Regional Networks Regional Networks compose the lower level of the overall system. The radius of a "region" varies from dozens to hundreds of kilometers, and mostly depends on environment conditions such as topography and weather. Two kinds of units are included in the network. One is known as "User". Us- ers are the radio-like equipments which are used directly by men to communicate with others. That is, we can talk with or even see each other or tranceive data through such an equipment. To accomplish their jobs Users can establish a dire- ct link with each other, or, when the target User can not be reached, to the o- ther kind of units called "Relay". Relays act very much like postmen. They receive data from the sender, and retransmit it to the recipient. If the recipient is located in the region, data would be delivered directly; if not, the Relay would send the data to the upper level of the system, the Global Network. This operation can also be seen in LAN /WAN architecture of the day. Besides, when the sender wants to "broadcast", a Relay can do the work by retransmitting the message to all reachable Users[3]. To ensure the secrecy of data, spread spectrum modulation was put to use[4] . Since DSSS and FHSS holds their advantage/disadvantage, most of which are co- mplementary, we decided to use the hybrid DSSS/FHSS. In fact, all data flow be- tween Users (and Relays) are DSSS/FHSS modulated; together with other measures to deal with eavesdropping and jamming. References: [3] The Second Raid Episode.3&4 The Communication post set up by Capt. Blueno served as a Relay , while Users are used by task force members such as AS units. All communications during the mission was broadcast. Thus the captain can moniter all communications. Note that the beacons lauched by ASs were repeaters, which would retransmit all valid signals they received. TDD also served as a Relay. [4] The Second Raid Episode.7 Description by Kaname Chidori. =================================以下是翻譯==================================== 地區網路 整套系統的低層由地區網路組成。一個「地區」的半徑從數十到數百公里不等，主要 受到地形和天候等環境因素影響。 地區網路包含兩種單位。其中一種被稱為「使用者」，是類似無線電機的裝置，供人 相互溝通。也就是說，我們可以透過此一裝置和對方交談甚至使用視訊，以及傳收資料。 各「使用者」之間會彼此建立連結以發揮功能；若無法直接和傳輸的目標連結，則會和另 一種單位「中繼站」建立連結。 「中繼站」和郵差有相似的作用。他們接收傳送端送出的資料，並轉達給接收端。當 接收端位在同一區域內時，資料會直接轉達；否則「中繼站」會將資料上傳至高層的全球 網路。這種運作模式類似於今日的LAN/WAN網路架構。此外，當傳送端想要「廣播」訊息 時，「中繼站」會將訊息轉達給所有接觸到的「使用者」，達成此一功能。[3] 為了確保資料的隱密，使用了展頻調變技術。[4] 因為FHSS(跳頻展頻)和DSSS(直序 展頻)各有優缺點—且經常為互補，我們決定使用兩者的混合型DSSS/FHSS。事實上，所有 在「使用者」和「中繼站」之間傳遞的資料都以DSSS/FHSS方式調變，配合其他措施來應 付竊聽和干擾。 參考來源：[3] The Second Raid 第3&4話 在這兩集中，布魯諾上尉架設的通訊站扮演「中繼站」的角色，特別應對 班的派遣隊，如AS駕駛員則為「使用者」。該行動中所有的通訊都屬於「 廣播」，因此上尉能監控所有的通訊。值得注意的是，AS發射的通訊信標 屬於「重複器」，一種將全部收到的合法訊號重新發送的裝置。 TDD潛艦也扮演「中繼站」的角色。 [4] The Second Raid 第7話 千鳥要對「密銀」通訊系統的敘述。 --

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