JP2778794B2 - Mobile propagation delay reduction method - Google Patents
Mobile propagation delay reduction methodInfo
- Publication number
- JP2778794B2 JP2778794B2 JP2080597A JP8059790A JP2778794B2 JP 2778794 B2 JP2778794 B2 JP 2778794B2 JP 2080597 A JP2080597 A JP 2080597A JP 8059790 A JP8059790 A JP 8059790A JP 2778794 B2 JP2778794 B2 JP 2778794B2
- Authority
- JP
- Japan
- Prior art keywords
- station
- transmission power
- wave
- mobile
- relay
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Mobile Radio Communication Systems (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、ディジタル信号を用いた陸上移動通信の伝
搬遅延軽減方法に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing propagation delay in land mobile communication using digital signals.
［従来の技術］ 陸上移動通信においては、電波がビル反射などにより
複数の伝搬路を通るため、受信局では時間的に遅れた複
数の電波が到来する。この伝搬遅延によって、ディジタ
ル信号を用いた移動通信では、複数の受信波の伝搬遅延
差が増加すると通信品質（信号誤り率）が悪化する（文
献「F.Adachi,J.D.Parsons:“Error Rate Performance
of Digital FM Mobile Radio with Postdetection Dive
rsity",IEEE Trans Commun.,vol.37,No3,pp200−210,Ma
r.1989.」参照）。[Related Art] In land mobile communication, radio waves pass through a plurality of propagation paths due to building reflection or the like, so that a plurality of radio waves delayed in time arrive at a receiving station. Due to the propagation delay, in mobile communication using digital signals, the communication quality (signal error rate) deteriorates when the propagation delay difference between a plurality of received waves increases (see "F. Adachi, JDParsons:" Error Rate Performance ").
of Digital FM Mobile Radio with Postdetection Dive
rsity ", IEEE Trans Commun., vol.37, No3, pp200-210, Ma
r.1989. ").
伝搬遅延による通信品質は（１）式で定義される伝搬
遅延時間の２次モーメント（以下遅延スプレッドと言
う）で評価することができ、遅延スプレッドが大きいと
通信品質が劣化する。Communication quality due to propagation delay can be evaluated by the second moment of propagation delay time (hereinafter referred to as delay spread) defined by equation (1). If the delay spread is large, communication quality deteriorates.
第１図は伝搬遅延が発生した場合の受信波の様子を表
わしており、受信電力がL0,L1……LNでL0に対する相対
遅延時間がT1,……TNとなるＮ波の例である。このとき
の遅延スプレッドは次のように計算される。Figure 1 represents the state of the reception wave when the propagation delay occurs, the received power is L 0, L 1 ...... relative delay time T 1 for L 0 at L N, the ...... T N N It is an example of a wave. The delay spread at this time is calculated as follows.
ここで、 である。 here, It is.
例えば、TV放送の受信において、伝搬遅延が生じてゴ
ーストが発生する場合の対策として、遅れて到来する反
射波の発生源となるビル等に電波散乱物を設ける方法
や、受信アンテナの設置位置を変える等の方法が上げら
れる。しかし、自由に動き回る移動局を対象とする有効
な改善方法は従来なかった。For example, in the reception of TV broadcasts, as a countermeasure for the case where a ghost occurs due to propagation delay, a method of providing a radio wave scattered object in a building or the like which is a source of a reflected wave arriving late, or an installation position of a receiving antenna is required. There are ways to change it. However, there has been no effective improvement method for mobile stations that move freely.
［発明が解決しようとする課題］ 通信品質を改善するために遅延スプレッドを減少させ
るには、受信電力の大きい波の電力をさらに大きくす
る、特定の受信波以外の波を無くすか、減少させる、
受信電力の大きい波を付け加える、相対遅延時間を
短くする、などが考えられる。[Problems to be Solved by the Invention] In order to reduce the delay spread in order to improve the communication quality, the power of a wave having a large received power is further increased, the wave other than the specific received wave is eliminated or reduced,
It is conceivable to add a wave having a large received power or to shorten the relative delay time.
これらの内の方法については、従来、例えば自動車
電話方式において、弱電界地域をカバーするためにブー
スタ増幅器が使用されている。Of these methods, booster amplifiers have been used to cover weak electric field areas, for example, in car telephone systems.
このようなブースタ増幅器によって遅延スプレッドを
減少させることができるが、以下にその原理を説明す
る。The delay spread can be reduced by such a booster amplifier, and its principle will be described below.
第３図は受信局でみた到来波の様子を示す図であり、
（ａ）は中継局を用いない場合で（ｂ）は線形増幅器を
備えた中継局を用いた場合を示している。例えば（ａ）
に示すように直接波L0とビル反射波L1が到来し、直接波
の受信電力はL0＝３、ビル反射波のそれはL1＝２、直接
波からの相対遅延時間はT1＝３の場合に（１）式で遅延
スプレッドを計算するとＳ＝1.5となる。（ｂ）では中
継波L2が加わった場合を計算すると遅延スプレッドはＳ
＝1.0となり減少することがわかる。FIG. 3 is a diagram showing the state of an incoming wave as viewed at a receiving station;
(A) shows a case where a relay station is not used, and (b) shows a case where a relay station having a linear amplifier is used. For example, (a)
As shown in FIG. 6, the direct wave L 0 and the building reflected wave L 1 arrive, the received power of the direct wave is L 0 = 3, that of the building reflected wave is L 1 = 2, and the relative delay time from the direct wave is T 1 = In the case of 3, when the delay spread is calculated by the equation (1), S = 1.5. A delay spread (b) the relay wave L 2 calculates the case where applied is S
= 1.0, which indicates a decrease.
このようにブースタ増幅器を用いれば遅延スプレッド
を低減せしめることができる。このとき、中継波の電力
を大きくすれば、遅延スプレッドを減少できるが高利得
の増幅器が必要となり、中継局が大型になると言う欠点
を生ずる。Thus, the delay spread can be reduced by using the booster amplifier. At this time, if the power of the relay wave is increased, the delay spread can be reduced, but a high-gain amplifier is required, resulting in a disadvantage that the relay station becomes large.
本発明は、上記のような従来の問題点に鑑み、受信電
力が一定となるように相手局の送信電力を制御する送信
電力制御を基地局あるいは移動局の少なくとも一方で行
なうディジタル信号を用いた陸上移動通信において、伝
搬遅延を軽減せしめ得る手段を提供することを目的とし
ている。The present invention, in view of the above-described conventional problems, uses a digital signal that performs transmission power control for controlling transmission power of a partner station so that reception power is constant at least one of a base station and a mobile station. It is an object of the present invention to provide means capable of reducing propagation delay in land mobile communication.
［課題を解決するための手段］ 本発明は、前述のような従来の問題点を解決するため
成されたものである。[Means for Solving the Problems] The present invention has been made to solve the conventional problems as described above.
すなわち、本発明は受信電力に関係なく、送信電力が
一定となるように自動的に利得の調整を行なう可変利得
増幅器を備えた中継局を基地局からの伝搬遅延が発生し
ない位置に設置し、該中継局の基地局向けおよび移動局
向けの平均送信電力を一定に保ち、送信電力制御によ
り、基地局および移動局の送信電力を低くすることによ
って、伝搬遅延による通信品質の劣化を軽減せしめる如
く構成した移動伝搬遅延軽減方法である。That is, regardless of the received power, the present invention installs a relay station having a variable gain amplifier that automatically adjusts the gain so that the transmission power becomes constant at a position where propagation delay from the base station does not occur, By keeping the average transmission power of the relay station for the base station and the mobile station constant and reducing the transmission power of the base station and the mobile station by the transmission power control, it is possible to reduce the deterioration of the communication quality due to the propagation delay. This is a configured mobile propagation delay reduction method.
［作 用］ 第３図（ｂ）に示すように線形増幅器を用いて遅延ス
プレッドを減少させているとき、さらに遅延スプレッド
を減少させるには、後述する第２図における中継波３を
減少させずに直接波１と反射波２を減少させればよい。
直接波１や反射波２を減少させるために送信電力制御を
行なうと従来の線形増幅器では中継波３も同じ割合で減
少してしまい、第３図（ｃ）に示すように遅延スプレッ
ドは変わらない。[Operation] As shown in FIG. 3 (b), when the delay spread is reduced by using a linear amplifier, the delay spread can be further reduced without reducing the relay wave 3 in FIG. In this case, the direct wave 1 and the reflected wave 2 may be reduced.
When transmission power control is performed to reduce the direct wave 1 and the reflected wave 2, the relay wave 3 decreases at the same rate in the conventional linear amplifier, and the delay spread does not change as shown in FIG. 3 (c). .
本発明では、送信電力制御を行なっているとき、受信
電力に関わらず送信電力が一定となる可変利得増幅器を
用いることにより、第３図（ｄ）に示すように、中継波
L2の電力は一定で直接波L0と反射波L1の電力を減少さ
せ、その結果遅延スプレッドを減少させるものである。In the present invention, when the transmission power control is performed, a variable gain amplifier is used in which the transmission power is constant irrespective of the reception power, as shown in FIG.
Power of L 2 reduces the power of the reflected wave L 1 and the direct wave L 0 at a constant, but to reduce the resulting delay spread.
基地局〜移動局間の電波を可変利得増幅器を備えた中
継局で中継している間は送信局（例えば基地局）の送信
電力の如何にかかわらず常に一定電力で中継局から送信
されるので受信局では充分高いレベルで受信することが
できるから、送信局は常に受信局からの送信電力制御に
よって、送信電力を下げるように制御される。While the radio wave between the base station and the mobile station is relayed by the relay station provided with the variable gain amplifier, the power is always transmitted from the relay station at a constant power regardless of the transmission power of the transmitting station (for example, the base station). Since the receiving station can receive at a sufficiently high level, the transmitting station is always controlled to reduce the transmission power by the transmission power control from the receiving station.
第４図は可変利得増幅器の入出力特性を示す図であ
る。同図に示すように、入力が小さい場合に一定出力V2
まで増幅すると雑音が発生するので、小さい入力では動
作しないようにスレッショルドV0を設定する。最低基準
入力V1以上では一定出力V2となる。入力が最低基準入力
V1付近で変動する場合に送信が途切れ途切れにならない
ように、入出力特性の立ち上がり部分は連続にする。移
動局がエリア外にいるとき、基地局からの送信波を中継
しないようにし、移動局からの送信波が中継可能になっ
てから初めて基地局からの送信波を中継する。そのため
に、中継局内の移動局送信周波数の増幅器によって基地
局送信周波数の増幅器の動作を制御できるようにする。FIG. 4 is a diagram showing input / output characteristics of the variable gain amplifier. As shown in the figure, when the input is small, the constant output V 2
Since noise is generated when amplified to, for small input to set the threshold V 0 so as not to operate. Constant output V 2 at the lowest reference input V 1 or more. Input is the lowest reference input
As it does not become choppy sent if fluctuates around V 1, the rising portion of the input-output characteristic is continuous. When the mobile station is out of the area, the transmission wave from the base station is not relayed, and the transmission wave from the base station is relayed only after the transmission wave from the mobile station can be relayed. For this purpose, the operation of the base station transmission frequency amplifier can be controlled by the mobile station transmission frequency amplifier in the relay station.
［実施例］ 第２図は本発明を実施するシステム構成を説明する図
であって、１は直接波、２はビル反射波、３は中継波、
４は移動機、５は無線基地局、６は可変利得増幅器を備
えた中継局、７は中継局の指向性アンテナ、８は中継局
のカバーエリア、９はビル、10は基地局５の無線ゾー
ン、８は中継局６の無線ゾーンを表わしている。同図に
示すように中継局６の無線ゾーンは無線ゾーン10の内部
に形成されるように構成される。Embodiment FIG. 2 is a diagram for explaining a system configuration for implementing the present invention, wherein 1 is a direct wave, 2 is a building reflected wave, 3 is a relay wave,
4 is a mobile station, 5 is a radio base station, 6 is a relay station equipped with a variable gain amplifier, 7 is a directional antenna of the relay station, 8 is a cover area of the relay station, 9 is a building, and 10 is a radio of the base station 5. The zone 8 indicates the radio zone of the relay station 6. As shown in the figure, the wireless zone of the relay station 6 is configured to be formed inside the wireless zone 10.
第５図は移動局送信、基地局受信の場合の送受信電力
のタイムチャートである。これを用いて移動局が中継局
のエリア外からエリア内に入り再びエリア外に移動する
までの動作を第２図を参照しながら説明する。なお、基
地局送信、移動局受信の場合も同様である。FIG. 5 is a time chart of transmission / reception power in the case of mobile station transmission and base station reception. With reference to FIG. 2, the operation until the mobile station enters the area from outside the relay station and moves again outside the area will be described with reference to FIG. The same applies to base station transmission and mobile station reception.
（移動局はカバーエリア８の外の場合） 移動局４がカバーエリア８の外にいる場合は、無線
ゾーン５の内部にいるから基地局と移動局間の従来と同
様の送信電力制御によって、基地局および移動局は一定
の所要電力V3を受信する。(When the mobile station is outside the cover area 8) When the mobile station 4 is outside the cover area 8, since the mobile station 4 is inside the radio zone 5, the transmission power control between the base station and the mobile station is performed in the same manner as in the related art. base station and the mobile station receives the constant power requirements V 3.
（移動局はカバーエリア８に入る場合） 〜 中継局は移動局がカバーエリアに近づいて、動
作入力V0（第４図参照）以上の電力を受信すると中継を
開始する。基地局では所要受信電力V3以上の電力が受信
されると、送信電力制御によって、移動局の送信電力を
下げるよう制御する。(Mobile station when entering the coverage area 8) to the relay station the mobile station is approaching the coverage area starts to relay and receive more power than operating input V 0 (see Figure 4). When the base station required received power V 3 or more power is received, the transmission power control to control to lower the transmission power of the mobile station.
すなわち、それ迄は直接波１だけであったのが中継波
３も受けるので受信電力が上昇し、送信電力制御によっ
て送信電力が下げられる。That is, the reception power increases because the relay wave 3 is received instead of the direct wave 1 until then, and the transmission power is reduced by the transmission power control.
移動局の送信電力が下げられ、中継局の入力が最低
基準入力V1（第４図参照）以下になると基地局の受信電
力が所要受信電力V3以下になるので、基地局は送信電力
制御によって移動局の送信電力を上げるよう制御する。
このように移動局がエリア周辺にいる場合は、送信電力
制御のフィードバックによって中継局の入力が最低基準
入力V1を中心に変動し基地局の受信電力も変動する。When the transmission power of the mobile station is reduced and the input of the relay station falls below the minimum reference input V 1 (see FIG. 4), the reception power of the base station falls below the required reception power V 3. Control to increase the transmission power of the mobile station.
In this case the mobile station is in the surrounding area as the input of the relay station also receives power of the base station varies around the minimum reference input V 1 fluctuates by the feedback of the transmission power control.
（移動局はカバーエリア内の場合） 送信電力制御によって移動局の送信電力が、その設
定された最低電力V4まで下がっても、中継局の入力が最
低基準入力V1以上であれば、中継局から充分な送信電力
V2で送信されるから基地局の受信電力も一定である。基
地局側でみると、移動局は最低設定電力V4で送信するの
で、直接波やビル反射波は減少し、また中継波は一定な
ので遅延スプレッドは減少する（すなわち、第３図
（ｄ）に示す状態が実現できる。）。Transmission power of the (mobile station in the case of the coverage area) the mobile station by the transmission power control, even down to the lowest power V 4 to set them, if the input of the relay station minimum reference input V 1 or more, the relay Sufficient transmission power from the station
Received power of the base station from being transmitted by the V 2 is also constant. Looking at the base station side, so the mobile station transmits at the lowest setting power V 4, decreased direct wave and buildings reflected wave, also relay wave delay spread decreases because constant (i.e., FIG. 3 (d) Can be realized.)
中継局は基地局からの伝搬遅延による遅延スプレッド
の大きいエリアをカバーするのに用いるものであるた
め、エリア内で遅延スプレッドがもともと小さい位置に
設置し、さらに指向性アンテナを用いて遅延スプレッド
を小さくしている。Since the relay station is used to cover an area where the delay spread due to the propagation delay from the base station is large, the relay station is installed at a position where the delay spread is originally small in the area, and the delay spread is reduced by using a directional antenna. doing.
（移動局がカバーエリアから出る場合） 〜 移動機がエリア外に移動してゆくにつれ、中継
局の入力が減少し、最低基準入力V1以下になると中継局
からの送信電力も減少し、受信電力が下がるので、基地
局からの送信電力制御命令で移動局の送信電力が増加す
る。カバーエリアに入る場合と同様に送信電力制御のフ
ィードバックによって基地局の受信電力が変動する。As (when the mobile station exits the coverage area) - mobile station slide into moves outside the area, decreasing the input of the relay station, also reduces transmission power from the relay station falls below a minimum reference input V 1, received Since the power is reduced, the transmission power of the mobile station is increased by the transmission power control command from the base station. As in the case of entering the coverage area, the reception power of the base station fluctuates due to the feedback of the transmission power control.
〜 移動局からの直接波が中継波より大きくなると
直接波によって送信電力制御が行なわれるので、移動局
がエリア外に移動することで中継波が減少しても送信電
力制御のフィードバックは行なわれない。中継局の入力
が動作入力V0以下になると中継は行なわれなくなる。When the direct wave from the mobile station becomes larger than the relay wave, the transmission power control is performed by the direct wave, so that even if the mobile station moves out of the area and the relay wave decreases, the feedback of the transmission power control is not performed. . Relay input and relay station is operating input V 0 below is not performed.
［発明の効果］ 以上説明したように、本発明によれば、受信電力が一
定となるように相手局の送信電力を制御する送信電力制
御を基地局および移動局で行なうディジタル信号を用い
た陸上移動通信において、受信電力に関係なく送信電力
が一定となるような特性を有する可変利得増幅器を備え
た中継局を設けることによって、伝搬遅延を容易に軽減
せしめることができる利点がある。[Effects of the Invention] As described above, according to the present invention, land power using digital signals in which the base station and the mobile station perform transmission power control for controlling the transmission power of the partner station so that the received power is constant. In mobile communication, by providing a relay station having a variable gain amplifier having characteristics such that transmission power is constant regardless of reception power, there is an advantage that propagation delay can be easily reduced.
第１図は伝搬遅延が発生した場合の受信波の様子を示す
図、第２図は本発明を実施するシステム構成を示す図、
第３図は受信局でみた到来波の様子を示す図、第４図は
可変利得増幅器の入出力特性を示す図、第５図は本発明
の場合の送受信電力の様子を示すタイムチャートであ
る。 １……直接波、２……ビル反射波、３……中継波、４…
…移動機、５……無線基地局、６……中継局、７……中
継局の指向性アンテナ、８……中継局のカバーエリア、
９……ビル、10……無線ゾーンFIG. 1 is a diagram showing a state of a received wave when a propagation delay occurs, FIG. 2 is a diagram showing a system configuration for implementing the present invention,
FIG. 3 is a diagram showing the state of the arriving wave seen by the receiving station, FIG. 4 is a diagram showing the input / output characteristics of the variable gain amplifier, and FIG. 5 is a time chart showing the state of the transmission / reception power in the case of the present invention. . 1 ... direct wave, 2 ... building reflected wave, 3 ... relay wave, 4 ...
… Mobile station, 5… radio base station, 6… relay station, 7… directional antenna of relay station, 8… cover area of relay station,
9 ... building, 10 ... wireless zone
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平３−166831（ＪＰ，Ａ) 特開 昭52−4702（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) H04Q 7/00 - 7/38────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-1666831 (JP, A) JP-A-52-4702 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) H04Q 7/00-7/38
Claims (1)
の送信電力を制御する送信電力制御を、基地局と移動局
の少なくとも一方で行なうディジタル信号を用いた陸上
移動通信において、 受信電力に関係なく送信電力が一定となるように自動的
に利得の調整を行なう可変利得増幅器を備えた中継局を
基地局からの伝搬遅延が発生しない位置に設置し、該中
継局の基地局向けおよび移動局向けの平均送信電力を一
定に保ち、 送信電力制御によって基地局および移動局の送信電力を
低くすることによって、伝搬遅延による通信品質の劣化
を軽減することを特徴とする移動伝搬遅延軽減方法。In land mobile communication using digital signals, transmission power control for controlling the transmission power of a partner station so that the reception power of the own station becomes constant is performed in at least one of a base station and a mobile station. A relay station equipped with a variable gain amplifier that automatically adjusts the gain so that the transmission power is constant regardless of the power is installed at a position where propagation delay from the base station does not occur. Mobile transmission delay reduction characterized by maintaining a constant average transmission power for mobile stations and lowering the transmission power of the base station and mobile station by transmission power control to reduce the deterioration of communication quality due to propagation delay. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2080597A JP2778794B2 (en) | 1990-03-30 | 1990-03-30 | Mobile propagation delay reduction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2080597A JP2778794B2 (en) | 1990-03-30 | 1990-03-30 | Mobile propagation delay reduction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03283724A JPH03283724A (en) | 1991-12-13 |
| JP2778794B2 true JP2778794B2 (en) | 1998-07-23 |
Family
ID=13722741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2080597A Expired - Lifetime JP2778794B2 (en) | 1990-03-30 | 1990-03-30 | Mobile propagation delay reduction method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2778794B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5634191A (en) * | 1994-10-24 | 1997-05-27 | Pcs Microcell International, Inc. | Self-adjusting RF repeater arrangements for wireless telephone systems |
| US8265551B2 (en) | 2007-07-19 | 2012-09-11 | Panasonic Corporation | Relay station, mobile station, and relay transmission method in mobile communication system |
| CN101960876A (en) | 2008-02-27 | 2011-01-26 | 松下电器产业株式会社 | Relay station in mobile communication system, mobile station, and relay transmission method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3946315A (en) * | 1975-06-27 | 1976-03-23 | Hughes Aircraft Company | Single frequency signalling in a radiotelephone communication system with idle condition signal generator at one terminal activated by another terminal |
| JPS5340097Y2 (en) * | 1976-10-14 | 1978-09-28 | ||
| PT95300A (en) * | 1989-09-14 | 1992-03-31 | Pcn One Ltd | RADIO-MOVEL COMMUNICATIONS SYSTEM |
-
1990
- 1990-03-30 JP JP2080597A patent/JP2778794B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03283724A (en) | 1991-12-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8244173B2 (en) | RF repeater | |
| US5603080A (en) | Radio coverage in closed environments | |
| US20020045461A1 (en) | Adaptive coverage area control in an on-frequency repeater | |
| US20080125033A1 (en) | Radio Frequency Repeater for Cancelling Feedback Interference Signal with Built In Antenna | |
| US5515365A (en) | Method and apparatus for reducing interference in a time division duplex communication system | |
| JPH0744495B2 (en) | Compartmental wireless telephone performance improvement circuit | |
| US20030211827A1 (en) | Repeater for radio communication system | |
| JP2000082983A (en) | Radio repeater amplifier device | |
| JP2778794B2 (en) | Mobile propagation delay reduction method | |
| EP1505744B1 (en) | Adaptive antenna transmission apparatus, and base station apparatus using the same | |
| JP2003179977A (en) | In-building wireless communication system and method for suppressing interference of reverse link | |
| JPH05259958A (en) | Radio repeater | |
| JP3154462B2 (en) | Mobile communication system and mobile station device | |
| JPH0897763A (en) | Bi-directional relay amplifier | |
| JP3095126B2 (en) | Mobile radio frequency selective repeater | |
| JPH08163019A (en) | Mobile communication system | |
| KR100718392B1 (en) | Wireless telecommunication system with rf split repeater | |
| JP3369842B2 (en) | Indoor wireless transmission equipment | |
| US20010046874A1 (en) | Apparatus for relaying a transmission signal | |
| KR100281627B1 (en) | Noise Reduction Circuit of Wireless Repeater | |
| KR100290924B1 (en) | Wireless communication Method, and system for the same | |
| JP2000269879A (en) | Relay amplifier | |
| JPS6238896B2 (en) | ||
| JPH0265532A (en) | Millimeter wave communication system | |
| JP2002234677A (en) | Radio communication system device for elevator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090508 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090508 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100508 Year of fee payment: 12 |
|
| EXPY | Cancellation because of completion of term |