US 6,662,019 B2 · Power control and transmission rate parameters of a secondary channel in a wireless communication system

Abstract

A method and apparatus for estimating the initial power level and transmission rate of a burst on a secondary channel when the secondary channel is on fewer legs of a handoff, such as a soft or softer handoff, than the primary channel. In accordance with the present invention, the initial power level of the burst transmitted over a current secondary channel on a particular leg(s) is a function of a power level of a previous burst transmitted over a previous secondary channel on the identical leg(s) as the current secondary channel. For example, the initial power level of the burst can be based on the power level at the end of the previous burst shortly prior to the termination of the previous burst, where the termination of the previous burst was within a predetermined time interval of the start of the burst. Optionally, the initial power level of a burst can also be additionally adjusted based on characteristics of the communication link of the primary channel, the previous secondary channel, and the current secondary channel. The transmission rate may then be adjusted based on the initial power level determined as described above to obtain a more efficient transmission rate.

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Claims36

Dependent claims

A method for use in a wireless communication system having at least one communication link including a primary channel over which a primary channel communication is transmitted, and wherein a previous secondary channel communication was transmitted on a previous secondary channel on the at least one communication link, the method comprising the steps of:

prior to a termination of the transmission of the primary communication, obtaining an initial power level for a subsequent secondary channel communication, the initial power level being a function of a power level of the previous secondary channel communication;
determining whether a predetermined time interval from termination of the previous secondary channel has elapsed;
and
if the predetermined time interval has not elapsed, transmitting the subsequent secondary channel communication using the initial power level.

1 more element

prior to a termination of the transmission of the primary channel communication, obtaining an initial power level for a subsequent secondary channel communication, as a function of a power level of the previous secondary channel communication;
determining whether a predetermined time interval from termination of the previous secondary channel has elapsed;
and
if the predetermined time interval has not elapsed, transmitting the subsequent secondary channel communication using the initial power level and at a transmission rate that is a function of the initial power level.

1 more element

establishing a first secondary channel on the at least one communication link;
transmitting a first signal burst over the secondary channel;
terminating the first secondary channel;
prior to a termination of the transmission of the primary channel communication, obtaining an initial power level of a second signal burst to be transmitted over a second secondary channel as a function of a power level of the first signal burst;
determining a transmission rate for the second secondary channel as function of the initial power level;
determining whether a predetermined time interval from termination of the first secondary channel has elapsed;
and
if the predetermined time interval has not elapsed, transmitting the second signal burst using the initial power level.

5 more elements

A method for use in a system having at least one communication link including a primary channel over which a primary channel communication is transmitted, the method comprising the steps of:

establishing a first secondary channel on the at least one communication link;
transmitting a first signal burst over the secondary channel;
terminating the first secondary channel;
determining whether a predetermined time interval from termination of the first secondary channel has elapsed;
and
prior to a termination of the primary channel and if the predetermined time interval has not elapsed, transmitting a second signal burst over a second secondary channel, the second signal burst having an initial power level that is a function of a power level of the first signal burst.

3 more elements

Dependencies are inferred from the claim text.

Description7,421 words

Summary1,454 words

#This invention relates to wireless communication systems and, more particularly, to the transmission of data in such systems.

#In wireless communication systems generally, base stations transmit signals to mobile terminals over a communication link referred to as a forward link, and mobile terminals transmit signals to base station over a communication link referred to as a reverse link. When a call—a communication session between a base station and a particular mobile terminal—is set up, a primary channel is set up on both a forward and reverse link. The primary channel can be used to transmit voice, data, and/or so-called signaling information, and transmits the signal at a particular, typically a fairly low, transmission rate. If it is desired to transmit a signal at a higher transmission rate, for example for a data transmission having a large amount of data, the wireless communication system may be able to set up a secondary channel—a communication channel over which signals may be transmitted at the same or at a higher transmission rate than that of the primary channel. The secondary channel is typically set up only over the particular communication link, i.e. forward or reverse, over which it is desired to transmit the signal.

#The way in which the secondary channel is set up takes into account the fact that data is often bursty, meaning that it is transmitted in bursts interspersed with periods of inactivity during which no data is transmitted. Typically, the secondary channel is maintained only for the duration of each data burst. Between data bursts, there is no secondary channel assigned to the call, whereas there is a primary channel maintained for the duration of the call.

Brief description of the drawings5 figures

#FIG. 1a illustrates a portion of a wireless communication system;

#FIG. 1b illustrates the channels and communication links on the legs of the handoff when the secondary channel is on all of the legs of the handoff;

#FIG. 1c illustrates the channels and communication links on the legs of the handoff when the secondary channel is on fewer than all of the legs of the handoff;

Detailed description5,871 words

#FIG. 1 illustrates a wireless communications system, such as Code Division Multiple Access (CDMA) system 100. The geographic area serviced by CDMA system 100 is divided into a plurality of spatially distinct areas called “cells.” For ease of analysis, cells 102, 104, and 106 are typically approximated and schematically rep resented by hexagons in a honeycomb pattern. However, each cell is actually of an irregular shape that depends on the topography of the terrain surrounding the cell. Each cell 102, 104, 106 can be divided into a plurality of sectors, such as three 120° sectors. Cell 102 is divided into sectors 102a, 102b, and 102c; cell 104 is divided into sectors 104a, 104b, and 104c; and cell 106 is divided into sectors 106a, and 106b and 106c. Cell 102, 104, 106 contain base stations 112, 114, 116, respectively, each of which includes equipment to communicate with Mobile Switching Center (“MSC”) 120. MSC 120 is connected to local and/or long-distance transmission network 122, such as a public switched telephone network. Each base station 112, 114, 116 also includes transmitters and/or receivers, and antennas. Typically, each base station includes different transmitters, receivers, and antennas for each sector that the base station serves. The base stations use the transmitters, receivers, and antennas to communicate with mobile terminals, such as mobile terminals 124, 126. The base stations transmit signals to the mobile terminals over a communication link referred to as a forward link, and the mobile terminals transmit signals to the base station over a communication link referred to as a reverse link.

#When a call—a communication session between a base station, such as base station 112, and a particular mobile terminal, such as mobile terminal 124—is set up, a primary channel is set up on both a forward and reverse link. (In some systems, the primary channel is referred to as a fundamental channel.) The primary channel can be used to transmit voice, data, and/or so-called signaling information, and transmits the signal at a particular, typically a fairly low, transmission rate. If it is desired to transmit a signal at a higher transmission rate, for example for a data transmission having a large amount of data, the CDMA system checks, as described below, whether it is able to and it is advantageous to set up a secondary channel—a communication channel over which signals may be transmitted at the same or at a higher transmission rate higher than that of the primary channel. (In some systems the secondary channel is referred to as a supplemental channel or as a data channel.) The secondary channel is typically set up only over the particular communication link, i.e. forward or reverse, over which it is desired to transmit the signal.

#The way in which the secondary channel is set up takes account of the fact that data is often bursty, meaning that it is transmitted in bursts interspersed by periods of inactivity during which no data is transmitted. Typically, the secondary channel is maintained only for the duration of each data burst. Between data bursts, there is no secondary channel assigned to the call, whereas there is a primary channel maintained for the duration of the call. Thus, the duration of the burst is shorter than the duration of the communication on the primary channel.

Facts

Application

09/742,613Filed 21 Dec 2000

Published

US 2002/0123362 A15 Sep 2002

Granted

9 Dec 2003

Term ended

24 Nov 2021

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 338 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification6 codes

H04W 52/40
TPC being performed in particular situations: during macro-diversity or soft handoff
H04L 1/0002
Systems modifying transmission characteristics according to link quality, e.g. power backoff: by adapting the transmission rate
H04W 52/50
TPC being performed in particular situations: at the moment of starting communication in a multiple access environment
H04W 52/16
TPC algorithms: deriving transmission power values from another channel

Power control and transmission rate parameters of a secondary channel in a wireless communication system

Life of this patent

Power control and transmission rate parameters of a secondary channel in a wireless communication system

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims36

Description7,421 words

Drawings

Classification6 codes

Life of this patent

Description7,421 words