CDMA communication system and method

• US 7,916,699 B2
• Filed: 06/08/2009
• Issued: 03/29/2011
• Est. Priority Date: 07/09/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Doi, Nobukazu, Shiga, Tesshin, Ohta, Yoshito, Ariyoshi, Masayuki
• Primary Examiner(s): Hoang; Thai D
• Application Number:
  US12/480,137
• Publication Number:
  US 20090245210A1
• Time in Patent Office: 659 Days
• Field of Search: 375229-235, 375260-270, 375279-283, 375302-308, 375322-336, 375346-349, 370206-208, 370/210, 370320-321, 370335-339, 370/342
• US Class Current: 370/335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0085 detecting a given structure in the signal

Abstract

In CDMA communications, a base station detects a difference between a reference phase of a spreading code and a phase of a received signal of each terminal station, and feeds a phase jump signal PJ-i representative of the phase difference back to each terminal station. After timing acquisition, the reception operation is performed using the reference phase, and a shift amount between the phase of a received signal and the reference phase is fed back to each terminal station as phase synchronization control information PC-i. Each terminal station coarsely adjusts the phase of the spreading code in accordance with the phase jump signal PJ-i, and thereafter finely adjusts the phase of its transmitting signal in accordance with the phase synchronization control information PC-i. It is therefore possible to synchronize the phases of the signals transmitted from terminal stations and received at the base station. Accordingly, an orthogonal code is used for spreading on the reverse links.

Claims

1. A communication method in a communication system for communication between a base station and a terminal station, comprising the steps of:

transmitting, from the terminal station, a first signal;

performing, in the base station, a timing acquisition of the first signal from the terminal station and transmitting first difference information for first adjustment which indicates a phase difference between the first signal and a reference phase;

inputting, in the terminal station, the first difference information to a generating circuit for generating an orthogonal signal;

generating, in the generator circuit of the terminal station, the orthogonal signal having a phase set according to the first difference information and transmitting a second signal using the generated orthogonal signal;

performing, in the base station, a tracking of the second signal from the terminal station and transmitting a second difference information for second adjustment between the second signal and the reference phase, the second adjustment being finer than the first adjustment; and

inputting, in the terminal station, the second difference information to a delay circuit between an antenna of the terminal station and the generating circuit; and

setting, in the terminal station, a delay amount of the delay circuit according to the second difference information.

2. A terminal station that communicates with a base station, comprising:

an antenna that transmits a first signal to the base station, transmits a second signal to the base station and receives, from the base station, first difference information indicating a phase difference for first adjustment between the first signal and a reference phase to be used in a timing acquisition of the first signal, said antenna further receiving, from the base station, second difference information indicating a difference for second adjustment during tracking between the reference phase and the second signal, the second adjustment being for finer adjustment than the first adjustment;

a generator which generates an orthogonal signal including a phase set according to the first difference information inputted from the antenna, and being assigned to the terminal station and used for transmitting the second signal; and

a delay circuit, between an antenna and the generator, having a delay set according to the second difference information inputted from the antenna.

3. The terminal station of claim 2,

wherein the generator is adapted to slide a phase of the orthogonal signal by a predetermined amount until receiving the first difference information transmitted via the antenna from the base station, and

wherein the first difference information indicates a completion of timing acquisition of the transmitting signal from the terminal station.

4. The terminal station of claim 3,

wherein the transmitting data are fixed as consecutive symbols before the completion of the timing acquisition.

5. The terminal station of claim 4,

further comprising a transmission phase controller, wherein the second difference information is input to the delay circuit via the transmission phase controller.

6. The terminal station of claim 3,

further comprising a transmission phase controller, wherein the second difference information is input to the delay circuit via the transmission phase controller.

7. The terminal station of claim 2,

further comprising a transmission phase controller, wherein the second difference information is input to the delay circuit via the transmission phase controller.