Reverse link initial power setting using effective radiated power message to compute path loss

Abstract

In an illustrative embodiment of the present invention, a reference signal including pilot information is transmitted from a base station to one or multiple field units over a pilot channel. A message is also sent to the field units over a paging channel to indicate an effective radiated power level at which the reference signal is transmitted on the pilot channel. Based on a received power level of the reference signal at a field unit and the effective radiated power level of the reference signal, a forward path loss is estimated at the field unit for the forward link between the base station and field unit. Assuming the path loss in the reverse link is approximately the same as the estimated forward link path loss, the field unit can transmit, a reply message in the reverse link so that the base station generally receives a message at-a desired power level.

What is claimed is:  
     
         1 . A method for supporting wireless communications, the method comprising the steps of: 
 detecting that a collision occurs at a first transceiver when two or more second transceivers attempt to send messages over a first channel, a collision occurring when each of the two or more second transceivers transmit messages on the first channel, at least a portion of each message transmitted in a time slot overlap, a common encoded sequence of the messages being detectable at a transceiver even though there is a collision;    notifying the two or more second transceivers of a collision on the first channel by sending a message from the first transceiver to the two or more second transceivers over a feedback channel;    adjusting a power output level of a corresponding one of the two or more second transceivers attempting to send a message over the first channel depending on whether a collision occurs on the first channel, the step of adjusting further comprising: 
 transmitting a first message from the first transceiver,  
 the first message including effective radiated power level information at which the first transceiver transmits a reference signal;  
 measuring a received power level of the reference signal received at the corresponding second transceiver;  
 decoding the first message at the second transceiver to determine the effective radiated power level information; and  
 estimating a path loss between the first and second transceivers by comparing the received power level and the effective radiated power level information.  
   
     
     
         2 . A method as in  claim 1  further comprising the step of: 
 transmitting a second message from the first transceiver to the second transceiver indicating a desired power level at which subsequent messages shall be received at the first transceiver.  
 
     
     
         3 . A method as in  claim 2  further comprising the step of: 
 transmitting a reply message from the second transceiver to the first transceiver at a power level so that the first transceiver receives the reply message at the desired power level.  
 
     
     
         4 . A method as in  claim 2  further comprising the step of: 
 determining a power output setting at the second transceiver based on an estimated path loss so that a message is received at the first transceiver at the desired power level.  
 
     
     
         5 . A method as in  claim 1 , wherein the first message is transmitted over a paging channel of a CDMA (Code Division Multiple Access) communication system.  
     
     
         6 . A method as in  claim 3 , wherein the reply message is transmitted over an access channel of a CDMA communication system.  
     
     
         7 . A method as in  claim 1 , wherein the second transceiver transmits an access request message to the first transceiver in a time slot of an allocated reverse channel.  
     
     
         8 . A method as in  claim 7 , wherein the access request message from the second transceiver to the first transceiver includes encoded information for measuring timing alignment of the second transceiver.  
     
     
         9 . A method as in  claim 1 , wherein the second transceiver, a mobile transceiver, sends a reply message to the first transceiver, a base station transceiver, the reply message including a reference marker that is monitored for generating feedback messages to synchronize the mobile transceiver to the base station transceiver.  
     
     
         10 . A method as in  claim 1 , wherein the first transceiver transmits the first message over a dedicated channel to multiple transceivers.  
     
     
         11 . A method as in  claim 1  further comprising the step of: 
 measuring a power level at which a reply message transmitted from the second transceiver is received at the first transceiver.  
 
     
     
         12 . A method in  claim 11  further comprising the steps of: 
 comparing a power level at which the reply message is received at the first transceiver with a desired power level at which messages should be received; and  
 transmitting a power adjustment message to the second transceiver for subsequent message transmissions.  
 
     
     
         13 . A method as in  claim 1 , wherein the reference signal includes pilot symbols.  
     
     
         14 . A method as in  claim 1 , wherein the reference signal is transmitted over a pilot channel.  
     
     
         15 . A method as in  claim 1 , wherein a path loss is calculated based on the difference between an effective radiated power level of the reference signal and power level of one or multiple received reference signals.  
     
     
         16 . A method for supporting wireless communications, the method comprising the steps of: 
 detecting that a collision occurs at a first transceiver when two or more second transceivers attempt to send messages over a first channel, a collision occurring when each of the two or more second transceivers transmit messages on the first channel, at least a portion of each message transmitted in a time slot overlap, a common encoded sequence of the messages being detectable at a transceiver even though there is a collision;    notifying the two or more second transceivers of a collision on the first channel by sending a message from the first transceiver to the two or more second transceivers over a feedback channel;    adjusting a power output level of a corresponding one of the two or more second transceivers attempting to send a message over the first channel depending on whether a collision occurs on the first channel, the step of adjusting further comprising: 
 transmitting a first message from the first transceiver, the first message including power level information at which the first transceiver transmits a reference signal;  
 measuring a received power level of the reference signal received at the corresponding second transceiver;  
 decoding the first message at the second transceiver to determine the effective radiated power level information;  
 estimating a path loss between the first and second transceivers by comparing the received power level and the effective radiated power level information;  
 measuring a power level at which a reply message transmitted from the second transceiver is received at the first transceiver; and  
 providing feedback information to the second transceiver how to adjust its power output level.  
   
     
     
         17 . A method in  claim 16  further comprising the steps of: 
 comparing a power level at which the reply message is received at the first transceiver with a desired power level at which messages should be received; and  
 transmitting a power adjustment message to the second transceiver for subsequent message transmissions.  
 
     
     
         18 . A method in  claim 1  further comprising the step of: 
 transmitting a second message from the first transceiver to the second transceiver indicating a desired power level at which subsequent messages shall be received at the first transceiver.  
 
     
     
         19 . A method in  claim 18  further comprising the step of: 
 transmitting a reply message from the second transceiver to the first transceiver at a power level so that the first transceiver receives the reply message at the desired power level.  
 
     
     
         20 . A method as in  claim 18  further comprising the step of: 
 determining a power output setting at the second transceiver based on an estimated path loss so that a message is received at the first transceiver at the desired power level.  
 
     
     
         21 . A method as in  claim 16 , wherein the first message is transmitted over a paging channel of a CDMA (Code Division Multiple Access) communication system.  
     
     
         22 . A method as in  claim 19 , wherein the reply message is transmitted over an access channel of a CDMA communication system.  
     
     
         23 . A method as in  claim 16 , wherein the second transceiver transmits an access request message to the first transceiver in a time slot of an allocated reverse channel.  
     
     
         24 . A method as in  claim 23 , wherein the access request message from the second transceiver to the first transceiver includes encoded information for measuring timing alignment of the second transceiver.  
     
     
         25 . A method as in  claim 16 , wherein the second transceiver sends a reply message to the first transceiver, the reply message including a reference marker that is monitored for timing alignment.  
     
     
         26 . A method as in  claim 16 , wherein the first transceiver transmits the first message over a dedicated channel to multiple transceivers.  
     
     
         27 . A method as in  claim 16 , wherein the, reference signal includes pilot symbols.  
     
     
         28 . A method as in  claim 16 , wherein the reference signal is transmitted over a pilot channel.  
     
     
         29 . A method as in  claim 16 , wherein a path loss is calculated based on the difference between an effective radiated power level of the reference signal and power level of one or multiple received reference signals.