Method of and an apparatus for effecting a smooth transition between adjacent symbol bursts transmitted in different modulation formats

An apparatus for effecting a smooth transition between adjacent digital information bursts transmitted in different modulation formats, the apparatus comprising:

• means for selecting a first sequence for a first digital symbol burst to be transmitted, which first sequence comprises a set of end symbols with a particular symbol pattern;
• means for selecting a second sequence for a second digital symbol burst to be transmitted after the first digital symbol burst, which second sequence comprises a set of start symbols with the particular symbol pattern;
• means for modulating the first digital symbol burst in a first modulation format and for modulating the second digital symbol burst in a second modulation format different than the first modulation format;
• and
• means for transmitting the modulated first and second digital symbol bursts, the transmission of the second digital symbol burst starting upon completion of the first digital information symbol at an instant so selected that transmission of the end set of bits of the first code sequence is synchronized in time with the start set of bits of the second code sequence.

A method of effecting a smooth transition between consecutive sequences of digital information transmitted in different modulation formats, the method comprising:

• selecting a first sequence of digital information to be transmitted with a first phase and a first amplitude in a radio signal;
• selecting a second sequence of digital information to be transmitted with a second phase and a second amplitude in the radio signal;
• transmitting, by a transmitter, the first sequence of digital information in a first modulation format;
• and
• transmitting the second sequence of digital information in a second modulation format different than the first modulation format, the transmission of the second sequence starting before completion of the first sequence at an instant so selected to minimize the respective differences between the first and second phases and the first and second amplitudes.

An apparatus for processing digital symbols prior to transmission of the symbols in two different modulation formats, the apparatus comprising:

• means for selecting from a set of symbols some of the symbols for modulation in a first modulation format and for selecting others of the symbols for modulation in a second modulation format different than the first modulation format;
• means for modulating the said some symbols in accordance with the first modulation format and for modulating the said others of the symbols in accordance with the second modulation format;
• and
• means for outputting the symbols as bursts for transmission, in which outputting means the burst of symbols in the first modulation format is separated from the burst of symbols in the second modulation format by a guard period comprising guard symbols that include at least one end symbol of the burst of symbols in the first modulation format and at least one symbol of the burst of symbols in the second modulation format.

An apparatus storing instructions operable, when executed by a processor, to cause the processor to:

• select a first sequence of digital information to be transmitted with a first phase and a first amplitude in a radio signal;
• select a second sequence of digital information to be transmitted with a second phase and a second amplitude in the radio signal;
• transmit the first sequence of digital information in a first modulation format;
• and
• transmit the second sequence of digital information in a second modulation format different than the first modulation format,
• wherein transmitting the second sequence begins before completing transmission of the first sequence and at a time selected to reduce a difference between the first phase and the second phase and to reduce a difference between the first amplitude and the second amplitude.

A system to communicate signals over a wireless communication channel, comprising:

• a controller configured to select a first sequence of digital information to be transmitted with a first phase and a first amplitude in a radio signal and further configured to select a second sequence of digital information to be transmitted with a second phase and a second amplitude in the radio signal;
• a modulator configured to modulate the first sequence using a first modulation format and further configured to modulate the second sequence using a second modulation format different than the first modulation format;
• and
• a transmitter configured to transmit the modulated first sequence in the first modulation format and further configured to transmit the modulated second sequence in the second modulation format,
• wherein transmitting the second sequence begins prior to completing transmission of the first sequence and at a time selected to reduce a difference between the first phase and the second phase and to reduce a difference between the first amplitude and the second amplitude.