System and method for credit-based channel transmission scheduling (cbcts)

A method scheduling wireless packet data unit (PDU) transmissions on a downlink channel of a communication system, comprising:

• initializing a set of credit accounts, one credit account for every packet data unit (PDU) queue, to a predetermined set of credit values that meet throughput requirements;
• calculating a cost associated with the credits needed to transmit a single PDU;
• setting an upper account limit and a lower account limit to meet predetermined time requirements;
• sorting the credit accounts in descending order, such that a first element in the sorted account set has the highest number of credits;
• searching the sorted account set to determine a first account having an associated PDU type that is ready for transmission and has a size equal to or less than free space in a medium access control (MAC) block of a MAC layer;
• inserting the selected PDU into the MAC block;
• updating a corresponding account for the inserted PDU by subtracting the cost of credits to transmit the single PDU;
• updating all accounts in the set of credit accounts by a predetermined credit value;
• subtracting the PDU size from the MAC block size;
• determining whether there is free space remaining on the MAC block for insertion of another PDU and if so, returning to the step of sorting;
• and
• otherwise, transmitting the MAC block on the downlink channel.