Adaptive time division duplexing method and apparatus for dynamic bandwidth allocation within a wireless communication system

• US 7,486,639 B2
• Filed: 04/26/2005
• Issued: 02/03/2009
• Est. Priority Date: 05/21/1999
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Klein, Israel Jay, Stanwood, Kenneth L., Gilbert, Sheldon L., Hadar, Rami, Mollenauer, James F.
• Primary Examiner(s): LY, ANH VU H
• Application Number:
  US11/114,662
• Publication Number:
  US 20050243745A1
• Time in Patent Office: 1,379 Days
• Field of Search: None
• US Class Current: 370/329
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/561 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0092 Indication of how the channel is divided
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 28/0268 using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] negotiating SLA or negotiating QoS H04W28/24
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 76/11 : Allocation or use of connection identifiers
• CPC Class Codes: H04W 8/24 : Transfer of terminal data

Abstract

An adaptive time division duplexing (ATDD) method and apparatus for duplexing transmissions on a communication link in wireless communication systems. Communication link efficient is enhanced by dynamically adapting to the uplink and downlink bandwidth requirements of the communication channels. Time slots are flexibly and dynamically allocated for uplink or downlink transmissions depending upon the bandwidth needs of a channel. Communication link bandwidth requirements are continuously monitored using sets of predetermined bandwidth requirement parameters. Communication channels are configured to have either symmetric or asymmetric uplink/downlink bandwidths depending upon the needs of the channel. Channel bandwidth asymmetry can be configured alternatively in favor of the uplink transmissions (i.e., more time slots are allocated for uplink transmissions than for downlink transmissions) or in favor of the downlink transmissions (i.e., more time slots are allocated for downlink transmissions than for uplink transmissions). A myriad of time slot allocation schemes are possible. One simplified time slot allocation scheme uses a “frame-based” approach. A preferred channel bandwidth analysis technique is disclosed which monitors and updates bandwidth requirement parameters associated with communication sessions, base stations and cell cluster controllers. In accordance with this technique, a communication session is preferably assigned both an “initial” and an “actual” set of bandwidth parameters.

Claims

1. A method for adaptively duplexing transmissions in a communication link using a time division duplexing scheme wherein transmissions are communicated in an uplink direction during uplink time slots and wherein transmissions are communicated in a downlink direction during downlink time slots, the method comprising:

predicting an initial uplink bandwidth requirement and an initial downlink bandwidth requirement of the communication link;

calculating an initial uplink/downlink bandwidth requirement ratio for a frame based upon the initial uplink and initial downlink bandwidth requirements of the link;

allocating initial uplink and downlink time slots in the frame in response to the calculated initial uplink/downlink bandwidth ratio;

transmitting information during the initial uplink and downlink time slots;

determining an actual uplink bandwidth requirement and an actual downlink bandwidth requirement based on the transmission during the initial uplink and downlink time slots;

calculating an actual uplinik/downlink bandwidth requirement ratio based upon the actual uplink and actual downlink bandwidth requirements of the link;

allocating actual uplink and downlink time slots in response to the calculated actual uplink/downlink bandwidth ratio; and

transmitting information during the actual uplink and downlink time slots.

2. A method for adaptively duplexing transmissions between a base station and at least one CPE using a series of uplink and downlink frames of information in an adaptive time division duplexing scheme, wherein transmissions are communicated in an uplink direction during uplink time slots and wherein transmissions are communicated in a downlink direction during downlink time slots comprising:

selecting a first service type for an uplink transmission;

selecting a second service type for a downlink transmission;

predicting an uplink bandwidth requirement that is associated with the selected first service type;

predicting a downlink bandwidth requirement that is associated with the selected second service type;

calculating an uplink/downlink bandwidth requirement ratio for a frame based upon the uplink and downlink bandwidth requirements;

allocating uplink and downlink time slots in the frame in response to the calculated uplink/downlink bandwidth ratio; and

periodically enabling uplink transmissions during the allocated uplink time slots and downlink transmissions during the allocated downlink time slots.

3. The method of claim 2, wherein the first service type is sensitive to transmission delays and the second service type is insensitive to transmission delays.

4. The method of claim 2, further comprising comparing sensitivities to a transmission delay for the first service type and the second service type.

5. The method of claim 4, further comprising shifting the uplinik/downlink bandwidth requirement ratio to reduce the transmission delay of the first service type at the expense of increasing the transmission delay of the second service type.

6. A method for adaptively duplexing transmissions in a communication link using a time division duplexing scheme wherein transmissions are communicated in an uplink direction during uplink time slots and wherein transmissions are communicated in a downlink direction during downlink time slots, the method comprising:

selecting a quality of service associated with the communication link;

predicting an initial uplink bandwidth requirement and an initial downlink bandwidth requirement of the communication link based on the selected quality of service;

calculating an initial uplink/downlink bandwidth requirement ratio for a frame based upon the initial uplink and initial downlink bandwidth requirements of the link;

allocating initial uplink and downlink time slots in the frame in response to the calculated initial uplink/downlink bandwidth ratio;

transmitting information during the initial uplink and downlink time slots;

determining an actual uplink bandwidth requirement and an actual downlink bandwidth requirement based on actual bandwidth utilization during the initial uplink and downlink time slots;

calculating an actual uplink/downlink bandwidth requirement ratio based upon the actual uplink and actual downlink bandwidth requirements of the link;

allocating actual uplink and downlink time slots in response to the calculated actual uplink/downlink bandwidth ratio; and

transmitting information during the actual uplink and downlink time slots.

7. The method of claim 6, wherein the initial uplink bandwidth requirement and the initial downlink bandwidth requirement split the uplink time slots and the downlink time slots into equal portions.

8. The method of claim 6, wherein the initial uplink bandwidth requirement and the initial downlink bandwidth requirement split the uplink time slots and the downlink time slots into unequal portions.

9. The method of claim 8, further comprising calculating the actual uplink/downlink bandwidth requirement ratio based on the selected quality of service.

10. The method of claim 6, wherein the selected quality of service is based on type of service and data latency requirements.