JP5774665B2 - Line allocation method and radio communication system - Google Patents

Line allocation method and radio communication system Download PDF

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JP5774665B2
JP5774665B2 JP2013230992A JP2013230992A JP5774665B2 JP 5774665 B2 JP5774665 B2 JP 5774665B2 JP 2013230992 A JP2013230992 A JP 2013230992A JP 2013230992 A JP2013230992 A JP 2013230992A JP 5774665 B2 JP5774665 B2 JP 5774665B2
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中平 勝也
勝也 中平
杉山 隆利
隆利 杉山
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Nippon Telegraph and Telephone Corp
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本発明は、複数の端末局が1台のノード局を介して通信を行う無線通信システムにおいて、周波数帯域(以下、帯域という)を有効利用するために端末局への回線割当を制御する回線割当方法および無線通信システムに関する。   In a wireless communication system in which a plurality of terminal stations communicate via a single node station, the present invention relates to line assignment for controlling line assignment to terminal stations in order to effectively use a frequency band (hereinafter referred to as a band). The present invention relates to a method and a wireless communication system.

図11に示す衛星通信システムまたは図12に示すセルラ通信システムのように、通信衛星やセルラ基地局(本明細書では、ノード局という)を介して端末局と端末局が通信を行う無線通信システムでは、全通信回線の帯域の総和はノード局が利用できる全帯域に制限される。この帯域を各端末局が有効利用あるいは公平利用するために、回線割当装置が端末局の通信開始時に、端末局が要求する伝送速度(以下、要求速度という)の達成に必要な帯域を端末局に割り当てる、要求時割当多元接続(DAMA:Demand Assign Multiple Access)方式による回線割当が用いられる。なお、図11および図12では、端末局Aが天候や建物の遮蔽により伝搬路が変動している状況を示す。   As in the satellite communication system shown in FIG. 11 or the cellular communication system shown in FIG. 12, a wireless communication system in which a terminal station and a terminal station communicate with each other via a communication satellite or a cellular base station (referred to as a node station in this specification). In this case, the sum of the bandwidths of all communication lines is limited to the entire bandwidth that can be used by the node station. In order for each terminal station to use this bandwidth effectively or fairly, the bandwidth required to achieve the transmission rate required by the terminal station (hereinafter referred to as the requested rate) when the line allocating device starts communication with the terminal station. A line assignment based on a demand assignment multiple access (DAMA) system is used. 11 and 12 show a situation in which the propagation path of the terminal station A is fluctuating due to the weather and the shielding of the building.

図13は、通信モードごとのスペクトラム利用効率(帯域あたりの伝送速度) と所要C/N(通信を行うために必要なキャリア電力対雑音電力比) との関係を示す。ここで、通信モードは、端末局が通信に用いる変復調方式(BPSK,QPSK,8PSK,16QAMなど) と、誤り訂正符号化率(1/2, 3/4, 2/3 など) の組み合わせをいう。例えば、変復調方式QPSKと誤り訂正符号化率1/2 の通信モードを「QPSK 1/2」と表記する。併せて、各通信モードの数値(スペクトラム利用効率,所要C/N)を示す。   FIG. 13 shows the relationship between the spectrum utilization efficiency (transmission rate per band) and the required C / N (carrier power to noise power ratio necessary for communication) for each communication mode. Here, the communication mode refers to a combination of a modulation / demodulation method (BPSK, QPSK, 8PSK, 16QAM, etc.) used by the terminal station for communication and an error correction coding rate (1/2, 3/4, 2/3, etc.). . For example, the communication mode of the modulation / demodulation method QPSK and the error correction coding rate 1/2 is expressed as “QPSK 1/2”. In addition, numerical values (spectrum utilization efficiency, required C / N) for each communication mode are shown.

スペクトラム利用効率をη、要求速度をRreq とするとき、要求速度を満たすために端末局に割り当てる帯域Wは次式となる。
W=Rreq /η …(1)
式(1) より、できるだけ少ない帯域で通信を行うには、端末局はスペクトラム利用効率の大きい通信モードを用いることが望ましい。
When the spectrum utilization efficiency is η and the required speed is Rreq, the bandwidth W allocated to the terminal station to satisfy the required speed is given by the following equation.
W = Rreq / η (1)
From equation (1), it is desirable that the terminal station use a communication mode with high spectrum utilization efficiency in order to perform communication in the smallest possible band.

一方、端末局の受信C/N(受信信号のキャリア電力対雑音電力比)は、端末局の伝搬路が悪くなったとき低下し、端末局の伝搬路が良くなったとき向上する。また、受信C/Nが所要C/Nよりも低くなると、ビットエラーが多くなり通信を行うことができない。そこで、図13より、スペクトラム利用効率の大きい通信モードほど所要C/Nが高くなることから、端末局は受信C/N以下となる最大の所要C/Nを持つ通信モードを選択すればよい。   On the other hand, the reception C / N (carrier power to noise power ratio of the received signal) of the terminal station is lowered when the propagation path of the terminal station is deteriorated, and is improved when the propagation path of the terminal station is improved. If the received C / N is lower than the required C / N, bit errors increase and communication cannot be performed. Therefore, as shown in FIG. 13, the required C / N becomes higher as the communication mode has a higher spectrum utilization efficiency. Therefore, the terminal station may select the communication mode having the maximum required C / N that is equal to or lower than the reception C / N.

図14は、従来の回線割当例を示す。
図14(1) は、伝搬路の受信C/Nがほぼ等しい端末局A,B,Cに、同じ要求速度(1Mbit/s )を達成する通信モード(QPSK 1/2)と帯域(1MHz )を割り当てた例である。ここで、図11および図12に示すように端末局Aの伝搬路が悪化し、図14(2) に示すように受信C/Nが所要C/Nよりも低くなると、端末局Aは通信を行うことができない。これに対応する従来の方法として、非特許文献1に示す適応変復調技術がある。この従来技術によれば、図14(3) に示すように、伝搬路が悪くなった端末局Aは、当初の通信モードよりも所要C/Nが低い通信モード(BPSK 1/2)に変更することにより通信を継続することができる。
FIG. 14 shows a conventional line allocation example.
FIG. 14 (1) shows a communication mode (QPSK 1/2) and a band (1 MHz) for achieving the same required speed (1 Mbit / s) for terminal stations A, B, and C having substantially the same reception C / N of the propagation path. Is an example in which is assigned. Here, if the propagation path of the terminal station A deteriorates as shown in FIGS. 11 and 12, and the received C / N becomes lower than the required C / N as shown in FIG. Can not do. As a conventional method corresponding to this, there is an adaptive modulation / demodulation technique shown in Non-Patent Document 1. According to this prior art, as shown in FIG. 14 (3), the terminal station A whose propagation path has deteriorated is changed to a communication mode (BPSK 1/2) having a lower required C / N than the original communication mode. By doing so, communication can be continued.

S. Cioni, R. De Gaudenzi and R. Rinaldo:“Adaptive coding and modulation for the reverse link of broadband satellite networks ”, IEEE Global Telecommunications Conference, GLOBECOM, Vol.2, Dallas, Texas, USA, pp.1101-1105 (2004).S. Cioni, R. De Gaudenzi and R. Rinaldo: “Adaptive coding and modulation for the reverse link of broadband satellite networks”, IEEE Global Telecommunications Conference, GLOBECOM, Vol.2, Dallas, Texas, USA, pp.1101-1105 (2004). J. Mashino and T. Sugiyama: “A sub-spectrum suppressed transmission scheme for highly efficient satellite communications ”, IEEE Vehicular Technology Conference Fall, VTC Fall, Anchorage, Alaska, pp.1-5 (2011).J. Mashino and T. Sugiyama: “A sub-spectrum suppressed transmission scheme for highly efficient satellite communications”, IEEE Vehicular Technology Conference Fall, VTC Fall, Anchorage, Alaska, pp.1-5 (2011). J. Abe, F. Yamashita, K. Nakahira and K. Kobayashi: “Direct spectrum division transmission for highly efficient frequency utilization in satellite communications”,IEICE Transactions on Communications, 95, 2, pp.563-571 (2012).J. Abe, F. Yamashita, K. Nakahira and K. Kobayashi: “Direct spectrum division transmission for highly efficient frequency utilization in satellite communications”, IEICE Transactions on Communications, 95, 2, pp.563-571 (2012). 風間, 阪田, 坂井, 加藤:“TDMA衛星通信システム用送信電力制御方式”, 電子情報通信学会論文誌, 76, 5, pp.354-362 (1993).Kazama, Sakata, Sakai, Kato: “Transmission power control method for TDMA satellite communication systems”, IEICE Transactions, 76, 5, pp.354-362 (1993). BHATTI, S., BATEMAN, M.:“Transport Protocol Throughput Fairness”. Journal of Networks, North America, 4, 9, pp.881-894 (2009).BHATTI, S., BATEMAN, M .: “Transport Protocol Throughput Fairness”. Journal of Networks, North America, 4, 9, pp.881-894 (2009).

図13および図14において、通信モードQPSK 1/2の所要C/Nは1.9dB であり、通信モードBPSK 1/2の所要C/Nは-1.1dBであり、その差は3dBである。従って、QPSK 1/2で通信をしていた端末局の受信C/Nの低下が3dB以内であれば、端末局は通信モードをQPSK 1/2からBPSK 1/2に変更することにより、受信C/Nが所要C/Nを上回り通信を継続することができる。しかし、スペクトラム利用効率は、QPSK 1/2の1bit/s/HzからBPSK 1/2は 0.5bit/s/Hzに半減するため、当初の帯域(1MHz )で通信を継続すると伝送速度が半分(1Mbit/s から 500kbit/s )になる。すなわち、当初の伝送速度(1Mbit/s )に必要な帯域は2倍(2MHz )となる。従って、従来技術では、受信C/Nが低くなった端末局が通信モードを変更しても、当初の帯域のままでは要求速度を達成できないことがある。   13 and 14, the required C / N of the communication mode QPSK 1/2 is 1.9 dB, the required C / N of the communication mode BPSK 1/2 is −1.1 dB, and the difference is 3 dB. Therefore, if the reception C / N reduction of the terminal station that has been communicating with QPSK 1/2 is within 3 dB, the terminal station receives the signal by changing the communication mode from QPSK 1/2 to BPSK 1/2. C / N exceeds the required C / N and communication can be continued. However, since the spectrum utilization efficiency is halved from 1 bit / s / Hz for QPSK 1/2 to 0.5 bit / s / Hz for BPSK 1/2, if the communication is continued in the original band (1 MHz), the transmission rate is half ( 1Mbit / s to 500kbit / s). That is, the bandwidth required for the initial transmission rate (1 Mbit / s) is doubled (2 MHz). Therefore, in the prior art, even if a terminal station having a low reception C / N changes the communication mode, the requested speed may not be achieved with the original bandwidth.

一方、伝搬路が良くなり受信C/Nが高くなった端末局にあっては、要求速度を達成するだけであれば帯域に余裕があることになる。すなわち、スペクトラム利用効率の大きい通信モードに切り替えることにより、必要な帯域を削減することができる。例えば、端末局の受信C/Nが9dB以上良好になり、通信モードをQPSK 1/2から8PSK 3/4に変更できる場合には、要求速度1Mbit/s に必要な帯域は1MHz から1/2.25=0.44MHz になり、0.56MHz の帯域が余裕となる。また、通信モードがQPSK 1/2のままで、要求速度を1Mbit/s から 750kbit/s に下げた場合に必要な帯域は1MHz から0.75MHz になり、0.25MHz の帯域が余裕となる。   On the other hand, in a terminal station where the propagation path is improved and the reception C / N is high, there is a margin in bandwidth if the required speed is only achieved. That is, the necessary bandwidth can be reduced by switching to a communication mode with a high spectrum utilization efficiency. For example, when the reception C / N of the terminal station is 9 dB or better and the communication mode can be changed from QPSK 1/2 to 8PSK 3/4, the bandwidth required for the required speed of 1 Mbit / s is from 1 MHz to 1 / 2.25. = 0.44 MHz, and a bandwidth of 0.56 MHz is sufficient. Further, when the communication mode remains QPSK 1/2 and the required speed is lowered from 1 Mbit / s to 750 kbit / s, the necessary bandwidth is 1 MHz to 0.75 MHz, and the bandwidth of 0.25 MHz is sufficient.

本発明は、端末局ごとに伝搬路の伝搬利得が変化する状況において、ノード局が利用できる全帯域の中から端末局間で帯域を融通し、全端末局が要求速度を達成するか、あるいは全端末局が公平かつできるだけ高い伝送速度を実現することができる回線割当方法および無線通信システムを提供することを目的とする。   In the present invention, in a situation where the propagation gain of the propagation path changes for each terminal station, the terminal station can be interchanged among all the bands that can be used by the node station, and all the terminal stations achieve the required speed, or It is an object of the present invention to provide a channel allocation method and a wireless communication system in which all terminal stations can achieve a transmission rate as high as possible fairly.

第1の発明は、複数の端末局と、当該端末局の通信を中継するノード局と、これらの通信に用いる通信回線の割り当てを行う基地局とにより構成され、端末局ごとの伝搬路の伝搬利得および要求速度に基づいて割り当てられた通信回線により各端末局が通信を行う無線通信システムの回線割当方法において、端末局は、一定間隔で伝搬路の伝搬利得を検知して基地局に通知し、基地局は、伝搬路の伝搬利得が低下し、当該低下した伝搬利得に対応してスペクトラム利用効率の低い通信モードに変更したときに帯域不足により要求速度を満たせない端末局(譲受局)に対して、回線割当当初の伝搬利得を維持または向上した端末局(譲渡局)から余剰となる帯域の一部を譲渡し、通信回線の再割り当てを行って譲受局および譲渡局が通信を継続する制御を行う。 The first invention is composed of a plurality of terminal stations, a node station that relays communication of the terminal stations, and a base station that allocates communication lines used for these communications. In a channel allocation method of a wireless communication system in which each terminal station communicates using a communication channel allocated based on a gain and a required speed, the terminal station detects a propagation gain of a propagation path at regular intervals and notifies the base station. The base station is a terminal station (transfer station) that cannot satisfy the required speed due to insufficient bandwidth when the propagation gain of the propagation path decreases and the communication mode is changed to a low spectrum use efficiency corresponding to the decreased propagation gain. against it, to transfer a part of the band of the excess from the terminal station which maintains or improves the propagation gains initially channel allocation (transfer station), continue the acquisition stations and transfer stations communicate reassign communication line It performs a control that.

第1の発明の回線割当方法において、基地局は、譲渡局でスペクトラム利用効率の高い通信モードに変えたときに、要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う。   In the line allocation method of the first invention, the base station calculates a surplus band for achieving the required speed when the transfer station changes to a communication mode with high spectrum use efficiency, and further uses the spectrum at the transfer station. A communication line including switching the communication mode by calculating a bandwidth that is insufficient to achieve the required speed when the communication mode is changed to a low-efficiency mode, transferring the surplus bandwidth to at least one transfer station to the transfer station Reassign

第1の発明の回線割当方法において、基地局は、譲渡局および譲受局の要求速度を下げたときに、譲渡局で要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、下げた要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う。   In the line allocating method of the first invention, the base station calculates a surplus band for achieving the requested speed at the assigning station when the requested speed of the assigning station and the assigning station is lowered, and further the spectrum at the assigning station. When switching to a communication mode with low usage efficiency, calculate the bandwidth that will be insufficient to achieve the reduced request speed, transfer the surplus bandwidth to the assigning station in at least one assigning station, and switch the communication mode. Reallocate the communication line that contains it.

第1の発明の回線割当方法において、基地局は、譲渡局でスペクトラム削減伝送を行ったときに、要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う。 In the line allocating method of the first invention, the base station calculates a surplus band for achieving the requested speed when performing spectrum reduction transmission at the transfer station, and further performs communication with low spectrum utilization efficiency at the transfer station. when changing the mode, to calculate the band of insufficient in attaining the request rate, the transfer of the band of surplus at least one transfer station on the acquisition stations, re-allocation of the communication line including the switching of communication mode I do.

第2の発明は、複数の端末局と、当該端末局の通信を中継するノード局と、これらの通信に用いる通信回線の割り当てを行う基地局とにより構成され、端末局ごとの伝搬路の伝搬利得および要求速度に基づいて割り当てられた通信回線により各端末局が通信を行う無線通信システムにおいて、端末局は、一定間隔で伝搬路の伝搬利得を検知して基地局に通知する手段を備え、基地局は、伝搬路の伝搬利得が低下し、当該低下した伝搬利得に対応してスペクトラム利用効率の低い通信モードに変更したときに帯域不足により要求速度を満たせない端末局(譲受局)に対して、回線割当当初の伝搬利得を維持または向上した端末局(譲渡局)から余剰となる帯域の一部を譲渡し、通信回線の再割り当てを行って譲受局および譲渡局が通信を継続する制御を行う制御手段を備える。 The second invention is composed of a plurality of terminal stations, a node station that relays the communication of the terminal station, and a base station that allocates a communication line used for the communication. In a wireless communication system in which each terminal station communicates through a communication line assigned based on a gain and a requested speed, the terminal station includes means for detecting a propagation gain of a propagation path at regular intervals and notifying the base station, For base stations that do not satisfy the required speed due to insufficient bandwidth when the propagation gain of the propagation path decreases and the communication mode with low spectrum utilization efficiency is changed corresponding to the decreased propagation gain. Te, the transfer of part of the band of the excess from the terminal station which maintains or improves the propagation gains initially channel allocation (transfer station), acquisition station and transfer station performs re-allocation of the communication line to continue the communication A control means for controlling.

第2の発明の無線通信システムにおいて、端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段を備え、基地局の制御手段は、譲渡局でスペクトラム利用効率の高い通信モードに変えたときに、要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う構成である。   In the wireless communication system of the second invention, the terminal station comprises means for switching to a communication mode with different spectrum utilization efficiency, and the control means of the base station is changed to a communication mode with high spectrum utilization efficiency at the transfer station, At least one transfer station calculates the bandwidth that will be surplus when achieving the required speed, and calculates the bandwidth that will be insufficient to achieve the required speed when the transfer station changes to a communication mode with low spectrum utilization efficiency. In this configuration, the surplus bandwidth is transferred to the transfer station, and the communication line is reassigned including the switching of the communication mode.

第2の発明の無線通信システムにおいて、端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段を備え、基地局の制御手段は、譲渡局および譲受局の要求速度を下げたときに、譲渡局で要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、下げた要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う構成である。   In the wireless communication system of the second invention, the terminal station includes means for switching to communication modes having different spectrum utilization efficiencies, and the control means of the base station is configured such that when the requested speed of the assigning station and the assigning station is reduced, the assigning station To calculate a bandwidth that is excessive to achieve the requested speed, and to calculate a bandwidth that is insufficient to achieve the reduced requested speed when the receiving station changes to a communication mode with low spectrum utilization efficiency. In this configuration, the surplus bandwidth is transferred to the transfer station by one transfer station, and the communication line is reassigned including the switching of the communication mode.

第2の発明の無線通信システムにおいて、端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段と、スペクトラム削減伝送を行う手段とを備え、基地局の制御手段は、譲渡局でスペクトラム削減伝送を行ったときに、要求速度を達成するにあたり余剰となる帯域を計算し、さらに譲受局でスペクトラム利用効率の低い通信モードに変えたときに、要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの譲渡局で余剰となる帯域を譲受局に譲渡し、通信モードの切り替えを含む通信回線の再割り当てを行う構成である。
In the wireless communication system of the second invention, the terminal station includes means for switching to communication modes having different spectrum utilization efficiencies and means for performing spectrum reduction transmission, and the control means of the base station performs spectrum reduction transmission at the transfer station. when you have made to calculate the band of surplus in attaining the required speed, when further changing the lower communication modes spectrum utilization efficiency in acquisition station, to calculate the band of insufficient in attaining the request rate The configuration is such that at least one transfer station transfers a surplus band to the transfer station and reassigns communication lines including switching of communication modes.

本発明は、端末局ごとの伝搬路の状況が変化しても、1つの譲受局に対して1つ以上の譲渡局があれば、それぞれの通信モードを変更し、あるいはスペクトラム削減伝送により譲渡局で余剰となる帯域を確保し、譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局で当初の要求速度を維持することができる。   In the present invention, even if the state of the propagation path for each terminal station changes, if there is one or more assigning stations for one assigning station, the respective communication modes are changed or the assigning station is changed by spectrum reduction transmission. By securing a surplus bandwidth and transferring the bandwidth from the assigning station to the assigning station, each terminal station can maintain the original requested speed.

本発明は、端末局ごとの伝搬路の状況が変化しても、1つの譲受局に対して1つ以上の譲渡局があれば、それぞれの要求速度を下げることにより譲渡局で余剰となる帯域を確保し、譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局に公平かつできるだけ高い伝送速度を提供することができる。   In the present invention, even if the state of the propagation path for each terminal station changes, if there are one or more transfer stations for one transfer station, the bandwidth that becomes surplus in the transfer station by reducing the respective request speeds By securing the bandwidth and transferring the bandwidth from the transfer station to the transfer station, it is possible to provide each terminal station with the highest possible transmission rate.

本発明における端末局と基地局の通信シーケンスを示す図である。It is a figure which shows the communication sequence of the terminal station and base station in this invention. 本発明における帯域譲渡の実施例1を示す図である。It is a figure which shows Example 1 of the band transfer in this invention. 本発明における帯域譲渡の実施例2を示す図である。It is a figure which shows Example 2 of the band transfer in this invention. 本発明における帯域譲渡の実施例3を示す図である。It is a figure which shows Example 3 of the band transfer in this invention. スペクトラム削減伝送による所要C/N特性を示す図である。It is a figure which shows the required C / N characteristic by spectrum reduction transmission. 本発明における帯域譲渡の実施例4を示す図である。It is a figure which shows Example 4 of the band transfer in this invention. 本発明における帯域譲渡の実施例5を示す図である。It is a figure which shows Example 5 of the band transfer in this invention. 本発明における帯域譲渡の実施例6を示す図である。It is a figure which shows Example 6 of the band transfer in this invention. 本発明の無線通信システムの基地局および端末局の構成例を示す図である。It is a figure which shows the structural example of the base station of the radio | wireless communications system of this invention, and a terminal station. 伝搬利得を測定する方法の例を説明する図である。It is a figure explaining the example of the method of measuring a propagation gain. 衛星通信システムの構成例を示す図である。It is a figure which shows the structural example of a satellite communication system. セルラ通信システムの構成例を示す図である。It is a figure which shows the structural example of a cellular communication system. 通信モードごとのスペクトラム利用効率と所要C/Nとの関係を示す図である。It is a figure which shows the relationship between the spectrum utilization efficiency for every communication mode, and required C / N. 従来の回線割当例を示す図である。It is a figure which shows the example of the conventional line allocation.

本発明は、端末局ごとに伝搬路の伝搬利得(伝搬路の状況を数値化した値、例えば受信C/N)が変化する状況において、回線割当が行われた当初の伝搬利得が低下した端末局に対して、伝搬利得を維持または伝搬利得が向上した端末局から帯域の一部を譲渡することにより、全端末局が所定の要求速度で通信を維持できるように制御することを特徴とする。ここで、帯域の一部を譲渡する端末局を譲渡局、帯域の譲渡を受ける端末局を譲受局という。   The present invention relates to a terminal in which a propagation gain of a propagation path (a value obtained by quantifying a propagation path condition, for example, reception C / N) changes for each terminal station, and the initial propagation gain in which line allocation is performed is reduced. Control is performed so that all terminal stations can maintain communication at a predetermined required speed by transferring a part of a band from a terminal station that maintains or improves propagation gain to the station. . Here, a terminal station that transfers a part of the band is called a transfer station, and a terminal station that receives the transfer of the band is called a transfer station.

本発明の第1の実施形態は、伝搬利得が低下して帯域の譲渡がなければ当初の要求速度を維持できない譲受局と、伝搬利得が向上して帯域の一部を譲渡しても当初の要求速度を維持できる譲渡局がそれぞれ出現したときに、譲渡局から譲受局へ帯域の一部を譲渡することにより、ともに当初の要求速度を維持しながら通信を可能にする。すなわち、伝搬利得が向上した譲渡局は、スペクトラム利用効率の高い通信モードに切り替え、またはスペクトラム削減伝送(詳しくは後述する)により、当初の要求速度の維持と譲渡する帯域を確保する。一方、伝搬利得が低下した譲受局は、スペクトラム利用効率の低い通信モードに切り替え、かつ譲渡された帯域を加えることにより、当初の要求速度を確保する。   In the first embodiment of the present invention, a transfer station that cannot maintain an initial required speed without a transfer of a band due to a decrease in propagation gain, and an original station that does not maintain the original request speed even if a transfer gain is increased and a part of the band is transferred. When a transfer station that can maintain the required speed appears, a part of the band is transferred from the transfer station to the transfer station, thereby enabling communication while maintaining the original required speed. That is, the transfer station with improved propagation gain switches to a communication mode with high spectrum use efficiency, or secures a band for transfer and maintenance of the initial required speed by spectrum reduction transmission (details will be described later). On the other hand, the assigning station whose propagation gain is reduced secures the initial required speed by switching to a communication mode with low spectrum use efficiency and adding the assigned band.

本発明の第2の実施形態は、伝搬利得が低下して帯域の譲渡がなければ当初の要求速度を維持できない譲受局が出現する一方で、伝搬利得が十分に向上していないため要求速度を維持したままでは譲渡する帯域を確保できない端末局があるときに、ノード局が利用できる全帯域の範囲で、各端末局に公平かつできるだけ高い要求速度を提供できるように、要求速度を下げて帯域の一部を譲渡できる譲渡局を確保する。例えば、各端末局の当初の要求速度が1Mbit/s であるときに、通信モードの切り替えによる譲渡帯域を確保できない場合に、各端末局の要求速度を1Mbit/s から例えば 750kbit/s に低下させるにより譲渡帯域を確保し、公平な要求速度の達成を実現する。   In the second embodiment of the present invention, there appears an assigning station that cannot maintain the initial required speed without a transfer of bandwidth due to a decrease in the propagation gain. On the other hand, since the propagation gain is not sufficiently improved, the required speed is reduced. When there is a terminal station that cannot secure the bandwidth to be transferred if it is maintained, the bandwidth can be reduced by reducing the request speed so that each terminal station can be provided with the highest possible request speed in the full range of bandwidth available to the node station. Secure a transfer office that can transfer a part of. For example, when the initial required speed of each terminal station is 1 Mbit / s and the transfer band cannot be secured by switching the communication mode, the required speed of each terminal station is reduced from 1 Mbit / s to 750 kbit / s, for example. To secure a transfer bandwidth and achieve a fair required speed.

以下、2つの実施形態をベースに、譲渡局において譲渡帯域を確保するための各実施例について説明するが、その前に端末局と基地局の通信シーケンスについて説明する。
図1は、本発明における端末局と基地局の通信シーケンスを示す。ここで、基地局(帯域割当装置)は、図11に示す衛星通信システムの通信衛星またはセルラ通信システムのセルラ基地局に接続され、端末局との間で帯域割当および帯域譲渡の制御を行う。
In the following, each example for securing a transfer band in a transfer station will be described based on two embodiments. Before that, a communication sequence between a terminal station and a base station will be described.
FIG. 1 shows a communication sequence between a terminal station and a base station in the present invention. Here, the base station (band allocation device) is connected to a communication satellite of the satellite communication system shown in FIG. 11 or a cellular base station of the cellular communication system, and controls band allocation and band transfer with the terminal station.

図1において、各端末局と基地局(帯域割当装置)は、それぞれ非同期に動作するが、帯域の譲渡に伴う伝送パラメータ(通信モード、帯域、中心周波数)の伝送(f),(f')は同期して行う必要がある。   In FIG. 1, each terminal station and base station (bandwidth allocation device) operate asynchronously, but transmission (f), (f ′) of transmission parameters (communication mode, bandwidth, center frequency) associated with bandwidth transfer. Must be done synchronously.

端末局は、一定間隔で伝搬利得(伝搬路の状況を数値化した値、例えば受信C/N)を検知して基地局に送信する((a),(a'))。端末局が通信開始時に回線要求信号を基地局に送信すると((b),(b'))、基地局は回線要求内容と伝搬利得をもとに伝搬パラメータを決定し、当該端末局に返信する((c),(c'))。その後、端末局は返信された伝送パラメータを用いてデータの送受信を行う((d),(d'))。   The terminal station detects a propagation gain (a value obtained by digitizing the state of the propagation path, for example, reception C / N) at regular intervals and transmits it to the base station ((a), (a ′)). When the terminal station transmits a line request signal to the base station at the start of communication ((b), (b ')), the base station determines the propagation parameter based on the contents of the line request and the propagation gain, and returns it to the terminal station. ((C), (c ′)). Thereafter, the terminal station transmits and receives data using the returned transmission parameters ((d), (d ′)).

次に、一定間隔で検知される伝搬利得が一方の端末局で向上し、他方の端末局で劣化した場合を想定する((e),(e'))。ここで、ある端末局の伝搬利得が低下し、受信C/Nが要求C/Nを下回ると、そのままでは通信を継続できないので、基地局は本発明の以下の手順に従って譲渡局から譲受局に帯域の譲渡を行う処理を行う。   Next, it is assumed that the propagation gain detected at a constant interval is improved at one terminal station and deteriorated at the other terminal station ((e), (e ′)). Here, if the propagation gain of a certain terminal station decreases and the received C / N falls below the required C / N, communication cannot be continued as it is, so that the base station changes from the assigning station to the assigning station according to the following procedure of the present invention. Processing to transfer the bandwidth is performed.

手順1:受信C/Nが要求C/Nを下回った端末局を譲受局とする。
手順2:譲受局以外の複数の端末局から譲渡局となりうる端末局を1台以上選出する。 手順3:譲渡局から譲受局に帯域を譲渡するために双方の伝搬パラメータを変更する。
Procedure 1: The terminal station whose received C / N is lower than the requested C / N is determined as the assigning station.
Procedure 2: One or more terminal stations that can become transfer stations are selected from a plurality of terminal stations other than the transfer station. Procedure 3: Change both propagation parameters in order to transfer the band from the transfer station to the transfer station.

基地局は、変更された伝送パラメータを譲渡局および譲受局双方に同期して送信する((f),(f'))。譲渡局および譲受局は、変更された伝送パラメータを用いてデータの送受信を行う((g),(g'))。   The base station transmits the changed transmission parameter in synchronization with both the assigning station and the assigning station ((f), (f ′)). The assigning station and the assigning station transmit and receive data using the changed transmission parameters ((g), (g ′)).

ここで、譲渡局となりうる端末局とは、当初の通信モードにおける所要C/Nよりも高い受信C/Nが得られて帯域に余裕があり、より高い所要C/Nの通信モードやスペクトラム削減率(詳しくは後述する)を選択できる端末局である。あるいは、当初の要求速度を下げて対応する場合(詳しくは後述する)には、受信C/Nが要求C/Nを上回る端末局でもよい。基地局は、先に譲渡局となりうる端末局を認識し、その後に譲受局となる端末局を認識した場合は、その時点で上記の手順1〜3を実行する。しかし、先に譲受局となる端末局を認識した場合は、譲渡局となりうる端末局が現れるまで所定の期間だけ手順の実行を保留する。所定の期間が経過しても譲渡局となりうる端末局が現れなければ、当該手順の実行をキャンセルする。   Here, a terminal station that can be a transfer station can obtain a reception C / N higher than the required C / N in the original communication mode and has a sufficient bandwidth, and can reduce the communication mode and spectrum of higher required C / N. It is a terminal station that can select a rate (details will be described later). Alternatively, when responding by lowering the initial request speed (details will be described later), the terminal station whose received C / N exceeds the required C / N may be used. When the base station recognizes a terminal station that can be a transfer station first, and then recognizes a terminal station that is a transfer station, the base station executes steps 1 to 3 described above. However, if the terminal station that becomes the transfer station is recognized first, the execution of the procedure is suspended for a predetermined period until a terminal station that can become the transfer station appears. If a terminal station that can be a transfer station does not appear after a predetermined period of time, the execution of the procedure is canceled.

なお、図1に示す通信シーケンスは、端末局と基地局の通信を前提としたが、端末局間の通信の場合は、基地局が送信側端末局と受信側端末局のそれぞれの伝送パラメータを決定して送信した後に、送信側端末局は、データ送信時に受信側端末局の端末局IDを付加すればよい。   The communication sequence shown in FIG. 1 is based on communication between the terminal station and the base station. However, in the case of communication between the terminal stations, the base station sets the respective transmission parameters of the transmitting terminal station and the receiving terminal station. After determining and transmitting, the transmitting terminal station may add the terminal ID of the receiving terminal station during data transmission.

図2は、本発明における帯域譲渡の実施例1を示す。実施例1は、端末局ごとの伝搬路の状況が変化しても、各端末局が当初の要求速度を達成するように各端末局間で帯域の譲渡を行う例を示す。   FIG. 2 shows a first example of band transfer according to the present invention. The first embodiment shows an example in which the bandwidth is transferred between the terminal stations so that each terminal station achieves the initial required speed even if the state of the propagation path for each terminal station changes.

図2(1) は、端末局A,B,Cの当初の帯域割当例を示す。端末局A,B,Cの要求速度をそれぞれ1Mbit/s とし、通信モードをQPSK 1/2(スペクトラム利用効率:1.00)とすると、各端末局には1MHz の帯域が割り当てられる。このとき、各端末局の受信C/Nは、QPSK 1/2の所要C/N以上になっている。   FIG. 2 (1) shows an initial band allocation example of the terminal stations A, B, and C. If the required speeds of the terminal stations A, B, and C are each 1 Mbit / s and the communication mode is QPSK 1/2 (spectrum utilization efficiency: 1.00), a band of 1 MHz is allocated to each terminal station. At this time, the reception C / N of each terminal station is equal to or higher than the required C / N of QPSK 1/2.

図2(2) は、端末局Aの受信C/Nが劣化して通信不可となり、端末局B,Cの受信C/Nが向上して帯域譲渡が可能となり、それぞれ譲受局A、譲渡局B,Cとなる例を示す。譲渡局B,Cでは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たす8PSK 3/4(スペクトラム利用効率:2.25)に変更する。このとき要求速度1Mbit/s に必要な帯域は1MHz から1/2.25=0.44MHz になり、0.56MHz の帯域が余裕となる。すなわち、譲渡局B,Cは、通信モードを変更することにより、当初の伝送速度を維持したまま、それぞれ0.56MHz ずつ合計1.12MHz の帯域が余裕となり、譲渡が可能となる。   In FIG. 2 (2), the reception C / N of the terminal station A deteriorates and communication becomes impossible, and the reception C / N of the terminal stations B and C is improved and the band can be transferred. An example of B and C will be shown. In the transfer stations B and C, the communication mode is changed from QPSK 1/2 to 8PSK 3/4 (spectrum utilization efficiency: 2.25) where the reception C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 1 Mbit / s is changed from 1 MHz to 1 / 2.25 = 0.44 MHz, and the bandwidth of 0.56 MHz is sufficient. That is, by changing the communication mode, the transfer stations B and C are able to transfer by maintaining a bandwidth of 1.12 MHz by 0.56 MHz while maintaining the original transmission speed.

図2(3) は、譲渡局B,Cから譲受局Aへの帯域の譲渡を示す。譲受局Aは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすBPSK 1/2(スペクトラム利用効率:0.50)に変更する。このとき、要求速度1Mbit/s に必要な帯域は1MHz から1/0.50=2MHz になる。譲受局Aは、譲渡局B,Cから余裕の帯域1.12MHz のうち1MHz を譲渡され、当初の帯域1MHz と合わせて2MHz を確保することにより、当初の伝送速度1Mbit/s を維持することができる。   FIG. 2 (3) shows the transfer of the band from the transfer stations B and C to the transfer station A. The assigning station A changes the communication mode from QPSK 1/2 to BPSK 1/2 (spectrum utilization efficiency: 0.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 1 Mbit / s is changed from 1 MHz to 1 / 0.50 = 2 MHz. The assigning station A is able to maintain the initial transmission speed of 1 Mbit / s by transferring 1 MHz out of the surplus bandwidth 1.12 MHz from the assigning stations B and C and securing 2 MHz together with the original band 1 MHz. .

なお、譲受局Aと、譲渡局B,Cは、それぞれの帯域の幅が変わるため、周波数が重なる場合には帯域の中心周波数を変更する。   In addition, since the widths of the respective bands of the assigning station A and the assigning stations B and C change, the center frequency of the band is changed when the frequencies overlap.

以上により、端末局ごとの伝搬路の状況が変化しても、1つの譲受局に対して1つ以上の譲渡局があれば、それぞれの通信モードを変更して譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局で当初の要求速度を維持することができる。   As described above, even if the state of the propagation path for each terminal station changes, if there are one or more transfer stations for one transfer station, the communication mode is changed to change the bandwidth from the transfer station to the transfer station. By performing the transfer, the initial required speed can be maintained at each terminal station.

図3は、本発明における帯域譲渡の実施例2を示す。実施例2は、端末局ごとの伝搬路の状況が変化しても、ノード局が利用できる全帯域の範囲で、各端末局に公平かつできるだけ高い伝送速度を提供できるように、各端末局間で帯域の譲渡を行う例を示す。   FIG. 3 shows a second embodiment of bandwidth transfer according to the present invention. In the second embodiment, even if the state of the propagation path for each terminal station changes, the terminal stations can be provided with a transmission rate that is fair and as high as possible in the range of the entire bandwidth that can be used by the node station. Shows an example of band transfer.

図3(1) は、端末局A,B,Cの当初の帯域割当例を示す。端末局A,B,Cの要求速度をそれぞれ1Mbit/s とし、通信モードをQPSK 1/2(スペクトラム利用効率:1.00)とすると、各端末局には1MHz の帯域が割り当てられる。このとき、各端末局の受信C/Nは、QPSK 1/2の所要C/N以上になっている。   FIG. 3 (1) shows an initial band allocation example of the terminal stations A, B, and C. If the required speeds of the terminal stations A, B, and C are each 1 Mbit / s and the communication mode is QPSK 1/2 (spectrum utilization efficiency: 1.00), a band of 1 MHz is allocated to each terminal station. At this time, the reception C / N of each terminal station is equal to or higher than the required C / N of QPSK 1/2.

図3(2) は、端末局Aの受信C/Nが劣化して通信不可となり、端末局B,Cの受信C/Nは向上しないが、それぞれ譲受局A、譲渡局B,Cとなる例を示す。ここで、ノード局が利用できる全帯域の範囲で、各端末局に公平かつできるだけ高い要求速度を提供するために、当初の要求速度1Mbit/s を 750kbit/s に下げる。   In FIG. 3 (2), the reception C / N of the terminal station A deteriorates and communication becomes impossible, and the reception C / N of the terminal stations B and C does not improve, but becomes the transfer station A and transfer stations B and C, respectively. An example is shown. Here, in order to provide each terminal station with the highest possible request speed in the range of the entire bandwidth that can be used by the node station, the initial request speed of 1 Mbit / s is reduced to 750 kbit / s.

譲渡局B,Cでは、通信モードをQPSK 1/2に維持したまま、伝送速度を1Mbit/s から 750kbit/s に下げると、必要とする帯域が1MHz から0.75MHz になり、0.25MHz の帯域が余裕となる。すなわち、譲渡局B,Cは、伝送速度を低下させて帯域の一部を削除することにより、それぞれ0.25MHz ずつ合計 0.5MHz の帯域が余裕となり、譲渡が可能となる。   In the transfer stations B and C, if the transmission rate is lowered from 1 Mbit / s to 750 kbit / s while maintaining the communication mode at QPSK 1/2, the required bandwidth is changed from 1 MHz to 0.75 MHz, and the bandwidth of 0.25 MHz is reduced. There will be room. That is, the transfer stations B and C reduce the transmission rate and delete a part of the band, so that a band of 0.25 MHz and a total of 0.5 MHz can be afforded and transfer is possible.

図3(3) は、譲渡局B,Cから譲受局Aへの帯域の譲渡を示す。譲受局Aは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすBPSK 1/2(スペクトラム利用効率:0.50)に変更する。このとき、要求速度 750kbit/s に必要な帯域は0.75MHz から0.75/0.50= 1.5MHz になる。譲受局Aは、譲渡局B,Cから余裕の帯域 0.5MHz を譲渡され、当初の帯域1MHz と合わせて 1.5MHz を確保することにより、要求速度 750kbit/s を達成することができる。   FIG. 3 (3) shows band transfer from the transfer stations B and C to the transfer station A. The assigning station A changes the communication mode from QPSK 1/2 to BPSK 1/2 (spectrum utilization efficiency: 0.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 750 kbit / s is changed from 0.75 MHz to 0.75 / 0.50 = 1.5 MHz. The assigning station A is able to achieve the required speed of 750 kbit / s by transferring the surplus band 0.5 MHz from the assigning stations B and C and securing 1.5 MHz together with the initial band 1 MHz.

なお、譲受局Aと、譲渡局B,Cは、それぞれの帯域の幅が変わるため、周波数が重なる場合には帯域の中心周波数を変更する。   In addition, since the widths of the respective bands of the assigning station A and the assigning stations B and C change, the center frequency of the band is changed when the frequencies overlap.

以上により、端末局ごとの伝搬路の状況が変化し、特に受信C/Nが低下して現状のままでは通信不可となる端末局が発生する一方で、受信C/Nが向上する端末局がない場合でも、要求速度を下げるとともに譲受局の通信モードを変更して譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局に公平かつできるだけ高い伝送速度を提供することができる。   As a result, the state of the propagation path for each terminal station changes. In particular, there are terminal stations that receive C / N is reduced and communication is impossible as it is. Even if there is not, it is possible to provide each terminal station with a transmission rate that is fair and as high as possible by lowering the required speed and changing the communication mode of the assigning station to transfer the band from the assigning station to the assigning station.

図4は、本発明における帯域譲渡の実施例3を示す。実施例3は、実施例1,2を合わせたものであり、受信C/Nが低下して現状のままでは通信不可となる端末局が発生する一方で、受信C/Nが向上する端末局があり、要求速度を下げるとともにそれぞれの通信モードを変更して譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局に公平かつできるだけ高い伝送速度を提供する例を示す。   FIG. 4 shows a third embodiment of bandwidth transfer according to the present invention. The third embodiment is a combination of the first and second embodiments. A terminal station in which the reception C / N is reduced and a terminal station in which communication is impossible as it is is generated, while the reception C / N is improved. An example will be shown in which each terminal station is provided with a transmission rate that is fair and as high as possible by lowering the requested speed and changing the respective communication mode to transfer the band from the transfer station to the transfer station.

図4(1) は、端末局A,Bの当初の帯域割当例を示す。端末局A,Bの要求速度をそれぞれ1Mbit/s とし、通信モードをQPSK 1/2(スペクトラム利用効率:1.00)とすると、各端末局には1MHz の帯域が割り当てられる。このとき、各端末局の受信C/Nは、QPSK 1/2の所要C/N以上になっている。   FIG. 4 (1) shows an initial band allocation example of the terminal stations A and B. If the required speeds of the terminal stations A and B are 1 Mbit / s and the communication mode is QPSK 1/2 (spectrum utilization efficiency: 1.00), a band of 1 MHz is allocated to each terminal station. At this time, the reception C / N of each terminal station is equal to or higher than the required C / N of QPSK 1/2.

図4(2) は、端末局Aの受信C/Nが劣化して通信不可となり、端末局Bの受信C/Nが向上して帯域譲渡が可能となり、それぞれ譲受局A、譲渡局Bとなる例を示す。ここでは、譲渡局Bにおいて通信モードの変更だけでは譲渡可能な十分な帯域を確保できない場合に、各端末局に公平かつできるだけ高い要求速度を提供するために、当初の要求速度1Mbit/s を 750kbit/s に下げる。   In FIG. 4 (2), the reception C / N of the terminal station A deteriorates and communication becomes impossible, and the reception C / N of the terminal station B improves and band transfer is possible. An example will be shown. Here, in the case where the transfer station B cannot secure a sufficient band that can be transferred only by changing the communication mode, the original request speed of 1 Mbit / s is set to 750 kbit in order to provide each terminal station with the highest possible request speed. Lower to / s.

譲渡局Bでは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすQPSK 3/4(スペクトラム利用効率:1.50)に変更する。このとき、要求速度1Mbit/s に必要とする帯域が1MHz から1/1.5 =0.67MHz になり、さらに要求速度 750kbit/s に下げると、必要な帯域は0.67×0.75=0.50MHz になり、0.50MHz の帯域が余裕となる。すなわち、譲渡局Bは、通信モードの変更と要求速度の低下により、0.50MHz の帯域が余裕となり、譲渡が可能となる。   In the transfer station B, the communication mode is changed from QPSK 1/2 to QPSK 3/4 (spectrum utilization efficiency: 1.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 1 Mbit / s is reduced from 1 MHz to 1 / 1.5 = 0.67 MHz, and further reduced to the required speed of 750 kbit / s, the required bandwidth is 0.67 × 0.75 = 0.50 MHz, 0.50 MHz. The bandwidth of will be enough. That is, the transfer station B can perform transfer with a margin of 0.50 MHz due to the change of the communication mode and the reduction of the required speed.

図4(3) は、譲渡局Bから譲受局Aへの帯域の譲渡を示す。譲受局Aは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすBPSK 1/2(スペクトラム利用効率:0.50)に変更する。このとき、要求速度 750kbit/s に必要な帯域は0.75MHz から0.75/0.50= 1.5MHz になる。譲受局Aは、譲渡局Bから余裕の帯域 0.5MHz を譲渡され、当初の帯域1MHz と合わせて 1.5MHz を確保することにより、要求速度 750kbit/s を達成することができる。   FIG. 4 (3) shows the band transfer from the transfer station B to the transfer station A. The assigning station A changes the communication mode from QPSK 1/2 to BPSK 1/2 (spectrum utilization efficiency: 0.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 750 kbit / s is changed from 0.75 MHz to 0.75 / 0.50 = 1.5 MHz. The assigning station A is assigned a surplus bandwidth of 0.5 MHz from the assigning station B, and can secure a required rate of 750 kbit / s by securing 1.5 MHz together with the initial bandwidth of 1 MHz.

なお、譲受局Aと、譲渡局Bは、それぞれの帯域の幅が変わるため、周波数が重なる場合には帯域の中心周波数を変更する。   In addition, since the widths of the respective bands of the assigning station A and the assigning station B change, the center frequency of the band is changed when the frequencies overlap.

以上により、端末局ごとの伝搬路の状況が変化し、特に受信C/Nが低下して現状のままでは通信不可となる端末局が発生する一方で、受信C/Nが向上する端末局があれば、それぞれの通信モードを変更し、かつ要求速度を下げて譲渡局から譲受局へ帯域の譲渡を行うことにより、各端末局に公平かつできるだけ高い伝送速度を提供することができる。   As a result, the state of the propagation path for each terminal station changes. In particular, there are terminal stations that receive C / N is reduced and communication is impossible as it is. If there is, by changing the respective communication modes and lowering the request speed and transferring the band from the transfer station to the transfer station, it is possible to provide each terminal station with the highest possible transmission rate.

実施例1の譲渡局B,Cは、受信C/Nが向上したために、所要C/Nが高くかつスペクトラム利用効率が高い通信モード、例えばQPSK 1/2から8PSK 3/4に変更することにより、スペクトラム利用効率のアップに伴う余剰帯域を確保して譲渡した。   The transfer stations B and C of the first embodiment change the communication mode having a high required C / N and high spectrum utilization efficiency, for example, from QPSK 1/2 to 8PSK 3/4 because the reception C / N is improved. The surplus bandwidth accompanying the increase in spectrum use efficiency was secured and transferred.

実施例2の譲渡局B,Cは、受信C/Nを維持しており、通信モードの切り替えによる帯域を確保できないが、各端末局に公平かつできるだけ高い伝送速度を提供するために、通信モードを維持したまま伝送速度を低下させて得られる余剰帯域を確保して譲渡した。   The transfer stations B and C of the second embodiment maintain the reception C / N and cannot secure a band by switching the communication mode. However, in order to provide each terminal station with a transmission rate that is fair and as high as possible, The surplus bandwidth obtained by reducing the transmission rate while maintaining the above was secured and transferred.

実施例3の譲渡局Bは、通信モードの切り替えによる余剰帯域を譲渡するだけでは、譲受局Aの通信速度を維持できない場合に、各端末局に公平かつできるだけ高い伝送速度を提供するために、通信モードの切り替えと伝送速度の低下による余剰帯域を確保して譲渡した。   In order to provide each terminal station with a transmission rate that is fair and as high as possible when the transfer station B of the third embodiment cannot maintain the communication speed of the transfer station A simply by transferring the surplus bandwidth by switching the communication mode. The surplus bandwidth was secured by switching the communication mode and reducing the transmission speed, and transferred.

実施例4の譲渡局は、受信C/Nが向上したときに、スペクトラム削減伝送方式(非特許文献2)により削減した帯域を譲渡する。スペクトラム削減伝送方式では、伝送速度を維持したまま、送信側で帯域の一部を削減して信号を送信する。このとき、受信側では、帯域の一部が削減されたことに伴って信号歪みが発生するが、信号補償技術により信号歪みを取り除いて正常な受信処理を行うことができる。すなわち、本方式による帯域譲渡のための帯域削減は、受信側の信号補償技術とセットで用いられることになる。   When the reception C / N is improved, the transfer station according to the fourth embodiment transfers the band reduced by the spectrum reduction transmission method (Non-Patent Document 2). In the spectrum reduction transmission method, a signal is transmitted by reducing a part of the band on the transmission side while maintaining the transmission speed. At this time, on the receiving side, signal distortion occurs as a part of the band is reduced, but normal reception processing can be performed by removing the signal distortion by the signal compensation technique. That is, the band reduction for band transfer by this method is used in combination with the signal compensation technique on the receiving side.

削減する帯域の幅を変えることにより、帯域当たりの伝送速度であるスペクトラム利用効率を変える。このとき、スペクトラム利用効率に対する所要C/Nの値は、図5に示すようにスペクトラム利用効率のアップとともにアップする。なお、スペクトラム利用効率に対する所要C/Nの変化の様子は、通信モードによって異なる。   By changing the width of the band to be reduced, the spectrum utilization efficiency, which is the transmission speed per band, is changed. At this time, the value of the required C / N for the spectrum utilization efficiency increases as the spectrum utilization efficiency increases as shown in FIG. Note that how the required C / N changes with respect to the spectrum utilization efficiency varies depending on the communication mode.

スペクトラム削減伝送方式において、削減前の帯域の幅をWb とし、削減後の帯域の幅をWa とするとき、スペクトラム削減率Cを次式で定義する。
C=1−Wa /Wb
In the spectrum reduction transmission method, when the bandwidth before reduction is Wb and the bandwidth after reduction is Wa, the spectrum reduction rate C is defined by the following equation.
C = 1-Wa / Wb

図6は、スペクトラム削減による帯域譲渡の実施例4を示す。
図6(1) は、端末局A,B,Cの当初の帯域割当例を示す。端末局A,B,Cの要求速度をそれぞれ1Mbit/s とし、通信モードをQPSK 1/2(スペクトラム利用効率:1.00)とすると、各端末局には1MHz の帯域が割り当てられる。このとき、各端末局の受信C/Nは、QPSK 1/2の所要C/N以上になっている。
FIG. 6 shows a fourth embodiment of band transfer by spectrum reduction.
FIG. 6 (1) shows an initial band allocation example of the terminal stations A, B, and C. If the required speeds of the terminal stations A, B, and C are each 1 Mbit / s and the communication mode is QPSK 1/2 (spectrum utilization efficiency: 1.00), a band of 1 MHz is allocated to each terminal station. At this time, the reception C / N of each terminal station is equal to or higher than the required C / N of QPSK 1/2.

図6(2) は、端末局Aの受信C/Nが劣化して通信不可となり、端末局B,Cの受信C/Nが向上して帯域譲渡が可能となり、それぞれ譲受局A、譲渡局B,Cとなる例を示す。   In FIG. 6 (2), the reception C / N of the terminal station A deteriorates and communication becomes impossible, and the reception C / N of the terminal stations B and C is improved so that the band can be transferred. An example of B and C will be shown.

譲渡局B,Cでは、通信モードQPSK 1/2と伝送速度1Mbit/s を維持したまま、スペクトラム削減率C=0.5 とすると、伝送速度1Mbit/s に必要とする帯域が1MHz から 0.5MHz になり、 0.5MHz の帯域が余裕となる。すなわち、譲渡局B,Cは、スペクトラム削減伝送により帯域の一部を削減することにより、それぞれ 0.5MHz ずつ合計1MHz の帯域が余裕となり、譲渡が可能となる。   In the transfer stations B and C, if the spectrum reduction rate C = 0.5 while maintaining the communication mode QPSK 1/2 and the transmission rate 1 Mbit / s, the bandwidth required for the transmission rate 1 Mbit / s is changed from 1 MHz to 0.5 MHz. A bandwidth of 0.5 MHz is sufficient. That is, the transfer stations B and C can reduce the part of the band by the spectrum reduction transmission, so that the band of 1 MHz can be afforded by a total of 0.5 MHz, and transfer is possible.

図6(3) は、譲渡局B,Cから譲受局Aへの帯域の譲渡を示す(図2(3) と同様)。譲受局Aは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすBPSK 1/2(スペクトラム利用効率:0.50)に変更する。このとき、要求速度1Mbit/s に必要な帯域は1MHz から1/0.50=2MHz になる。譲受局Aは、譲渡局B,Cから余裕の帯域1MHz を譲渡され、当初の帯域1MHz と合わせて2MHz を確保することにより、当初の伝送速度1Mbit/s を維持することができる。   FIG. 6 (3) shows the band transfer from the transfer stations B and C to the transfer station A (similar to FIG. 2 (3)). The assigning station A changes the communication mode from QPSK 1/2 to BPSK 1/2 (spectrum utilization efficiency: 0.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 1 Mbit / s is changed from 1 MHz to 1 / 0.50 = 2 MHz. The assigning station A can transfer the surplus band 1 MHz from the assigning stations B and C, and can maintain the initial transmission rate of 1 Mbit / s by securing 2 MHz together with the original band 1 MHz.

図7は、スペクトラム削減による帯域譲渡の実施例5を示す。ここでは、譲渡局B,Cが、スペクトラム削減伝送と通信モードの変更を同時に行い、譲渡する帯域を確保する例を示す。図7(1),(3) は、図6(1),(3) の実施例4と同様である。   FIG. 7 shows a fifth embodiment of band transfer by spectrum reduction. Here, an example is shown in which the transfer stations B and C perform spectrum reduction transmission and change of the communication mode at the same time to secure the band to be transferred. FIGS. 7 (1) and (3) are the same as the fourth embodiment of FIGS. 6 (1) and (3).

図7(2) において、譲渡局B,Cは、通信モードをQPSK 1/2から、受信C/Nが所要C/Nを満たすQPSK 3/4(スペクトラム利用効率:1.50)に変更する。このとき要求速度1Mbit/s に必要な帯域は1MHz から1/1.50=0.67MHz になり、0.33MHz の帯域が余裕となる。すなわち、譲渡局B,Cは、通信モードを変更することにより、当初の伝送速度を維持したまま、それぞれ0.33MHz ずつ合計0.66MHz の帯域が余裕となり、譲渡が可能となる。   In FIG. 7 (2), the transfer stations B and C change the communication mode from QPSK 1/2 to QPSK 3/4 (spectrum utilization efficiency: 1.50) where the received C / N satisfies the required C / N. At this time, the bandwidth required for the required speed of 1 Mbit / s is changed from 1 MHz to 1 / 1.50 = 0.67 MHz, and the bandwidth of 0.33 MHz is sufficient. That is, by changing the communication mode, the transfer stations B and C can perform transfer with a margin of 0.36 MHz and a total bandwidth of 0.66 MHz while maintaining the original transmission speed.

しかし、このままでは1MHz の帯域譲渡を必要としている譲受局Aの要求を満たすことができない。そこで、伝送速度1Mbit/s を維持したまま、スペクトラム削減率C=0.25とすると、伝送速度1Mbit/s に必要とする帯域が0.67MHz から 0.5MHz になり、 0.5MHz の帯域が余裕となる。すなわち、譲渡局B,Cは、通信モードの変更と、スペクトラム削減伝送により帯域の一部を削減することにより、それぞれ 0.5MHz ずつ合計1MHz の帯域が余裕となり、譲渡が可能となる。   However, if it remains as it is, it will not be possible to satisfy the request of the assigning station A that needs to transfer the bandwidth of 1 MHz. Therefore, if the spectrum reduction rate C is set to 0.25 while maintaining the transmission rate of 1 Mbit / s, the bandwidth required for the transmission rate of 1 Mbit / s is changed from 0.67 MHz to 0.5 MHz, and the bandwidth of 0.5 MHz is sufficient. That is, the transfer stations B and C can transfer by changing the communication mode and reducing a part of the band by the spectrum reduction transmission, so that a total of 1 MHz band can be obtained by 0.5 MHz respectively.

同様に、譲渡局B,Cは、通信モードの変更と、スペクトラム削減伝送による帯域の一部削減と、要求速度を下げることにより、譲渡局B,Cから譲受局Aへ譲渡する帯域を確保し、各端末局に公平かつできるだけ高い伝送速度を提供するようにしてもよい。このように、以上示した各実施例は適宜組み合わせることができる。   Similarly, the transfer stations B and C secure the band to be transferred from the transfer stations B and C to the transfer station A by changing the communication mode, partially reducing the band by spectrum reduction transmission, and reducing the request speed. It is also possible to provide each terminal station with a transmission rate that is fair and as high as possible. Thus, the embodiments described above can be combined as appropriate.

また、以上の各実施例において、各端末局の要求速度を均一の1Mbit/s としたが、必ずしも均一である必要はなく、端末局ごとに異なる要求速度を維持するように帯域譲渡を行うようにしてもよい。また、各端末局に対する公平かつできるだけ高い伝送速度は、必ずしも均一である必要はなく、当初の要求速度に対する伝送速度の比率が公平であってもよい。   Further, in each of the embodiments described above, the requested speed of each terminal station is set to a uniform 1 Mbit / s, but it is not necessarily uniform, and band transfer is performed so as to maintain a different requested speed for each terminal station. It may be. In addition, the transmission rate that is fair and as high as possible for each terminal station does not necessarily have to be uniform, and the ratio of the transmission rate to the initial required rate may be fair.

実施例1〜実施例5の譲受局Aでは、当初の帯域1MHz と、譲渡局B,Cまたは譲受局Bから譲渡された帯域とを連続した帯域として利用したが、実施例6の譲受局Aは、スペクトラム合成伝送方式(非特許文献3)を用いることにより、譲渡された帯域をそのまま利用する。図8は、実施例1に適用した帯域譲渡の実施例6を示すが、実施例2〜実施例5に適用する場合にも同様である。譲受局Aは、譲渡局B,Cから譲渡された帯域を含む合計2MHz の帯域でスペクトラム合成伝送を行う。   In the assigning station A of the first to fifth embodiments, the initial band 1 MHz and the band assigned from the assigning stations B, C or the assigning station B are used as continuous bands. Uses the assigned band as it is by using the spectrum synthesis transmission system (Non-patent Document 3). FIG. 8 shows a band transfer embodiment 6 applied to the embodiment 1, but the same applies to the case of applying the embodiment 2 to the embodiment 5. The assigning station A performs spectrum synthesis transmission in a band of 2 MHz in total including the bands assigned from the assigning stations B and C.

スペクトラム合成伝送方式は、送信側で伝送速度を保ったまま、周波数軸上で連続した帯域を複数の狭い帯域(サブスペクトラム)に分割して信号の送信を行う。受信側では、複数の狭い帯域を送信側と同じ周波数軸上で連続した帯域に合成し、伝送データを復元する。このスペクトラム合成伝送方式を用いることにより、帯域の譲渡前後のスペクトラムの中心周波数を変える必要がない利点がある。   In the spectrum synthesis transmission system, signals are transmitted by dividing a continuous band on the frequency axis into a plurality of narrow bands (sub-spectrums) while maintaining the transmission speed on the transmission side. On the receiving side, a plurality of narrow bands are combined into a continuous band on the same frequency axis as that on the transmitting side to restore the transmission data. By using this spectrum synthesis transmission method, there is an advantage that it is not necessary to change the center frequency of the spectrum before and after the band transfer.

図9は、本発明の無線通信システムの基地局および端末局の構成例を示す。
図9において、無線通信システムを構成する基地局10は、アンテナ部11、送受信部12、アクセス制御部13、回線管理データベース(DB)14、回線割当処理部15、データ入出力部16により構成され、端末局20は、アンテナ部21、送受信部22、アクセス制御部23、伝搬路測定部24、回線要求部25、データ入出力部26により構成される。
FIG. 9 shows a configuration example of a base station and a terminal station of the wireless communication system of the present invention.
In FIG. 9, a base station 10 constituting a wireless communication system includes an antenna unit 11, a transmission / reception unit 12, an access control unit 13, a line management database (DB) 14, a line allocation processing unit 15, and a data input / output unit 16. The terminal station 20 includes an antenna unit 21, a transmission / reception unit 22, an access control unit 23, a propagation path measurement unit 24, a line request unit 25, and a data input / output unit 26.

基地局10は、回線管理DB14において、端末局IDと関連付けて端末局ごとの伝搬利得(伝搬路の状況を数値化した値、例えば受信C/N)と伝送パラメータをデータベース化している。送受信部12から回線要求信号を受信すると、アクセス制御部13が端末局IDと要求速度の情報を取り出し、回線割当処理部15に通知する。回線割当処理部15は、回線管理DB14から端末局IDに対する伝搬利得を取り出し、要求速度と伝搬利得から、通信モードと帯域を決定する。さらに、回線管理DB14から帯域を配置できる未使用帯域の中心周波数を決定する。その後、当該端末局へ決定した伝送パラメータを返信すると共に、回線管理DB14の当該端末局の端末局IDに対する伝送パラメータをアップデートする。送受信部12から伝搬利得を受信すると、アクセス制御部13が端末局IDと伝搬利得を取り出し、回線管理DB14の内容をアップデートする。このとき伝搬利得から当該端末局IDの受信C/Nを計算し、所要C/Nを下回る場合、当該端末局IDを譲受局とする。また、回線管理DB14から譲渡局を決定し、本発明の方法により譲受局と譲渡局の伝送パラメータを決定し、それらの局に返信すると共に、回線管理DB14の伝送パラメータをアップデートする。また、データ入出力部16から送受信部12にデータが入力されると、アクセス制御部13でデータに送信先の端末局IDを付加して送受信部12から送信する。また、送受信部から受信したデータに基地局IDが付加されていることをアクセス制御部で検知すると、データをデータ入出力部から出力する。   In the line management DB 14, the base station 10 creates a database of propagation gains (values obtained by digitizing propagation path conditions, for example, reception C / N) and transmission parameters for each terminal station in association with the terminal station ID. When a line request signal is received from the transmission / reception unit 12, the access control unit 13 extracts information on the terminal station ID and the requested speed and notifies the line allocation processing unit 15. The line allocation processing unit 15 extracts the propagation gain for the terminal station ID from the line management DB 14, and determines the communication mode and band from the requested speed and the propagation gain. Further, the center frequency of the unused band where the band can be allocated is determined from the line management DB 14. Thereafter, the determined transmission parameter is returned to the terminal station, and the transmission parameter for the terminal station ID of the terminal station in the line management DB 14 is updated. When the propagation gain is received from the transmission / reception unit 12, the access control unit 13 extracts the terminal station ID and the propagation gain, and updates the contents of the line management DB 14. At this time, the received C / N of the terminal station ID is calculated from the propagation gain, and if the received C / N is lower than the required C / N, the terminal station ID is set as the assigning station. Also, the transfer station is determined from the line management DB 14, the transmission parameters of the transfer station and the transfer station are determined by the method of the present invention, and the transmission parameters of the line management DB 14 are updated while returning to those stations. When data is input from the data input / output unit 16 to the transmission / reception unit 12, the access control unit 13 adds the transmission destination terminal station ID to the data and transmits the data from the transmission / reception unit 12. When the access control unit detects that the base station ID is added to the data received from the transmission / reception unit, the data is output from the data input / output unit.

端末局20は、伝搬路測定部24で一定間隔で伝搬利得を測定し、アクセス制御部23で伝搬利得に端末局IDを付加して送受信部22から基地局10に送信する。また、通信要求が発生すると、アクセス制御部23で要求速度に端末局IDを付加して送受信部22から基地局10に送信する。また、アクセス制御部23において、送受信部22から受信した伝送パラメータに当該端末局の端末局IDが付加されていることを検知すると、伝送パラメータの内容を送受信部22に設定し、以降は当該伝送パラメータを用いて信号の送受信を行う。また、データ入出力部26から送受信部22にデータが入力されると、アクセス制御部23でデータに送信先の基地局IDを付加して送受信部22から送信する。また、送受信部22から受信したデータに当該端末局の端末局IDが付加されていることをアクセス制御部23で検知すると、データをデータ入出力部26から出力する。   In the terminal station 20, the propagation path measurement unit 24 measures the propagation gain at regular intervals, the access control unit 23 adds the terminal station ID to the propagation gain, and transmits the transmission gain from the transmission / reception unit 22 to the base station 10. When a communication request is generated, the access control unit 23 adds the terminal station ID to the requested speed and transmits the request from the transmission / reception unit 22 to the base station 10. When the access control unit 23 detects that the terminal station ID of the terminal station is added to the transmission parameter received from the transmission / reception unit 22, the content of the transmission parameter is set in the transmission / reception unit 22, and thereafter the transmission parameter is transmitted. Signals are transmitted and received using parameters. When data is input from the data input / output unit 26 to the transmission / reception unit 22, the access control unit 23 adds the transmission destination base station ID to the data and transmits the data from the transmission / reception unit 22. When the access control unit 23 detects that the terminal station ID of the terminal station is added to the data received from the transmission / reception unit 22, the data is output from the data input / output unit 26.

端末局20において、伝搬利得を測定する方法として、図10に示す3通りの方法がある(非特許文献4)。
図10(1) のオープンループ方式は、通信衛星(ノード局)から一定電力で常時送信されるビーコン波を端末局が受信し、ビーコン波の受信レベルから伝搬利得を得る。
As a method for measuring the propagation gain in the terminal station 20, there are three methods shown in FIG. 10 (Non-Patent Document 4).
In the open loop system of FIG. 10 (1), a terminal station receives a beacon wave that is constantly transmitted from a communication satellite (node station) at a constant power, and obtains a propagation gain from the reception level of the beacon wave.

図10(2) のクローズドループ方式は、通信衛星(ノード局)へ折り返し信号を送信し、自局に折り返された信号の受信レベルから伝搬利得を得る。
図10(3) のフィードバック方式は、端末局から一定電力で送信される信号を通信衛星(ノード局)を介して基地局で受信し、その受信レベルから伝搬利得を測定し、端末局にフィードバックする。
In the closed loop system of FIG. 10 (2), a return signal is transmitted to a communication satellite (node station), and a propagation gain is obtained from the reception level of the signal returned to the own station.
In the feedback system of FIG. 10 (3), a signal transmitted at a constant power from a terminal station is received by a base station via a communication satellite (node station), a propagation gain is measured from the received level, and feedback is provided to the terminal station. To do.

(性能評価)
無線サービスエリア内をランダム移動する多数の端末局への回線割当のシミュレーションを行い、従来技術と本発明による伝送速度の公平性指標を比較する。公平性指標は公平性を示す一般的な指標であり、非特許文献5に記載がある。0から1までの値をとり1に近いほど公平性が高い。要求速度は当初は1600kbit/s とするが、1600kbit/s が達成できないときは、順次800, 400, 200, 100kbit/s へと低下させる。また、端末局の伝搬路の状況が変化し可能な場合は、より高い要求速度に変更する。ノード局の全帯域は72MHz とした。その結果、公平性指標および伝送速度合計は次のようになった。
従来技術: 0.43 、 975Mbit/s
本発明 : 0.90 、1068Mbit/s
このように、本発明は従来技術によりも公平性指標が1に近くなると同時に、全端末局の伝送速度の合計値も高くなる。
(Performance evaluation)
A simulation of line allocation to a large number of terminal stations moving randomly in a wireless service area is performed, and the fairness index of the transmission rate according to the prior art and the present invention is compared. The fairness index is a general index indicating fairness and is described in Non-Patent Document 5. The value from 0 to 1 is closer to 1, and the fairness is higher. The required speed is initially 1600 kbit / s, but when 1600 kbit / s cannot be achieved, the speed is reduced to 800, 400, 200, 100 kbit / s. In addition, when the state of the propagation path of the terminal station can be changed, it is changed to a higher required speed. The total bandwidth of the node station is 72 MHz. As a result, the fairness index and the total transmission rate are as follows.
Conventional technology: 0.43, 975Mbit / s
The present invention: 0.90, 1068 Mbit / s
As described above, according to the present invention, the fairness index is close to 1 as compared with the prior art, and at the same time, the total value of the transmission rates of all the terminal stations is increased.

10 基地局
11 アンテナ部
12 送受信部
13 アクセス制御部
14 回線管理データベース(DB)
15 回線割当処理部
16 データ入出力部
20 端末局
21 アンテナ部
22 送受信部
23 アクセス制御部
24 伝搬路測定部
25 回線要求部
26 データ入出力部
DESCRIPTION OF SYMBOLS 10 Base station 11 Antenna part 12 Transmission / reception part 13 Access control part 14 Line management database (DB)
DESCRIPTION OF SYMBOLS 15 Line allocation process part 16 Data input / output part 20 Terminal station 21 Antenna part 22 Transmission / reception part 23 Access control part 24 Propagation path measurement part 25 Line request part 26 Data input / output part

Claims (8)

複数の端末局と、当該端末局の通信を中継するノード局と、これらの通信に用いる通信回線の割り当てを行う基地局とにより構成され、端末局ごとの伝搬路の伝搬利得および要求速度に基づいて割り当てられた通信回線により各端末局が通信を行う無線通信システムの回線割当方法において、
前記端末局は、一定間隔で前記伝搬路の伝搬利得を検知して前記基地局に通知し、
前記基地局は、前記伝搬路の伝搬利得が低下し、当該低下した伝搬利得に対応してスペクトラム利用効率の低い通信モードに変更したときに帯域不足により要求速度を満たせない端末局(以下、譲受局という)に対して、回線割当当初の伝搬利得を維持または向上した端末局(以下、譲渡局という)から余剰となる帯域の一部を譲渡し、前記通信回線の再割り当てを行って譲受局および譲渡局が通信を継続する制御を行う
ことを特徴とする回線割当方法。
It is composed of a plurality of terminal stations, a node station that relays the communication of the terminal station, and a base station that allocates a communication line used for these communications, and is based on the propagation gain and required speed of the propagation path for each terminal station In the line assignment method of the wireless communication system in which each terminal station communicates with the assigned communication line,
The terminal station detects the propagation gain of the propagation path at regular intervals and notifies the base station,
The base station reduces the propagation gain of the propagation path, and when changing to a communication mode with low spectrum utilization efficiency corresponding to the reduced propagation gain, the base station cannot satisfy the required speed due to insufficient bandwidth (hereinafter referred to as transfer). A portion of the surplus bandwidth from a terminal station (hereinafter referred to as a transfer station) that has maintained or improved the propagation gain at the time of line allocation to the station, and reassigns the communication line to the transfer station. And a line assignment method, wherein the transfer station performs control to continue communication.
請求項1に記載の回線割当方法において、
前記基地局は、前記譲渡局でスペクトラム利用効率の高い通信モードに変えたときに、前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う
ことを特徴とする回線割当方法。
The line allocation method according to claim 1,
The base station calculates a surplus band to achieve the required speed when the transfer station changes to a communication mode with high spectrum use efficiency, and further sets the communication mode with low spectrum use efficiency at the transfer station. When the change is made, the bandwidth that is insufficient to achieve the required speed is calculated, the surplus bandwidth at at least one of the transfer stations is transferred to the transfer station, and the communication line including the switching of the communication mode A circuit allocation method characterized by performing reallocation.
請求項1に記載の回線割当方法において、
前記基地局は、前記譲渡局および前記譲受局の前記要求速度を下げたときに、前記譲渡局で前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記下げた要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う
ことを特徴とする回線割当方法。
The line allocation method according to claim 1,
The base station calculates a surplus bandwidth in achieving the requested speed at the assigning station when the requested speed of the assigning station and the assigning station is lowered, and further, the base station calculates spectrum utilization efficiency. When the communication mode is changed to a low communication mode, a bandwidth that is insufficient to achieve the reduced request speed is calculated, and at least one of the transfer stations transfers an excess band to the transfer station, and the communication mode is switched. A line allocating method comprising: reallocating the communication line including:
請求項1に記載の回線割当方法において、
前記基地局は、前記譲渡局でスペクトラム削減伝送を行ったときに、前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う
ことを特徴とする回線割当方法。
The line allocation method according to claim 1,
The base station, when performing spectrum reduction transmission at the transfer station, calculates a surplus band to achieve the required speed, and when the transfer station changes to a communication mode with low spectrum utilization efficiency , before Kiyo calculates a band of insufficient in attaining a determined speed, the transfer of the band of surplus at least one of said transfer station to said acquisition station, reallocation of the communication line including a switching of the communication mode A circuit allocation method characterized by:
複数の端末局と、当該端末局の通信を中継するノード局と、これらの通信に用いる通信回線の割り当てを行う基地局とにより構成され、端末局ごとの伝搬路の伝搬利得および要求速度に基づいて割り当てられた通信回線により各端末局が通信を行う無線通信システムにおいて、
前記端末局は、一定間隔で前記伝搬路の伝搬利得を検知して前記基地局に通知する手段を備え、
前記基地局は、前記伝搬路の伝搬利得が低下し、当該低下した伝搬利得に対応してスペクトラム利用効率の低い通信モードに変更したときに帯域不足により要求速度を満たせない端末局(以下、譲受局という)に対して、回線割当当初の伝搬利得を維持または向上した端末局(以下、譲渡局という)から余剰となる帯域の一部を譲渡し、前記通信回線の再割り当てを行って譲受局および譲渡局が通信を継続する制御を行う制御手段を備えた
ことを特徴とする無線通信システム。
It is composed of a plurality of terminal stations, a node station that relays the communication of the terminal station, and a base station that allocates a communication line used for these communications, and is based on the propagation gain and required speed of the propagation path for each terminal station In a wireless communication system in which each terminal station communicates through a communication line assigned in
The terminal station comprises means for detecting a propagation gain of the propagation path at regular intervals and notifying the base station;
The base station reduces the propagation gain of the propagation path, and when changing to a communication mode with low spectrum utilization efficiency corresponding to the reduced propagation gain, the base station cannot satisfy the required speed due to insufficient bandwidth (hereinafter referred to as transfer). A portion of the surplus bandwidth from a terminal station (hereinafter referred to as a transfer station) that has maintained or improved the propagation gain at the time of line allocation to the station, and reassigns the communication line to the transfer station. And a wireless communication system comprising control means for controlling the transfer station to continue communication.
請求項5に記載の無線通信システムにおいて、
前記端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段を備え、
前記基地局の制御手段は、前記譲渡局でスペクトラム利用効率の高い通信モードに変えたときに、前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う構成である
ことを特徴とする無線通信システム。
The wireless communication system according to claim 5, wherein
The terminal station comprises means for switching to a communication mode with different spectrum utilization efficiency,
The control means of the base station calculates a surplus band to achieve the required speed when the transfer station changes to a communication mode with high spectrum use efficiency, and further, the transfer station has low spectrum use efficiency. Calculating a bandwidth that is insufficient to achieve the required speed when changing to the communication mode, transferring a surplus bandwidth to at least one of the transfer stations to the transfer station, and including switching the communication mode A wireless communication system, characterized in that the communication line is reassigned.
請求項5に記載の無線通信システムにおいて、
前記端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段を備え、
前記基地局の制御手段は、前記譲渡局および前記譲受局の前記要求速度を下げたときに、前記譲渡局で前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記下げた要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う構成である
ことを特徴とする無線通信システム。
The wireless communication system according to claim 5, wherein
The terminal station comprises means for switching to a communication mode with different spectrum utilization efficiency,
The control means of the base station calculates a surplus band in achieving the requested speed at the assigning station when the requested speed of the assigning station and the assigning station is lowered, and further the spectrum at the assigning station When changing to a communication mode with low utilization efficiency, a bandwidth that is insufficient to achieve the reduced request speed is calculated, and an excess bandwidth is assigned to the assigning station in at least one of the assigning stations, and the communication A wireless communication system, wherein the communication line is reassigned including mode switching.
請求項5に記載の無線通信システムにおいて、
前記端末局は、スペクトラム利用効率の異なる通信モードに切り替える手段と、スペクトラム削減伝送を行う手段とを備え、
前記基地局の制御手段は、前記譲渡局でスペクトラム削減伝送を行ったときに、前記要求速度を達成するにあたり余剰となる帯域を計算し、さらに前記譲受局でスペクトラム利用効率の低い通信モードに変えたときに、前記要求速度を達成するにあたり不足となる帯域を計算し、少なくとも1つの前記譲渡局で余剰となる帯域を前記譲受局に譲渡し、前記通信モードの切り替えを含む前記通信回線の再割り当てを行う構成である
ことを特徴とする無線通信システム。
The wireless communication system according to claim 5, wherein
The terminal station comprises means for switching to a communication mode with different spectrum utilization efficiency, and means for performing spectrum reduction transmission,
The control means of the base station calculates a surplus band for achieving the required speed when spectrum transfer is performed at the transfer station, and further changes to a communication mode with low spectrum use efficiency at the transfer station. when the, the band of insufficient in attaining the pre Kiyo determined rate is calculated, the transfer of the band of surplus at least one of said transfer station to said acquisition station, said communication line including a switching of the communication mode A wireless communication system, characterized by being configured to perform reallocation.
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