Packet buffer memory control for statistical multiplexing

Claim 2

Apparatus for transmitting packets, CHARACTERIZED BY means (1104) for storing packet data, and means (1102, 1105, 1110, 1111, 1112) responsive to the amount of packet data presently stored in said means for storing packet data for controlling the amount of packet data being inputted into said means for storing.

Claim 3

The apparatus as defined in claim 1 wherein each of said packets includes a header and an information field including a plurality of bits, and CHARACTERIZED IN THAT said means for controlling the amount of packet data being inputted into said means for storing includes means for determining the amount of packet data presently stored in said means for storing, means for comparing the amount of the presently stored packet data to predetermined threshold levels, and means responsive to the result of said comparing for determining whether bits should be dropped from the packet information field of a packet to be inputted into said means for storing.

Claim 4

The apparatus as defined in claim 2 CHARACTERIZED IN THAT said means for determining the amount of packet data stored in said means for storing includes counter means responsive to a first representation of the packet data being inputted to said means for storing and to a second representation of the packet data being outputted from said means for storing.

Claim 5

The apparatus as defined in claim 3 CHARACTERIZED IN THAT said counter means comprises an up/down counter which is responsive to said first representation for counting up and to said second representation for counting down.

Claim 6

The apparatus as defined in claim 2 CHARACTERIZED IN THAT said information field bits are in a format in which like bits from individual samples from a plurality of repetitive frames are grouped together and wherein said means for controlling the amount of packet data stored in said storing means includes means responsive to the result of said comparing for controllably dropping individual groups of said information bits, if necessary.

Claim 7

The apparatus as defined in claim 5 CHARACTERIZED IN THAT said means for controllably dropping includes means responsive to the result of said comparing for dropping individual groups of said information bits beginning with a group including the least significant bits of the samples from the plurality of repetitive frames, if necessary, toward a group including the most significant bits of the samples from the plurality of repetitive frames.

Claim 8

The apparatus as defined in claim 6 CHARACTERIZED IN THAT said means for determining the amount of packet data stored in said means for storing includes counter means responsive to a first representation of the packet data being inputted to said means for storing and to a second representation of the packet data being outputted from said means for storing.

Claim 9

The apparatus as defined in claim 7 CHARACTERIZED IN THAT said counter means comprises an up/down counter which is responsive to said first representation for counting up and to said second representation for counting down.

Claim 10

The apparatus as defined in claim 6 CHARACTERIZED IN THAT said means for controllably dropping includes means responsive to a prescribed result of said comparing for dropping the entire packet.

Claim 11

The apparatus as defined in claim 6 CHARACTERIZED IN THAT said storage means includes a plurality of memory locations, each byte of said packet being stored in parallel in a predetermined number of said memory locations, a single additional one of said memory locations being associated with said predetermined number of parallel memory locations, means for generating an end of packet signal having first and second states, said first state being indicative of the end of a packet, said second state being indicative of packet data other than the end of a packet, and means for inserting said end of packet signal into said additional memory location, wherein the first state of said end of packet signal is inserted in the additional memory locations associated with the last byte of the packet data thereby indicating the end of a packet.