Automatic mapping and handling pim and other uplink interferences in digital distributed antenna systems

Abstract

Disclosed herein is an algorithm that leverages the unique features and capabilities of a DCC-DAS in order to perform automatic measurements of uplink noise, PIM, and any uplink interference. Once an interference in the uplink is detected, this algorithm may automatically measure its parameters such as frequency, intensity, bandwidth, etc., and identify the source of the problem. It may automatically isolate and identify which element or cable of the DCC-DAS is the root cause of the problem or also which external source is generating the problem.

We claim: 
     
         1 . A method for automatic mapping and handling noise and interference in a distributed antenna system (DAS), the method comprising:
 (a) measuring any excessive noise and interference in uplink channels of the DAS when one or more downlink channels of the DAS are muted,   comparing any measured excessive noise and interference from step (a) to a desired noise level,   wherein the desired noise level is determined by an initial DAS layout design of uplink channels of the DAS;   (b) measuring any excessive noise and interference in uplink channels of the DAS when one or more of the downlink channels of the DAS are active in a zero traffic mode,   comparing any measured excessive noise and interference from step (b) to the desired noise level; and   (c) measuring any excessive noise and interference in uplink channels of the DAS when one or more of the downlink channels of the DAS are fully operational,   comparing any measured excessive noise and interference from step (c) to the desired noise level and the excessive noise and interference measured in step (a); and to the zero traffic mode measurement (b)   
     
     
         2 . The method of  claim 1 , wherein the measuring in steps (a), (b), and (c) is performed on one or more cell resources of the DAS. 
     
     
         3 . The method of  claim 1 , wherein the comparing from steps (a), (b), and (c), generates an excessive noise and interference alarm report. 
     
     
         4 . The method of  claim 1 , wherein the measuring in steps (a), (b), and (c) is performed in one or more uplink channels of one or more on one or more Remote Radio Units (RRUs) of the DAS. 
     
     
         5 . The method of  claim 1 , wherein the measuring in steps (a), (b), and (c) is performed on one or more DAS test points between an antenna and an interface of a base transceiver station (BTS) along an uplink receive path. 
     
     
         6 . The method of  claim 1 , further comprising:
 (d) automatically adjusting gain of one or more of the uplink channels or downlink channels based upon the comparing performed in steps (a), (b), and (c).   
     
     
         7 . The method of  claim 1 , further comprising:
 automatically adjusting downlink power of one or more RRUs or cell resources based upon the comparing performed in steps (a), (b), and (c).   
     
     
         8 . The method of  claim 1 , further comprising:
 automatically switching off downlink power to one or more cell resources based upon the comparing performed in steps (a), (b), and (c).   
     
     
         9 . The method of  claim 1 , further comprising:
 automatically switching off downlink power to one or more cell resources based upon the comparing performed in steps (a), (b), and (c).   
     
     
         10 . The method of  claim 2 , wherein the baseline noise level is measured before the DAS becomes operational. 
     
     
         11 . The method of  claim 1 , wherein the DAS performs step (c) on a regular scheduled basis. 
     
     
         12 . The method of  claim 1 , wherein the DAS performs step (c) when there is a suspicion that that one or more BTS uplink channels are malfunctioning. 
     
     
         13 . The method of  claim 1 , wherein the DAS utilizes a fast Fourier transform algorithm in order to separate and identify any uplink excessive noise and interference from the uplink desired signals in the comparison of steps (b) and (c). 
     
     
         14 . A digital distributed antenna system (DAS) for coupling to output ports of a plurality of base transceiver stations (BTS's)
 a plurality of remote radio units (RRUs) in communication with mobile devices;   a central digital hub for routing and processing digitized RF signals, wherein the central digital hub is coupled to the RRUs and to the BTS's;   at least one uplink digital filter bank comprising a plurality of uplink digital filters, such digital filter bank in the plurality of the RRUs; and   and each of the plurality of uplink digital filters being matched to a unique cell resource, each cell resource including at least one or more signals being received from one or more mobile devices in an uplink direction,   wherein one or more the downlink channels are shut off or muted and in the uplink direction the DAS is able to:   measure and map in one or more RRUs any excessive noise in one or more of uplink cell resources compared to the design levels,   or measure and map one or more interferences that may be received or generated in one or more of the uplink cell resources due to one or more external or internal sources compared to the design levels   
     
     
         15 . The system of  claim 14 , wherein the DAS sends an alarm and a report to a user delineating one or more parameters of the one or more excessive noise levels or interferences in the one or more cell resources. 
     
     
         16 . A digital distributed antenna system (DAS) for coupling to output ports of a plurality of base transceiver station (BTS's) comprising:
 a plurality of remote radio units (RRUs) in communication with mobile devices;   a central digital hub for routing and processing digital RF signals, wherein the central digital hub is coupled to the RRUs and to the BTS's;   at least one uplink digital filter bank comprising a plurality of uplink digital filters, such digital filter bank in the plurality of the RRUs; and   and each of the plurality of uplink digital filters being matched to a unique cell resource, each cell resource including at least one or more signals being received from one or more mobile devices in an uplink direction, there being at least two separate and distinct cell resources;   wherein one or more of the BTSs coupled to the DAS may be activated in zero traffic mode and the DAS measures and maps in one or more RRUs any excessive noise in one or more of uplink cell resources generated due to one or more downlink transmissions such as PIM signals or any other interference generated in the uplink path by downlink transmission.   
     
     
         17 . The system of  claim 16 , wherein one or more synthesizers in the DAS are activated by the DAS to simulate downlink transmission in lieu of or in addition to the aforementioned BTSs in no traffic mode 
     
     
         18 . The system of  claim 16 , where excessive noise or PIM generated by one or more downlink transmissions is measured and mapped in one or more cell resources in one or more test points between an antenna and an interface to the BTSs along the uplink path. 
     
     
         19 . A digital distributed antenna system (DAS) for coupling to output ports of a plurality of base transceiver station (BTS's) comprising:
 a plurality of remote radio units (RRUs) in communication with mobile devices;   a central digital hub for routing and processing digital RF signals, wherein the central digital hub is coupled to the RRUs and to the BTS's;   at least one uplink digital filter bank comprising a plurality of uplink digital filters, such digital filter bank in the plurality of the RRUs; and   and each of the plurality of uplink digital filters being matched to a unique cell resource, each cell resource including at least one or more signals being received from one or more mobile devices in an uplink direction, there being at least two separate and distinct cell resources;   wherein one or more of the synthesizers in the DAS are activated by the DAS to simulate downlink transmission and the DAS measures and maps in one or more RRUs any excessive noise in one or more of uplink cell resources generated due to one or more downlink transmissions such as PIM signals or any other interference generated in the uplink path by downlink transmission.   
     
     
         20 . The system of  claim 19 , where excessive noise or PIM generated by one or more downlink transmissions is measured and mapped in one or more cell resources in one or more test points between an antenna and an interface to the BTSs along the uplink path. 
     
     
         21 . The system of  claim 14 , wherein the DAS automatically changes one or more DAS settings such as gain, Digital filters, routing, transmission power according to one or more parameters of the one or more excessive noise levels or interferences in the one or more cell resources. 
     
     
         22 . The system of  claim 16 , wherein the DAS automatically changes one or more DAS settings such as gain, Digital filters, routing, transmission power according to one or more parameters of the one or more excessive noise levels or interferences in the one or more cell resources. 
     
     
         23 . The system of  claim 19 , wherein the DAS automatically changes one or more DAS settings such as gain, Digital filters, routing, transmission power according to one or more parameters of the one or more excessive noise levels or interferences in the one or more cell resources.