201014388 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種用於一無線通訊系統之方法及其通訊裝置， 尤指一種用於無線通訊系統之方法及其通訊裝置，以節省一漫遊用 戶端之特屬細胞選擇操作的耗電。 【先前技術】 系統架構演進（SystemArchitectureEvolution，SAE)系統，係 ©由第三代行動通訊聯盟（3GPP)規範，為一種通用移動通信系統 (Universal Mobile Telecommunications System，UMTS )新的核心網 路架構，爲網際網路通訊協定（Intemetpr〇t〇c〇l ’ IP)的大眾市場 提供尚成本效益的部署和運作。網路演進主要包含滿足一長期演進 (lcrngtermev—，LTE)系統之無線介面需求、簡化網路結構、 王IP網路其即所有服務皆利用封包交換進行傳輸、無線路交換， 以及支持不同接取網路間的行動及服務的連續性，例如，長 ❹期演進系統’及非3GPP接取系統之間。 系統架構演進系統包含有一行動管理實體（M〇bmty201014388 VI. Description of the Invention: [Technical Field] The present invention relates to a method for a wireless communication system and a communication device thereof, and more particularly to a method for a wireless communication system and a communication device thereof, to save a roaming The power consumption of the user-specific cell selection operation. [Prior Art] System Architecture Evolution (SAE) system, which is a new core network architecture of the Universal Mobile Telecommunications System (UMTS), is regulated by the 3rd Generation Mobile Communications Alliance (3GPP). The mass market for Internet Protocol (Intemetpr〇t〇c〇l 'IP) provides cost-effective deployment and operation. The network evolution mainly includes satisfying the wireless interface requirements of a long-term evolution (LTE) system, simplifying the network structure, and all the services of the King IP network, which use packet switching for transmission, wireless channel switching, and support for different access. Inter-network mobility and service continuity, for example, between long-term evolution systems and non-3GPP access systems. The system architecture evolution system includes an action management entity (M〇bmty
Management Entity ’ MME )，一服務通道（Serving Gateway，S-GW )， 以及a用-貝料網路通道（pDNGateway，P-GW)。行動管理實體 係為-控制平面實體，用以管理網路服務附加，用戶端認證，及協 調演進式無線接取網路之相關無線負載的建立。 系統架構演進系統的功能包含有閒置模式的用戶端所進行之非 接取層功此，用戶端與演進封包核心網路之間透過一演進式通用移 201014388 動通信系統（EvolvedUMTS ’ E_UTRAN)所進行之 流程’以及肝端與演進封包核心網路之間透過非3Gpp接取網路 所傳輸之第三層信令流程。其巾，演進式賴移動通料統包含複 數個演進式基地台。 於非接取層巾，闕細胞（H()meCell)部署為將單—個基地台 用於-住家範圍、-建築細或—小型細胞群組（如—校園範土圍中口) 中。特屬細胞的存取資格僅限定於申訂用戶。一封_戶組（Management Entity ’ MME ), a Serving Gateway (S-GW), and a-PBG network (p-GW). The Action Management Entity is a Control Plane entity that manages network service attach, client authentication, and the establishment of associated wireless bearers for the Evolved Wireless Access Network. The function of the system architecture evolution system includes the non-access layer function of the idle mode client, and the user terminal and the evolved packet core network are performed by an evolved universal mobile 201014388 mobile communication system (EvolvedUMTS 'E_UTRAN). The process 'and the third layer signaling process transmitted between the liver and the evolved packet core network through the non-3Gpp access network. Its towel, the evolutionary mobile system contains a plurality of evolved base stations. In the case of non-accessible layers, the sputum cells (H() meCell) are deployed to use a single base station in a home range, a building fine, or a small cell group (eg, a campus Fantuwei middle mouth). Eligibility for access to a particular cell is limited to the intended user. a _ group (
Su—哪’ CSG)細胞可視為特屬細胞，其為絲陸地移動 式網路（Public Land Mobi丨eNetwork，PLMN)的—部分。此外，每 -封閉用戶組細胞之細胞識別存於一用戶端之—白名單時，則侧田 戶端可存取該封_戶組細胞。換岐說，白名單时提供複數個 可存取之賴用戶組細胞的細胞姻，_戶端可駐留於白名單上 的^閉用戶組細胞。—般來說，白名單是由絲陸地移動式網路所 :漫遊用戶端係指―用戶端從—大眾騎移動式網路移至其他 大眾場所移動式網路。用戶端所_之大眾場所機式網路稱為— 本地.周路而用戶端暫駐之大眾場所移動式網路則稱為一參訪網 路。當具有一白名單之一用戶端漫遊至一參訪網路時，該參訪網路 無=知^續祕終_細嫩處理該 。虽用戶端駐於該參訪網路之一巨集細胞（Macro Celi)時 該用戶端⑽編術蝴_蝴。細， 的封閉用戶組_術娜雜撕。杨姐下，用^ 端不斷週雛地進行封_戶組細猶尋，約會搜制任 201014388 • 取的封閉用戶組細胞，這樣不必要之細胞搜尋程序會造成用戶端多 餘的耗電。 【發明内容】 本發明提供一種方法及相關通訊裝置，用來節省一無線通訊系 統之一漫遊用戶端之特屬細胞選擇操作的耗電。 本發明揭露一種節省特屬細胞選擇操作之耗電的方法’用於一 無線通訊系統之一用戶端，該用戶端包含有一白名單，用來提供複 ©數個可存取之特屬細胞，該方法包含有：當該用戶端漫遊至一參訪 網路時，清除該白名單。 本發明另揭露一種用於一無線通訊系統之一通訊裝置，用來節 省一用戶端之特屬細胞選擇操作的耗電，該用戶端包含有一白名 單’用來提供複數個可存取之特屬細胞。該通訊裝置包含有一處理 器、-通訊介面單元、-控制單元，以及一計算機可讀取紀錄媒體。 該處理器’用來處理-儲存資料；該通訊介面單元，用來與該無線 ❹通訊遠端軌裝置交換無線峨；該控鮮元，耦接於該 處理器及該通訊介面單元，用來根據該處理器之處理結果控制該 通訊介面單元及該通訊裝置；該計算機可讀取紀錄媒體，耦接該處 理器，用來儲存該儲存資料。其中，該儲存資料包含有一程式，用 來當_戶端漫遊至-參訪網路時，清_白名單。 本發明另揭露_種節省觸細胞選擇操作之耗電的方法，用於 1線通訊系統之-用戶端’朗戶端包含有—白名單，用來提供 =數個可存取讀屬細歧對應賊複數個可存取之糾細胞的網 路’财衫含有：當_戶崎虹—參賴路，錄於該參訪 201014388 網路之一巨集細胞時，搜尋在該白名單中之特屬細胞；偵測該參訪 網路在該白名單中的存在性；以及當該參訪鱗賴該白名翠中偏 測到時，停止搜尋該白名單中之該複數個特屬細胞。 本發明另揭露一種用於一無線通訊系統之一通訊裝置，用來節 省一用戶端之特屬細胞選擇操作的耗電，該用戶端包含有一白名 單，用來提供複數個可存取之特屬細胞。該通訊裝置包含有一處理 器、一通訊介面單元、一控制單元，以及—計算機可讀取紀錄媒體。 該處理器’絲處理-齡資料；魏訊介面單元，用來與該無線 通汛系統之一遠端通訊裝置交換無線訊號；該控制單元，耦接於該 處理器及該通齡Φ料，肖綠魏處理n讀理躲，控制該 通訊介面單元及該通贿置；斜算射讀取紀錄雜，耦接該處 理器，用來儲存該儲存資料。其中，該儲存資料包含有一白名單， 用來提供複數個可存取之特屬細胞及對應於該複數個可存取之特屬 細胞的網n-程式，用來當該用戶端漫遊至—參訪網路，且 駐於該參訪網路之n細胞時，偵測該參賴路在齡名單中的 存在性’以及-第二程式，用來當該參訪網路未從該白名單中偵測 到時，停止搜尋該白名單中之該複數個特屬細胞。 【實施方式】 請參考第i ffi，第i圖為-無線通訊系統10之示意圖。無線通 訊系統10之架構係根據-系統架構演進系統（SystemArchiteetoe Evolution，SAE)、-通用移動通信系统（UniversaiM〇biieThe Su-CSG cell can be regarded as a specific cell, which is a part of the Public Land Mobi丨e Network (PLMN). In addition, when the cell identification of each of the closed user group cells is stored in a white list of a user terminal, the side bank terminal can access the cell group. In other words, when the whitelist is used, a plurality of cells that can be accessed by the user group cells are provided, and the _user can reside on the whitelisted group of cells. In general, the whitelist is made up of a silk-land mobile network: the roaming client means that the client moves from the public to the mobile network of the public. The public space network of the user terminal is called a local network. The mobile network of the public place is called a visitor network. When a client with one whitelist roams to a visiting network, the visiting network has no knowledge of the end of the network. Although the client is stationed in one of the visiting networks (Macro Celi), the client (10) edits the butterfly. Fine, closed user group _ surgery Na miscellaneous tear. Under Yang Jie, the end of the week is used to seal the _ household group is still looking for, dating search for 201014388 • Take the closed user group cells, so unnecessary cell search program will cause more power consumption on the user side. SUMMARY OF THE INVENTION The present invention provides a method and associated communication device for conserving power consumption of a particular cell selection operation of a roaming client of a wireless communication system. The invention discloses a method for saving power consumption of a special cell selection operation, which is used for a user terminal of a wireless communication system, and the user terminal comprises a white list for providing a plurality of accessible special cells. The method includes: when the client roams to a visited network, the whitelist is cleared. The invention further discloses a communication device for a wireless communication system, which is used for saving the power consumption of a special cell selection operation of a user terminal, and the user terminal includes a white list 'for providing a plurality of accessible specialties. Is a cell. The communication device includes a processor, a communication interface unit, a control unit, and a computer readable recording medium. The processor is configured to process and store data; the communication interface unit is configured to exchange wireless data with the wireless communication remote track device; the control element is coupled to the processor and the communication interface unit for Controlling the communication interface unit and the communication device according to the processing result of the processor; the computer can read the recording medium and coupled to the processor for storing the stored data. The stored data includes a program for clearing the whitelist when the _ client roams to the visited network. The invention further discloses a method for saving power consumption of a cell-selecting operation, which is used in a 1-line communication system - the client terminal "language terminal" includes a white list for providing = several accessible read-only sub-divisions Corresponding to the thief's multiple accessible cell-correcting networks, the geeks contain: When _Tosaki-Shin-Ri, recorded in one of the 201014388 network macro cells, search for the white list. a unique cell; detecting the presence of the visiting network in the whitelist; and stopping searching for the plurality of unique cells in the whitelist when the visiting scale is biased in the white name. The invention further discloses a communication device for a wireless communication system, which is used for saving power consumption of a special cell selection operation of a user terminal, and the user terminal comprises a white list for providing a plurality of accessible specialities. Is a cell. The communication device includes a processor, a communication interface unit, a control unit, and a computer readable recording medium. The processor is configured to exchange wireless signals with a remote communication device of the wireless communication system; the control unit is coupled to the processor and the medium-sized material. Xiao Luwei handles n reading and hiding, controls the communication interface unit and the bribe; the oblique calculation reads the records and is coupled to the processor for storing the stored data. The stored data includes a white list for providing a plurality of accessible special cells and a network n-program corresponding to the plurality of accessible special cells for roaming to the client- Visiting the Internet and detecting the presence of the participating in the age list when the n-cells of the visiting network are located, and - the second program is used when the visiting network is not from the white When detected in the list, the search for the plurality of unique cells in the white list is stopped. [Embodiment] Please refer to the i-fifi, and the i-th is a schematic diagram of the wireless communication system 10. The architecture of the wireless communication system 10 is based on System Architecture Evolution (SAE), Universal Mobile Communication System (UniversaiM〇biie)
TelecommunieatkmsSystem ’ UMTS) ’麵統架構演進祕與通用 移動通信系統之一混合系統。無線通訊系統1〇包含一用戶端1〇〇 201014388 及大眾場所移動式網路（Public Land Mobile Network，PLMN) 110 及120’其中PLMN 110及120包含本地位.置寄存器（HomeLocation Registers ’ HLRs) 112 及 122、參訪位置寄存器（Visitor L〇cati〇n Registers，VLRs ) 114 及 124，以及基電台系統（Base Station Systems， BSSs) 116及126。用戶端100可支援系統架構演進系統與通用移 動通信系統，且可應用於無線通訊系統1〇。其中，本地位置寄存器 112紀錄用戶端1〇〇為一特屬用戶端。當用戶端励駐於pLMN 11〇 ❹之一巨集細胞時，pLMN 110可處理用戶端1〇〇之一白名單，其提 供複數個可存取之封閉用戶組（Cl〇sed Subscriber Group，CSG )細 胞，其為此領域具通常知識者所熟知之特屬細胞（H〇mecell)。用 戶端100根據白名單，搜尋適當之CSG細胞，以用於CSG服務。 當用戶端100從PLMN 110漫遊至plmN 120 B夺，PLMN 110 視為一本地網路，而PLMN 120視為一參訪網路。參訪位置寄存器 124認定用戶端⑽為一參訪者’因此透過基電台系統提供之 ❹ 無線介面’進行用戶端之行動管理、驗註以及授權與計費流程。 在漫遊過財，PLMN12〇無法得知用戶端1〇〇是否有儲存一白名 單。 立胃參考第2圖，第2圖為本發明實施例一無線通訊裝置之示 =圖無線通訊裝置20可為第1圖中之用戶端⑽，其包含一處理 =2〇〇 :-計算機可讀取紀錄媒體。，一通訊介面單元娜，以及 一控制單it 230。計算機可讀取紀錄媒體21G可為任—資料儲存裝 f ’用以儲存一鍺存資料212，其包含有一程式及-白名單，並由 理器細棘及處理。計算機可讀取紀錄媒體⑽可為唯讀式記 201014388 憶體（read-only memory ’ R0M)、隨機存取記憶體（rand〇m access memory，RAM)、光碟唯讀記憶體（CD_R〇Ms)、磁帶（magnetic tapes )、軟碟（floppy disks)、光學資料儲存裝置（〇ptical data st〇rage devices)以及載波訊號（如網際網路的資料傳輸）。控制單元23〇 用來根據該處理器200之處理結果，控制通訊介面單元及通訊 裝置20之狀態與相關運作。通訊介面單元22〇較佳地為一無線接收 器，用以與基地台進行無線通訊，其中，基地台可為第〖圖之基電 台系統126中之一基地台。 上述通訊裝置20之白名單可提供複數個CSG細胞及相關網 路，其CSG細胞可被通訊裝置2〇存取，且由一本地網路提供。透 過白名單，當通訊裝置2〇駐於本地網路之一巨集細胞時，通訊裝置 2〇可搜尋白名單中之CSG細胞，以使用CSG服務。當通訊裝置2〇 從本地網·遊至-參糊糾，軌裝置2G根縣發明概念，停 止搜尋CSG細胞。 本發明之一實施例提供一白名單清除流程，用以避免通訊裝置 2〇搜尋CSG細胞。 請參考第3圖’第3圖為本發明實施例一白名單清除流程如 八意圖白名單除流程用於一無線通訊系統之一參訪網路， 用來郎省-用戶端（如用戶端励）之CSG細胞選擇操作的耗電， 且可編縣儲存於計算機可讀取紀錄媒體⑽之儲存資_ 212中的 程式。白名單清除流程30包含以下步驟： 步驟300 :開始。 步驟302 :當朗戶端漫遊至—參訪網路時，清除該白名單。 201014388 步驟304 :結束。 根據白名單清除流程3〇，當用戶端漫遊至參訪網路時，參訪網 路可清除白名單。較佳地’參訪網路是使用一白名單更新流程清除 該白名單。白名單更新流程可為用戶端所啟動之一附加流程、一追 蹤區域更新流程、-位置區域更新流程，以及一路由區域更新流程 之中至少其一。 當用戶端漫遊至參訪網路時，透過白名單清除流程3()，用戶端 ❹不會搜尋CSG細胞’且當用戶端駐於一巨集細胞時，因白名單所列 之CSG細胞皆被清除，故不會進行CSG細胞選擇。因此，用戶端 可避免CSG細胞搜尋時之耗電。 白名單清除流程30之實施例可應用於第1圖的用戶端1〇〇。當 用戶端100從PLMN 110漫遊至PLMN 120，用戶端透過傳送一 ^ 加請求（ATTACH REQUEST)訊息至PLMN 12〇，以啟動附加流程。 PLMN 120則置入一空白白名單於一附加接受（ATTACH ACCEpT)TelecommunieatkmsSystem ’ UMTS) A hybrid system of evolutionary architecture and one of the universal mobile communication systems. The wireless communication system 1 includes a client terminal 1〇〇201014388 and a Public Land Mobile Network (PLMN) 110 and 120', wherein the PLMNs 110 and 120 include HomeLocation Registers 'HLRs 112. And 122, visitor location registers (Visitor L〇cati〇n Registers, VLRs) 114 and 124, and base station systems (BSSs) 116 and 126. The client 100 can support a system architecture evolution system and a universal mobile communication system, and can be applied to a wireless communication system. The local location register 112 records the client 1 as a special client. When the UE is stationed in one of the macro cells of the pLMN 11〇❹, the pLMN 110 can process a white list of the client terminals, which provides a plurality of accessible closed user groups (Cl〇sed Subscriber Group, CSG). A cell, which is a specialized cell (H〇mecell) well known to those of ordinary skill in the art. The user 100 searches for appropriate CSG cells for use in the CSG service based on the whitelist. When the client 100 roams from the PLMN 110 to the plmN 120B, the PLMN 110 is treated as a local network and the PLMN 120 is considered a visited network. The visitor location register 124 asserts that the client (10) is a visitor' so the user interface management, verification, and authorization and billing procedures are performed via the wireless interface provided by the base station system. After roaming, PLMN12 cannot know whether the client has stored a white list. The second embodiment of the present invention is a wireless communication device. Read the recording media. , a communication interface unit Na, and a control unit it 230. The computer readable recording medium 21G can be a data storage device f ’ for storing a stored data 212, which includes a program and a white list, and is processed by the processor. The computer readable recording medium (10) can be a read-only memory (R0M), a random access memory (RAM), and a CD-ROM (CD_R〇Ms). Magnetic tapes, floppy disks, 〇ptical data st〇rage devices, and carrier signals (such as data transmission over the Internet). The control unit 23 is configured to control the status and related operations of the communication interface unit and the communication device 20 according to the processing result of the processor 200. The communication interface unit 22 is preferably a wireless receiver for wireless communication with the base station, wherein the base station can be one of the base stations in the base station system 126 of the figure. The white list of the communication device 20 can provide a plurality of CSG cells and related networks, and the CSG cells can be accessed by the communication device 2 and provided by a local network. Through the whitelist, when the communication device 2 is stationed in a macro cell of the local network, the communication device 2 can search for CSG cells in the white list to use the CSG service. When the communication device 2 游 本地 本地 本地 本地 本地 , , , , , 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨 轨One embodiment of the present invention provides a whitelist removal procedure to prevent communication devices from searching for CSG cells. Please refer to FIG. 3'. FIG. 3 is a white list clearing process according to an embodiment of the present invention. For example, the eight intent whitelisting process is used for one of the wireless communication systems to access the network, and is used for the lang-client (such as the client). The CSG cell selection operation consumes power, and the program can be stored in the computer-readable storage medium (10). The whitelist removal process 30 includes the following steps: Step 300: Start. Step 302: When the roaming end roams to the visited network, the whitelist is cleared. 201014388 Step 304: End. According to the whitelist clearing process, when the user roams to the visited network, the visiting network can clear the whitelist. Preferably, the visiting network uses a whitelist update process to clear the whitelist. The whitelist update process may be at least one of an additional process initiated by the client, a tracking area update process, a location area update process, and a routing area update process. When the client roams to the visited network, through the whitelist clearing process 3 (), the client does not search for CSG cells' and when the user is stationed in a macro cell, the CSG cells listed in the white list are all It is cleared, so CSG cell selection is not performed. Therefore, the user can avoid power consumption when searching for CSG cells. The embodiment of the whitelist removal process 30 can be applied to the client side of FIG. When the UE 100 roams from the PLMN 110 to the PLMN 120, the UE initiates an additional procedure by transmitting an ATTACH REQUEST message to the PLMN 12. PLMN 120 puts a blank white list on an additional acceptance (ATTACH ACCEpT)
❾訊息中，且傳送該附加接受訊息，以回覆該附加請求訊息。於用戶 端接收及讀取該附加接受訊息後’則移除所有在白名單中之CSG細 胞。因此，用戶端100於漫遊至PLMN 120後，不會繼續搜尋CSG 細胞。 本發明之另一實施例提供一參訪網路偵測流程，用以避免通訊 裝置20搜尋CSG細胞。 請參考第4圖，第4圖為本發明實施例一參訪網路偵測流程4〇 之示意圖。參訪網路偵測流程40用於一用戶端中，用來節省用戶端 之CSG細胞選擇操作的耗電，且可編譯為儲存於計算機可讀取紀錄 201014388 · 媒體210之儲存資料212中的程式。參訪網路_流程4〇包含以下 步驟· r 步驟400 :開始。 步驟402 :當制戶端駐於—參訪網路之—巨集細胞時，_ 該參訪網路在該白名單中的存在性。 步驟概：當未從該白名單中偵測到該參訪網路時，停止搜尋 該白名單令之CSG細胞。 步驟406 ··結束。 根據參訪網路偵測流程4〇，當漫遊至參訪網路且駐於其巨集細 胞時，先偵測參訪網路於白名單中的存在性，以判斷參訪網路是否田 在白名單之可存取網路名單中。當用戶端未從白名單中偵測到參訪 網路時’則停止搜尋白名單中之CSG細胞。 參訪網路偵測流程40之實施例可應用於第i圖之用戶端1〇〇。 為了提供CSG服務，PLMN110提供用戶端100 一白名單，其包含 多個可存取之CSG細胞及其相關網路的名單。舉例來說，白名單包 含可存取CSG細胞之識別及對應於這些CSG細胞之網路識別。當 用戶端100從PLMN 110漫遊至PLMN 120時，用戶端1〇〇判斷 PLMN 120是否在白名單中。當用戶端1〇〇無法在白名單中找到 PLMN 120 ’則代表白名單中所有的CSG細胞不在PLMN 120的範 圍中。在此情況下，用戶端100停止CSG細胞搜尋，以節省耗電。 其中，用戶端1〇〇可根據PLMN 120所廣播之系統資訊，決定是否 停止CSG細胞搜尋，系統資料會包含PLMN 120的網路識別。 根據參訪網路偵測流程40，步驟404及步驟402可簡化為：用 201014388 戶端偵測參訪網路之存在性；當參訪網路存在（進入）時，用戶端 停止搜尋CSG細胞。 以下為參訪網路偵測流程4〇應用於用戶端1〇〇之另一實施例。 同樣地’ ’PLMN 110提供用戶端1〇〇 一白名單，以提供cSg服務。 白名單包含可存取CSG細胞之識別及其相關網路之識別。當用戶端 100 從 PLMN 110 漫遊至 PLMN 120，用戶端 1〇(H貞測 PLMN 12〇 是否為一參訪網路。當用戶端100判斷PLMN12〇為一參訪網路時， ❾停止CSG細胞搜尋’以節省耗電。同樣地，用戶端1〇〇可根據pLMN 120所廣播之系統資料中的網路識別，決定是否停止CSG細胞搜尋。 综上所述，本發明之實施例透過清除白名單或偵測參訪網路之 存在性，解決漫遊用戶端之CSG細胞搜尋浪費電力的問題。 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍 所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖為一無線通訊系統之示意圖。 第2圖為本發明實施例一通訊裝置之示意圖。 第3圖為本發明實施例一白名單清除流程之示意圖。 第4圖為本發明實施例一參訪網路偵測流程之示意圖。 【主要元件符號說明】 10 無線通訊系統 100 用戶端 110、120 大眾場所移動式網路 112 、 122 本地位置寄存器 201014388 114 、 124 參訪位置寄存器 116 、 126 基電台系統 20 通訊裝置 200 處理器 210 計算機可讀取紀錄媒體 220 通訊介面單元 230 控制單元 212 儲存資料 30、40 流程 300、302、304、400、402 - 、404、406 步驟 12In the message, and the additional acceptance message is transmitted to reply to the additional request message. After receiving and reading the additional acceptance message on the client side, all CSG cells in the whitelist are removed. Therefore, after roaming to the PLMN 120, the UE 100 does not continue to search for CSG cells. Another embodiment of the present invention provides a visited network detection process to prevent the communication device 20 from searching for CSG cells. Please refer to FIG. 4, which is a schematic diagram of a visited network detection process 4〇 according to an embodiment of the present invention. The network detection process 40 is used in a client to save power consumption of the CSG cell selection operation of the client, and can be compiled and stored in the storage data 212 of the computer readable record 201014388 · media 210. Program. Visiting Network_Process 4〇 contains the following steps: r Step 400: Start. Step 402: When the maker is stationed in the accessing network - the macro cell, the existence of the visiting network in the white list. Step: When the visited network is not detected from the whitelist, stop searching for the whitelisted CSG cells. Step 406 ·· End. According to the process of visiting the network detection process, when roaming to the visiting network and stationing in the macro cell, the presence of the visiting network in the whitelist is first detected to determine whether the visiting network is a field. In the whitelisted list of accessible networks. When the client does not detect the visited network from the whitelist, it stops searching for CSG cells in the whitelist. The embodiment of the visited network detection process 40 can be applied to the client side of the i-th diagram. In order to provide CSG services, PLMN 110 provides a whitelist of client 100 that contains a list of a plurality of accessible CSG cells and their associated networks. For example, the whitelist contains the identification of accessible CSG cells and network identification corresponding to these CSG cells. When the UE 100 roams from the PLMN 110 to the PLMN 120, the UE 1 determines whether the PLMN 120 is in the white list. When the UE 1 cannot find the PLMN 120 ' in the white list, it means that all CSG cells in the white list are not in the range of the PLMN 120. In this case, the client 100 stops the CSG cell search to save power. The UE 1 may determine whether to stop the CSG cell search according to the system information broadcast by the PLMN 120, and the system data may include the network identification of the PLMN 120. According to the visited network detection process 40, step 404 and step 402 can be simplified as: using the 201014388 client to detect the existence of the visited network; when the visiting network exists (enters), the user stops searching for the CSG cell. . The following is another embodiment of the visit network detection process 4 applied to the client terminal. Similarly, the 'PLMN 110 provides a white list of clients to provide cSg services. The whitelist contains the identification of accessible CSG cells and the identification of their associated networks. When the UE 100 roams from the PLMN 110 to the PLMN 120, the UE 1〇(H) tests whether the PLMN 12〇 is a visited network. When the UE 100 determines that the PLMN 12 is a visiting network, the CSG cell is stopped. Search for 'to save power. Similarly, the client 1 can decide whether to stop the CSG cell search based on the network identification in the system data broadcast by the pLMN 120. In summary, the embodiment of the present invention clears the white List or detect the existence of the visited network, solve the problem of CSG cells searching for wasted power in the roaming client. The above is only a preferred embodiment of the present invention, and the average variation of the scope of the patent application according to the present invention The present invention is intended to cover the scope of the present invention. [Fig. 1 is a schematic diagram of a wireless communication system. Fig. 2 is a schematic diagram of a communication device according to an embodiment of the present invention. FIG. 4 is a schematic diagram of a visit network detection process according to an embodiment of the present invention. [Main component symbol description] 10 wireless communication system 100 client 110, 120 Public place mobile network 112, 122 local location register 201014388 114, 124 visit location register 116, 126 base station system 20 communication device 200 processor 210 computer readable recording medium 220 communication interface unit 230 control unit 212 storage data 30 , 40 Processes 300, 302, 304, 400, 402 - , 404, 406 Step 12