Methods And Apparatus For Communication With Time-Division Duplexing

• US 20080137562A1
• Filed: 04/29/2005
• Published: 06/12/2008
• Est. Priority Date: 05/01/2004
• Status: Active Grant

• Current Assignee: Guangdong OPPO Mobile Telecommunications Corporation Limited
• Original Assignee: Neocific Incorporated
• Inventors: Lo, Titus, Huang, Haiming, Li, Xiaodong, Li, Kemin
• Granted Patent: US 8,014,264 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 27/2627 Modulators
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/1484 operating bytewise
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 72/30 Resource management for broadcast services

Abstract

Methods and apparatus for an adaptable frame structure are disclosed, where a transmission frame consists of multiple subframes, each containing a downlink transmission period and an uplink transmission period. A downlink broadcasting signal is used to indicate the configuration of each subframe. The downlink and uplink period configuration in each subframe can be independently adapted to support applications with a variety of traffic patterns, from symmetric to highly asymmetric. A great variety of applications from normal two-way data communications to voice communications and video or data broadcasting can be supported efficiently in a single frequency band, while multiple frequency bands can be used to increase capacity or add more flexibility.

Claims

1. A process of generating an adaptable signal for wireless transmission in a communication system, the process comprising:

utilizing subcarriers and subchannels that include groups of subcarriers to makeup the signal; and

forming a signal transmission frame, wherein the transmission frame is partitioned into multiple subframes, and wherein each subframe is further divided into multiple time-slots;

configuring a number of downlink time-slots and a number of uplink time-slots within each subframe with a predetermined ratio, wherein the ratio of the number of downlink time-slots and the number of uplink time-slots may be different from one subframe to the next;

inserting a guard period at the beginning of a subframe, before the down link time-slots, and another guard period before the uplink time-slots, both within the subframe; and

inserting at least one special downlink period (SDP) in a frame, during which a base station broadcasts control and system information, and inserting at least one special uplink period (SUP) in a frame, during which a mobile station is capable of carrying out radio functions.

2. The process of claim 1, wherein a subframe is limited to a relatively small duration relative to a channel coherence time, and wherein:

during at least one of the SDP the base station broadcasts signals comprising ratios of downlink and uplink time-slots in each subframe, a cell identity information, and adaptive control information, and wherein the SDP can be placed either outside of the subframes or within the downlink period of a subframe, and wherein multiple SDPs can be inserted into a frame and multiple subframes can share an SDP;

during at least one of the SUP mobile stations carry out radio functions including initial ranging during power-up and handoff, periodic ranging and bandwidth request, and channel sounding, and wherein the SUP can be placed either outside of the subframes or within the uplink period of individual subframes, and wherein multiple SUPs can be inserted into a frame and multiple subframes can share an SUP; and

wherein the SUP is either based on contention or coordination, where, in the coordination case, a use of SUP is fully or partially scheduled by the base station and scheduling information is carried in the downlink signal.

3. The process of claim 1, wherein adaptive transmission techniques are applied to downlink transmission, uplink transmission, or both, and wherein:

a mobile station monitors the downlink signal quality and sends channel quality information (CQI), power control request, or both to a serving base station that in turn adjusts modulation and coding schemes (MCS), transmission power level, or both on the downlink transmission to the mobile station and sends an indication of MCS to the mobile station;

a base station monitors uplink signals from a mobile station and sends the CQI, power control request, or both to the mobile station, which in turn adjust the MCS, transmission power level, or both accordingly and sends the indication of MCS to the base station;

or

a base station monitors uplink signals from a mobile station and makes decisions on the MCS and the uplink transmission power level for the mobile station and sends a command to the mobile station to dictate to the mobile station the decided MCS and transmission power.

4. The process of claim 1, wherein hybrid ARQ (Automatic Repeat Request) is applied to the downlink transmission, uplink transmission, or both, and wherein:

a mobile station detects a transmitted packet from a base station and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the base station, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the mobile station; and

a base station detects the transmitted packet from a mobile station and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the mobile station, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the base station.

5. The process of claim 1, wherein different subframes within a frame are configured with different system parameters in accordance with transmission characteristics required by different types of services, and a configuration wherein:

in a two-way data subframe, a scrambler or a randomizer, subchannel configuration and a training symbol configuration are structured differently in individual cells;

in a broadcast subframe, the scrambler or the randomizer, subchannel configuration and the training symbol configuration on the downlink are structured in the same way in all the cells, forming a single frequency network (SFN);

a broadcast subframe is used for downlink broadcasting, or at least one uplink time-slot within the subframe is used to facilitate a continuous flow of channel feedback information;

a base station provides two-way data communication services using the two-way data subframe and another base station provides broadcasting services using the broadcast subframe and cell sizes are not necessarily the same for these two base stations;

a subframe within a frame is capable of being allocated for use by a different group of cells;

a subframe within a frame can be temporarily set idle for a group of cells in the network such that this particular subframe is reconfigured to meet service requirements while normal services are maintained by other subframes;

or

any combination thereof.

6. The process of claim 1, wherein time-slots are composed of a specified number of OFDM symbols, and wherein:

within a subframe, an OFDM symbol is used on the downlink to indicate a downlink modulation and coding scheme (MCS) for each used subchannel and a command for uplink MCS and power control; and

within a subframe, an OFDM symbol is used on the uplink to indicate a measured downlink channel quality information (CQI) by mobile stations, each of which uses a bit field that corresponds to a mobile station'"'"'s own downlink subchannel in the OFDM symbol.

7. The process of claim 1, wherein the communication system is a multi-carrier system of any format including OFDM and Multi-Carrier Code Division Multiple Access (MC-CDMA), and wherein the process can be applied to downlink, uplink, or both, where the duplexing technique is either Time Division Duplexing (TDD) or Frequency Division Duplexing (FDD).

8. In an adaptable wireless communication system capable of communicating under multiple different communication schemes, wherein a mobile transceiver transmits signals to a stationary transceiver in an uplink transmission and the stationary transceiver transmits signals to the mobile transceiver in a downlink transmission, a signal comprising:

signal transmission frames, wherein each frame is partitioned into multiple subframes, and wherein each subframe is further divided into multiple time-slots, wherein;

a number of downlink time-slots and a number of uplink time-slots incorporated within each subframe has one of multiple predetermined ratios, and wherein the ratio of at least one subframe in a frame differs from the ratio of another subframe in one other frame or in the same frame; and

a guard period is inserted in relation to down link time-slots, and another guard period in relation to uplink time-slots.

9. The signal of claim 8, wherein at least one special downlink period (SDP) is inserted in a frame, during which a base station broadcasts control and/or system information, or at least one special uplink period (SUP) is inserted in the frame, during which mobile stations is capable of carrying out radio functions, and wherein:

during at least one of the SDP the stationary transceiver broadcasts signals comprising ratios of downlink and uplink time-slots in each subframe, a cell identity information, and adaptive control information, and wherein the SDP can be placed either outside of the subframes or within the downlink period of a subframe, and wherein multiple SDPs can be inserted into a frame and multiple subframes can share an SDP;

during at least one of the SUP the mobile transceiver carries out radio functions including initial ranging during power-up and handoff, periodic ranging and bandwidth request, and channel sounding; and

wherein the SUP can be placed either outside of the subframes or within the uplink period of individual subframes, and wherein multiple SUPs can be inserted into a frame and multiple subframes can share an SUP; and

wherein the SUP is either based on contention or coordination, where in the coordination case, a use of SUP is fully or partially scheduled by the stationary transceiver and scheduling information is carried in the downlink signal.

10. The signal of claim 8, wherein:

a mobile transceiver monitors the downlink signal quality and sends channel quality information (CQI), power control request, or both to a serving stationary transceiver that in turn adjusts modulation and coding schemes (MCS), transmission power level, or both on the downlink transmission to the mobile transceiver and sends an indication of MCS to the mobile transceiver;

a stationary transceiver monitors uplink signals from a mobile transceiver and sends the CQI, power control request, or both to the mobile transceiver, which in turn adjust the MCS, transmission power level, or both accordingly and sends the indication of MCS to the stationary transceiver;

or

a stationary transceiver monitors uplink signals from a mobile transceiver and makes decisions on the MCS and the uplink transmission power level for a mobile transceiver and dictates to the mobile transceiver the decided MCS and transmission power.

11. The signal of claim 8, wherein hybrid ARQ (Automatic Repeat Request) is applied to the downlink transmission, uplink transmission, or both, and wherein:

a mobile transceiver detects a transmitted packet from a serving stationary transceiver and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the stationary transceiver, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the mobile transceiver; and

a stationary transceiver detects the transmitted packet from a mobile transceiver and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the mobile transceiver, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the stationary transceiver.

12. The signal of claim 8, wherein different subframes within a frame are configured with different system parameters in accordance with transmission characteristics required by different types of services, and a configuration wherein:

in a two-way data subframe, a scrambler or a randomizer, subchannel configuration and a training symbol configuration are structured differently in individual cells;

in a broadcast subframe, the scrambler or the randomizer, subchannel configuration and the training symbol configuration on the downlink are structured in the same way in all the cells;

a broadcast subframe is used for downlink broadcasting, or at least one uplink time-slot within the subframe is used to facilitate a continuous flow of channel feedback information;

a stationary transceiver provides two-way data communication services using the two-way data subframe and another stationary transceiver provides broadcasting services using the broadcast subframe and cell sizes are not necessarily the same for these two stationary transceivers;

a subframe within a frame can be allocated for use by a different group of cells;

a subframe within a frame can be temporarily set idle for a group of cells in the network such that this particular subframe is reconfigured to meet service requirements while normal services are maintained by other subframes;

or

any combination thereof.

13. The signal of claim 8, wherein time-slots are composed of a specified number of OFDM symbols, and wherein:

within a subframe, an OFDM symbol is used on the downlink to indicate a downlink modulation and coding scheme (MCS) and a command for uplink MCS; and

within a subframe, an OFDM symbol is used on the uplink to indicate a measured downlink channel quality information (CQI) by mobile stations.

14. A mobile station capable of receiving, generating, and transmitting adaptable frame wireless signals in a wireless communication network, the mobile station comprising:

a signal generator facility for generating adaptable signal frames, wherein each of the signal frames is partitioned into multiple subframes, and wherein each of the subframes is further partitioned into at least one downlink time-slot and at least zero uplink time-slot, and wherein;

the number of downlink time-slots and the number of uplink time-slots between two subframes of at least one frame differs; and

at least one special downlink period (SDP) is provided in a frame, during which a downlink control signal dictates the number of downlink time-slots and the number of uplink time-slots of the subframes of the frame, or at least one special uplink period (SUP) is provided in a frame, during which the mobile station is capable of carrying out radio functions.

15. The mobile station of claim 14, wherein:

the SDP can be placed either outside of the subframes or within the downlink period of a subframe, and wherein multiple SDPs can be inserted into a frame and multiple subframes can share an SDP; and

the SUP can be placed either outside of the subframes or within the uplink period of individual subframes, and wherein multiple SUPs can be inserted into a frame and multiple subframes can share an SUP.

16. The mobile station of claim 14, wherein the mobile station is in communication with a control station and exchanges information and control signals with the control station, and wherein:

the mobile station monitors the downlink signal quality and sends channel quality information (CQI), power control request, or both to the control station that in turn adjusts modulation and coding schemes (MCS), transmission power level, or both on the downlink transmission to the mobile station and sends an indication of MCS to the mobile station;

the control station monitors uplink signals from the mobile station and sends the CQI, power control request, or both to the mobile station, which in turn adjust the MCS, transmission power level, or both accordingly and sends the indication of MCS to the control station;

or

the control station monitors uplink signals from the mobile station and makes decisions on the MCS and the uplink transmission power level for the mobile station and dictates to the mobile station the decided MCS and transmission power.

17. The mobile station of claim 14, wherein the mobile station is in communication with a control station and exchanges information and control signals with the control station, and wherein:

the mobile station detects a transmitted packet from a control station and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the control station, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the mobile station; and

the control station detects the transmitted packet from a mobile station and sends an acknowledgement (ACK) or a negative acknowledgement (NAK) to the mobile station, which, upon receiving the NAK, either re-transmits the same packet or transmits more redundancy to facilitate further decoding of the previously failed packet at the control station.

18. The mobile station of claim 14, wherein time-slots are further composed of a specified number of OFDM symbols.

19. A wireless communication method utilizing differing subframes, the method comprising:

forming signal frames of fixed duration;

partitioning each frame into a fixed number of subframes;

partitioning each subframe into at least one downlink time-slot and at least zero uplink time-slot, wherein a total number of downlink time-slots and uplink time-slots is fixed for all subframes of a frame, and wherein for at least some frames a number of downlink and uplink time-slots in one subframe differs from a number of downlink and uplink time-slots in another subframe of the frame;

partitioning each time-slot into a fixed number of Code Division Multiple Access (CDMA) or Orthogonal Frequency Division Multiplexed (OFDM) symbols; and

inserting at least one special downlink portion in at least some frames to indicate a number of downlink and a number of uplink time-slots for subframes.

20. The method of claim 19, wherein within a subframe an OFDM symbol is used:

on the downlink to indicate a downlink modulation and coding scheme (MCS) and a command for uplink MCS and power control; and

on the uplink to indicate a measured downlink channel quality information (CQI).

21. The method of claim 19, wherein at least one special uplink period is inserted in a frame for carrying out radio functions, and wherein at least one guard period is inserted in a subframe.

22. The method of claim 19, wherein a same structure of the signal frame is used by all cells within a wireless communication network, and wherein a signal frame begins and ends at substantially a same time at each cell.

23. A means for generating wireless adjustable frame signals, the means comprising:

a means for generating adaptable signal frames;

a means for partitioning the frames into multiple subframes;

a means for partitioning the subframes into at least zero downlink time-slots and at least zero uplink time-slots, wherein the number of downlink time-slots and the number of uplink time-slots in one subframe of a frame may be different from another subframe of the frame;

a means for inserting at least one guard period within a subframe; and

a means for inserting at least one special downlink period (SDP) in a frame, during which a downlink control signal dictates the number of downlink time-slots and the number of uplink time-slots of the subframes of the frame.