Variable rate transmission method, transmitter and receiver using the same

A variable rate transmission method which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length,

• wherein a transmitting side comprises the steps of:
• calculating in each frame an error detecting code of data to be transmitted;
• periodically inserting pilot symbols of a known pattern into said each frame;
• disposing important data of said data to be transmitted near said pilot symbols;
• transmitting said data to be transmitted and said error detecting code in said each frame at a predetermined fixed transmission rate;
• and
• pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent, and
• wherein a receiving side comprises the steps of:
• receiving said each frame at said fixed transmission rate;
• detecting said pilot symbols;
• compensating said transmitted data and said error detecting code which are received using said pilot symbols which are detected;
• relocating said transmitted data to its original order;
• detecting said error detecting code in said each frame;
• and
• recovering said transmitted data of the variable length in said each frame in response to a detecting result of said error detecting code.

A variable rate transmission method which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length,

• wherein a transmitting side comprises the steps of:
• calculating in each frame an error detecting code of data to be transmitted;
• transmitting said data to be transmitted and said error detecting code in said each frame at a predetermined fixed transmission rate;
• pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent;
• when a total amount of said data to be transmitted and said error detecting code is equal to or less than 1/K of a maximum amount of data that can be transmitted by one frame, generating repeat frames, in each of which each bit of said data to be transmitted and said error detecting code is repeated K times;
• transmitting said repeat frames at a transmission power of 1/K of transmission power used when said each bit is not repeated;
• and
• informing said receiving side that said data to be transmitted and said error detecting code are repeated K times in said repeat frames, where K is a positive integer,
• wherein a receiving side comprises the steps of:
• receiving said each frame at said fixed transmission rate;
• detecting said error detecting code in said each frame;
• recovering said transmitted data of the variable length in said each frame in response to a detecting result of said error detecting code;
• and
• recovering original data from said repeat frames by thinning out data using said K informed from said transmitting side.

A variable rate transmission method which varies an average transmission rate by transmitting frames of a fixed duration, each frame holding data of a variable length,

• wherein a transmitting side comprises the steps of:
• calculating in each frame an error detecting code of data to be transmitted;
• allocating said frames to a plurality of channels;
• periodically inserting pilot symbols of a known pattern into each frame of one of said plurality of channels;
• disposing important data of said data to be transmitted near said pilot symbols;
• transmitting said data to be transmitted and said error detecting code in said each frame of said plurality of channels at a predetermined fixed transmission rate;
• pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent;
• spreading said data to be transmitted simultaneously using different spreading code sequences assigned to said plurality of channels to transmit spread data through each channel, and
• wherein a receiving side comprises the steps of:
• simultaneously receiving said plurality of channels at said fixed transmission rate;
• detecting pilot symbols of said one of said plurality of channels;
• compensating received signals of said plurality of channels using pilot symbols detected;
• relocating said transmitted data received to its original order;
• detecting said error detecting code in said each frame;
• and
• recovering said transmitted data of the variable length in said each frame in response to a detecting result of said error detecting code.

A variable rate transmission method which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length,

• wherein a transmitting side comprises the steps of:
• calculating in each frame an error detecting code of data to be transmitted;
• disposing said error detecting code at a fixed position in and relative to said each frame;
• transmitting said data to be transmitted and said error detecting code in said each frame at a predetermined fixed transmission rate;
• and
• pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent, and
• wherein a receiving side comprises the steps of:
• receiving said each frame at said fixed transmission rate;
• extracting said error detecting code placed at said fixed position in said each frame;
• detecting an error detecting code in said each frame;
• obtaining the number of bits of said transmitted data on the basis of said error detecting code;
• and
• recovering said transmitted data of the variable length in said each frame in response to the obtained number of bits of said transmitted data.

A variable rate transmission method which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length,

• wherein a transmitting side comprises the steps of:
• calculating in each frame an error detecting code of data to be transmitted;
• adding to a fixed position in said each frame, transmission rate information representative of the number of bits of data in said each frame and said error detecting code;
• transmitting said data to be transmitted, said transmission rate information and said error detecting code in said each frame at a predetermined fixed transmission rate;
• and
• pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent, and
• wherein a receiving side comprises the steps of:
• receiving said each frame at said fixed transmission rate;
• obtaining an end bit position of said transmitted data in each said frame in response to said transmission rate information;
• calculating error detecting code of said transmitted data to said end position;
• comparing said calculated error detecting code with said error detecting code which has been received;
• deciding that said transmitted data to said end bit position is correct when a compared result of the step of comparing coincides;
• and
• recovering said transmitted data of the variable length in said each frame.

A transmitter which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length, said transmitter comprising:

• a memory for storing said data to be transmitted;
• pilot symbol inserting means for periodically inserting pilot symbols of a known pattern into said each frame;
• data relocating means for disposing near said pilot symbols important data of said data to be transmitted stored in said memory;
• means for calculating in said each frame an error detecting code of data to be transmitted;
• and
• means for transmitting said data to be transmitted and said error detecting code in said each frame at a predetermined fixed transmission rate, and for pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent.

A transmitter which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length, said transmitter comprising:

• means for calculating in said each frame an error detecting code of data to be transmitted;
• pilot symbol inserting means for periodically inserting pilot symbols of a known pattern into said each frame;
• a memory for storing said data to be transmitted, said memory capable of reading multiple sets of transmitted data to be transmitted in association with a plurality of channels;
• means for pausing transmission in a blank of each frame, said blank being a part of said frame at which said transmitted data or said error detecting code is absent;
• data relocating means for writing data into said memory such that important data of said transmitted data to be transmitted stored in said memory is placed near said pilot symbols;
• a plurality of primary modulators for primary modulating said multiple sets of transmitted data at a predetermined fixed transmission rate;
• a plurality of transmission power control means for controlling transmission power of said each frame output from said primary modulators;
• a plurality of secondary modulators for spreading data in said each frame output from said transmission power control means by using different spreading code sequences;
• and
• an adder for adding multiple signals output from said secondary modulators, wherein said data relocating means divides said data to be written into said memory, simultaneously reads from said memory said multiple sets of data which have been formed by the dividing, and supplies read data to said plurality of primary modulators, said pilot symbol inserting means is connected after one of said plurality of primary modulators for periodically inserting said pilot symbols, and said plurality of transmission power control means increase transmission power while transmitting said important data.

A transmitter which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length, said transmitter comprising:

• means for calculating in said each frame an error detecting code of data to be transmitted;
• means for adding said error detecting code to a fixed position in and relative to said each frame;
• and
• means for transmitting said data to be transmitted and said error detecting code in said each frame at a predetermined fixed transmission rate, and for pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent.

A transmitter which varies an average transmission rate by transmitting each frame of a fixed duration, said frame holding data of a variable length, said transmitter comprising:

• means for calculating in said each frame an error detecting code of data to be transmitted;
• adding means for adding, to a fixed position in and relative to said each frame, transmission rate information representative of the total number of data in said each frame and said error detecting code;
• and
• means for transmitting said data to be transmitted, transmission rate information and said error detecting code in said each frame at a predetermined fixed transmission rate, and for pausing transmission in a blank of each frame, said blank being a part of said frame at which said data to be transmitted or said error detecting code is absent.

A receiver, comprising:

• means for receiving, at a fixed transmission rate, frames which each include transmitted data;
• detecting means for detecting error detecting code in said each frame;
• and
• means for recovering said transmitted data of a variable length in said each frame in response to a detection result of said error detecting code,
• wherein said detecting means sequentially divides received data in each said frame by predetermined data while shifting said received data bit by bit, and decides that said error detecting code is detected at a point at which said received data can be divided.

A receiver, comprising:

• means for receiving, at a fixed transmission rate, frames which each include transmitted data;
• means for detecting error detecting code in said each frame;
• means for recovering said transmitted data of a variable length in said each frame in response to a detection result of said error detecting code;
• means for detecting pilot symbols of a known pattern, which are inserted into said each frame periodically;
• a memory for storing data transmitted in said each frame;
• and
• data relocating means for rearranging data written in said memory to an original order when receiving transmitted data in said each frame which has important data disposed near said pilot symbols.

A receiver comprising:

• a plurality of secondary demodulators for despreading each of a multiple series of frames simultaneously transmitted through a plurality of channels;
• a compensator for compensating data in said multiple series of frames by using pilot symbols which are periodically inserted into one of said multiple series of frames and which are sent through one of said plurality of channels;
• a plurality of primary demodulators for demodulating compensated data;
• a memory for storing said multiple series of data at the same time;
• data relocating means for rearranging important data disposed near said pilot symbols to its original order by simultaneously writing said multiple series of frames in separated areas of said memory, and by reading written data in an order different from that of writing;
• means for detecting error detecting code in said each frame;
• and
• means for recovering said transmitted data of a variable length in said each frame in response to a detection result of said error detecting code.

A receiver comprising:

• a secondary demodulator for despreading a received spread signal, and for outputting a despread signal;
• a primary demodulator for recovering data in each frame from said despread signal;
• an error detecting code memory for storing said error detecting code placed at a fixed position in said each frame;
• means for calculating an error detecting code from said data in said each frame;
• and
• comparing means for comparing said calculated error detecting code with said error detecting code stored in said error detecting code memory,
• wherein the number of bits of variable bit data in said each frame is obtained in response to a result of the comparison.

A receiver, comprising:

• means for receiving, at a fixed transmission rate, frames which include transmitted data, transmission rate information and an error correcting code;
• means for obtaining an end bit position of said transmitted data in each said frame which has been received in response to said transmission rate information which is placed at a fixed position of said each frame, said end bit position determining the number of bits of said transmitted data in said each frame;
• means for calculating error detecting code of said transmitted data to said end position;
• means for comparing the calculated error detecting code with said error detecting code which has been transmitted in said each frame;
• and
• means for deciding that said transmitted data to said end bit position is correct in said each frame when a compared result coincides.

A variable rate transmission method, comprising the steps of:

• inserting pilot symbols of a known pattern into each frame periodically and disposing important data of data to be transmitted near said pilot symbols;
• detecting said pilot symbols;
• compensating by the detected pilot symbols said data to be transmitted and error detecting code which have been received;
• and
• rearranging said data to be transmitted which has been received to its original order,
• wherein said step of disposing said important data near said pilot symbols comprises the steps of:
• placing said important data at an initial position of said data to be transmitted;
• writing said data to be transmitted row by row into a memory with N rows and M columns alternately from a top row and a bottom row of said memory;
• reading from said memory, column by column, said data which has been stored in said memory;
• and
• inserting said pilot symbols each time said column is read.