US 6,192,029 B1Granted

Method and apparatus for performing flow control in a wireless communications system

AssigneeMotorola, Inc.

InventorsRod Averbuch, Jeff Blanchette, Richard Van Egeren, Todd A. Leigh

Life of this patent

Estimating the term…

Loading patent…

Abstract

A data communications system includes a server router (102), such as an access controller gateway, operably coupled to at least one client router (104), such as a base radio controller, by an asynchronous link, such as a LAN (106). The client router forwards data received from the server router and stored in the client router's outbound queue (110) synchronously to a device, such as a mobile station (202). The client router's outbound queue is maintained between a lower queue limit and an upper queue limit so as to both reduce the occurrence of data starvation and reduce the amount of data lost should the mobile station hand off to a new serving site. The server router calculates an optimum average send rate and transmits data in bursts at regular intervals, and adjusts the average send rate in response to changes in the outbound rate of the client router. The client router is state machine driven, and sends flow control messages only when entering a new state so as to reduce the amount of flow control messaging.

Claims7

Dependent claims

A method of performing flow control in a wireless communications system while transmitting data from a server router to a client router, the client router transmitting data synchronously at an outbound rate and having an outbound queue having a queue depth, the server router receiving data units from a data source, the method comprising:

filling the client router's outbound queue;
calculating a RATE variable, having an integer portion and a fractional portion, having a value equal to the outbound rate of the client router;
adding the value of the RATE variable to a COUNT variable, the COUNT variable having an integer portion and a fractional portion, performed by the server router;
transmitting, to the client router from the server router, an asynchronous data burst having a number of data units equal to the integer portion of the COUNT variable upon the expiration of a send interval timer, and decrementing the COUNT variable by 1 for every data unit so transmitted;
accumulating the fractional portion of the COUNT variable in the COUNT variable;
and
repeating the steps of adding, transmitting, and accumulating.

4 more elements

Dependencies are inferred from the claim text.