Method and apparatus for network transmission capacity enhancement for the telephone circuit switched network

Abstract

Adjunct apparatus for increasing network transmission capacity provides a low-cost, efficient solution for increasing the network transmission capacity of the existing telephone circuit switched network, while keeping the current network equipment unchanged. A Local Switch Network (LSN) Adjunct (LSNA) and a Tandem/Toll Switch Network (TSN) Adjunct (TSNA) interface with standard network elements, such as switches and cross connect equipment. These network adjuncts, comprising a set of low-bit rate speech coders, a dynamic timeslot manager and other supporting functions, advantageously transmit to and receive from a T1/T3/OC3/E1 trunk. More than one channel of voice is carried on one 64 Kbps DS0 timeslot, while still maintaining the voice at toll quality. A sub-timeslot and sub-timeslot bundling are introduced in the standard T1 or E1 frame where each sub-timeslot is analogous to a single bit of the typical eight bit word to provide more than 24 or 30 voice channels respectively. Inband control information is generated for carrying over a T1 or E1 trunk, for example, for mapping sub-timeslot bundles to channels. Conventional out-of-band signaling is provided via SS-7 or other out-of-band signaling system.

1 . Apparatus for increasing transmission capacity of a telephone circuit switched network, comprising: 
 a first connection for routing all inband traffic from a first tandem switch to said apparatus, said apparatus a first network adjunct, said apparatus adapted to detect compressed silence data in sub-timeslotted frames, said apparatus adapted to fill non-sub-timeslotted frames with uncompressed silence data;    a second connection for routing traffic from said apparatus back to said first tandem switch;    a third connection for routing outgoing traffic from said apparatus to an input of a second network adjunct connected to a second tandem switch that serves said first tandem switch;    a fourth connection for routing outgoing traffic from said apparatus to an input of a third network adjunct connected to a toll switch that serves said first tandem switch; and    a fifth connection for routing outgoing traffic from said first tandem switch to the input of a fourth network adjunct connected to a local switch that serves said first tandem switch.    
   
   
       2 . Apparatus for increasing the capacity of the telephone circuit switched network, comprising: 
 a first connection for routing all inband traffic from a first toll switch to said apparatus;    a second connection for routing traffic from said apparatus back to said first toll switch, said apparatus a first network adjunct, said apparatus adapted to detect compressed silence data in sub-timeslotted frames, said apparatus adapted to fill non-sub-timeslotted frames with uncompressed silence data;    a third connection for routing outgoing traffic from said apparatus to the input of a second network adjunct connected to a tandem switch that serves said first toll switch; and    a fourth connection for routing outgoing traffic from said apparatus to the input of a third network adjunct connected to a second toll switch that serves said first toll switch.    
   
   
       3 . Apparatus for increasing the capacity of a telephone circuit switched network, comprising: 
 a first connection for routing inband traffic, from a local switch to said apparatus, said apparatus adapted to compress a voice signal responsive to detecting silence on a busy channel trunk, said apparatus adapted to, prior to transmission to the telephone circuit switched network, put the compressed voice signal and inband control data into a sub-timeslot format;    a second connection for routing traffic from said apparatus back to said local switch;    a third connection for routing outgoing traffic from said apparatus to a network adjunct connected to a tandem switch that serves said local switch, wherein said apparatus is adapted to use a protocol stack in communicating with a network adjunct.