Time of arrival information passing in a distributed antenna system

A distributed antenna system (DAS) comprising:

• a host unit;
• a plurality of active antenna units (AAUs) communicatively coupled to the host unit over a respective communication link, the AAUs configured to wirelessly communicate with one or more wireless devices,
• wherein a first AAU of the plurality of AAUs is configured to identify a first time of arrival of a wireless signal in a time and frequency unit and to send the first time of arrival to a location estimation module comprising processing circuitry;
• wherein a second AAU of the plurality of AAUs is configured to identify a second time of arrival of the wireless signal in a time and frequency unit and to send the second time of arrival from the second AAU to the location estimation module;
• wherein the location estimation module is configured to estimate a location of a wireless unit transmitting the wireless signal based on a location of the first AAU, a location of the second AAU, and a difference between the first time of arrival and the second time of arrival;
• and
• wherein the host unit is configured to receive a map of an allocation of time and frequency units, and to determine the time and frequency unit of the first signal and the second signal based on the map.

A method of estimating a location of a wireless unit with a distributed antenna system (DAS), the method comprising:

• receiving a request at a location estimation module in the DAS to determine a location of a wireless unit allocated to a first time and frequency unit in the uplink RF spectrum;
• wherein the request identifies a resource block in the uplink RF spectrum that is allocated to the wireless unit;
• sending a command from the location estimation module to a plurality of AAUs of the DAS to determine respective times of arrival for a wireless signal in the first time and frequency unit;
• identifying a first time of arrival of a wireless signal in the first time and frequency unit;
• identifying a second time of arrival of the wireless signal in the first time and frequency unit;
• sending the first time of arrival from the first AAU to the location estimation module;
• sending the second time of arrival from the second AAU to the location estimation module;
• and
• estimating a location of the wireless unit based on a location of the first AAU, a location of the second AAU, and a difference between the first time of arrival and a second time of arrival.