Harmonizing noise aggregation and noise management in distributed antenna system

Abstract

The present invention is directed to systems and methods for reducing noise levels by harmonization in a DCC-DAS using smart weighted aggregation of noise and signal resources to achieve an optimal signal to noise ratio in varying traffic and interference conditions.

We claim: 
     
         1 . A digital routing hub coupled to a plurality of base transceiver stations (BTS's) and plurality of remote radio units (RRUs), the digital routing hub comprising:
 a digital noise level control module,   wherein the noise level control module:
 receives a plurality of individual uplink cell resource data samples from the plurality of RRUs; 
 allocates an individual weighted pre-aggregation gain to one or more of the plurality of uplink cell resource data samples; and 
 aggregates one or more of the plurality of individual uplink cell resource data samples into a combined uplink cell resource data sample; and 
 transmits the combined uplink cell resource data sample to an assigned BTS. 
   wherein a cell resource comprises a band of contiguous frequencies within a frequency spectrum that an operator manages.   
     
     
         2 . The digital routing hub according to  claim 1 , wherein the individual weighted pre-aggregation gain is set to equalize all noise levels belonging to a same cell resource coming from the plurality of RRUs prior to aggregation in the plurality of individual uplink cell resource data samples. 
     
     
         3 . The digital routing hub according to  claim 2 , wherein the individual weighted pre-aggregation gain is set according to a targeted noise level determined by a total number of the plurality of individual uplink cell resource data units that are aggregated into the combined uplink cell resource data sample. 
     
     
         4 . The digital routing hub according to  claim 2 , further comprising;
 a thermal noise measurement module for measuring thermal noise in each of the plurality of individual uplink cell resource data samples,   wherein an individual weighted pre-aggregation gain is set per each cell resource in each RRU based upon the measured thermal noise in that cell resource.   
     
     
         5 . The digital routing hub according to  claim 2 , further comprising;
 an interference measurement module for measuring interference levels in each of the plurality of individual uplink cell resource data samples in each of the plurality of RRU,   wherein the individual weighted pre-aggregation gain is set per one or more cell resources belonging to one or more RRUs based upon the measured interference levels measured in the one or more of the individual uplink cell resources   
     
     
         6 . The digital routing hub according to  claim 1 , further comprising;
 an uplink traffic measurement module for measuring a level of uplink traffic in each cell resource in each RRU;   wherein the individual weighted pre-aggregation gain per each cell resources is set differently based upon the measured uplink traffic.   
     
     
         7 . The digital routing hub according to  claim 1 , further comprising;
 a signal-to-noise ratio (SNR) measurement module for measuring the SNR in each of the plurality of individual uplink cell resource data samples,   wherein the individual weighted pre-aggregation gain is set to equalize the SNR in each of the plurality of individual uplink cell resource data samples.   
     
     
         8 . The digital routing hub according to  claim 1 , further comprising;
 a cell resource traffic estimator allocated per one or more cell resources,   wherein the individual weighted pre-aggregation gain is set to a certain level so that it reduces the contribution of lower traffic or no traffic uplink digital filtered cell resources noise to a post aggregation noise.   
     
     
         9 . The digital routing hub according to  claim 7 , wherein the noise level control module allocates additional sectors to a portion of a building to decrease a number of cell resources being aggregated per each sector thus improving the SNR in each of the plurality of individual uplink cell resource data samples. 
     
     
         10 . The digital routing hub according to  claim 1 , further comprising:
 an interference measurement module for measuring interference levels in each of the plurality of individual uplink cell resource data samples,   wherein the noise level control module sets the individual weighted pre-aggregation gain to a level that eliminates an interference in order to prevent the interference from being aggregated.   
     
     
         11 . The digital routing hub according to  claim 1 , wherein the noise level control module allocates a full BTS sector cell resource to only a specific RRU in order to eliminate any noise aggregation and to improve the signal-to-noise ratio of the full BTS sector cell resource. 
     
     
         12 . The digital routing hub according to  claim 1 , wherein the digital routing hub is coupled to at least one other digital routing hub. 
     
     
         13 . The digital routing hub according to  claim 1 , further comprising:
 a timing reference jitter cleaner to generate an internal timing reference for the digital routing hub to ensure that all transfer is synchronous across all data links and avoid a need for retiming where data is interchanged between the digital routing hub and other devices.   
     
     
         14 . The digital routing hub according to  claim 1 , further comprising:
 at least one Ethernet port on one or more of the plurality of remote radio units (RRUs) coupled to the digital routing hub,   wherein the Ethernet port serves as an IP Backhaul link for one or more IP devices coupled to the one or more RRUs, and   wherein backhaul data on the IP Backhaul link is connected through a corresponding Ethernet port on the digital routing hub to enable integration of the digital routing hub with any of the one or more IP devices.   
     
     
         15 . A digital distributed antenna system (DAS) for coupling to output ports of a plurality of base transceiver stations (BTS's) comprising:
 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   at least one downlink digital filter bank comprising a plurality of downlink digital filters,   each of the plurality of downlink digital filters being matched to a unique cell resource, a cell resource comprising a band of contiguous frequencies within a frequency spectrum owned by an operator, and each cell resource including at least one or more downlink signals being received from one or more of the BTS's,   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 in uplink direction, a noise aggregation process is performed on two or more RRUs for each cell resource of an two or more RRUs and not across a whole frequency band of the two or more RRUs.   
     
     
         16 . A method for harmonizing noise aggregation for a digital DAS coupled to a plurality of base transceiver stations (BTS's) and plurality of remote radio units (RRUs) antenna, the method comprising:
 receiving, at a noise level control module, a plurality of individual uplink cell resource data samples from the plurality of RRUs;   allocating an individual weighted pre-aggregation gain to one or more of the plurality of individual uplink cell resource data samples; and   aggregating the one or more of the plurality of individual uplink cell resource data samples into a combined uplink cell resource data sample; and   transmitting the combined uplink cell resource data sample to an assigned BTS.   wherein a cell resource comprises a band of contiguous frequencies within a frequency spectrum that an operator manages.   
     
     
         17 . The method according to  claim 16 , wherein the individual weighted pre-aggregation gain is set to equalize all the noise levels belonging to a same cell resource coming from the plurality of RRUs prior to aggregation in the plurality of individual uplink cell resource data samples. 
     
     
         18 . The method according to  claim 17 , wherein the individual weighted pre-aggregation gain is set according to a targeted noise level determined by a total number of the plurality of individual uplink cell resource data units that are aggregated into the combined uplink cell resource data sample. 
     
     
         19 . The method according to  claim 17 , wherein the individual weighted pre-aggregation gain is set for one or more cell resource in one or more RRUs based upon a measured thermal noise in that individual cell resource. 
     
     
         20 . The method according to  claim 17 , wherein the individual weighted pre-aggregation gain is set for one or more cell resources belonging to one or more RRUs based upon a measured interference level measured in the one or more of the individual uplink cell resources 
     
     
         21 . The method according to  claim 16 , wherein the individual weighted pre-aggregation gain for one or more cell resources is set differently based upon a measured uplink traffic cell resource belonging to one or more RRUs; 
     
     
         22 . The method for harmonizing noise aggregation according to  claim 16 , wherein the individual weighted pre-aggregation gain is set to equalize a SNR in one or more of the plurality of individual uplink cell resource data samples. 
     
     
         23 . The method for harmonizing noise aggregation according to  claim 16 , wherein the individual weighted pre-aggregation gain is set to a certain level so that it reduces one or more of the contribution of lower traffic or no traffic uplink digital filtered cell resources noise to a post aggregation noise. 
     
     
         24 . The method for harmonizing noise aggregation according to  claim 22 ,
 wherein the noise level control module allocates additional sectors to a portion of a building to decrease a number of cell resources being aggregated per each sector thus improving the SNR in each of the plurality of individual uplink cell resource data samples.   
     
     
         25 . The method for harmonizing noise aggregation according to  claim 16 , wherein the noise level control module sets the individual weighted pre-aggregation gain to a level that eliminates an interference in order to prevent the interference from being aggregated. 
     
     
         26 . The method for harmonizing noise aggregation according to  claim 16 , wherein the noise level control module allocates a full BTS sector cell resource to only a specific RRU in order to eliminate any noise aggregation and to improve the signal-to-noise ratio of the full BTS sector cell resource.