Private branch exchange systems for packet communications

• US 6,744,757 B1
• Filed: 12/14/1999
• Issued: 06/01/2004
• Est. Priority Date: 08/10/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Viswanathan, Vishu R., McCree, Alan V., Anandakumar, Krishnasamy
• Primary Examiner(s): Marcelo, Melvin
• Assistant Examiner(s): DO, NHAT Q
• Application Number:
  US09/460,065
• Time in Patent Office: 1,631 Days
• Field of Search: 370/351, 370/352, 370/389, 370/395.1, 370/465
• US Class Current: 370/352
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

A process (111,101) of sending packets of real-time information at a sender (311) includes steps of initially generating at the sender the packets of real-time information with a source rate (s11) greater than zero kilobits per second, and a time or path or combined time/path diversity rate (d11), the amount of diversity (d11) initially being at least zero kilobits per second. The process sends the packets, thereby resulting in a quality of service QoS, and optionally obtains at the sender (311) a measure of the QoS. Rate/diversity adaptation decision may be performed at receiver (361′) instead. Another step compares the QoS with a threshold of acceptability (Th1), and when the QoS is on an unacceptable side of said threshold (Th1) increases the diversity rate (d11 to d22) and sends not only additional ones of the packets of real-time information but also sends diversity packets at the diversity rate as increased (d22). Increasing the diversity rate (d11 to d22) while either reducing or keeping unchanged the overall transmission rate (sij+dij) is an important new improvement in even solely-time-diversity embodiments. In another form of the invention a single-chip integrated circuit includes a processor circuit (1511), and a rate-and-diversity control (1561). Here again, the diversity is contemplated to be time diversity, path diversity, and combined time/path diversity in various embodiments. Other embodiments disclosed encompass other processes, improved packets and packet ensembles, integrated circuits, chipsets, computer add-in cards, information storage articles, systems, computers, gateways, routers, cellular telephone handsets, wireless base stations, appliances, and packet networks, and other forms as claimed.

Claims

1. A private branch exchange comprising:

A. telephone interface circuitry having plural connectors ready for connection to plural telephone units;

B. a digital network interface ready for connection to a public switched telephone network; and

C. at least one integrated circuit assembly coupling the telephone interface circuitry to the digital network interface, said at least one integrated circuit assembly providing voice over packet transmission and reception and holding processor instruction bits defining reconstruction of a packet stream with each packet having a primary stage and a secondary stage, the secondary stage having LPC parameters, and at least one of LTP lags, parity check, and adaptive and fixed codebook gains, the received packet stream having an instance of single packet loss, and the reconstruction comprising;

i. receiving a packet sequence represented by P(n)P(n−

1)′

, [Lost Packet], P(n+2)P(n+1)′

, and P(n+3)P(n+2)′

;

ii. obtaining as information from the secondary stage the LPC parameters, and the at least one of LTP lags, parity check, and adaptive and fixed codebook gains; and

iii. performing an excitation reconstruction of the lost packet utilizing the received information.

2. The private branch exchange of claim 1 in which the processor instruction bits define the performing an excitation to produce the following reconstructed packet sequence:

P(n), [P(n+1)′

|−

](excitation), P(n+2), and P(n+3)

where “

(excitation)”

refers to reconstruction of the dashed part of the packet symbol.

3. The private branch exchange of claim 1 in which the secondary stage includes no fixed codebook pulses, and the processor instruction bits further define performing an excitation with an adaptive codebook contribution reconstructed from the adaptive codebook gain and LTP lag.

4. The private branch exchange of claim 1 in which the secondary stage includes no fixed codebook pulses, and the processor instruction bits further define performing an excitation with an adaptive codebook contribution set to zero if the absolute value of the adaptive codebook gain is less than 0.4.

5. The private branch exchange of claim 1 in which the secondary stage includes fixed codebook pulses, and the processor instruction bits further define performing an excitation with the fixed codebook pulses.

6. The private branch exchange of claim 5 in which the secondary stage includes some of all the possible fixed codebook pulses, and the processor instruction bits further define performing the excitation with the some of all the possible fixed codebook pulses.

7. The private branch exchange of claim 6 in which the processor instruction bits further define performing and excitation with the fixed codebook pulses, other than the some of all the possible fixed codebook pulses, set to zero.