Signal quality measurement system

An access point comprising:

• a receiver configured to:
• receive an uplink signal from a transmitter wherein the uplink signal contains a data portion and a transmitted result of a hash function, wherein the uplink signal is received at a time based on a slot start time and a random timing offset, and further wherein the uplink signal is received while at least a portion of a second signal is received from a second transmitter;
• measure a noncoherent energy metric for the uplink signal;
• compute a local result of the hash function using the data portion;
• and
• discard the uplink signal if the transmitted result matches the local result, but the noncoherent energy metric is below a threshold value.

A system comprising:

• a node configured to:
• transmit an uplink signal from wherein the uplink signal contains a data portion and a transmitted result of a hash function;
• a receiver configured to:
• receive the uplink signal, wherein the uplink signal is received at a time based on a slot start time and a random timing offset, and further wherein the uplink signal is received while at least a portion of a second signal is received from a second node;
• measure a noncoherent energy metric for the uplink signal;
• compute a local result of the hash function using the data portion;
• and
• discard the uplink signal if the transmitted result matches the local result, but the noncoherent energy metric is below a threshold value.