Realizing FDD capability by leveraging existing TDD technology
First Claim
Patent Images
1. A cellular communication system, comprising:
- a base transmission station (BTS), that transmits information on a downlink (DL) frequency band to one or more mobile devices and concurrently receives information on an uplink (UL) frequency band from the one or more mobile devices;
a frequency division duplex (FDD) processor that alternately applies first and second time division duplexed (TDD) carriers to a transmission signal on the DL frequency band with downlink transmissions according to a predefined switching schedule, and employs a receive time gap (RTG) on the UL frequency band immediately preceding each of a plurality of transition gaps to prevent concurrent transmission on the DL frequency band and reception on the UL frequency using the same TDD carrier; and
a memory that stores information related to the predefined switching schedule, TDD carrier identity, and DL and UL frequency bands, wherein the BTS transmits the downlink transmissions on the DL frequency band using the first TDD carrier for a first portion of a downlink transmission frame, and using the second TDD carrier for a second portion of the downlink transmission frame, and wherein the BTS receives uplink transmissions on the UL frequency band using the second TDD carrier for a first portion of an uplink transmission frame, and using the first TDD carrier for a second portion of the uplink transmission frame, wherein TDD carriers are shared between uplink and downlink frequencies in an alternating fashion.
12 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods are disclosed for using two TDD carriers in the same paired spectrum by offsetting the DL and UL transmissions in frequency to cause the TDD carriers to behave as two half-duplex FDD carriers. DL and UL transmission and reception periods are predefined such that only one of the TDD carriers is transmitting on the DL at any instant in time while the other TDD carrier is transmitting on the UL.
10 Citations
18 Claims
-
1. A cellular communication system, comprising:
-
a base transmission station (BTS), that transmits information on a downlink (DL) frequency band to one or more mobile devices and concurrently receives information on an uplink (UL) frequency band from the one or more mobile devices; a frequency division duplex (FDD) processor that alternately applies first and second time division duplexed (TDD) carriers to a transmission signal on the DL frequency band with downlink transmissions according to a predefined switching schedule, and employs a receive time gap (RTG) on the UL frequency band immediately preceding each of a plurality of transition gaps to prevent concurrent transmission on the DL frequency band and reception on the UL frequency using the same TDD carrier; and a memory that stores information related to the predefined switching schedule, TDD carrier identity, and DL and UL frequency bands, wherein the BTS transmits the downlink transmissions on the DL frequency band using the first TDD carrier for a first portion of a downlink transmission frame, and using the second TDD carrier for a second portion of the downlink transmission frame, and wherein the BTS receives uplink transmissions on the UL frequency band using the second TDD carrier for a first portion of an uplink transmission frame, and using the first TDD carrier for a second portion of the uplink transmission frame, wherein TDD carriers are shared between uplink and downlink frequencies in an alternating fashion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method that facilitates wireless communication by causing two time division duplexed (TDD) carriers to behave as half-duplex frequency division duplex (FDD) carriers, comprising:
-
transmitting a DL signal on a DL frequency band using a first TDD carrier during a first portion of a transmission frame; receiving a UL signal on a UL frequency band using a second TDD carrier during the first portion of the transmission frame; transmitting the DL signal on the DL frequency band applying the second TDD carrier during a second portion of the transmission frame; receiving the UL signal on the UL frequency band applying the first TDD carrier during the second portion of the transmission frame, wherein TDD carriers are shared between uplink and downlink frequencies in an alternating fashion; switching from the first TDD carrier to the second TDD carrier on the DL frequency band, and from the second TDD carrier to the first TDD carrier on the UL frequency band, during a first transition gap that occurs between the first and second portions of the transmission frame; and switching from the second TDD carrier to the first TDD carrier on the DL frequency band, and from the first TDD carrier to the second TDD carrier on the UL frequency band, during a second transition gap that occurs at the end of the transmission frame; and employing a receive time gap (RTG) on the UL frequency band immediately preceding each transition gap to prevent concurrent transmission on the DL frequency band and reception on the UL frequency using the same TDD carrier. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. A system that facilitates wireless communication by causing two time division duplexed (TDD) carriers to behave as half-duplex frequency division duplex (FDD) carriers during communication with a base station, comprising:
-
one or more transmitters that transmit a DL signal on a DL frequency band using a first TDD carrier during a first portion of a transmission frame; one or more receivers that receive a UL signal on a UL frequency band using a second TDD carrier during the first portion of the transmission frame; wherein the one or more transmitters transmit the DL signal on the DL frequency band using the second TDD carrier during a second portion of the transmission frame; wherein the one or more receivers receive the UL signal on the UL frequency band using the first TDD carrier during the second portion of the transmission frame; an FDD processor configured to switch from the first TDD carrier to the second TDD carrier on the DL frequency band, and from the second TDD carrier to the first TDD carrier on the UL frequency band, during a first transition gap that occurs between the first and second portions of the transmission frame; and wherein the FDD processor is further configured to switch from the second TDD carrier to the first TDD carrier on the DL frequency band, and from the first TDD carrier to the second TDD carrier on the UL frequency band, during a second transition gap that occurs at the end of the transmission frame; wherein transmission, reception, and carrier switching are performed iteratively across multiple transmission frames during a communication event; wherein the first and second TDD carriers are 802.16e-based Worldwide Interoperability for Microwave Access (WiMax) TDD carriers.
-
Specification