 2. Here, the description will focus on the case of the embodiment and the modification. Similar to the modified example, the allocating unit 22 specifies that a plurality of narrowband channels and a plurality of wideband channels that are wider than the narrowband channels are frequency-division multiplexed. Here, each wideband channel is formed by an OFDM signal, that is, by a plurality of subcarriers. Here, for convenience, a narrow-band channel corresponding to a subcarrier is referred to as a “subchannel”. Each narrowband channel has a bandwidth equivalent to the subchannel of the OFDM signal. Furthermore, the peak interval of adjacent narrowband channels is defined to be an integer multiple of 2 or more of the peak interval of adjacent subchannels in the OFDM signal. That is, the narrowband channel is defined not to use adjacent subchannels in the OFDM signal. This can be said to be defined such that at least one subchannel is skipped.

  FIG. 11 shows the configuration of a channel according to another modification of the present invention. Since the arrangement of the broadcast channel is the same as in FIG. 8, illustration and description thereof are omitted here. Further, in FIG. 11, the wideband channel is arranged on the high frequency side of the narrowband channel as in FIG. 8. Each wideband channel is formed by a plurality of subchannels. As shown in the figure, the peak interval between adjacent subchannels is defined as Δf. On the other hand, the peak interval of the narrowband channel is defined as 2Δf, but may be a value larger than this, such as 3Δf and 4Δf. Return to the description of the configuration. With such an arrangement, the broadcast channel, the control channel, and the narrowband channel are arranged at the subcarrier frequency position of the wideband channel. The allocation unit 22 allocates a combination of a narrowband channel and a broadband channel or a narrowband channel to a terminal device.

  Therefore, since the communication device 20 and the terminal device corresponding to the wideband channel perform OFDMA on the narrowband channel and the wideband channel, such as the broadcast channel, by providing one FFT circuit, these are collectively Can modulate and demodulate. That is, simultaneous demodulation is realized by extracting the entire frequency channel of this band with a band filter and inputting it to the FFT circuit. On the other hand, a terminal device corresponding to a narrowband channel only needs to extract a desired subchannel, and the desired subchannel has little overlap with an adjacent subchannel, so that it is not necessary to use an FFT circuit. . That is, a normal FDMA circuit can be used, and an increase in circuit scale is suppressed.

  Even if phase detection or the like is impossible, the presence or absence of a subchannel can be detected. The presence / absence of the subchannel is effective when the communication system 100 has a cellular configuration including a plurality of cells. That is, it is not necessary to set a narrowband channel for a subchannel already used in another cell. Similarly, the frequency of the control channel, random access channel, paging channel, etc. may be determined so as to reduce interference between cells. The signal thus determined is notified to the terminal device 12 in the service area by broadcast information, and the influence of inter-cell interference is reduced on important control channels, random access channels, paging channels, and the like.

  The communication unit 20 executes communication with the terminal device 12 to which a combination of a narrowband channel and a broadband channel or a narrowband channel is assigned. The communication unit 20 includes data in the narrowband channel when a narrowband channel is assigned to execute communication with the terminal device 12. On the other hand, when a wideband channel is assigned to execute communication with the terminal device 12, the communication unit 20 includes information on the wideband channel to be used in the narrowband channel while including data in the wideband channel.

  According to the embodiment of the present invention, the bandwidth to be allocated to the terminal device is determined while the bandwidth of the communication channel is divided according to the required bandwidth by comparing the required priority among the plurality of terminal devices. Therefore, even if there are a plurality of types of communication speeds required from each of the plurality of terminal devices, the bandwidth can be flexibly divided. In addition, since the necessary bandwidth is allocated in order from the terminal device having the highest necessary priority, the processing can be easily executed. In addition, the priority included in the communication start request is compared with the priority of another terminal device that is already performing communication, so that the bandwidth of the communication channel is divided according to the required bandwidth. Since the bandwidth is determined, the bandwidth can be flexibly divided even when there are a plurality of types of communication speeds required from each of the plurality of terminal devices. Also, prioritized communication and maximum efficiency as a communication path can be realized.

  Even when a wideband channel is allocated, the narrowband channel is used while including information on the wideband channel to be used in the narrowband channel. Even if there are a plurality of required communication speeds, the communication speed can be easily switched. In addition, since the wideband channel is assigned after the narrowband channel is assigned, the communication speed can be easily switched even if there are a plurality of types of communication speeds required from each of the plurality of terminal devices. In addition, regardless of whether or not a wideband channel is allocated, the narrowband channel is continuously allocated, so that a connection can be ensured. In addition, the base station apparatus and the terminal apparatus can grasp the band usage status without demodulating the wideband channel by simply confirming the broadcast channel, random access channel, control channel, and narrowband channel. Further, since the use status of the band can be grasped without demodulating the wideband channel, the channel control method can be simplified. Also, a terminal device that does not perform broadband communication can grasp communication band information in the service area without receiving and demodulating the broadband channel.

  In addition, each wideband channel is formed by an OFDM signal, and each narrowband channel has a bandwidth equivalent to that of a subchannel in the OFDM signal, so that a plurality of communication speeds required from each of a plurality of terminal devices are provided. Even if there are types, the communication speed can be easily switched. Even when a wideband channel is allocated, the narrowband channel is used while including information on the wideband channel to be used in the narrowband channel. Even if there are a plurality of required communication speeds, the communication speed can be easily switched. In addition, multiple channels can be demodulated simultaneously with simple demodulation.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the allocating unit 22 specifies that a communication channel such as a broadcast channel is frequency division multiplexed. However, the present invention is not limited to this, and the allocator 22 may execute OFDMA having a plurality of subcarriers for these channels, may execute TDMA separated in time, and may perform a plurality of codes. The used CDMA may be executed. According to this modification, the present invention can be applied to various multiplexing methods.

The features of the invention described in the embodiments may be defined by the following items.
(Item 1-1)
An informing unit for informing the informing information through an informing channel;
A receiving unit that receives a communication start request including information on communication priority and necessary bandwidth from a terminal device that has received the notification information notified by the notification unit, via a random access channel;
By comparing the priority included in the communication start request received in the reception unit with the priority of another terminal device that is already performing communication, the bandwidth of the communication channel is set according to the required bandwidth. An allocation unit that determines the bandwidth to be allocated to the terminal device,
A notification unit for notifying the terminal device of the bandwidth determined by the allocation unit via a control channel;
A communication unit that performs communication with a terminal device in a communication channel with the bandwidth notified in the notification unit;
A base station apparatus comprising:

(Item 1-2)
A first reception unit that receives broadcast information from the base station device via the broadcast channel;
A request unit that outputs a communication start request including information on communication priority and necessary bandwidth to a base station apparatus that has transmitted the broadcast information received in the first reception unit via a random access channel. When,
In the base station apparatus that has received the communication start request output from the request unit, the priority included in the communication start request is compared with the priority of another terminal apparatus that has already performed communication. A bandwidth that is allocated while the bandwidth of the communication channel is divided according to the required bandwidth, and a second reception unit that receives the determined bandwidth from the base station device via the control channel; ,
A communication unit that performs communication with a base station apparatus in a communication channel with the bandwidth received in the second reception unit;
A terminal device comprising:

(Item 2-1)
An assigning unit for assigning a communication channel to at least one terminal device;
A communication unit that performs communication with a terminal device to which a communication channel is allocated in the allocation unit;
The assigning unit defines a narrowband channel and a wideband channel wider than the narrowband channel as communication channels,
When a narrowband channel is assigned to execute communication with the terminal device, the communication unit includes data in the narrowband channel, and a wideband channel is assigned to execute communication with the terminal device. In this case, the base station apparatus includes information on the wideband channel to be used in the narrowband channel while including data in the wideband channel.

(Item 2-2)
The allocating unit allocates a narrowband channel first when allocating a communication channel to a terminal device, and information on the allocated wideband channel among the already allocated narrowband channels when allocating a wideband channel to the terminal device. The base station apparatus according to (Item 2-1), including means for notifying the terminal apparatus of the allocated broadband channel by including

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the structure of the base station apparatus of FIG. It is a figure which shows the information regarding the terminal device memorize | stored in the memory | storage part of FIG. FIGS. 4A to 4B are diagrams showing the configuration of channels to be allocated by the base station apparatus of FIG. It is a sequence diagram which shows the communication procedure in case the connection is made from a terminal device in the communication system of FIG. It is a sequence diagram which shows the communication procedure in case the connection is made from a base station apparatus in the communication system of FIG. 3 is a flowchart showing a communication channel assignment procedure in the base station apparatus of FIG. It is a figure which shows the structure of the channel which concerns on the modification of this invention. FIGS. 9A and 9B are diagrams showing the format of signals arranged in the narrowband channel of FIG. It is a flowchart which shows the communication procedure in the base station apparatus which concerns on the modification of this invention. It is a figure which shows the structure of the channel which concerns on another modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 base station apparatus, 12 terminal device, 14 network, 20 communication part, 22 allocation part, 24 memory | storage part, 26 IF part, 28 control part, 100 communication system.

Claims (2)

A plurality of narrowband channels and a plurality of wideband channels that are wider than the narrowband channels are frequency division multiplexed, and an allocation unit that assigns a combination of narrowband channels and wideband channels or narrowband channels to a terminal device;
A communication unit that performs communication with a terminal device that has allocated a narrowband channel or a combination of a narrowband channel and a wideband channel in the allocation unit;
In the allocation unit, each wideband channel is formed by an OFDM signal, each narrowband channel has a bandwidth equivalent to a subchannel of the OFDM signal, and the peak interval between adjacent narrowband channels is OFDM A base station apparatus, wherein the base station apparatus is an integral multiple of 2 or more of a peak interval between adjacent subchannels of a signal.   The communication unit, when a narrowband channel is assigned to execute communication with the terminal device, including data in the narrowband channel, when a wideband channel is assigned to execute communication with the terminal device, 2. The base station apparatus according to claim 1, wherein information on a wideband channel to be used is included in the narrowband channel while data is included in the wideband channel.

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