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کامپیوتر و شبکه::
نرخ بیت جریان کد
Specifically, the scheme has four modules: (1) a train uses its on-board sensors to obtain its speed, location, and RSSI (Received Signal Strength Indicator) of train-trackside WiFi channel; (2) the train reports these real-time measurements to the railway control center with the legacy GSM-R networks; (3) according to the measurements, the control center or its WiFi AP adaptively customizes the protected codestream bitrate and AP-train handover time; (4) the train renders the received codestream which passes the authenticity verification process.
Hence, it is valuable to directly reduce the video codestream bitrate as the process of codestream decoding and re-encoding is time-consuming at the AP side.
If there are several passing-by trains around an AP, the AP will broadcast the smallest codestream bitrate such that all the trains can verify their received codestreams.
Thus if the actual AP throughput rate ra is higher than codestream rate rc, codestream buffering is a viable solution to ensure the stability of codestream bitrate.
However, when the data-rate of AP is selected to be higher than the codestream bitrate, some codestream shall be prepared in advance.
واژگان شبکه مترجمین ایران