Browse Prior Art Database

REAL-TIME TIME SLOT ASSIGNMENT AND COMPACTION METHOD

IP.com Disclosure Number: IPCOM000008141D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2002-May-21
Document File: 8 page(s) / 303K

Publishing Venue

Motorola

Related People

Albert Chen: AUTHOR [+3]

Abstract

Slot assignment of RF channels in a TDMA sys- tem is simple if only one time-slot is involved in a service call, this is typically the case with wireless POTS service. In the Hybrid Fibre Coaxial (HFC) RF environment, where services such as two-line POTS, multi-line POTS, Basic Rate ISDN and multi-rate ISDN can be integrated in a subscriber unit, time-slots assignment becomes more challeng- ing since the requested bandwidth and scheme from calls can be varying, and that is further complicated by the presence of cable ingress noise. Inadequate channel management will result in inefficient use of cable RF resource, and consequently, quality of ser- vice can be affected and call blocking probability will increase.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 26% of the total text.

Page 1 of 8

MO-LA Technical Developments

REAL-TIME TIME SLOT ASSIGNMENT AND COMPACTION METHOD

by Albert Chen, Simon Shen and Shekhar Somanath

INTRODUCTION

  Slot assignment of RF channels in a TDMA sys- tem is simple if only one time-slot is involved in a service call, this is typically the case with wireless POTS service. In the Hybrid Fibre Coaxial (HFC) RF environment, where services such as two-line POTS, multi-line POTS, Basic Rate ISDN and multi-rate ISDN can be integrated in a subscriber unit, time-slots assignment becomes more challeng- ing since the requested bandwidth and scheme from calls can be varying, and that is further complicated by the presence of cable ingress noise. Inadequate channel management will result in inefficient use of cable RF resource, and consequently, quality of ser- vice can be affected and call blocking probability will increase.

PRESENT DAY SOLUTION

  Most channel management schemes exist today are designed for single time-slot calls, this includes two-line POTS, multi-line POTS, and Basic Rate ISDN services. Multi-rate ISDN, which allows mul- tiple time-slots assigned in a single service call, is a new capability that is being explored by the cable transport. Multi-rate access has been defined by ref- erence However, no channel management algo- rithms have been specified. Particularly, a scheme that will optimize the RF resource in the situation with mixed single time-slot and multi-rate c$ls. Some techniques used in memory compaction are not suitable for this environment because the carrier size is limited as opposed to the long stream of memory capacity.

DESCRIPTION OF NEW CONCEPT

  The invention is a channel management scheme which dynamically assigns time slots at the time of call setup and link transfer. The scheme defines sorted carrier lists and associated algorithms for

mixed single-slot and multi-rate calls. The scheme described below provides a solution for optimal use of RF resource.

  In the HFC circuit-switched environment, a Cable Access Unit (CAU) is a multi-function sub- scriber unit that supports integrated voice, data, and video services. The multi-service CAU connects to terminal devices through defined interfaces such as POTS, Ethernet, ISDN, and RS232. The terminal device may initiate a single time-slot or multi-rate call depending on the application. An example of multi-rate call is HO-based videoconferencing call, which requires 384 Kbps or 6 time slots bandwidth. Time slots on a carrier can be assigned to multiple CAUs that am tuned to the same carrier. Each CAU can have multiple active calls which are single or multiple time slots.

  When originating a multi-rate call, the call may desire contiguous or flexible time-slot assignment for all the time slots it intends to acquire. In the contiguous scheme, time slots are adjacent to each other in the HFC 600 KHz carrier that consists of 8 TDM time slots (Figure la); in the flexible scheme, assigned time slots can be in any time slot position wi...