Robust Techniques for Upstream Communication Between Subscriber Stations and a Base Station

Abstract

A number of features for enhancing the performance of a communication system, in which data is transmitted between a base station and a plurality of subscriber stations located different distances from the base station, are presented. The power transmission level, slot timing, and equalization of the subscriber stations are set by a ranging process. Data is transmitted by the subscriber stations in fragmented form. Various measures are taken to make transmission from the subscriber stations robust. The uplink data transmission is controlled to permit multiple access from the subscriber stations.

What is claimed is: 
     
         1 . A base station comprising:
 a receiver configured to process an upstream signal received on an uplink channel from a subscriber station;   a transmitter configured to send a downstream signal on a downlink channel from the base station to the subscriber station; and   a monitoring circuit configured to:
 collect packet based statistics representative of a channel quality of the uplink channel based on the upstream signal, 
 send a message to the transmitter, based on the collected statistics indicating the channel quality to be at a first level, for the subscriber station to change a coding gain associated with the uplink channel used to send upstream signals, and 
 send a message to the transmitter, based on the collected statistics indicating the channel quality to be at a second level, for the subscriber station to reallocate the uplink channel to a different frequency, wherein the second level is associated with a poorer channel quality than the first level. 
   
     
     
         2 . The base station of  claim 1 , wherein the collected statistics include a number of undetected packets transmitted over the uplink channel. 
     
     
         3 . The base station of  claim 1 , wherein the collected statistics include a number of packets transmitted over the uplink channel without a unique word. 
     
     
         4 . The base station of  claim 1 , wherein the collected statistics include a number of packets transmitted over the uplink channel with corrected errors. 
     
     
         5 . The base station of  claim 1 , wherein the collected statistics include a number of packets transmitted over the uplink channel with uncorrectable errors. 
     
     
         6 . The base station of  claim 1 , wherein the collected statistics include a number of forward error correction (FEC) blocks transmitted over the uplink channel with corrected errors. 
     
     
         7 . The base station of  claim 1 , wherein the collected statistics include a number of forward error correction (FEC) blocks transmitted over the uplink channel with uncorrectable errors. 
     
     
         8 . A method, comprising:
 collecting packet based statistics representative of a channel quality of an uplink channel based on an upstream signal received from a subscriber station;   sending a message to the subscriber station, based on the collected statistics indicating the channel quality to be at a first level, to change a coding gain associated with the uplink channel used to send upstream signals; and   sending a message to the subscriber station, based on the collected statistics indicating the channel quality to be at a second level, to reallocate the uplink channel to a different frequency, wherein the second level is associated with a poorer channel quality than the first level.   
     
     
         9 . The method of  claim 8 , wherein the collected statistics include a number of undetected packets transmitted over the uplink channel. 
     
     
         10 . The method of  claim 8 , wherein the collected statistics include a number of packets transmitted over the uplink channel without a unique word. 
     
     
         11 . The method of  claim 8 , wherein the collected statistics include a number of packets transmitted over the uplink channel with corrected errors. 
     
     
         12 . The method of  claim 8 , wherein the collected statistics include a number of packets transmitted over the uplink channel with uncorrectable errors. 
     
     
         13 . The method of  claim 8 , wherein the collected statistics include a number of forward error correction (FEC) blocks transmitted over the uplink channel with corrected errors. 
     
     
         14 . The method of  claim 8 , wherein the collected statistics include a number of forward error correction (FEC) blocks transmitted over the uplink channel with uncorrectable errors. 
     
     
         15 . A base station comprising:
 a receiver configured to process an upstream signal received on an uplink channel from a subscriber station;   a transmitter configured to send a downstream signal on a downlink channel from the base station to the subscriber station; and   a monitoring circuit configured to:
 collect packet based statistics representative of a channel quality of the uplink channel based on the upstream signal, 
 based on the statistics indicating the channel quality to be at a first level, changing a coding gain associated with the downlink channel, and 
 based on the statistics indicating the channel quality to be at a second level, reallocating the downlink channel to a different frequency, wherein the second level is associated with a poorer channel quality than the first level. 
   
     
     
         16 . The base station of  claim 15 , wherein the collected statistics include a number of undetected packets transmitted over the uplink channel. 
     
     
         17 . The base station of  claim 15 , wherein the collected statistics include a number of packets transmitted over the uplink channel without a unique word. 
     
     
         18 . The base station of  claim 15 , wherein the collected statistics include a number of packets transmitted over the uplink channel with corrected errors. 
     
     
         19 . The base station of  claim 15 , wherein the collected statistics include a number of packets transmitted over the uplink channel with uncorrectable errors. 
     
     
         20 . The base station of  claim 15 , wherein the collected statistics include a number of forward error correction (FEC) blocks transmitted over the uplink channel with corrected errors.