Method and apparatus for dynamic power control in TDMA portable radio systems

United States Patent m

Ariyavisitakul et al.

[ii]

[45]

USO05333175A

Patent Number:
Date of Patent:

5,333,175 Jul. 26,1994

[54] METHOD AND APPARATUS FOR

DYNAMIC POWER CONTROL IN TDMA
PORTABLE RADIO SYSTEMS

[75] Inventors: Sirikiat Ariyavisitakul, Tinton Falls;

Justin C. Chuang, Holmdel; Nelson
R. Sollenberger, Tinton Falls, all of
N.J.

[73] Assignee: Bell Communications Research, Inc.,

Livingston, N.J.

[21] Appl. No.: 10,111

[22] Filed: Jan. 28, 1993

[51] Int. CI.* H04M 11/00

[52] U.S. CI 379/58; 455/38.3;

455/69; 455/127

[58] Field of Search 379/58, 63; 370/95.3;

455/38.3, 69, 88, 127, 343

[56] References Cited

U.S. PATENT DOCUMENTS

4,309,771 1/1982 Wilkens 455/69

4,580,262 4/1986 Naylor et al 455/69

4,849,991 7/1989 Arnold et al. .

4,937,841 6/1990 Chuang et al. .

4,941,155 7/1990 Chuang et al. .

5,084,891 1/1992 Ariyavisitakul et al. .

5,086,508 2/1992 Furuno 455/127

5,128,965 7/1992 Henriksson 455/69

5,155,742 10/1992 Ariyavisitakul et al. .

5,177,769 1/1993 Arnold et al. .

5,204,970 4/1993 Stengel et al 455/69

5,220,678 6/1993 Fee'i 455/127

5,241,565 8/1993 Kloc et al 455/127

5,241,690 8/1993 Larsson et al 455/69

5,257,283 10/1993 Gilhousen et al 455/38.3

5,267,262 11/1993 Wheatley, III 455/69

OTHER PUBLICATIONS

"Portable Digital Radio Communications—An Approach to Tetherless Access", Donald C. Cox, IEEE Communications Magazine, Jul. 1989, pp. 30-40. "Universal Digital Portable Radio Communications",

In a TDM/TDMA portable radio communications system the uplink power transmitted by the transmitter of a portable unit to a fixed port is dynamically controlled by monitoring three measures in each uplink burst received by the port. These measures are a received signal strength indicator (RSSI), a quality measure (QM), and a word error indicator (WEI). The WEI is used to adjust an RSSI threshold upward and downward. If the QM is below a predetermined QM threshold or the RSSI is below the current value of the adjustable RSSI threshold, then additional uplink power is required, unless the RSSI is greater than a predetermined maximum RSSI value. If additional power is required a power control bit (PC), included within each downlink burst transmitted to the portable, is set to ONE and the portable, in response thereto, increases its output transmitter power. If both the QM is greater than the predetermined QM threshold and the RSSI is greater than the RSSI threshold, or if the RSSI is greater than the predetermined maximum RSSI value, then PC is set to ZERO and the portable transmitter power is decreased.

41 Claims, 5 Drawing Sheets

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