Reverse checksum method for telecommunication systems
First Claim
1. A method for synchronizing communication between a first unit and a second unit in a telecommunication system, the method comprising the steps of:
- at the first unit;
serially transmitting data, the data including a length indicator and a checksum;
at the second unit;
receiving the data including the length indicator;
storing the data in a buffer, including storing first-received data at an initial location and storing last-received data at a final location;
storing the length indicator at a predetermined location;
beginning at the final location, calculating a calculated checksum while maintaining a length count;
verifying the calculated checksum; and
synchronizing communication if the length count matches the length indicator.
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Accused Products
Abstract
A method for synchronizing communication between a transmitting unit (102) and a receiving unit (104) in a telecommunication system (100) includes calculating a reverse checksum for the received data. At the transmitting unit (102), data including a length indicator is serially transmitted. At the receiving unit (104), the data are received and stored in a buffer. A checksum is calculated beginning with the last-received data while maintaining a length count. When the checksum verifies and when the length count matches the transmitted length indicator, the received data is considered valid and communication is considered synchronized.
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Citations
20 Claims
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1. A method for synchronizing communication between a first unit and a second unit in a telecommunication system, the method comprising the steps of:
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at the first unit; serially transmitting data, the data including a length indicator and a checksum; at the second unit; receiving the data including the length indicator; storing the data in a buffer, including storing first-received data at an initial location and storing last-received data at a final location; storing the length indicator at a predetermined location; beginning at the final location, calculating a calculated checksum while maintaining a length count; verifying the calculated checksum; and synchronizing communication if the length count matches the length indicator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for verifying received data in a telecommunication device, the telecommunication device receiving data from a remote transmitter, the data being organized in one or more segments, the data including a length indicator, the method comprising the steps of:
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reading a final segment of data, the final segment being a last-received segment of the one or more segments; calculating a checksum for the final segment; maintaining a length count while calculating the checksum, the length count being indicative of an amount of data over which the checksum is calculated; verifying a checksum; identifying the final segment of data as valid if the length count and the length indicator match; determining if the final segment of data includes as acknowledgment message; if the final segment of data includes an acknowledgment message, reading a next-to-last segment of data, the next-to-last-segment being a segment received immediately preceding receipt of the final segment of data; calculating an information frame checksum for the final segment and the next-to-last segment; maintaining an information frame length count while calculating the information frame checksum; verifying the information frame checksum; and identifying the final segment and next-to-last segment as valid if the information frame length count matches the length indicator. - View Dependent Claims (13, 14, 15, 16)
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17. A radiotelephone handset configured for radio communication with a remotely located transceiver, the radiotelephone handset comprising:
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an antenna configured to detect radio signals transmitted by the remotely located transceiver; a receiver coupled to the antenna for receiving the detected radio signals; a demodulator coupled to the receiver for demodulating the received radio signals to produce received data, the received data including first-received data and last-received data, the received data being organized in one or more segments including a last-received segment of data, the received data further including a length indicator indicative of an amount of data transmitted by the remotely located transceiver; and a controller coupled to the demodulator for processing the received data, the controller including a receive data buffer for storing the received data, the controller storing the first-received data in an initial location and the last-received data in a final location, the controller reading the last-received segment of data including the last-received data from the receive data buffer, the controller calculating a checksum for the last-received segment of data and maintaining a length count indicative of the amount of data for which the checksum is calculated, the radiotelephone handset obtaining synchronized communication with the transmitter when the controller verifies the checksum and when the length count matches the length indicator. - View Dependent Claims (18, 19)
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20. A method for synchronizing communication between a first unit and a second unit in a telecommunication system, the method comprising the steps of:
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at the first unit; serially transmitting data, the data including a length indicator and a checksum; at the second unit; receiving the data including the length indicator; storing the length indicator at a predetermined location; storing the data in a buffer, including storing last-received data at a final location; detecting a predetermined data reception indicator, the predetermined data reception indicator including a pause in reception of the data; in response to the predetermined data reception indicator and beginning at the final location, calculating a calculated checksum while maintaining a length count; verifying the calculated checksum; and synchronizing communication if the length count matches the length indicator.
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Specification