Title:
【発明の名称】TDMA無線通信システム用のライセンスされたおよびライセンスされていない帯域で互換性のあるポータブル・ハンドセット・ユニット
Document Type and Number:
Japanese Patent JPH10501397
Kind Code:
A
Abstract:
In a TDM/TDMA portable radio communications system, a portable handset is compatible for operation in both a frequency-division duplexing (FDD) mode for communication in the licensed portion of the Emerging Technologies frequency band, and in a time-division duplexing (TDD) mode for communication in the unlicensed portion of the Emerging Technologies frequency band. In the FDD mode, different frequencies are used to separate a downlink transmission to a portable from a port from an uplink transmission from a port to a portable. In the TDD mode, uplink and downlink transmissions are separated in different time-slots, but at the same frequency. The handset includes common transmit and receive circuitry that operates at fixed IF frequencies that are separated in frequency by the fixed FDD frequency difference between corresponding uplink and downlink signals. In the FDD mode, therefore, a frequency synthesizer (301), which is used to tune to transmit and receive at different frequencies from different ports, does not have to switch its frequency between transmitting and receiving a burst to and from a single port. In the TDD mode, however, even though uplink and downlink signals are at the same frequency, the synthesizer is switched in frequency between transmitting uplink and receiving downlink.
Inventors:
Arnold, Hamilton, Webster
Chang, Lee, Fan
Nopel, anthony, robert
Sallenburger, Nelson, Ray
Ziegler, Robert, Anthony
Chang, Lee, Fan
Nopel, anthony, robert
Sallenburger, Nelson, Ray
Ziegler, Robert, Anthony
Application Number:
JP52103695A
Publication Date:
February 03, 1998
Filing Date:
December 15, 1995
Export Citation:
Assignee:
Bell Communications Research, Inc.
International Classes:
H04B1/40; H04B7/06; H04B7/08; H04B7/26; H04J3/00; H04J4/00; H04M1/00; H04W88/06; H04W4/18; H04W88/02; (IPC1-7): H04Q7/32; H04B1/40; H04J3/00; H04M1/00
Attorney, Agent or Firm:
Yoshikazu Tani (1 person outside)