Multiple bit complex bit modulation

A method of modulating a spread-spectrum datastream with a scrambling code, comprising the steps of:

• receiving a datastream of digital values representing in-phase data values and corresponding quadrature data values;
• receiving a scrambling code of digital values representing in-phase code values and corresponding quadrature code values;
• for each of the bits in the datastream, adding a digital data word of corresponding bits in the in-phase and quadrature data values with a digital code word of corresponding bits of the in-phase and quadrature code values, to produce an in-phase combined bit value and a quadrature combined bit value;
• generating a quadrature amplitude modulation signal corresponding to the result of the adding step;
• and
• wherein the adding step comprises:
• Gray Code adding the digital data word and the digital code word;
• storing the data output bits from the Gray Code adding step in corresponding bit positions of an output register.

A digital communications base station, comprising:

• a radio subsystem for amplifying modulated signals for transmission over an antenna;
• a radio frequency interface circuit, coupled to the radio subsystem, for converting digital signals into analog signals for transmission;
• network interface circuitry, coupled to a communications network, for generating a digital input sequence corresponding to a data signal to be forwarded to a remote user;
• digital circuitry, coupled to the network interface circuitry and to the radio frequency interface circuit, the digital circuitry for modulating the received digital input sequence into a spread-spectrum digital datastream having in-phase and quadrature data components, the digital circuitry having a circuit for applying a scrambling code having in-phase and quadrature code components to the spread-spectrum datastream by adding, for each of a plurality of bits, a digital data word including a bit of the in-phase data component value and a corresponding bit of the quadrature data component value with a digital code word including corresponding bit of the in-phase code component value and a corresponding bit of the quadrature code component value to forward a combined digital word having in-phase and quadrature components to the radio frequency interface circuit;
• and
• wherein the addition performed by the digital circuitry provides an equivalent digital signal as a complex multiplication of the having in-phase and quadrature data components with the in-phase and quadrature code components in combination with a phase shift and amplitude scaling.