The disclosure relates generally to a wireless distribution system (WDS), and more particularly, to assigning unique temporal delays to signal paths assigned to remote units in a WDS.
Wireless customers are increasingly demanding digital data services, such as streaming video and other multimedia contents, for example. Some wireless customers use their wireless devices in areas poorly serviced by conventional cellular networks, such as inside certain buildings or areas. One response to the intersection of these two concerns has been the use of WDSs, such as a distributed antenna system (DAS) as an example. A DAS can be particularly useful when deployed inside buildings or other indoor environments where client devices may not otherwise be able to effectively receive radio frequency (RF) signals from a base transceiver station (BTS), for example, of a conventional cellular network. The DAS is configured to provide multiple coverage areas inside the buildings to support higher capacity and improved RF coverage. Each coverage area includes one or more remote units configured to provide communications services to the client devices within antenna ranges of the remote units.
Many context-aware and location-aware wireless services, such as enhanced 911 (E911) services, rely on accurately detecting the locations of wireless communications devices. A satellite-based location detection system, such as global positioning system (GPS) in the United States, is unreliable in indoor environments served by the DASs due to the inherent inability of a satellite signal to penetrate obstacles like building walls. Although it may be possible to determine general locations of wireless communications devices based on base stations in the convention cellular network, it remains challenging for base stations to pinpoint the locations of the wireless communications devices with a higher degree of accuracy.
No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.
Embodiments of the disclosure relate to assigning unique temporal delays to signal paths assigned to remote units in a wireless distribution system (WDS), particularly for supporting location services for client devices. In this regard, the WDS comprises a plurality of remote units configured to distribute received downlink communications signals to client devices (e.g., mobile cellular devices) in the antenna coverage area of the remote units, and distribute received uplink communications signals from client devices to a network (e.g., a cellular network). In one exemplary aspect, the plurality of remote units is each assigned a unique identification temporal delay. Received communications signals, including the received downlink communications signals and/or the received uplink communications signals, communicated by the remote units are delayed according to the respective assigned unique identification temporal delay for the remote unit. By examining the delay of received communications signals in the WDS and associating the delay with a unique temporal delay assigned to the remote units, it is possible to uniquely identify the remote unit from which the received communications signal is communicated. In this regard, the location of client devices in the WDS relative to the remote units can be determined.
Further, to mitigate uplink propagation delay drifts resulting from factors inherent to wireless communications systems (e.g., multipath) causing inaccuracies in determining the plurality of remote units based on the assigned unique temporal delays, in another aspect, the unique identification temporal delays assigned to adjacent remote units differ by more than one predefined timing advance (TA) step. A TA step is a time duration designed to accommodate propagation delays in a specific communications system, such as long-term evolution (LTE) for example. Remote units are determined to be adjacent to each other if remote units are separated by a TA-defined distance that a client device can traverse at a predefined velocity (e.g., nomadic velocity) within a predefined interval. By separating the unique identification temporal delays assigned to adjacent remote units by more than one predefined TA step, it is possible to tolerate propagation variations resulting from factors inherent to wireless communications systems (e.g., multipath), thus improving reliability in uniquely identifying a plurality of remote units in the WDS.
One embodiment of the disclosure relates to a WDS. The WDS comprises a central unit. The central unit is configured to communicate a plurality of downlink communications signals over a plurality of downlink signal paths to a plurality of remote units in the WDS, respectively. The central unit is also configured to receive a plurality of uplink communications signals over a plurality of uplink signal paths assigned to the plurality of remote units, the plurality of assigned uplink signal paths disposed respectively between the central unit and the plurality of remote units. The WDS also comprises a plurality of delay elements provided in a plurality of signal paths among the plurality of downlink signal paths and the plurality of uplink signal paths and assigned to the plurality of remote units, respectively. Each of the plurality of delay elements is configured to delay a respective communications signal communicated on a respective assigned signal path by an assigned unique identification temporal delay that differs from at least one assigned unique identification temporal delay assigned to at least one adjacent remote unit among the plurality of remote units by more than one predefined TA step. An adjacent remote unit is a remote unit physically located from another remote unit among the plurality of remote units within a TA-defined distance that a client device can traverse at a predefined velocity within a predefined interval.
An additional embodiment of the disclosure relates to a method for identifying a plurality of remote units in a WDS. The method comprises communicating a plurality of downlink communications signals over a plurality of downlink signal paths to the plurality of remote units in the WDS, respectively. The method also comprises receiving a plurality of uplink communications signals over a plurality of uplink signal paths assigned to the plurality of remote units. The method also comprises delaying each of a plurality of communications signals among the plurality of downlink communications signals and the plurality of uplink communications signals by an assigned unique identification temporal delay that differs from at least one assigned unique identification temporal delay assigned to at least one adjacent remote unit among the plurality of remote units by more than one predefined TA step.
An additional embodiment of the disclosure relates to a WDS. The WDS comprises a central unit. The central unit is configured to communicate one or more first downlink communications signals over one or more first downlink signal paths to one or more first remote units in at least one first remote unit cluster, respectively. The central unit is also configured to communicate one or more second downlink communications signals over one or more second downlink signal paths to one or more second remote units in at least one second remote unit cluster, respectively. The central unit is also configured to receive one or more first uplink communications signals over one or more first uplink signal paths assigned to the one or more first remote units, the one or more assigned first uplink signal paths disposed respectively between the central unit and the one or more first remote units. The central unit is also configured to receive one or more second uplink communications signals over one or more second uplink signal paths assigned to the one or more second remote units, the one or more assigned second uplink signal paths disposed respectively between the central unit and the one or more second remote units. The WDS also comprises one or more first delay elements provided in the one or more first uplink signal paths and assigned to the one or more first remote units, respectively. The WDS also comprises one or more second delay elements provided in the one or more second uplink signal paths and assigned to the one or more second remote units, respectively.
Each of the one or more first delay elements is configured to delay a respective first uplink communications signal communicated over a respective assigned first uplink signal path by a respective assigned first unique identification temporal delay that differs from at least one assigned first unique identification temporal delay assigned to at least one other first remote unit in the at least one first remote unit cluster by more than one predefined TA step. Each of the one or more second delay elements is configured to delay a respective second uplink communications signal communicated over a respective assigned second uplink signal path by a respective assigned second unique identification temporal delay that differs from at least one assigned second unique identification temporal delay assigned to at least one other second remote unit in the at least one second remote unit cluster by more than one predefined TA step. The at least one first remote unit cluster is separated from the at least one second remote unit cluster by at least a TA-defined distance that a client device is unable to traverse at a predefined velocity within a predefined interval. An assigned first unique identification temporal delay assigned to a first remote unit in the at least one first remote unit cluster differs from an assigned second unique identification temporal delay assigned to a second remote unit in the at least one second remote unit cluster by less than two predefined TA steps.
An additional embodiment of the disclosure relates to a method for assigning unique identification temporal delays to remote units in a WDS. The method comprises determining at least one first remote unit cluster comprising one or more first remote units. The method also comprises determining at least one second remote unit cluster comprising one or more second remote units, wherein the at least one second remote unit cluster is separated from the at least one first remote unit cluster by a TA-defined distance that a client device is unable to traverse at a predefined velocity within a predefined interval. The method also comprises logically organizing the one or more first remote units in the at least one first remote unit cluster into a first sequential queue. The method also comprises selecting a beginning first remote unit at a head of the first sequential queue and assigning the beginning first remote unit an assigned first unique identification temporal delay that is greater than or equal to one predefined TA step. The method also comprises assigning a respective assigned first unique identification temporal delay that differs from a respective assigned first unique identification temporal delay of an immediate preceding first remote unit in the first sequential queue by more than one predefined TA step for each first remote unit subsequent to the beginning first remote unit in the first sequential queue.
The method also comprises logically organizing the one or more second remote units in the at least one second remote unit cluster into a second sequential queue. The method also comprises selecting a beginning second remote unit at a head of the second sequential queue and assigning the beginning second remote unit an assigned second unique identification temporal delay that differs from the assigned first unique identification temporal delay of the beginning first remote unit in the first sequential queue by at least one predefined TA step. The method also comprises assigning a respective assigned second unique identification temporal delay that differs from a respective assigned second unique identification temporal delay of an immediate preceding second remote unit in the second sequential queue by more than one predefined TA step for each second remote unit subsequent to the beginning second remote unit in the second sequential queue.
Additional features and advantages will be set forth in the detailed description which follows and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments.
Embodiments of the disclosure relate to assigning unique temporal delays to signal paths assigned to remote units in a wireless distribution system (WDS), particularly for supporting location services for client devices. In this regard, the WDS comprises a plurality of remote units configured to distribute received downlink communications signals to client devices (e.g., mobile cellular devices) in the antenna coverage area of the remote units, and distribute received uplink communications signals from client devices to a network (e.g., a cellular network). In one exemplary aspect, the plurality of remote units is each assigned a unique identification temporal delay. Received communications signals, including the received downlink communications signals and/or the received uplink communications signals, communicated by the remote units are delayed according to the respective assigned unique identification temporal delay for the remote unit. By examining the delay of received communications signals in the WDS and associating the delay with a unique temporal delay assigned to the remote units, it is possible to uniquely identify the remote unit from which the received communications signal is communicated. In this regard, the location of client devices in the WDS relative to the remote units can be determined.
Further, to mitigate uplink propagation delay drifts resulting from factors inherent to wireless communications systems (e.g., multipath) causing inaccuracies in determining the plurality of remote units based on the assigned unique temporal delays, in another aspect, the unique identification temporal delays assigned to adjacent remote units differ by more than one predefined timing advance (TA) step. A TA step is a time duration designed to accommodate propagation delays in a specific communications system, such as long-term evolution (LTE) for example. Remote units are determined to be adjacent to each other if remote units are separated by a TA-defined distance that a client device can traverse at a predefined velocity (e.g., nomadic velocity) within a predefined interval. By separating the unique identification temporal delays assigned to adjacent remote units by more than one predefined TA step, it is possible to tolerate propagation variations resulting from factors inherent to wireless communications systems (e.g., multipath), thus improving reliability in uniquely identifying a plurality of remote units in the WDS.
Before discussing examples of identifying remote units in WDSs starting at
In this regard,
With reference to
With reference to
The WDS 200 also includes a plurality of delay elements 218(1)-218(N) provided in the signal paths 217(1)-217(N) and assigned to the remote units 202(1)-202(N), respectively. Each of the delay elements 218(1)-218(N) is configured to delay a respective communications signal among the communications signals 215(1)-215(N) by a respective assigned unique identification temporal delay 204(1)-204(N). In a first non-limiting example, the delay elements 218(1)-218(N) are provided in the downlink signal paths 212(1)-212(N), respectively. In this regard, each of the delay elements 218(1)-218(N) is configured to delay a respective downlink communications signal among the downlink communications signals 210(1)-210(N) by the respective assigned unique identification temporal delay among the assigned unique identification temporal delays 204(1)-204(N). In a second non-limiting example, the delay elements 218(1)-218(N) are provided in the uplink signal paths 216(1)-216(N). In this regard, each of the delay elements 218(1)-218(N) is configured to delay a respective uplink communications signal among the uplink communications signals 214(1)-214(N) by the respective assigned unique identification temporal delay among the assigned unique identification temporal delays 204(1)-204(N). In a third non-limiting example, the delay elements 218(1)-218(N) are provided in both the downlink signal paths 212(1)-212(N) and the uplink signal paths 216(1)-216(N), respectively.
In this regard, each of the delay elements 218(1)-218(N) is configured to delay the respective downlink communications signal among the downlink communications signals 210(1)-210(N) and the respective uplink communications signal among the uplink communications signals 214(1)-214(N) by the respective assigned unique identification temporal delay among the assigned unique identification temporal delays 204(1)-204(N). As such, the central unit 206 and/or the signal source 208 will receive a plurality of delayed uplink communications signals 214′(1)-214′(N). The delayed uplink communications signals 214′(1)-214′(N) are the same as the uplink communications signals 214(1)-214(N), but are delayed by the delay elements 218(1)-218(N) according to the assigned unique identification temporal delays 204(1)-204(N). In this regard, according to the first non-limiting example discussed above, the assigned unique identification temporal delays 204(1)-204(N) associated with the delayed uplink communications signals 214′(1)-214′(N) are provided in the downlink signal paths 212(1)-212(N). Similarly, according to the second non-limiting example discussed above, the assigned unique identification temporal delays 204(1)-204(N) associated with the delayed uplink communications signals 214′(1)-214′(N) are provided in the uplink signal paths 216(1)-216(N). Likewise, according to the third non-limiting example discussed above, the assigned unique identification temporal delays 204(1)-204(N) associated with the delayed uplink communications signals 214′(1)-214′(N) are provided in both the downlink signal paths 212(1)-212(N) and the uplink signal paths 216(1)-216(N). As is further discussed next, the central unit 206 and/or the signal source 208 can analyze the delayed uplink communications signals 214′(1)-214′(N) to determine the assigned unique identification temporal delays 204(1)-204(N), respectively. The central unit 206 and/or the signal source 208 can then uniquely identify the remote units 202(1)-202(N) based on the determined assigned unique identification temporal delays 204(1)-204(N).
With continuing reference to
The remote units 202(1)-202(N) are configured to receive the uplink communications signals 214(1)-214(N) over a plurality of uplink wireless signal paths 224(1)-224(N), respectively. Each of the remote units 202(1)-202(N) receives a respective uplink communications signal among the uplink communications signals 214(1)-214(N) from the respective client device 222.
With continuing reference to
For the convenience of illustration and reference, the remote unit 202(1), the downlink communications signal 210(1), the uplink communications signal 214(1), the delayed uplink communications signal 214′(1), the uplink signal path 216(1), and the client device 222 transmitting the uplink communications signal 214(1) are discussed hereinafter as a non-limiting example. It shall be appreciated that the configuration and operation principles discussed herein are applicable to all other elements in the WDS 200.
With continuing reference to
Distance=(Round-trip Propagation Delay)×(Speed of Light in Air) (Eq. 1)
In this regard, the TA 226 is determined to be the round-trip propagation delay. As it is well known, the speed of light in air is approximately three hundred million meters per second (3×108 m/s). The round-trip propagation delay, on the other hand, is typically measured in TA units. In the LTE communications systems, for example, a TA unit is defined as five hundred twenty and eight tenths nanoseconds (520.8 ns or 520.8×10−9 second). The TA 226, as discussed in the present disclosure, is based on a predefined TA step that equals the LTE TA units. According to Equation 1.1 (Eq. 1.1) below, the distance that light can traverse in air during one predefined TA step, which is hereinafter referred to as a “TA distance in air,” is approximately seventy-eight meters (78 m).
However, the speed of light in an optical medium (e.g., optical fiber) is slower than the speed of light in air. In a non-limiting example, the speed of light in optical medium is approximately two hundred million meters per second (2×108 m/s). In this regard, according to Equation 1.2 (Eq. 1.2) below, the distance that light can traverse in optical medium during one predefined TA step, which is hereinafter referred to as a “TA distance in optical medium,” is approximately fifty-two meters (52 m).
As previously stated, each of the delay elements 218(1)-218(N) is configured to delay a respective downlink communications signal among the downlink communications signals 210(1)-210(N) and/or a respective uplink communications signal among the uplink communications signals 214(1)-214(N) by a respective assigned unique identification temporal delay among the assigned unique identification temporal delays 204(1)-204(N). As such, the downlink communications signals 210(1)-210(N) and/or the uplink communications signals 214(1)-214(N) are further delayed by the delay elements 218(1)-218(N) for the assigned unique identification temporal delays 204(1)-204(N), respectively, in addition to the respective TA 226. As a result, each of the delayed uplink communications signals 214′(1)-214′(N) will have a respective total delay as determined in Equation 2 (Eq. 2) below.
According to previous discussions, the assigned unique identification temporal delay 204(1) may be generated by the delay element 218(1) in the downlink signal path 212(1), in the uplink signal path 216(1), or in both the downlink signal path 212(1) and the uplink signal path 216(1). In this regard, for example, the total delay of the delayed uplink communications signal 214′(1) will equal the TA 226 plus the assigned unique identification temporal delay 204(1). If the TA 226 assigned to the client device 222 is six tenths of the predefined TA step (0.6*(TA step)) and the assigned unique identification temporal delay 204(1) is equal to one predefined TA step (1*(TA step)), then the total delay of the delayed uplink communications signal 214′(1) will equal one and six tenths of the predefined TA step when the delayed uplink communications signal 214′(1) arrives at the signal source 208.
In a non-limiting example, the assigned unique identification temporal delays 204(1)-204(N) may be assigned to the remote units 202(1)-202(N) sequentially based on a one predefined TA step increment. For example, the assigned unique identification temporal delay 204(1) is equal to one predefined TA step (1*(TA step)), the assigned unique identification temporal delay 204(2) is equal to two predefined TA steps (2*(TA step)), the assigned unique identification temporal delay 204(3) is equal to three predefined TA steps (3*(TA step)), and the assigned unique identification temporal delay 204(N) is equal to N predefined TA steps (N*(TA step)).
When the signal source 208 receives the delayed uplink communications signal 214′(1), for example, the signal source 208 is aware of the TA 226 associated with the client device 222, because the signal source 208 has assigned the TA 226 to the client device 222 to accommodate for the uplink propagation delay from the client device 222. Therefore, using Equation 2 above, the signal source 208 is able to determine the assigned unique identification temporal delay 204(1) by subtracting the TA 226 from the total delay of the delayed uplink communications signal 214′(1). As a result, the signal source 208 is able to uniquely identify the remote unit 202(1) based on the determined assigned unique identification temporal delay 204(1). Hence, by determining the assigned unique identification temporal delays 204(1)-204(N) from the delayed uplink communications signals 214′(1)-214′(N), the signal source 208 can uniquely identify all of the remote units 202(1)-202(N) in the WDS 200.
With continuing reference to
For example, if the assigned unique identification temporal delay 204(1) assigned to the remote unit 202(1) is 1*(TA step), the assigned unique identification temporal delay 204(2) assigned to the remote unit 202(2) is 2*(TA step), and the TA 226 assigned to the client device 222 associated with the remote unit 202(1) is six tenths of the predefined TA step (0.6*(TA step)), then the total delay of the delayed uplink communications signal 214′(1), as determined based on Equation 2, is supposed to be one and six tenths of the predefined TA step (1.6*(TA step)). If the uplink communications signal 214(1) does not experience the additional delay over the uplink wireless signal path 224(1), the delayed uplink communications signal 214′(1) will arrive at the signal source 208 with the anticipated total delay of 1.6*(TA step). By subtracting the TA 226 from the total delay of the delayed uplink communications signal 214′(1), the signal source 208 can determine the assigned unique identification temporal delay 204(1) and, thus, uniquely identify the remote unit 202(1).
If the uplink communications signal 214(1) experienced an additional delay that is equal to eight tenths of the predefined TA step (0.8*(TA step)) over the uplink wireless signal path 224(1), the uplink propagation delay will increase from 0.6*(TA step) to one and four tenths of the predefined TA step (1.4*(TA step). As a result, the total delay of the delayed uplink communications signal 214′(1) will increase from 1.6*(TA step) to be equal to two and four tenths of the predefined TA step (2.4*(TA step)). The signal source 208, however, still considers the uplink propagation delay as being equal to the TA 226 that equals 0.6*(TA step). By subtracting the TA 226 from the total delay of the delayed uplink communications signal 214′(1), which now stands at 2.4*(TA step), the signal source 208 will determine the assigned unique identification temporal delay 204(1) as being one and eight tenths of the predefined TA step (2.4*(TA step)−0.6*(TA step)=1.8*(TA step)). Since the assigned unique identification temporal delays 204(1)-204(2) of the remote units 202(1)-202(2) are 1*(TA step) and 2*(TA step), respectively, the signal source 208 will have difficulty definitively identifying either the remote unit 202(1) or the remote unit 202(2) based on the determined assigned unique identification temporal delay of 1.8*(TA step). Further, if the determined assigned unique identification temporal delay is mathematically rounded up to a closest multiple of the predefined TA step, for example two predefined TA steps (2*(TA step)), the signal source 208 may misidentify the remote unit 202(2) based on the rounded-up assigned unique identification temporal delay. Hence, it may be desired to enhance the WDS 200 to ensure unambiguous identification of the remote units 202(1)-202(N).
In this regard, it may be necessary to determine adjacencies between the remote units 202(1)-202(N) before assigning the assigned unique identification temporal delays 204(1)-204(N).
In this regard, with reference to
TA-defined Distance=N×(TA distance in Air) (N=1, 2, 3 . . . ) (Eq. 3)
Once the TA-defined distance between the first remote unit 300 and the second remote unit 302 is determined, it is possible to define whether the first remote unit 300 is adjacent to the second remote unit 302. In this regard, the first remote unit 300 is adjacent to the second remote unit 302 if a client device 308 is able to traverse the TA-defined distance at a predefined velocity 310 and within a predefined interval 312. In contrast, the first remote unit 300 is non-adjacent to the second remote unit 302 if the client device 308 is unable to traverse the TA-defined distance at the predefined velocity 310 and within the predefined interval 312.
In a non-limiting example, the predefined velocity 310 may be a pedestrian velocity (also referred to herein as pedestrian velocity 310) that is up to three (3) miles per hour (mph), or 1.3 meters per second (m/s). In another non-limiting example, the predefined velocity 310 may be a nomadic velocity (also referred to herein as nomadic velocity 310) that is up to 5 mph, or approximately 2.2 m/s. The predefined interval 312, on the other hand, may be an interval between two consecutive examinations of an uplink communications signal 314 transmitted by the client device 308. For example, if a first examination and a second examination of the uplink communications signal 314 occur at times T0 and T1, respectively, the predefined interval 312 will then be equal to time T1 minus time T0 (T1−T0).
With continuing reference to
However, if the client device 308 is moving at the nomadic velocity 310 of 2.2 m/s and the predefined interval 312 remains as 50 s, then the client device 308 will be able to traverse one hundred ten meters (110 m) during the predefined interval 312. As a result, the first remote unit 300 and the second remote unit 302, which are separated by the TA-defined distance of 78 m, will become adjacent. In this regard, the likelihood of adjacency between the first remote unit 300 and the second remote unit 302 is inversely related to the TA-defined distance, but proportionally related to the predefined velocity 310 and the predefined interval 312. The longer the TA-defined distance is, the less likely the first remote unit 300 and the second remote unit 302 are adjacent. In contrast, the higher the predefined velocity 310 and the longer the predefined interval 312, the more likely the first remote unit 300 and the second remote unit 302 are adjacent. If the first remote unit 300 and the second remote unit 302 are separated by a relatively shorter TA-defined distance, for example less than one TA distance in air, it may be necessary to further separate the assigned unique identification temporal delays 204(1)-204(N) by more than one predefined TA step.
In this regard,
With reference to
Since the remote units 202(1)-202(N) are determined to be adjacent, the client device 308 of
To help overcome possible uplink propagation delay variations associated with the uplink communications signals 214(1)-214(N), a specified temporal delay separation X is defined to be more than one predefined TA step (X>1*(TA step)). The specified temporal delay separation X may be set according to environments in which the remote units 202(1)-202(N) are deployed. In a non-limiting example, the specified temporal delay separation X may be determined based on in-field measurements or experimental simulations.
With continuing reference to
For example, if the assigned unique identification temporal delay 204′(1) of the beginning remote unit 202(1) is one predefined TA step (1*(TA step)), the assigned unique identification temporal delay 204′(2) of the subsequent remote unit 202(2) shall differ from the assigned unique identification temporal delay 204′(1) by at least the specified temporal delay separation X. In other words, the assigned unique identification temporal delay 204′(2) shall at least be (1+X)*(TA step). The assigned unique identification temporal delay 204′(3) of the subsequent remote unit 202(3) shall differ from the assigned unique identification temporal delay 204′(2) by at least the specified temporal delay separation X. In other words, the assigned unique identification temporal delay 204′(3) shall at least be (1+2X)*(TA step). Likewise, the assigned unique identification temporal delay 204′(N) of the subsequent remote unit 202(N) shall differ from the assigned unique identification temporal delay 204′(N-1) (not shown) by at least the specified temporal delay separation X. In other words, the assigned unique identification temporal delay 204′(N) shall at least be (1+(N−1)X)*(TA step).
In a non-limiting example, the specified delay separation X may need to be three predefined TA steps (3*(TA step)) to provide adequate temporal delay separations between the plurality of assigned unique identification temporal delays 204′(1)-204′(N). Accordingly, if the assigned unique identification temporal delay 204′(1) is 1*(TA step), the assigned unique identification temporal delay 204′(2) will be four predefined TA steps (4*(TA step)), the assigned unique identification temporal delay 204′(3) will be seven predefined TA steps (7*(TA step)), and so on.
In this regard, in the examples previously described with reference to
With continuing reference to
In a non-limiting example, each of the delay elements 218(1)-218(N) may include digital circuitry (not shown) to delay a respective uplink communications signal among the uplink communications signals 214(1)-214(N) and/or a respective downlink communications signal among the downlink communications signals 210(1)-210(N) via digital signal processing. In another non-limiting example, each of the delay elements 218(1)-218(N) may include data buffers (not shown) to delay the uplink communications signals 214(1)-214(N) and/or the downlink communications signals 210(1)-210(N). In another non-limiting example, the WDS 200′ may be an optical fiber-based WDS. The downlink signal paths 212(1)-212(N) may be optical fiber-based downlink signal paths and the uplink signal paths 216(1)-216(N) may be optical fiber-based uplink signal paths. In this regard, the delay elements 218(1)-218(N) may be optical fiber-based delay elements that are provided in the optical fiber-based uplink signal paths and assigned to the remote units 202(1)-202(N), respectively. Each of the optical fiber-based delay elements is configured to delay a respective uplink communications signal communicated on a respective assigned optical fiber-based uplink signal path by the assigned unique identification temporal delay. For example, it may be possible to delay the respective uplink communications signal by the assigned unique identification temporal delay via increasing respective length of the respective assigned optical fiber-based uplink signal path.
According to previous discussions in
In this regard,
With reference to
The one or more first remote units 608(1,1)-608(1,N) are logically organized into a first sequential queue 612. In a non-limiting example, the one or more first remote units 608(1,1)-608(1,N) are organized according to an ascending order in the first sequential queue 612. In this regard, the first remote unit 608(1,1) is the beginning first remote unit in the first sequential queue 612 and the first remote unit 608(1,N) is the last remote unit in the first sequential queue 612. In the first sequential queue 612, the first remote unit 608(1,1) is the immediate preceding remote unit to the first remote unit 608(1,2), the first remote unit 608(1,2) is the immediate preceding remote unit to the first remote unit 608(1,3) (not shown), and the first remote unit 608(1,N-1) (not shown) is the immediate preceding remote unit to the first remote unit 608(1,N).
With continuing reference to
For example, if the assigned first unique identification temporal delay 614(1,1) of the beginning first remote unit 608(1,1) is 1*(TA step), the assigned first unique identification temporal delay 614(1,2) of the first remote unit 608(1,2) shall differ from the assigned first unique identification temporal delay 614(1,1) by the specified temporal delay separation X. In other words, the assigned first unique identification temporal delay 614(1,2) shall be (1+X)*(TA step). Likewise, the assigned first unique identification temporal delay 614(1,N) of the first remote unit 608(1,N) shall differ from the assigned first unique identification temporal delay 614(1,N-1) (not shown) by the specified temporal delay separation X. In other words, the assigned first unique identification temporal delay 614(1,N) shall be (1+(N−1)X)*(TA step). In a non-limiting example, if the specified temporal delay separation X is 3*(TA step) and the assigned first unique identification temporal delay 614(1,1) is 1*(TA step), the assigned first unique identification temporal delay 614(1,2) will be 4*(TA step), and so on.
The one or more second remote units 610(2,1)-610(2,M) are logically organized into a second sequential queue 616. In a non-limiting example, the one or more second remote units 610(2,1)-610(2,M) are organized according to an ascending order in the second sequential queue 616. In this regard, the second remote unit 610(2,1) is the beginning second remote unit in the second sequential queue 616 and the second remote unit 610(2,M) is the last remote unit in the second sequential queue 616. In the second sequential queue 616, the second remote unit 610(2,1) is the immediate preceding remote unit to the second remote unit 610(2,2), the second remote unit 610(2,2) is the immediate preceding remote unit to the second remote unit 610(2,3) (not shown), and the second remote unit 610(2,M-1) (not shown) is the immediate preceding remote unit to the second remote unit 610(2,M).
With continuing reference to
For example, if the assigned second unique identification temporal delay 618(2,1) of the beginning second remote unit 610(2,1) is 2*(TA step), the assigned second unique identification temporal delay 618(2,2) of the second remote unit 610(2,2) shall differ from the assigned second unique identification temporal delay 618(2,1) by the specified temporal delay separation X. In other words, the assigned second unique identification temporal delay 618(2,2) shall be (2+X)*(TA step). Likewise, the assigned second unique identification temporal delay 618(2,M) of the second remote unit 610(2,M) shall differ from the assigned second unique identification temporal delay 618(2,M-1) (not shown) by at least the specified temporal delay separation X. In other words, the assigned second unique identification temporal delay 618(2,M) shall be at least (2+(M−1)X)*(TA step). In a non-limiting example, if the specified temporal delay separation X is 3*(TA step) and the assigned second unique identification temporal delay 618(2,1) is 2*(TA step), then the assigned second unique identification temporal delay 618(2,2) will be 5*(TA step), and so on.
With continuing reference to
The WDS 600 also includes one or more first delay elements 628(1,1)-628(1,N) provided in the one or more first uplink signal paths 626(1,1)-626(1,N) and assigned to the one or more first remote units 608(1,1)-608(1,N), respectively. Each of the one or more first delay elements 628(1,1)-628(1,N) is configured to delay a respective first uplink communications signal among the one or more first uplink communications signals 624(1,1)-624(1,N) by a respective assigned first unique identification temporal delay among the one or more assigned first unique identification temporal delays 614(1,1)-614(1,N). As such, the location determination controller 402 will receive one or more delayed first uplink communications signals 624′(1,1)-624′(1,N). The one or more delayed first uplink communications signals 624′(1,1)-624′(1,N) are the same as the one or more first uplink communications signals 624(1,1)-624(1,N) but are delayed by the one or more first delay elements 628(1,1)-628(1,N) according to the one or more assigned first unique identification temporal delays 614(1,1)-614(1,N). The location determination controller 402 can analyze the one or more delayed first uplink communications signals 624′(1,1)-624′(1,N) to determine the one or more assigned first unique identification temporal delays 614(1,1)-614(1,N), respectively. The location determination controller 402 can then uniquely identify the one or more first remote units 608(1,1)-608(1,N) based on the one or more assigned first unique identification temporal delays 614(1,1)-614(1,N).
With continuing reference to
The WDS 600 also includes one or more second delay elements 638(2,1)-638(2,M) provided in the one or more second uplink signal paths 636(2,1)-636(2,M) and assigned to the one or more second remote units 610(2,1)-610(2,M), respectively. Each of the one or more second delay elements 638(2,1)-638(2,M) is configured to delay a respective second uplink communications signal among the one or more second uplink communications signals 634(2,1)-634(2,M) by a respective assigned second unique identification temporal delay among the one or more assigned second unique identification temporal delays 618(2,1)-618(2,M). As such, the location determination controller 402 will receive one or more delayed second uplink communications signals 634′(2,1)-634′(2,M). The one or more delayed second uplink communications signals 634′(2,1)-634′(2,M) are the same as the one or more second uplink communications signals 634(2,1)-634(2,M) but are delayed by the one or more second delay elements 638(2,1)-638(2,M) according to the one or more assigned second unique identification temporal delays 618(2,1)-618(2,M). The location determination controller 402 can analyze the one or more delayed second uplink communications signals 634′(2,1)-634′(2,M) to determine the one or more assigned second unique identification temporal delays 618(2,1)-618(2,M), respectively. The location determination controller 402 can then uniquely identify the one or more second remote units 610(2,1)-610(2,M) based on the one or more assigned second unique identification temporal delays 618(2,1)-618(2,M).
As previously discussed in
Subsequently, the one or more second remote units 610(2,1)-610(2,M) in the second remote unit cluster 604 are logically organized into the second sequential queue 616 (block 714). Next, the beginning second remote unit 610(2,1) at the head of the second sequential queue 616 is selected and assigned the assigned second unique identification temporal delay 618(2,1) that is greater than or equal to one predefined TA step (block 716). A test is then performed to determine if a second remote unit subsequent to the beginning second remote unit 610(2,1) exists in the second sequential queue 616 (block 718). If a second remote unit subsequent to the beginning second remote unit 610(2,1) exists in the second sequential queue 616, the second remote unit subsequent to the beginning second remote unit 610(2,1) is assigned a respective assigned second unique identification temporal delay that differs from the respective assigned second unique identification temporal delay of an immediate preceding second remote unit in the second sequential queue 616 by more than one predefined TA step (block 720). The steps in blocks 718 and 720 are repeated until the one or more assigned second unique identification temporal delays 618(2,1)-618(2,M) are assigned to the one or more second remote units 610(2,1)-610(2,M) in the second remote unit cluster 604, respectively.
With reference back to
In this regard,
With reference to
In a non-limiting example, the DX and the TA are configured to be eight point six predefined TA steps (8.6*(TA step)) and three tenths of the predefined TA step (0.3*(TA step)), respectively. Accordingly, the DT corresponding to the delayed uplink communications signal 214′ will be eight point nine predefined TA steps (8.9*(TA step)) according to Equation 2 above. To determine the radius 802, the location determination controller 402 first rounds the DT up to a nearest integer multiple of the predefined TA step. In this regard, the rounded-up DT (DT′) will equal nine predefined TA steps (9*(TA step)). Next, the location determination controller 402 determines a temporal delay offset by subtracting the DX from the DT′. In this regard, the temporal delay offset equals four tenths of the predefined TA step (0.4*(TA step)). The location determination controller 402 then multiplies the temporal delay offset by the speed of light to determine the radius 802. As previously discussed in
For example, one RIM 902 may be configured to support the Personal Communication Services (PCS) radio band. Another RIM 902 may be configured to support the 800 MHz radio band. In this example, by inclusion of these RIMs 902, the central unit 904 could be configured to support and distribute communications signals on both PCS and LTE 700 radio bands, as an example. RIMs 902 may be provided in the central unit 904 that support any frequency bands desired, including but not limited to the US Cellular band, Personal Communication Services (PCS) band, Advanced Wireless Services (AWS) band, 700 MHz band, Global System for Mobile communications (GSM) 900, GSM 1800, and Universal Mobile Telecommunications System (UMTS). The RIMs 902(1)-902(M) may also be provided in the central unit 904 that support any wireless technologies desired, including but not limited to Code Division Multiple Access (CDMA), CDMA200, 1xRTT, Evolution-Data Only (EV-DO), UMTS, High-speed Packet Access (HSPA), GSM, General Packet Radio Services (GPRS), Enhanced Data GSM Environment (EDGE), Time Division Multiple Access (TDMA), LTE, Integrated Digital Enhanced Network (iDEN), and Cellular Digital Packet Data (CDPD).
The RIMs 902(1)-902(M) may be provided in the central unit 904 that support any frequencies desired, including but not limited to US FCC and Industry Canada frequencies (824-849 MHz on uplink and 869-894 MHz on downlink), US FCC and Industry Canada frequencies (1850-1915 MHz on uplink and 1930-1995 MHz on downlink), US FCC and Industry Canada frequencies (1710-1755 MHz on uplink and 2110-2155 MHz on downlink), US FCC frequencies (698-716 MHz and 776-787 MHz on uplink and 728-746 MHz on downlink), EU R & TTE frequencies (880-915 MHz on uplink and 925-960 MHz on downlink), EU R & TTE frequencies (1710-1785 MHz on uplink and 1805-1880 MHz on downlink), EU R & TTE frequencies (1920-1980 MHz on uplink and 2110-2170 MHz on downlink), US FCC frequencies (806-824 MHz on uplink and 851-869 MHz on downlink), US FCC frequencies (896-901 MHz on uplink and 929-941 MHz on downlink), US FCC frequencies (793-805 MHz on uplink and 763-775 MHz on downlink), and US FCC frequencies (2495-2690 MHz on uplink and downlink).
With continuing reference to
The OIMs 908(1)-908(N) each include E/O converters to convert the downlink electrical communications signals 906D(1)-906D(R) into the downlink optical communications signals 910D(1)-910D(R). The downlink optical communications signals 910D(1)-910D(R) are communicated over downlink optical fiber communications medium 912D to a plurality of remote units 914(1)-914(S), which may be remote antenna units (“RAUs 914(1)-914(S)”). The notation “1-S” indicates that any number of the referenced component 1-S may be provided. O/E converters provided in the RAUs 914(1)-914(S) convert the downlink optical communications signals 910D(1)-910D(R) back into the downlink electrical communications signals 906D(1)-906D(R), which are provided to antennas 916(1)-916(S) in the RAUs 914(1)-914(S) to client devices (not shown) in the reception range of the antennas 916(1)-916(S).
E/O converters are also provided in the RAUs 914(1)-914(S) to convert uplink electrical communications signals 918U(1)-918U(S) received from client devices (not shown) through the antennas 916(1)-916(S) into uplink optical communications signals 910U(1)-910U(S). The RAUs 914(1)-914(S) communicate the uplink optical communications signals 910U(1)-910U(S) over an uplink optical fiber communications medium 912U to the OIMs 908(1)-908(N) in the central unit 904. The OIMs 908(1)-908(N) include O/E converters that convert the received uplink optical communications signals 910U(1)-910U(S) into uplink electrical communications signals 920U(1)-920U(S), which are processed by the RIMs 902(1)-902(M) and provided as uplink electrical communications signals 920U(1)-920U(S). The central unit 904 may provide the uplink electrical communications signals 920U(1)-920U(S) to a base station or other communications system.
Note that the downlink optical fiber communications medium 912D and uplink optical fiber communications medium 912U connected to each RAU 914(1)-914(S) may be a common optical fiber communications medium, wherein for example, wave division multiplexing (WDM) may be employed to provide the downlink optical communications signals 910D(1)-910D(R) and the uplink optical communications signals 910U(1)-910U(S) on the same optical fiber communications medium.
The WDS 200 of
With reference to
The computer system 1100 in this embodiment includes a processing circuit (“processor 1102”), a main memory 1104 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM), etc.), and a static memory 1106 (e.g., flash memory, static random access memory (SRAM), etc.), which may communicate with each other via a data bus 1108. Alternatively, the processor 1102 may be connected to the main memory 1104 and/or the static memory 1106 directly or via some other connectivity bus or connection. The main memory 1104 and the static memory 1106 may be any type of memory.
The processor 1102 may be a microprocessor, central processing unit, or the like. More particularly, the processor 1102 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing other instruction sets, or other processors implementing a combination of instruction sets. The processor 1102 is configured to execute processing logic in instructions for performing the operations and steps discussed herein.
The computer system 1100 may further include a network interface device 1110. The computer system 1100 also may or may not include an input 1112, configured to receive input and selections to be communicated to the computer system 1100 when executing instructions. The computer system 1100 also may or may not include an output 1114, including, but not limited to, a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device (e.g., a keyboard), and/or a cursor control device (e.g., a mouse).
The computer system 1100 may or may not include a data storage device that includes instructions 1116 stored in a computer-readable medium 1118. The instructions 1116 may also reside, completely or at least partially, within the main memory 1104 and/or within the processor 1102 during execution thereof by the computer system 1100, the main memory 1104 and the processor 1102 also constituting the computer-readable medium 1118. The instructions 1116 may further be transmitted or received over a network 1120 via the network interface device 1110.
While the computer-readable medium 1118 is shown in an exemplary embodiment to be a single medium, the term “computer-readable medium” should be taken to include a single medium or multiple mediums (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “computer-readable medium” shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the processing device and that cause the processing device to perform any one or more of the methodologies of the embodiments disclosed herein. The term “computer-readable medium” shall accordingly be taken to include, but not be limited to, solid-state memories, optical mediums, and magnetic mediums.
The embodiments disclosed herein include various steps. The steps of the embodiments disclosed herein may be formed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, the steps may be performed by a combination of hardware and software.
The embodiments disclosed herein may be provided as a computer program product, or software, that may include a machine-readable medium (or computer-readable medium) having stored thereon instructions, which may be used to program a computer system (or other electronic devices) to perform a process according to the embodiments disclosed herein. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable medium includes: a machine-readable storage medium (e.g., ROM, random access memory (“RAM”), a magnetic disk storage medium, an optical storage medium, flash memory devices, etc.), and the like.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the invention. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.
This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application No. 62/312,192, filed on Mar. 23, 2016, the content of which is relied upon and incorporated herein by reference in its entirety.
Number | Date | Country | |
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62312192 | Mar 2016 | US |