Receiving device for spread spectrum communication

A receiving device for spread spectrum communication and for receiving a signal spread and modulated with a first spreading code, the receiving device comprising:

• a phase determining unit calculating a cross correlation between the received signal and a second spreading code and determining a phase P(0) of the received signal based on the cross correlation, the phase P(0) being a synchronizing point with the first spreading code;
• and
• a data demodulating unit synchronizing the phase P(0) and the first spreading code and despreading and demodulating the received signal with the first spreading code, wherein:
• the number of components in each of the first spreading code and the second spreading code is defined as Y;
• Y is an integer greater than or equal to 2;
• the phase determining unit includes a cross-correlation calculating element;
• the cross correlation calculating element selects a combination of N phases from the received signal;
• the combination of N phases is defined as {P(x1), P(x2), . . . , P(xN)};
• x1, x2, . . . , xN represent phase shifting amounts from the phase P(0) and each of the phase shifting amounts is not specified before the phase P(0) is determined;
• a phase shifting difference between two of the phase shifting amounts is a predetermined number of chips;
• the cross-correlation calculating element calculates a product sum of the received signal for Y chips included in each of the N phases {P(x1), P(x2), . . . , P(xN)} and the second spreading code so that a combination of N cross-correlation values defined as {Q(x1), Q(x2), . . . , Q(xN)} corresponding to the combination of N phases {P(x1), P(x2), . . . , P(xN)} is obtained;
• the combination of N cross-correlation values {Q(x1), Q(x2), . . . ,Q(xN)} provides a specific combination corresponding to the phase shifting amount x1;
• the cross-correlation calculating element specifies the phase shifting amount x1 based on the combination of N cross-correlation values {Q(x1), Q(x2), . . . , Q(xN)};
• the cross-correlation calculating element determines the phase P(0) as a phase shifted by the phase shifting amount x1 from the phase P(x1);
• and
• N represents a predetermined integer that is less than Y and that is set so that the phase shifting amount x1 is specified as one of 0, 1, . . . , (Y−1) when a changing pattern of the combination of N cross-correlation values {Q(x1), Q(x2), . . . , Q(xN)} is determined.