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REAL-TIME MANAGEMENT OF RADIO TURNAROUND IN A TDMA/TDD SYSTEM

IP.com Disclosure Number: IPCOM000007209D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2002-Mar-05
Document File: 3 page(s) / 207K

Publishing Venue

Motorola

Related People

Dale Buchholz: AUTHOR [+4]

Abstract

This article addresses the management of radio turnarounds in a TDMA/TDD data system where the radios operate in half duplex mode and the allo- cation of TDMA/TDD slots is managed by a cen- tral controller.

This text was extracted from a PDF file.
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This is the abbreviated version, containing approximately 30% of the total text.

Page 1 of 3

MO-LA Technical Developments Volume 22 June 1994

REAL-TIME MANAGEMENT OF RADIO TURNAROUND IN A TDMA/TDD SYSTEM

by Dale Buchholz, Kevin Doss, Jim McGrath and Karen Robbins

  This article addresses the management of radio turnarounds in a TDMA/TDD data system where the radios operate in half duplex mode and the allo- cation of TDMA/TDD slots is managed by a cen- tral controller.

  In typical TDMA/TDD systems today, there is a portion of the TDMA frame which is dedicated to outbound trahic (from the central controller) and another portion of the TDMA frame which is dedi- cated to inbound trafhc (to the central controller). These portions of the TDMA Frame are separated by a fixed radio turnaround (central controller switches from transmit to receive while remote devices switch from receive to transmit and vice versa). In a TDMA data communications system, the traffic pattern is much more irregular. There are times when there is a lot of outbound traffic and very little inbound traffic and other times when the opposite is true. It would be extremely advantageous to have a method that dynamically adjusts the posi- tion of the radio turnaround every TDMA frame thereby maximizing the data throughput of the system.

  This article identifies a real-time method for adjusting the position of turnarounds every TDMA/TDD frame.

The context of the algorithm is shown in Figure
1. A TDMA hame is divided into three distinct areas. The Request portion is an inbound area where remote devices can transmit small control messages to request usage of inbound TDMA slots in the Data portion of the TDMA hame. The Grant portion is an outbound area where the central controller trans- mits small control messages to assign usage of inbound TDMA slots in the Data portion of the TDMA frame. The Data portion is divided into an outbound area where the central controller trans- mits data packets to remote devices and an inbound area where the remote devices transmit data pack- ets to the central controller (after having been assigned an inbound slot). The Data portion is shown to have four TDMA data slots which can be configured in live different ways by adjusting the position of the turnaround. The actual number of data slots in the TDMA frame is not important to the algorithm.

< ,IR TDMA Fmne >

IReqYes, & man, IFA

T/R mnlrder

Data IS{

Trn :m M mwde

CCRX CCRX M ctn ccn:

clam snr '0 Dam sG101

.I I..'? mu I*l, .* &$ CAY 54 0

RDTX Ron Tra ilow PmRX

CCRX CCRX CCRX RIT ccn

Da11 sat IO Dam SUI r1 mm Sal 02 ,,& 0111 ylf "3

ROT* RDTX aon Tia RORX

ccn CCTX ccn ccn WT

owa San .a DSO se/ .1 Dad %a .2 o~msm,"3 &$

RDRX RORX ma RDRX TIR

Figure 1: TDMA Frame Structure with Dynamically Adjustable Turnaround

0 Motorola. 1°C. ,994

71

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Page 2 of 3

0 M MO-LA

Technical Developments Volume 22 June 1994

  The algorithm for controlling the position ofthe turnaround is distributed across the central control- ler and multiple remote devices....