Browse Prior Art Database

DYNAMIC FDMA/TDMA GRID DISPLAY

IP.com Disclosure Number: IPCOM000147711D
Original Publication Date: 2007-Mar-22
Included in the Prior Art Database: 2007-Mar-22
Document File: 4 page(s) / 71K

Publishing Venue

Motorola

Related People

Malcolm Goddard: AUTHOR

Abstract

This paper describes a grid display that shows FDMA and/or TDMA call activity on the repeaters of a site. The display dynamically changes in the vertical direction to accommodate changes between an FDMA and a TDMA call on a repeater. Thus the horizontal positioning of the display is independent of the call mode – making it easier to monitor call activity on a given repeater.

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DYNAMIC FDMA/TDMA

GRID DISPLAY

by Malcolm Goddard

Abstract:

This paper describes a grid display that shows FDMA and/or TDMA call activity on the repeaters of a site. The display dynamically changes in the vertical direction to accommodate changes between an FDMA and a TDMA call on a repeater. Thus the horizontal positioning of the display is independent of the call mode – making it easier to monitor call activity on a given repeater.

The Problem:

In an APCO-compliant FDMA trunked radio system each site has a control channel and a pool of repeaters that can be allocated calls. Typically these systems have applications that can be used to visually monitor the allocation of calls to the repeaters at a site. They monitor call signaling traffic and display, for any repeater at a site, whether it is:

·        Currently allocated to a call

·        Currently acting as Control Channel

·        Currently free.

The information is typically displayed in a grid, with each cell representing a repeater, and a call icon displayed in the cell depending on the call type (e.g. private call, Group call, etc.) that is currently allocated to that repeater - see figure 1. In FDMA systems each repeater can accommodate either a single control channel or a single call. Therefore, as calls are allocated and de-allocated to/from repeaters, the grid display and the cells do not move or change their size – only the contents of a cell changes to represent changing call types currently allocated to that repeater.

1

 

             Figure 1: Grid Display for an FDMA RF Site with 3 repeaters.

 Repeater #1 is currently acting as the control channel for the site, Repeater #2 is idle, and Repeater #3 is allocated to a Private call.

The APCO standard is being revised to accommodate TDMA calls. APCO-compliant systems will then be able to use FDMA/TDMA agile repeaters. This means repeaters that can function in either FDMA mode or TDMA mode at any point in time. In the simplest case each repeater has two TDMA slots and could accommodate up to two calls – one in each TDMA slot. The repeater’s mode can change so that at one moment it could have a single FDMA call and, after that call is over, it could then be used for one or two TDMA calls.

The problem is to extend the existing FDMA grid display to provide to the customer a display that dynamically changes to accommodate both the situation when a single FDMA call is on a repeater and also the situation when the repeater has TDMA call(s). In addition, the display should not have any 'flicker' - so that the position of a repeater does not move around on the screen as a call on that repeater changes between FDMA and TDMA.

Solution:

In the existing FDMA grid display the cells for each repeater are displayed horizontally (s...