JP3165347B2 - Handover control method - Google Patents
Handover control methodInfo
- Publication number
- JP3165347B2 JP3165347B2 JP9672395A JP9672395A JP3165347B2 JP 3165347 B2 JP3165347 B2 JP 3165347B2 JP 9672395 A JP9672395 A JP 9672395A JP 9672395 A JP9672395 A JP 9672395A JP 3165347 B2 JP3165347 B2 JP 3165347B2
- Authority
- JP
- Japan
- Prior art keywords
- handover
- communication quality
- value
- communication
- threshold value
- 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
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- Mobile Radio Communication Systems (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は簡易形携帯電話システ
ム（ＰＨＳ）や屋内携帯電話システムなどのコードレス
電話システムにおける通信中の無線ゾーンの移動に伴う
ハンドオーバ制御方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handover control method associated with movement of a wireless zone during communication in a cordless telephone system such as a simplified portable telephone system (PHS) or an indoor portable telephone system.
【０００２】[0002]
【従来の技術】ハンドオーバとはコードレス電話機が通
信中に無線ゾーン間を移動する場合、旧無線ゾーンの通
信チャネルから新無線ゾーンの通信チャネルに通信チャ
ネルを切り替えて通信を継続することであり、コードレ
ス電話機では、図３に示すように通信中に通信チャネル
電波を受信し（Ｓ1 ），その受信した電波の通信品質を
検出し（Ｓ2 ），その検出した１回の通信品質とハンド
オーバしきい値を比較し（Ｓ3 ），受信した電波の通信
品質がハンドオーバしきい値より悪くなった場合、ハン
ドオーバ処理を起動し（Ｓ4 ），検出した通信品質がし
きい値より悪くなければステップＳ1 に戻る。つまり、
通信品質を定期的に検出し、各１回の検出ごとにしきい
値と比較していた。2. Description of the Related Art Handover means that when a cordless telephone moves between radio zones during communication, the communication channel is switched from a communication channel of an old radio zone to a communication channel of a new radio zone to continue communication. As shown in FIG. 3, the telephone receives a communication channel radio wave during communication (S 1 ), detects the communication quality of the received radio wave (S 2 ), and determines the communication quality and handover threshold for one detected communication quality. The values are compared (S 3 ). If the communication quality of the received radio wave is lower than the handover threshold, the handover process is started (S 4 ). If the detected communication quality is not lower than the threshold, step S 4 is performed. Return to 1 . That is,
The communication quality is periodically detected, and is compared with a threshold value for each detection.
【０００３】[0003]
【発明が解決しようとする課題】前述した従来の技術で
は、ハンドオーバしきい値と比較する通信品質の回数を
１回としていたためフェージングの影響により同一の場
所においても通信品質が常時変動している条件下では、
ハンドオーバ処理を起動する場所にばらつきが生じ、通
信領域内にいる場合にもハンドオーバ処理を起動するよ
うな問題があった。In the prior art described above, the number of times of communication quality comparison with the handover threshold is set to one, so that the communication quality constantly fluctuates even in the same place due to the effect of fading. Under conditions,
There is a problem that the location where the handover process is started varies, and the handover process is started even when the mobile terminal is in the communication area.
【０００４】この発明は、このうような課題を解決し、
無線ゾーン内においてはハンドオーバ処理を起動する場
所のばらつきを抑え、安定したハンドオーバを行うこと
を可能とするハンドオーバ制御方法を提供することを目
的とする。[0004] The present invention solves such a problem,
It is an object of the present invention to provide a handover control method capable of suppressing a variation in a place where a handover process is activated in a wireless zone and performing a stable handover.
【０００５】[0005]
【課題を解決するための手段】この発明によれば、ハン
ドオーバ機能を有する移動電話機の通信中に無線ゾーン
間を移動することに基づく通信チャネルの切替えを行う
ハンドオーバ制御方法において、通信中に受信電波の所
定時間内の通信品質を順次連続して測定すると共に、上
記測定通話品質を、第１しきい値より悪い第２しきい値
と比較し、上記測定通話品質が第２しきい値よりも悪い
場合はハンドオーバ処理に移行し、悪くなければ、これ
を順次所定段数のシフトレジスタに記憶し、上記所定時
間内の通話品質を測定する毎に、上記所定段数のシフト
レジスタに記憶された通信品質の平均値を求め、その平
均通信品質値を上記第１しきい値と比較し、上記平均通
信品質値が上記第１しきい値より悪ければハンドオーバ
処理に移行し、悪くなければ、ハンドオーバ処理に移行
せず上記手順を順次連続して行うハンドオーバ制御方法
である。According to the present invention, there is provided a handover control method for switching a communication channel based on moving between radio zones during communication of a mobile telephone having a handover function. while the measured successive communication quality within a predetermined time, the upper
A second threshold value worse than the first threshold value
The measured call quality is worse than the second threshold
In this case, the processing shifts to handover processing. If not bad, the processing is sequentially stored in a predetermined number of shift registers, and each time the communication quality within the predetermined time is measured, the communication quality stored in the predetermined number of shift registers is measured. An average value is obtained, and the average communication quality value is compared with the first threshold value. If the average communication quality value is lower than the first threshold value, handover is performed.
Move to processing, if not, move to handover processing
This is a handover control method in which the above procedure is performed sequentially and continuously without performing the above procedure .
【０００６】[0006]
【実施例】図１に請求項２の発明の方法を実行する携帯
電話機におけるこの発明と関連のある部分の機能構成例
を示す。携帯電話機１０のアンテナ１１により受信され
た通信チャネルの電波は通信品質検出手段１２により通
信品質が検出される。例えば、1.２秒ごとにフレーム誤
り率が測定され、1.２秒中のフレーム数は２４０であ
り、各フレームに誤りが検出されるか否かは、いわゆる
ＣＲＣビットにより検出され、1.２秒間におけるフレー
ム誤り率が検出され、連続する複数の検出通信品質の平
均値が求められる。この例では連続する３つの通信品質
の平均値を常に求めるようにされ、検出通信品質は通信
品質の検出ごとにレジスタ１３，１４，１５に順次移さ
れる。従ってレジスタ１３，１４，１５には常に検出し
た通信品質の最新のものと、その直前の２つとが格納さ
れていることになる。つまり、レジスタ１３，１４，１
５はシフトレジスタを構成している。これらレジスタ１
３，１４，１５に格納されている３つの通信品質の平均
値が平均化手段１６で求められる。FIG. 1 shows an example of a functional configuration of a portion related to the present invention in a portable telephone which executes the method of the present invention. The communication quality of the radio wave of the communication channel received by the antenna 11 of the mobile phone 10 is detected by the communication quality detecting means 12. For example, the frame error rate is measured every 1.2 seconds, the number of frames in 1.2 seconds is 240, and whether an error is detected in each frame is detected by a so-called CRC bit. A frame error rate in two seconds is detected, and an average value of a plurality of continuous detected communication qualities is obtained. In this example, an average value of three consecutive communication qualities is always obtained, and the detected communication quality is sequentially transferred to the registers 13, 14, and 15 every time the communication quality is detected. Therefore, the registers 13, 14 and 15 always store the latest detected communication quality and the two immediately preceding ones. That is, the registers 13, 14, 1
Reference numeral 5 denotes a shift register. These registers 1
The average value of the three communication qualities stored in 3, 14, and 15 is obtained by the averaging means 16.
【０００７】その平均通信品質はレジスタ１７内の第１
しきい値（ハンドオーバしきい値）と比較器１８で比較
される。第１しきい値は例えば従来技術で用いられてい
たハンドオーバしきい値と等しい値とされ、フレーム誤
り率の場合５〜１０％程度の値とされる。平均通信品質
が第１しきい値より悪いと、ハンドオーバ手段１９を起
動する。The average communication quality is determined by the first
The threshold value (handover threshold value) is compared with the comparator 18. The first threshold value is, for example, a value equal to the handover threshold value used in the related art, and is about 5 to 10% in the case of a frame error rate. If the average communication quality is lower than the first threshold, the handover unit 19 is activated.
【０００８】さらに、通信品質検出手段１２より検出し
た通信品質は比較器２０でレジスタ２１内の第２しきい
値（強制ハンドオーバしきい値）と比較される。第２し
きい値はレジスタ１７内の第１しきい値よりも悪い値で
あり、例えば通信品質がフレーム誤り率の場合７０％程
度以上、つまり通信ができない程度に選定される。比較
器２０で第２しきい値よりも検出通信品質が悪いと、ハ
ンドオーバ手段１９が起動される。Further, the communication quality detected by the communication quality detecting means 12 is compared by a comparator 20 with a second threshold value (forcible handover threshold value) in a register 21. The second threshold value is lower than the first threshold value in the register 17, and is selected to be, for example, about 70% or more when the communication quality is the frame error rate, that is, such that communication cannot be performed. When the detected communication quality is lower than the second threshold value in the comparator 20, the handover means 19 is activated.
【０００９】この処理の流れは図２に示すように、通信
チャネル電波を受信し（Ｓ1 ），その通信品質値を検出
し（Ｓ2 ），その検出通信品質値を第２しきい値と比較
し（Ｓ3 ），第２しきい値より悪いとハンドオーバ処理
に移り（Ｓ4 ），第２しきい値より悪くないと検出通信
品質値をｎ段（図１ではｎ＝３）のシフトレジスタの初
段に入力し（Ｓ5 ），次にそのシフトレジスタの終段に
データがあるかを調べ（Ｓ6 ），データ、つまり検出通
信品質値がなければステップＳ1 に戻り、終段にデータ
があればｎ段シフトレジスタ中のｎ個の検出通信品質値
を平均し、平均通信品質値を求める（Ｓ7 ）。この平均
通信品質値を第１しきい値と比較し（Ｓ8 ），第１しき
い値より悪ければハンドオーバ処理に移り、第１しきい
値より悪くなければステップＳ1 に戻る。As shown in FIG. 2, this processing flow receives a communication channel radio wave (S1), detects its communication quality value (S2), and compares the detected communication quality value with a second threshold value. (S3) If it is lower than the second threshold, the process proceeds to the handover process (S4). If it is not lower than the second threshold, the detected communication quality value is set to the first stage of the n-stage (n = 3 in FIG. 1) shift register. Input (S5), and then check whether there is data at the last stage of the shift register (S6). If there is no data, that is, no detected communication quality value, return to step S1. If there is data at the last stage, shift by n stages. The n detected communication quality values in the register are averaged to obtain an average communication quality value (S7). The average communication quality value is compared with the first threshold value (S8). If the average communication quality value is not worse than the first threshold value, the process proceeds to the handover process, and if not worse, the process returns to step S1.
【００１０】平均通信品質値を第１しきい値と比較して
いるため、通信中の無線ゾーン内でフェージングにより
一時的に通信品質が劣化してもハンドオーバ処理に移る
おそれはない。しかし、市街地の曲がり角のように、通
信中の無線ゾーンから急に外れると、検出通信品質値が
急に劣化し、第２しきい値より悪くなり、直ちにハンド
オーバ処理に移ることができる。[0010] Since the average communication quality value is compared with the first threshold value, even if the communication quality is temporarily degraded due to fading in the communicating radio zone, there is no possibility that the process will proceed to the handover process. However, when the vehicle suddenly departs from the wireless zone in communication, such as at a corner of an urban area, the detected communication quality value suddenly deteriorates, becomes worse than the second threshold value, and can immediately proceed to the handover process.
【００１１】上述において、検出通信品質の平均をとる
数は３回としたが、この数に限ることなく２回でもよ
く、４回以上でもよい。しかし、平均通信品質のバラツ
キの変動幅はそれ程小さくならないから、３回程度が好
ましい。また通信品質の検出としてはフレーム誤り率に
限らず、例えば受信レベルを用いてもよい。受信レベル
の場合は、例えば各受信フレームのレベルを測定し、1.
２秒間における、つまり２４０フレームの平均レベルを
検出通信品質とし、この平均受信レベルの連続する複数
回、例えば２〜４回程度の平均値を求めて、第１しきい
値と比較、この第１しきい値より悪く、つまり平均受信
レベルが低下すれば、ハンドオーバ処理に移る。第２し
きい値との比較は受信レベルでもよいが、フレーム誤り
率が好ましい。また、通信品質の検出としてはフレーム
誤り率と、受信レベルとの両者を用い、それぞれを連続
する例えば３回（７２０フレーム）平均し、その平均通
信品質が所定値より大で、かつ平均受信レベルが所定レ
ベルより小のときを第１しきい値より悪いとしてハンド
オーバ処理に移り、平均フレーム誤り率が所定値より小
さいか、平均受信レベルが所定値より大であれば、ハン
ドオーバ処理に移らないようにすることもできる。上述
において、フレーム誤り率の測定を２４０フレームごと
に行うことなく、他の所定フレーム数ごとに行ってもよ
い。上述において、ＰＨＳのみならず、屋内コードレス
電話システムにおいても、例えば１階と、２階とに基地
局を設け、例えば１階で受信した移動局電話機で話をし
ながら、２階に移る場合のハンドオーバ制御にもこの発
明を適用できる。In the above description, the average of the detected communication qualities is three, but the number is not limited to this number and may be two or four or more. However, since the fluctuation width of the variation of the average communication quality does not become so small, it is preferable to be about three times. Further, the detection of the communication quality is not limited to the frame error rate, and for example, a reception level may be used. In the case of the reception level, for example, the level of each reception frame is measured, and 1.
The average communication level in two seconds, that is, 240 frames, is used as the detected communication quality, and the average value of the average reception level is calculated a plurality of times, for example, about 2 to 4 times, and is compared with the first threshold value. If it is worse than the threshold value, that is, if the average reception level decreases, the process proceeds to the handover process. The comparison with the second threshold value may be the reception level, but the frame error rate is preferable. For detecting the communication quality, both the frame error rate and the reception level are used, and each is averaged, for example, three consecutive times (720 frames), and the average communication quality is larger than a predetermined value and the average reception level Is lower than the first threshold value when the average frame error rate is lower than the predetermined value, and proceeds to the handover process. If the average frame error rate is smaller than the predetermined value or the average reception level is higher than the predetermined value, the process does not proceed to the handover process. You can also In the above description, the frame error rate may not be measured every 240 frames but may be measured every other predetermined number of frames. In the above description, not only in the PHS but also in the indoor cordless telephone system, for example, base stations are provided on the first floor and the second floor, and when the mobile station telephone received on the first floor talks, for example, the user moves to the second floor. The present invention can be applied to handover control.
【００１２】[0012]
【発明の効果】以上述べたように、この発明によれば連
続する複数の検出通信品質値を平均し、その平均通信品
質値と第１しきい値（例えば従来のハンドオーバしきい
値）と比較するため、フェージングの影響を受け難い。
しかも、請求項２の発明によれば、さらにＰＨＳのよう
に市街地の曲がり角で通信中無線ゾーンから急に外れた
場合は、１回の検出通信品質が急に著しく劣化し、第２
しきい値より悪くなり、直ちにハンドオーバ処理に移る
ことができる。As described above, according to the present invention, a plurality of continuous detected communication quality values are averaged, and the average communication quality value is compared with a first threshold value (for example, a conventional handover threshold value). Therefore, it is hardly affected by fading.
In addition, according to the second aspect of the present invention, when the wireless communication zone suddenly departs from the wireless zone during communication at a corner of an urban area like a PHS, the quality of one detected communication suddenly deteriorates remarkably.
It becomes worse than the threshold, and the process can immediately proceed to the handover process.
【図１】この発明の方法が用いられる携帯無線機におけ
る、この発明と関連する部分の機能構成例を示すブロッ
ク図。FIG. 1 is a block diagram showing a functional configuration example of a portion related to the present invention in a portable wireless device using the method of the present invention.
【図２】請求項２の発明の処理手順の例を示す流れ図。FIG. 2 is a flowchart showing an example of a processing procedure according to the invention of claim 2;
【図３】従来のハンドオーバ制御の処理手順を示す流れ
図。FIG. 3 is a flowchart showing a processing procedure of a conventional handover control.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 根本 能成 東京都千代田区内幸町１丁目１番６号 日本電信電話株式会社内 (56)参考文献 特開 昭63−245142（ＪＰ，Ａ) 特開 平５−41689（ＪＰ，Ａ) 特開 平６−335051（ＪＰ，Ａ) 特開 平１−313770（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H04Q 7/00 - 7/38 H04B 7/26 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinari Nemoto 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-63-245142 (JP, A) JP-A-Hei 5-41689 (JP, A) JP-A-6-335051 (JP, A) JP-A-1-313770 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H04Q 7/00 -7/38 H04B 7/26
Claims (1)
通信中に無線ゾーン間を移動することに基づく通信チャ
ネルの切替えを行うハンドオーバ制御方法において、通
信中に受信電波の所定時間内の通信品質を順次連続して
測定すると共に、上記測定通話品質を、第１しきい値よ
り悪い第２しきい値と比較し、上記測定通話品質が第２
しきい値よりも悪い場合はハンドオーバ処理に移行し、
悪くなければ、これを順次所定段数のシフトレジスタに
記憶し、上記所定時間内の通話品質を測定する毎に、上
記所定段数のシフトレジスタに記憶された通信品質の平
均値を求め、その平均通信品質値を上記第１しきい値と
比較し、上記平均通信品質値が上記第１しきい値より悪
ければハンドオーバ処理に移行し、悪くなければ、ハン
ドオーバ処理に移行せず上記手順を順次連続して行うこ
とを特徴とする請求項１記載のハンドオーバ制御方法。1. A handover control method for switching a communication channel based on moving between radio zones during communication of a mobile telephone having a handover function, wherein the communication quality of a received radio wave within a predetermined time is continuously continuous during communication. And measure the above-mentioned measured call quality from the first threshold value.
And the measured call quality is higher than the second threshold value.
If the value is lower than the threshold, the process proceeds to handover processing,
If it is not bad, this is sequentially stored in a predetermined number of shift registers, and every time the communication quality within the predetermined time is measured, an average value of the communication quality stored in the predetermined number of shift registers is obtained. the quality value is compared with the first threshold value, the average communication quality value adversely than the first threshold value
If it is not bad, move to handover processing.
The handover control method according to claim 1, wherein the steps are sequentially and continuously performed without shifting to a handover process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9672395A JP3165347B2 (en) | 1995-04-21 | 1995-04-21 | Handover control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9672395A JP3165347B2 (en) | 1995-04-21 | 1995-04-21 | Handover control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08294158A JPH08294158A (en) | 1996-11-05 |
| JP3165347B2 true JP3165347B2 (en) | 2001-05-14 |
Family
ID=14172665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9672395A Expired - Lifetime JP3165347B2 (en) | 1995-04-21 | 1995-04-21 | Handover control method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3165347B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002232929A (en) | 2001-02-01 | 2002-08-16 | Ntt Docomo Inc | Hand-over control method, mobile station and communication controller |
| AU2002368478A1 (en) | 2002-12-19 | 2004-07-14 | Fujitsu Limited | Mobile node |
| BRPI0413316A (en) | 2003-08-08 | 2006-10-10 | Sony Corp | communication system, communication terminal device, control method for a communication terminal device, program, and communication method for a communication terminal device |
| JP4605428B2 (en) * | 2003-08-08 | 2011-01-05 | ソニー株式会社 | COMMUNICATION SYSTEM, COMMUNICATION TERMINAL DEVICE, COMMUNICATION METHOD, AND PROGRAM |
| KR20140062177A (en) | 2008-04-25 | 2014-05-22 | 인터디지탈 패튼 홀딩스, 인크 | Method and apparatus for cell reselection in a mobile communications network |
-
1995
- 1995-04-21 JP JP9672395A patent/JP3165347B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08294158A (en) | 1996-11-05 |
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