Redundant and fault tolerant das features

Abstract

Systems and methods for redundant and fault tolerant DAS features are described herein. In certain embodiments, a system includes a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system. Further, the multiple components include one or more master units configured to receive at least one signal from a signal source. The multiple components also include one or more remote units in communication with the one or more master units. Additionally, the one or more redundancy features comprise at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.

Description

Docket No. 6635 WO W1 / 376.2115WO01REDUNDANT AND FAULT TOLERANT DAS FEATURESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application Serial No. 63 / 693,548 entitled “REDUNDANT AND FAULT TOLERANT DAS FEATURES,” filed on September 11, 2024, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] A distributed antenna system (DAS) typically includes one or more central units or nodes (also referred to here as “central access nodes (CANs)” or “master units”) that are communicatively coupled to a plurality' of remotely located access points or antenna units (also referred to here as “remote units” or “radio units”). Each access point can be coupled directly to one or more of the central access nodes. Also, each access point can be coupled indirectly via one or more other remote units or via one or more intermediary or expansion units or nodes (also referred to here as “transport expansion nodes (TENs)”). A DAS is typically used to improve the coverage provided by one or more base stations coupled to the central access nodes. These base stations can be coupled to one or more central access nodes via one or more cables or via a wireless connection, for example, using one or more donor antennas. The wireless service provided by the base stations can include commercial cellular service or private or public safety wireless communications.

[0003] In general, each central access node receives one or more downlink signals from one or more base stations and generates one or more downlink transport signals derived from one or more of the received downlink base station signals. Each central access node transmits one or more dow nlink transport signals to one or more of the access points. Each access point receives the downlink transport signals transmitted to it from one or more central access nodes and uses the received downlink transport signals to generate one or more downlink radio frequency signals for radiation from one or more coverage antennas associated with that access point. The downlink radio frequency signals are radiated for reception by user equipment (UEs). Typically, the downlink radio frequency signals associated with each base station are simulcasted from multiple remote units. In this way, the DAS increases the coverage area for the downlink capacity provided by the base stations.Docket No. 6635 WO W1 / 376.2115WO01

[0004] Likewise, each access point receives one or more uplink radio frequency signals transmited from the user equipment. Each access point generates one or more uplink transport signals derived from the uplink radio frequency signals and transmits the uplink transport signals to one or more of the central access nodes. Each central access node receives the respective uplink transport signals transmited to it from one or more access points and uses the received uplink transport signals to generate one or more uplink base station radio frequency signals that are provided to the one or more base stations associated with that central access node. Typically, receiving the uplink signals involves, among other things, summing uplink signals received from the multiple access points to produce the base station signal provided to each base station. In this way, the DAS increases the coverage area for the uplink capacity provided by the base stations.

[0005] A DAS can use either digital transport, analog transport, or combinations of digital and analog transport for generating and communicating the transport signals between the central access nodes, the access points, and any transport expansion nodes.

[0006] Traditionally, a DAS is operated in a “full simulcast” mode in which downlink signals for each base station are transmited from multiple access points of the DAS and in which uplink signals for each base station are generated by summing uplink data received from the multiple access points.

[0007] The 3GPP fifth generation (5G) radio access network (RAN) architecture includes a set of base stations (also referred to as “gNBs”) connected to the 5G core network (5GC) and to each other. Each gNB typically comprises three entities — a centralized unit (CU), a distributed unit (DU), and a set of one or more radio units (RUs). The CU can be further split into one or more CU control plane entities (CU- CPs) and one or more CU user plane entities (CU-UPs). The functions of the RAN can be split among these entities in various ways. For example, the functional split between the DU and the RUs can be configured so that the DU implements some of the Layer- 1 processing functions (for the wireless interface), and each RU implements the Layer- 1 functions that are not implemented in the DU as well as the basic RF and antenna functions. The DU is coupled to each RU using a fronthaul network (for example, one implemented using a switched Ethernet network) over which data is communicated between the DU and each RU. The data includes, for example, user-Docket No. 6635 WO W1 / 376.2115WO01 plane data (for example, in-phase and quadrature (IQ) data representing time-domain or frequency-domain symbols). One example of such a configuration is a “cloud radio access network” or “cloud RAN” configuration in which each CU and DU are associated with multiple RUs.SUMMARY

[0008] Systems and methods for redundant and fault tolerant DAS features are described herein. In certain embodiments, a system includes a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system. Further, the multiple components include one or more master units configured to receive at least one signal from a signal source. The multiple components also include one or more remote units in communication with the one or more master units. Additionally, the one or more redundancy features comprise at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Drawings accompany this description and depict only some embodiments associated with the scope of the appended claims. Thus, the described and depicted embodiments should not be considered limiting in scope. The accompanying drawings and specification describe the exemplary embodiments, and features thereof, with additional specificity and detail, in which:

[0010] FIG. 1 is a block diagram of a distributed antenna system according to an aspect of the present disclosure;

[0011] FIGS. 2A-2D is a block diagram of components of a DAS implementing N+l network connections according to an aspect of the present disclosure;

[0012] FIG. 3 is a block diagram of components of a DAS implementing MIMO splitting along a single communication path according to an aspect of the present disclosure;Docket No. 6635 WO W1 / 376.2115WO01

[0013] FIG. 4 is a block diagram of components of a DAS implementing MIMO splitting across multiple communication paths according to an aspect of the present disclosure;

[0014] FIGS. 5A and 5B are block diagrams of components of a DAS implementing MIMO to SISO with air combining according to an aspect of the present disclosure;

[0015] FIG. 6 is a block diagram of a DAS incorporating redundant components according to an aspect of the present disclosure;

[0016] FIG. 7 is a block diagram of remote units arranged in a ring topology according to an aspect of the present disclosure;

[0017] FIGS. 8A-8D are block diagrams illustrating RUs that implement redundant switching between different connections according to an aspect of the present disclosure; and

[0018] FIG. 9 is a flow diagram of a method for implementing redundancy according to an aspect of the present disclosure.

[0019] Per common practice, the drawings do not show the various described features according to scale, but the drawings show the features to emphasize the relevance of the features to the example embodiments.DETAILED DESCRIPTION

[0020] The following detailed description refers to the accompanying drawings that form a part of the present specification. The drawings, through illustration, show specific illustrative embodiments. However, it is to be understood that other embodiments may be used and that logical, mechanical, and electrical changes may be made.

[0021] Systems and embodiments for implementing redundant and fault tolerant features within distributed antenna systems (DASs) are described herein. As disclosed herein, a DAS may be coupled to a distribution unit and include a master unit, one or more aggregation switches, one or more access switches, and one or more remote units. Additionally, the DAS may include redundant features to increase the tolerance of the DAS to operational faults of the DAS components or of components connected to the DAS.Docket No. 6635 WO W1 / 376.2115WO01

[0022] Typically, a DAS is a system used to distribute signals between base stations and remote radio units. The remote radio units are associated with coverage areas, where the remote radio units can distribute signals to user equipment within the coverage areas. Often, multiple base stations associated with multiple sectors are routed through a DAS to communicate with user equipment in multiple coverage areas.

[0023] Often, a DAS includes multiple system elements that are connected using various topologies. Depending on the topology, the failure of one or more system elements or of connections between the components can affect the ability of base stations to communicate through the DAS. For example, failures in components or connections can lead to outages that can range in severity from a failure of a single remote unit to an entire system failure. A DAS is often a critical part of communication infrastructures for the associated coverage areas. Redundancy and fault-tolerant features can help prevent component failures from significantly affecting communications between the base stations and user equipment associated with coverage areas.

[0024] FIG. 1 is a block diagram of an exemplary DAS 100 in communication with multiple distribution units (or base stations). While a DAS could be employed using multiple different topologies, the topology illustrated in FIG. 1 is provided as an example for supporting the description of redundant and fault-tolerant features within a DAS. As illustrated, the DAS 100 is in communication with multiple distribution units or base stations 120, which communicate through the DAS 100 with user equipment (not shown) within coverage areas in communication with the remote units 107. There may be multiple coverage areas associated with the position of the remote units 107.

[0025] In certain embodiments, the DAS 100 includes one or more master units 101. The master units 101 provide physical and logical interfaces for connecting to the base stations 120. As shown, multiple base stations 120 can be connected to a master unit 101. When connected to multiple base stations 120, the master unit 101 can combine user data from the connected base stations 120 onto one or more high-speed network connections. Additionally, the master units 101 may be virtual master units executing on a processor or other computer. Alternatively, the master units 101 mayDocket No. 6635 WO W1 / 376.2115WO01 be physical devices connected to the base stations 120 and other components within the DAS 100.

[0026] As illustrated, the master units 101 are each in communication with one or more base stations 120. The base stations 120 may represent base stations that are connected to the DAS 100. While multiple base stations 120 are shown, the DAS 100 may also be connected to a single base station 120. The DAS 100 is coupled to one or more base stations 120 to improve the coverage provided by the base stations 120. That is. each base station 120 is configured to provide wireless capacity’, whereas the DAS 100 is configured to provide improved wireless coverage for the wireless capacity provided by the base stations 120. As used here, unless otherwise explicitly indicated, references to a “base station” include both (1) a “complete” base station that interfaces with the DAS 100 using the analog radio frequency (RF) interface that would otherwise be used to couple the complete base station to a set of antennas as well as (2) a first portion of a base station (such as a baseband unit (BBU), distributed unit (DU), or similar base station entity) that interfaces with the DAS 100 using a digital fronthaul interface that would otherwise be used to couple that first portion of the base station 120 to a second portion of the base station 120 (such as a remote radio head (RRH), radio unit (RU), or similar radio entity). In the latter case, different digital fronthaul interfaces can be used (including, for example, a Common Public Radio Interface (CPRI) interface, an evolved CPRI (eCPRI) interface, an IEEE 1914.3 Radio-over-Ethemet (RoE) interface, a functional application programming interface (FAPI) interface, a network FAPI (nF API) interface), or an O-RAN fronthaul interface) and different functional splits can be supported (including, for example, functional split 8, functional split 7-2, and functional split 6). The O-RAN Alliance publishes various specifications for implementing RANs in an open manner. (“O- RAN” is an acronym that also stands for “Open RAN,” but in this description references to “O-RAN” should be understood to be referring to the O-RAN Alliance and / or entities or interfaces implemented in accordance with one or more specifications published by the O-RAN Alliance.)

[0027] Each base station 120 coupled to the DAS 100 can be co-located with the master unit 101 to which it is coupled. A co-located base station 120 can be coupled to the master unit 101 to which it is coupled using one or more point-to-point links (for example, where the co-located base station 120 comprises a 4G LTE BBUDocket No. 6635 WO W1 / 376.2115WO01 supporting a CPRI fronthaul interface, the 4G LTE BBU can be coupled to the master unit 101 using one or more optical fibers that directly connect the BBU to the master unit 101) or a shared network (for example, where the co-located base station 120 comprises a DU supporting an Ethernet-based fronthaul interface (such as an O-RAN or eCPRI fronthaul interface), the co-located DU can be coupled to the master unit 101 using a switched Ethernet network). Each base station 120 coupled to the DAS 100 can also be located remotely from the master unit 101 to which it is coupled. A remote base station 120 can be coupled to the master unit 101 to which it is coupled via a wireless connection (for example, by using a donor antenna to wirelessly couple the remote base station 120 to the master unit 101 using an analog RF interface) or via a wired connection (for example, where the remote base station 120 comprises a DU supporting an Ethernet-based fronthaul interface (such as an O-RAN or eCPRI fronthaul interface), the remote DU can be coupled to the master unit 101 using an Internet Protocol (IP)-based network such as the Internet).

[0028] In additional embodiments, the DAS 100 includes an aggregation switch 103. The aggregation switch 103 functions as a physical and logical interface for the one or more master units 101. For example, the aggregation switch 103 is in communication with the one or more master units 101 through a physical interface, such as an Ethernet port. Alternatively, the aggregation switch 103 may function as an interface on a device executing the master units 101. The aggregation switch 103 functions as a switch that allows user data from connected master units 101 to be appropriately directed through a fronthaul network to other components within the DAS 100. Also, the aggregation switch 103 can also include a copy / combine function that can receive user data that allows data to be communicated between the base stations 120 and user equipment in coverage areas associated with radio units. In some embodiments, the aggregation switch 103 can be implemented as a physical switch or a virtual switch.

[0029] In further embodiments, the DAS 100 includes one or more copy / combine access switches 105 coupled to one or more aggregation switches 103. An access switch 105 functions as a physical and logical interface for the aggregation switch 103. For example, the access switch 105 is in communication with the one or more aggregation switches 103 through a physical interface. The access switch 105 may connect to one or more remote units. Further, in the downlink direction, the access switch 105 may perform a copy function. Additionally, in the uplink direction, theDocket No. 6635 WO W1 / 376.2115WO01 access switch 105 may perform a combine functionality. Thus, the access switch 105 enables the simulcasting of data from the base station 120 to remote units connected to the access switch 105.

[0030] In certain embodiments, the DAS 100 includes one or more remote units 107. The remote units 107 connect to the access switch 105 through a physical and logical interface. In the downlink direction, a remote unit 107 performs digital -to-analog conversion of user data for transmission to user equipment in a coverage area associated with the remote unit 107. In the uplink direction, a remote unit 107 performs analog-to-digital conversion of signals received from user equipment in the associated coverage area for conveyance to one or more of the base stations 120.

[0031] As shown, the DAS 100 includes multiple components and connections that are used to convey signals between the base stations 120 and user equipment in the coverage areas associated with the DAS 100. When components within the DAS 100 fail, user equipment may become unable to communicate with the base stations 120 through the DAS 100. Accordingly, a DAS 100 may include redundant features to prevent outages that result from the failure of components in the DAS 100.

[0032] FIGs. 2A-2D illustrate the implementation of N+l network connection redundancy between components of the DAS 100. In particular, FIGs. 2A-2D are exemplary block diagrams of connections between an aggregation switch 203 and an access switch 205. While the connections are shown as being between an aggregation switch 203 and an access switch 205, the netw ork connections may be between other components or intermediate nodes of a DAS. Additionally, the aggregation switch 203 and the access switch 205 may operate similarly to the aggregation switch 103 and the access switch 105 in FIG. 1.

[0033] FIG. 2A illustrates an aggregation switch 203 and an access switch 205 connected to each other in normal operation in a non-redundant configuration. A component within the DAS may have one or more ports that can connect to cables for communicating with other components in the DAS. In some implementations, each port, and the cable connections between different ports of different components, maybe associated with different traffic. For example, as shown in FIG. 2A, an aggregation switch 203. and an access switch 205 may each have two ports through which separate cable connections 211-1 and 211-2 connect the ports to one another. Further,Docket No. 6635 WO W1 / 376.2115WO01 the different ports and associated connections 211-1 and 211-2 are associated with different communication traffic. In particular, first communication traffic is communicated through the first connection 21 1-1, and second communication traffic is communicated through the second connection 211-2. During normal operation, the aggregation switch and access switch are able to communicate data across both the first connection 211-1 and the second connection 211-2.

[0034] FIG. 2B illustrates an aggregation switch 203 and access switch 205 connected to each other in a non-redundant configuration when one of the connections experiences a failure. For example, the second connection 211-2 may experience a failure that causes the second connection 21 1-2 to become unusable. When the second connection 211-2 becomes unusable, traffic is only transmissible across the first connection 211-1. The failure of the second connection 211-2 may lead to a substantial decrease in capacity through the DAS and may cause the failure of the DAS to provide adequate communications into a coverage area.

[0035] FIG. 2C illustrates an aggregation switch 203 and access switch 205 having an idle backup connection 221-3 in addition to a first connection 221-1 and a second connection 221-2. In a similar manner to the first connection 211-1 described in FIG. 2A. the first connection 221-1 may initially be used for the transmission of first communication traffic between the aggregation switch 203 and the access switch 205. Also similar to the second connection 211-2 described in FIG. 2A, the second connection 221-2 may initially be used for the transmission of second communication traffic between the aggregation switch 203 and the access switch 205. When the first connection 221-1 and the second connection 221-2 are in use. the third connection 221-3 may initially be idle.

[0036] FIG. 2D illustrates an aggregation switch 203 and access switch 205 having an idle backup connection 221-3, where one of the active connections experiences a failure. For example, as shown, the second connection 221-2 may experience a failure that causes the second connection to become unusable. When the second connection 221-2 becomes unusable, circuitry within the aggregation switch 203 and the access switch 205 may identify monitor the operation and performance of the second connection 221-2 and determine that the aggregation switch 203 is no longer adequate for the transmission of second communication traffic. Accordingly, circuitry in the aggregation switch 203 and the access switch 205 may then transfer the secondDocket No. 6635 WO W1 / 376.2115WO01 communication traffic from the second connection 221-2 to the idle backup connection 221-3. Accordingly, the DAS may be able to use the idle backup connection 221-3 to maintain capacity and performance in the event of a connection failure between different nodes (like the aggregation switch 203 and the access switch 205) of the DAS.

[0037] FIG. 3 is a block diagram illustrating a DAS 310 having redundant protections that employ multiple input multiple output (MIMO) splitting. A DAS 310 may employ MIMO to enhance data transmission rates, reliability and overall system capacity. In particular, different components may transmit separate data streams within different MIMO channels within the same frequency band between different nodes and utilize various techniques to separate and decode the data streams at the receiver. Because multiple data streams may be transmitted between different nodes, MIMO techniques can be used to increase channel capacity. For example, the system 300 may include a DAS 310 that communicates with multiple DUs 320, which can perform some of the functions of a base station 120.

[0038] As illustrated, each of the DUs 320 may communicate with a MU 301 in a DAS 310 through multiple MIMO channels. For example, a first DU 320 may communicate through MIMO A channels with the MU 301 and a second DU 320 may communicate through MIMO B channels with the MU 301. As shown, both the first DU 320 and the second DU 320 may communicate through 4x4 MIMO channels. However, the first DU 320 and the second DU 320 may communicate through other MIMO configurations.

[0039] While it is desirable to use all the MIMO signals for communication from a DU 320 through a DAS 310 with a UE, a DU 320 may still successfully communicate with a UE when not all MIMO signals are available. For example, with 2x2 MIMO, a DU 320 may communicate with a UE through a single MIMO signal, and with 4x4 MIMO, a DU 320 may communicate with a UE through two MIMO signals, although at lesser data rates. Thus, a system can provide redundancy to a MIMO channel by ensuring that at least some of the available MIMO signals are available when a portion of the system experiences a failure.

[0040] In certain embodiments, the DAS 310 may include multiple communication links between the various components of the DAS 310. For example, the DAS 310Docket No. 6635 WO W1 / 376.2115WO01 may include multiple communication links between the MU 301 and any connected aggregation switches 303, multiple communication links between aggregation switches 303 and any access switches 305. The access switches 305 may then be connected to respective remote units 307 that communicate directly with UEs within respective coverage areas. While only one of each component is shown, it is intended to be understood that the various components illustrated may have multiple connections with multiple other components. For example, the MU 301 may have multiple connections to multiple aggregation switches 303 and vice versa. Also, the MU 301 may be directly connected to one or more access switches 305.

[0041] In some potential implementations, if signals for a MIMO channel from one of the DUs 320 were wholly transmitted on one of the communication links between the MU 301, an aggregation switch 303. and an access switch 305, then a failure on any one of the communication links would cause the associated DU 320 to be unable to communicate through the DAS 310 using the associated IMO channel. Accordingly, the DAS 310 may split the signals for a MIMO channel from the DUs 320 onto different communication links between the components of the DAS 310. For example, a first DU 320 may send four signals associated with MIMO channel A and a second DU 320 may send four signals associated with MIMO channel B. After the MU 301 receives the signals from both the first and second DUs 320, the MU 301 may split portions of the signals from MIMO channel A and MIMO channel B onto a first communication link between the MU 301 and other components in the DAS 310 and portion of the signals from MIMO channel A and MIMO channel B onto a second communication link between the MU 301 and other components in the DAS 310. For example, the MU 301 may communicate signals 1 and 2 from MIMO channel A and signals 3 and 4 from MIMO channel B on the first communication link between the MU 301 and an aggregation switch 303. Also, the MU 301 may communicate signals 3 and 4 from MIMO channel A and signals 1 and 2 from MIMO channel B on the second communication link between the MU 301 and an aggregation swatch 303.

[0042] Accordingly, when a communication link within the DAS 310 experiences a failure, a DU 320 is still able to communicate with UEs through the DAS 310. For example, if the second communication link betw een the aggregation switch 303 and the access switch 305 (carrying signals 3 and 4 from MIMO channel A and signals 1 and 2 from MIMO channel B) w ere to experience a failure, then the first DU 320Docket No. 6635 WO W1 / 376.2115WO01 would still be able to communicate using signals 1 and 2 from MIMO channel A on the first communication link, and the second DU 320 would be able to communicate using signals 3 and 4 from MIMO channel B on the first communication link. Thus, splitting signals from a MIMO channel onto different communication links may increase the redundancy of the DAS 310 against failures of communication links between components.

[0043] In further embodiments, some signals from the DUs 320 may be critical for reception by the UEs. For example, it is critical that synchronization signals from the DUs 320 be transmitted from the RUs 307 to UEs. However, some synchronization signals from the DUs 320 may be associated with signals on a MIMO channel that are assigned to only one of potential communication links between the components of the DAS 310. Thus, if the critical signals are assigned to a single communication link between the components and the component experiences a failure, there is a risk that the failure can prevent the transmission of the critical signal from the RUs 307. Accordingly, the MU 301 and other components of the DAS 310 may identify critical signals, like synchronization signals, and then replicate the critical signals on the available communication links between components of the DAS 310. Thus, the critical signals are provided for transmission to or reception from the RUs 307 when a communication link between one of the components of the DAS 310 experiences a failure.

[0044] FIG. 4 is an additional block diagram illustrating a further implementation of MIMO splitting when a DAS 410 has separate equipment paths 430-1 and 430-2 within the DAS 410, where the DAS 410 functions similarly to the DAS 310 described above in FIG. 3. However, each equipment path 430-1 and 430-2 respectively include separate MUs 401-1 and 401-2, aggregation switches 403-1 and 403-2, access switches 405-1 and 405-2, and RUs 407-1 and 407-2. Each DU 420 connects to separate equipment paths 430-1 and 430-2. When the DAS 410 includes multiple equipment paths 430-1 and 430-2, the DAS 410 may implement MIMO splitting.

[0045] In certain embodiments, the MUs 401 or other components within the DAS 410 may split half of the MIMO signals communicated with a DU 420 for transport through the other equipment path. For example, the MU 401-1 of the first equipment path 430-1 may connect to a first DU 420 through MIMO channel A and the MU 401-Docket No. 6635 WO W1 / 376.2115WO012 of the second equipment path 430-2 may connect to a second DU 420 through MIMO channel B. The MU 401-1 may exchange half of the MIMO signals for the MIMO channel A for transport through the second equipment path 430-2 and the MU 401-2 may exchange half of the MIMO signals from the MIMO channel B for transport through the first equipment path 430-1 1. Accordingly, half of the MIMO signals for MIMO channel A and half of the MIMO signals for MIMO channel B may be transported through the first equipment path 430-1. Further, half of the MIMO signals for MIMO channel A and half of the MIMO signals for the MIMO channel B may be transported through the second equipment path 430-2. Accordingly, the components of the respective equipment paths transport mixed signals from multiple MIMO channels.

[0046] In further embodiments, the RUs 407 may also split MIMO signals communicated with UEs with components of the DAS 410 in the other equipment path. For example, the RU 407-1 may exchange half of the signals for MIMO channel A communicated with UEs with the access switch 405-2 and the RU 407-2 may exchange half of the signals for MIMO channel B communicated with UES with the access switch 405-1. Thus, by exchanging the half of the signals at the RUs 407-1 and 407-2, the RUs may communicate signals associated with the appropriate DU 420. Additionally, critical signals may be transmitted through both equipment paths 430-1 and 430-2. Thus, MIMO splitting into different equipment paths 430-1 and 430-2 may also provide redundant protections against the failure of different communication links within a particular equipment path.

[0047] FIGs. 5A and 5B are block diagrams illustrating an RU 507 that relies on air combining when providing redundancy for MIMO communications. For example, FIG. 5A illustrates an RU 507 that is 2x2 MIMO capable. The RU 507 may function in a similar manner to the RU 107 described in FIG. 1. Further, as the RU 507 is 2x2 MIMO capable, the RU 507 may receive two MIMO signals through a MIMO channel. Also, the RU 507 may include a switch 511 that directs a first MIMO signal to a first amplifier 513 and directs a second MIMO signal to a second amplifier 513. The first and second amplifiers 513 may then direct the first and second signals into a coverage area through antennas for reception by at least one UE.

[0048] However, when a component in the DAS that provides signals to the RU 507 fails, the RU 507 may receive a single MIMO signal. As each amplifier 513 isDocket No. 6635 WO W1 / 376.2115WO01 associated with separate MIMO signals, the loss of a MIMO signal may result in one of the amplifiers 513 becoming idle. However, as illustrated in FIG. 5B, when the RU 507 only receives a single MIMO signal, the switch 511 may provide the single MIMO signal to both the first and second amplifiers 513. By providing the same MIMO signal to both amplifiers 513, the signals emitted by the antennas may combine with each other in the air, leading to an increase in the power of the single MIMO signal received by the UE. While FIG. 5B illustrates the replication of the MIMO signal within a 2x2 MIMO system, the techniques described herein apply to higher order MIMO systems as well. For example, in a 4x4 MIMO channel, a switch may replicate two received signals for transmission through four antennas.

[0049] Returning to FIG. 1, the DAS 100 may have multiple network links that connect the various components to one another. Each of the network links potentially may experience a failure. For example, a network link may fail due to a port failure, a fiber failure, a cable failure, or other types of failures. When one of these network links fails, the DAS 100 may continue operating if the traffic carried by the DAS 100 is reduced below the available bandwidth. When the available bandwidth of the DAS 100 is reduced, the DAS 100 may then prioritize types of communication to reduce the bandwidth needs of the traffic carried by the DAS 100. In particular, the DAS 100 may implement one or more different methods to reduce the bandwidth needs of the traffic.

[0050] In some embodiments, the DAS 100 may disable some of the communication channels based on some pre-defined criteria. For example, criteria like signal quality on the channel, the ty pe of data communicated through the channel, among other criteria that can be used to identify whether at least one channel of several channels should be disabled. When a channel is identified for being disabled, the MU 101 may communicate with a DU within a base station 120 such that the DU disables the transmission of the identified channels. Alternatively, the DAS 100 may simply stop the routing of the channels identified for disabling.

[0051] In additional embodiments, the DAS 100 may disable communication bands based on some pre-defined criteria. For example, the criteria may include the usage proportion of certain communication bands. If the use of the communication band is below a pre-defined threshold, the communication band may be disabled.Alternatively, a communication band may disable a band based on other criteria suchDocket No. 6635 WO W1 / 376.2115WO01 as signal quality among other criteria that can be used to identify a communication band for disabling. When a band is identified for being disabled, the MU 101 may communicate with a DU within a base station 120 such that the DU disables the transmission of the identified channels. Alternatively, the DAS 100 may simply stop the routing of the channels identified for disabling.

[0052] Also, the DAS 100 may give priority' to channels of some operators over the channels of others. For example, an operator may own the DAS 100 or have a contract that gives it higher priority than other operators. Alternatively, the channels of some operators may be used more than the channels of other operators. When bandwidth needs to be reduced, communications from the lesser used operators may be disabled. When an operator is identified for being disabled, the MU 1-1 may communicate with a DU within a base station 120 such that the DU disables communications associated with the identified operator. Alternatively, the DAS 100 may disable communications associated with the identified operator.

[0053] In further embodiments, the DAS 100 may reduce the MIMO order. For example, 4x4 MIMO channels may be reduced to 2x2 MIMO channels. Also, modulation and coding schemes could be changed to reduce bandwidth needs. For example, 256-QAM may be reduced to 64-QAM or 16-QAM. Further, channel bandwidth may be reduced to change configurations to smaller bandwidth channels to reduce total bandw idth needs. For example, bandwidth for a channel operating w ith a bandwidth of 100 MHz may be reduced to a bandwidth of 50 MHz. The changes to MIMO order, modulation and coding schemes, and bandwidth needs may be made within a DU. Alternatively, the changes may be made within the DAS 100. Changes to the operation of the DAS 100 that reduce the bandwidth needs coupled with traffic prioritization may help the DAS 100 provide sendee to operators that meet the more important performance objectives.

[0054] In some embodiments, the DAS 100 may be connected to multiple DUs that provide sectors of channels for distribution to the RUs 107. Each channel from a DU is typically simulcast to multiple RUs 107. For instance, assume there are five DUs, and each DU provides four sectors of coverage for one channel (twenty sectors total), and each sector / channel is simulcast to four RUs 107 (80 RUs 107 total). If one DU fails, then four sectors will be lost, and eight RUs will have no channels assigned to them. In some implementations, a DAS 100 may compensate for the lost sectors byDocket No. 6635 WO W1 / 376.2115WO01 placing the RUs which were connected through the switches to the DUs that failed into a simulcast group associated with one of the remaining DUs that were still working properly. Thus, post failure, a simulcast size of ten of the remaining eighteen sectors would be increased from four to five, with the RUs previously connected to the failed DU, now connected to one of the remaining DUs.

[0055] FIG. 6 is a block diagram illustrating a DAS 600 that includes redundant or backup hardware. For example, the DAS 600 may include one or more MUs 601 that may function similar to the one or more MUs 101 discussed in FIG. 1. Additionally, the DAS 600 may also include an aggregation switch 603 that functions similar to the aggregation switch 103, one or more access switches 605 that function similar to the access switch 105, and one or more RUs 607 that are similar to the RUs 107. In contrast to the DAS 100, the DAS 600 may include redundant hardware components to provide improved fault tolerance.

[0056] For example, the DAS 600 may include one or more backup switches. For example, the DAS 600 may include a backup aggregation switch 604. As shown, the backup switches may be placed in parallel with operational switches. For example, the aggregation switch 603 may be connected to multiple system elements (MUs 601 and access switches 605) within the DAS 600, and the backup aggregation switch 604 may be connected to the same multiple system elements within the DAS 600. If the operational aggregation switch 603 fails, the DAS 600 may route the traffic through the aggregation switch 603 through the backup aggregation switch 604.

[0057] In an alternative embodiment, during initial operation, a DAS 600 may divide the traffic associated with a primary element between a primary element and a backup element. When one of the primary element and the backup element experiences a failure, the DAS 600 may route the traffic that was routed through the failed element onto the element that remains operable. For example, the DAS 600 may route a portion of the traffic associated with the aggregation switch 603 through the aggregation switch 603 and a portion through backup aggregation switch 604. When one of the aggregation switch 603 and the backup aggregation switch 604 experiences a failure, the DAS 600 may route the traffic through the failed component onto the operable component, such that all the traffic associated with the aggregation switch 603 is passing through the operable component. While the redundancy is illustrated in connection with the aggregation switch 603. other components (such as the MUs 601,Docket No. 6635 WO W1 / 376.2115WO01 access switches 605, and the RUs 607) within the DAS 600 may include similar redundant components.

[0058] Further, one or more of the components within the DAS 600 may receive power from one or more power supplies 609. Power supplies are often the subassemblies for a DAS with the highest failure rate. Thus, if a power supply 609 fails and the power supply 609 is non-redundant, components within the DAS 600 that receive power from the power supply 609 may also fail. Accordingly, the DAS 600 may also receive power from a backup power supply 610 in the event that the power supply 609 fails. For example, when the power supply 609 fails, the DAS 600 may then switch to receive power from the backup PS 610.

[0059] In an additional embodiment, only some of the components in the DAS 600 may receive power from redundant power supplies. For example, the redundant power supplies 609 and 610 may provide power to components that receive higher levels of traffic. For example, the redundant power supplies 609 and 610 may provide power to the aggregation switches 603, master units 601, access switches 605 and other components. Other components that receive lesser traffic levels may receive power from a non-redundant power supply.

[0060] Further, some components within the DAS 600 may receive power from the power supply 609 and other components within the DAS 600 may receive power from the backup power supply 610. When one of the power supply 609 and the backup power supply 610 experiences a failure, the DAS 600 may use the remaining operational power supply to provide power to the components associated with the failed power supply. For example, the aggregation switch 604 receives power from the power supply 609, and the MUs 601 receive power from the backup power supply 610. When the power supply 609 fails, the DAS 600 may then switch the aggregation switch 603 to receive power from the backup power supply 610. Using the various configurations of the power supply 609 and the backup power supply 610, the DAS 600 may inure the operation of the DAS against the negative effects of power supply failures.

[0061] Additionally, a DAS may employ various topologies of remote units to increase fault tolerance. For example, FIG. 7 illustrates a senes of RUs 707 that are connected to an access switch 705 in a ring topology. In a ring topology, two RUs 707Docket No. 6635 WO W1 / 376.2115WO01 may connect to an access switch 705. The two RUs 707 connected to the access switch 705 are each connected to additional RUs 707 such that multiple RUs 707 are connected in a ring 700, where each RU 707 in the ring 700 are connected to two RUs 707 and the RUs 707 connected to the access switch 705 form the ends of the ring 700. Further, the network connections between the RUs 707 in the ring 700 may have sufficient bandwidth to carry the traffic for all the RUs 707 in the ring 700.

[0062] In a certain embodiment, by arranging the RUs 707 in a ring 700, each RU 707 may have two communication paths back to the access switch 705. Thus, if one of the communication paths between the access switch and any one of the RUs 707 were to fail, then the remaining path can be used to provide a path between the RUs 707 and the access switch 705. Further, the topology may be useful when the RUs 707 in the ring 700 are simulcasting the same signals, meaning that each RU 707 in the ring 700 transmits the same downlink signal, and each RU 707 calculates intermediate sums in the uplink direction. When the RUs 707 in the ring 700 simulcast the same signals, the bandwidth needs do not increase in either the downlink or uplink direction.

[0063] FIGs. 8-11 illustrate block diagrams of DAS components, where an RU within the DAS receives multiple connections from one or more components within the DAS. For example, the RU may receive multiple connections from a single component, where one of the connections functions as a redundant connection in a similar manner as described above in connection with FIGS. 2A-2D. Alternatively, the RU may receive multiple connections from multiple components, where at least one of the components functions as a redundant component in a similar manner as described above in connection with FIG. 6.

[0064] In some implementations, where a DAS includes one or more master units or other DAS components that are communicatively coupled with one or more remote antenna units, where each remote antenna unit can be coupled directly to one or more of the master units or indirectly via one or more other remote antenna units and / or via one or more intermediary or expansion units, the DAS can be used to improve the coverage provided by one or more base stations that are coupled to the master units. These base stations can be coupled to the master units via one or more cables or via a wireless connection, for example, using one or more donor antennas. The wireless service provided by the base stations can include commercial cellular service and / orDocket No. 6635 WO W1 / 376.2115WO01 private or public safety wireless communications as described above in connection with FIG. 1.

[0065] When planning for providing coverage for tunnels, buildings, train stations, airports, stadiums and similar facilities where public safety is a concern, it is important to maintain DAS communication within the coverage area in the facility during emergency events. Thus, a DAS may be provisioned where remote units are connected to a master unit using two redundant cables (for example, optical fibers or wired connections) that are laid through two different, spatial separated, independent areas.

[0066] In some implementations, the DAS may use optical link redundancy (OLR), which provides for multiple optical paths or links between an MU and an RU, where one path functions as a main optical link and at least one other optical path functions as a redundant optical link. Alternatively, the DAS may use optical fiber redundancy (OFR), where an optical switch switches between the different optical fibers laid beside each other. Further, when a DAS is a digital system, digital signal processing and selection methods may be used to provide additional redundancy options between an RU and other components within a DAS.

[0067] FIG. 8A illustrates a block diagram of a portion of a DAS 800 that includes an MU 801 connected to an RU 807 through multiple connections. The RU 807 may monitor the status of the connections between the MU 801 and the RU 807, where the RU 807 is able to switch between the different connections based on the status of the connections between the RU 807 and the MU 801.

[0068] In certain embodiments, the MU 801 may be one of multiple MUs within the DAS 800, where each MU in the DAS 800 is communicatively coupled to one or more RUs 807 via one or more cable pairs 845, where each pair 845 includes a main (i.e. primary) cable 845-1 and a parallel coupled substitute (i.e. secondary’, backup, or redundant) cable 845-2 that can serve as a backup cable to maintain connectivity from one or more MUs 801 to the RU 807 in the event that the primary' cable 845-1 fails to provide sufficient capabilities due to degradation, faults, or other situations that negatively affect the ability’ of the primary cable 845-1 to provide adequate performance. Each remote unit 807 can be communicatively coupled directly to one or more of the MUs 801 or indirectly via one or more other remote units 807 and / orDocket No. 6635 WO W1 / 376.2115WO01 via one or more intermediary or expansion units (like an aggregation switch or access switch as described above).

[0069] Each MU 801 is also communicatively coupled to one or more base stations (such as the base stations 120 connected to MUs 101, illustrated in FIG. 1). In some implementations, one or more of the base stations can be co-located with a respective MUs 801 to which it is coupled (for example, where the base station is dedicated to providing base station capacity to the DAS 800 and is coupled to the respective MUs 801). Also, one or more of the base stations can be located remotely from a respective MU 801 to which it is coupled (for example, where the base station provides base station capacity' to an area beyond the coverage area of the DAS 800). In this latter case, the MU 801 can be coupled to a donor antenna and repeater or bi-directional amplifier in order to wirelessly communicate with the remotely located base station.

[0070] In some implementations, a base station may be used to provide public and / or private safety wireless services (for example, wireless communications used byemergency services organizations (such as police, fire and emergency medical services) to prevent or respond to incidents that harm or endanger persons or property ). Such base stations may be referred to as “safety- wireless sen-ice base stations” or “safety base stations.” The base stations may also, in addition to safety base stations, be used to provide commercial cellular wireless service. Such base stations are also referred to here as “commercial wireless service base stations” or “commercial base stations.” The base stations can be coupled to an MU 801 such that the MU 801 can output the desired set or RF channels in the downlink and in the upstream, the MU 801 can provide the desired set of carriers to the base station.

[0071] As shown in FIG. 8A, in general, each MU 801 includes a system processor 821 among other circuitry that is configured to receive one or more downlink signals from one or more base stations. These signals are also referred to here as “base station downlink signals.” Each base station downlink signal includes one or more radio frequency- channels used for communicating in the downlink direction with user equipment (UE) (such as tablets or cellular telephone, for example) over the relevant wireless air interface. Typically, each base station downlink signal is received as an analog radio frequency signal, though in some embodiments one or more of the base station signals are received in a digital form (for example, in a digital baseband form complying with the Common Public Radio Interface (“CPRI”) protocol, Open RadioDocket No. 6635 WO W1 / 376.2115WO01Equipment Interface (“ORI”) protocol, the Open Base Station Standard Initiative (“OBSAI”) protocol, or other protocol). The system processor 821 in each MU 801 is also configured to generate one or more downlink transport signals derived from the one or more base station downlink signals and to transmit one or more downlink transport signals to one or more of the RUs 807. While the DAS 800 illustrates the system processor 821 as being configured to receive the base station downlink signal and to generate the downlink transport signals, the DAS 800 may also include additional downlink circuitry (such as analog circuitry) configured to perform at least a portion of the functions ascribed to the system processor 821.

[0072] Additionally, the system processor 821 of the MU 801 may be configured to receive the respective uplink transport signals transmitted to it from one or more RUs 807 and to use the received uplink transport signals to generate one or more base station uplink radio frequency signals that are provided to one or more base stations 140 in communication with the master unit 110. Typically, this involves, among other things, combining or summing uplink signals received from multiple RUs 807 in order to produce the base station signal provided to each base station. Each base station uplink signal includes one or more of the uplink radio frequency channels used for communicating with user equipment over the wireless air interface. In this way, the DAS 800 increases the coverage area for the uplink capacity provided by a base station. While the DAS 800 illustrates the system processor 821 as being configured to receive the uplink transport signals and to generate the base station uplink radio frequency signals, the DAS 800 may also include additional uplink circuitry (such as analog circuitry) configured to perform at least a portion of the functions ascribed to the system processor 821.

[0073] In certain embodiments, to provide the downlink transport signals to the RU 807 and to receive the uplink transport signals from the RU 807, the MU 801 may include multiple optical transport (OPT) cards 823, where each OPT card 823 is associated with one of the cables 845 connecting the MU 801 to a RU 807. Thus, one of the OPT cards 823 may function as a primary OPT card 823-1 and a secondary OPT card 823-2. In particular, the primary' OPT card 823-1 may be associated with the primary cable 845-1 and the secondary OPT card 823-2 may be associated with the secondary cable. As used herein, an OPT card 823 may refer to a module used in networking equipment that is used to facilitate optical signal transmissions betweenDocket No. 6635 WO W1 / 376.2115WO01 the MU 801 and the RU 807. The OPT card 823 may be able to convert electrical signals from the system processor 821 into optical signals for transmission to the RU 807. Also, the OPT card 823 may be able to convert optical signals received from the RU 807 into electrical signals for processing by the system processor 821. In implementations described herein, the system processor 821 provides the generated downlink transport signals to both the primary OPT card 823-1 and the secondary’ OPT card 823-2. Alternatively, the system processor 821 may provide the generated downlink transport signals to only one OPT card 823 that is currently active.

[0074] In additional embodiments, to facilitate the communication of optical signals between the MU 801 and the RU 807, each OPT card 823 may include a small formfactor pluggable (SFP) module 825. As used herein, an SFP module 825 may refer to a network interface module format that is commonly used in networking. Additionally, the SFP module 825 may be an SFP+ module, which is an enhanced SFP module. The SFP module 825 is used to connect network devices to optical networks. For example, the primary’ SFP module 825-1 connects the primary’ OPT card 823-1 to the primary' cable 845-1 and the secondary' SFP module 825-2 connects the secondary’ OPT card 823-2 to the secondary cable 845-2.

[0075] In certain embodiments, an RU 807 connected to the MU 801 through the primary' cable 845-1 and the secondary' cable 845-2 may also include RU SFP modules 827 configured to facilitate communications between a baseband card of the RU 807 and the MU 801. For example, the RU 807 may include a primary RU SFP module 827-1 connected to the primary cable 845-1 and a secondary RU SFP module 827-2 connected to the secondary cable 845-2. As illustrated, each of the RU SFP modules 827 may include one or more LEDs that emit an optical indicator as a control and status (C / S) signal or detect a received optical signal and emit an electrical signal as the C / S signal. The control and status signal may be used to indicate whether a particular RU SFP module 827 is transmitting data, operational, experiencing an error condition, or other SFP status.

[0076] In further embodiments, when the RU 807 receives an optical signal through one of the RU SFP modules 827, the respective RU SFP module 827 will transform the optical signal into an electrical signal, where the electrical signal is provided to an ethemet IP 831. The Ethernet IP 831 then encapsulates the data received from the respective RU SFP module 827 for ensuring the data is formatted correctly forDocket No. 6635 WO W1 / 376.2115WO01Ethernet communication. Also, when the RU 807 transmits an optical signal through one of the RU SFP modules 827, the respective Ethernet IP 831 will receive Ethernet IP communications and decapsulate the data and provide the data as an electrical signal to the associated SFP module 827. The associated SFP module 827 then converts the electrical signal into an optical signal for transmission across the associated cable 845.

[0077] In additional embodiments, the RU 807 includes an Ethernet switch 833, wherein the downlink outputs from the one or more Ethernet IPs 831 are coupled into the Ethernet switch 833. Also, the uplink outputs from the switch are coupled into one of the Ethernet IPs 831. The Ethernet switch 833 as used herein switches between the different Ethernet IPs 831 and selects which Ethernet IP 831 (and associated cable 845) will be used for communication with a UE through the RU 807. In some implementations, the Ethernet switch 833 may be a gigabit media independent interface (GMII) used to connect the media access control layer and the physical layer. In particular, the Ethernet switch 833 may connect the Ethernet communications received from the Ethernet IPs 831 for transmission from the RU 807 to UEs within a coverage area. Additionally, the Ethernet switch 833 includes a recovery clock 835 that receives synchronization signals from each of the Ethernet IPs 831.

[0078] In certain embodiments, when switching between the Ethernet IPs 831, the Ethernet switch 833 may need to synchronize communications. When establishing the connection between an Ethernet IP 831 and the UE. The Ethernet switch 833 may include a recovery clock 835 for synchronizing communications through the RU 807. For example, signals received from one of the Ethernet IPs 831 may include an embedded clock signal, that is received by the recovery clock 835. When the recovery clock 835 receives the clock signal, the recovery clock 835 may extract the embedded clock signal to synchronize itself with the communications and also pass on the signal as a reference clock to other downstream devices that operate on the same clock signal. The synchronization of the clock may be performed according to one of multiple timing protocols, like Synchronous Ethernet (SyncE), precision time protocol (PTP), and the like. Often times, the recovery clock 835 may use phase-locked loops (PLLs) to lock onto the frequency of incoming signals to generate a stable clock signal that is synchronized with incoming data, where the acquired stable clock signalDocket No. 6635 WO W1 / 376.2115WO01 is used to synchronize the switch and downstream devices with the received communications. As shown, the recovery clock 835, may perform the synchronization process, when the Ethernet switch 833 switches between different Ethernet IPs 831.

[0079] In additional embodiments, the Ethernet switch 833 may be coupled to a framer / deframer 839. The framer / deframer 839 receives Ethernet IP data from the Ethernet switch 833. In the downlink direction, the framer / deframer 839 may segment and encapsulate the Ethernet IP data for subsequent modulation and transmission through an RF channel. Further, the digital RF data is then provided to an ADC / DAC 841 that converts the digital RF data into an analog signal for modulation and transmission through an antenna(s) 843. In the uplink direction, the framer / deframer 839 may receive digital RF data from the ADC / DAC 841, where the framer / deframer 839 decapsulates the RF data and reassembles the data into Ethernet frames for communication as Ethernet IP data.

[0080] In some implementations, the RU 807 includes a processor 829 that is configured to control the operation of some of the components on the RU 807. Also, the processor 829 may be configured to monitor the C / S optical indicators of the SFP modules 827 to identify the operational status of the cables 845 connected to the RU 807 through the SFP modules 827. Accordingly, the processor 829 or other monitoring circuitry within the RU 807 may determine whether the RU 807 is receiving data through one or more of the SFP modules 827. Thus, the processor 829 may determine when one of the links between the RU 807 and the MU 801 experiences a fault. For example, the MU 801 may communicate the same signal across both the primary cable 845-1 and the secondary cable 845-2. Alternatively, the MU 801 may only communicate with the RU 807 over one of the cables 845.

[0081] In certain embodiments, to implement the redundancy afforded by the multiple cables 845, a first cable 845-1 may connect the MU 801 to the RU 807 through first SFP modules 825-1 and 827-1. Additionally, a second cable 845-2 may connect the MU 801 to the RU 807 through second SFP modules 825-2 and 827-1. However, the MU 801 will communicate IP data through only the first cable 845-1. Further, the MU 801 will establish IP communications with the RU 807 through the first cable 845-1, establishing the end of transmission group (EOTG), initialization of the RU 807, joining the RU 807 to a network, path calculation with the RU 807, and synchronizing communications through the RU 807.Docket No. 6635 WO W1 / 376.2115WO01

[0082] In the event the RU 807 loses communications with the MU 801 through the first cable 845-1. the light on the first SFP module 827-1 may turn off. As the processor 829 or other circuit device on the RU 807 monitors the light and determines that the light is off, the processor 829 may determine that communication across the first cable 845-1 has failed. Alternatively, where the SFP module provides an electrical C / S signal, the processor 829 may determine that the communications have failed based on the received C / S signal. The processor 829 will then direct the Ethernet switch 833 to switch to the communication path through the second cable 845-2. Also, the Ethernet switch 833 will switch the recovery clock 835 to the clock signal from the second Ethernet IP 831-2. After switching, the MU 801 will attempt to establish communications with the RU 807 through the second cable 845-2, which will require the re-establishment of the EOTG, initialization joining, path calculation, and synchronization.

[0083] The process of establishing communications with the RU 807 through the second cable 845-2 may take some time, for example, up to five minutes. Upon establishing a connection through the second cable 845-2. the RU 807 may send an alarm to the MU 801 to indicate that the connection through the first cable 845-1 was lost. If the first SFP module 827-1 indicates that the first cable 845-1 has become active after a failure, the RU 807 may then notify the MU 801 that the first cable 845- 1 is available again for communication. When the first cable 845-1 becomes available again, the MU 801 may send a command to the RU 807 to switch back to communicating through the first cable 845-1. Alternatively, the MU 801 and the RU 807 may continue communicating through the second cable 845-2, using the first cable 845-1 as a redundant cable. Thus, the two cables 845-1 and 845-2 can function together to provide a redundant connection betw een the MU 801 and the RU 807.

[0084] FIG. 8B illustrates a block diagram of a portion of a DAS 800 that includes a first MU 801-1 and a second MU 801-2 connected to a single RU 807 through separate connections 845-1 and 845-2. As illustrated, each of the first MU 801-1 and the second MU 801-2 may function in a similar manner to the MU 801 described in FIG. 8A. Also, the RU 807 may function in a similar manner to the RU 807 described in FIG. 8A. While only two MUs 801 are illustrated, an RU 807 may also connect to more MUs 801 based on the number of connective interfaces provided by the RU 807.Docket No. 6635 WO W1 / 376.2115WO01

[0085] In contrast to the system illustrated in FIG. 8A, where a single MU 801 is connected through redundant cables to an RU 807, FIG. 8B illustrates a system where each cable 845 is associated with a different MU 801. For example, a first MU 801-1 connects to the RU 807 through a first cable 845-1 and a second MU 801-2 connects to the RU 807 through a second cable 845-2. Accordingly, the first MU 801-1 and the second MU 801-1 may also provide redundancy in addition to the redundancy provided by the first cable 845-1 and the second cable 845-2. For example, the first MU 801-1 and the second MU 801-1 may be connected to equipment belonging to the same sendee provider.

[0086] In certain embodiments, to implement the redundancy afforded by the multiple cables 845 and multiple MUs 801, a first cable 845-1 may connect the first MU 801-1 to the RU 807 through first SFP modules 825-1 and 827-1. Additionally, a second cable 845-2 may connect the second MU 801-2 to the RU 807 through second SFP modules 825-2 and 827-1. However, the RU 801 may only receive communications from the first MU 801-1 through the first cable 845-1. The second MU 801-2 may function as a backup MU for situations where the first MU 801-1 is unavailable. Further, the first MU 801-1 will establish IP communications with the RU 807 through the first cable 845-1, establishing the end of transmission group (EOTG), initialization of the RU 807, joining the RU 807 to a network, path calculation with the RU 807, and synchronizing communications through the RU 807.

[0087] In the event the RU 807 loses communications with the first MU 801-1, the first SFP module 827-1 will provide a C / S signal indicating the failure of the communications. As the processor 829 or other circuit device on the RU 807 monitor the C / S signal, the processor 829 may determine that communication across the first cable 845-1 has failed. The processor 829 will then direct the Ethernet switch 833 to switch to the communication path through the second cable 845-2 that is connected to the second MU 801-1. Also, the Ethernet switch 833 will switch the recovery clock 835 to the clock signal from the second Ethernet IP 831-2 connected to the second SFP module 827-2. After switching, the second MU 801-1 may attempt to establish communications with the RU 807 through the second cable 845-2, which will require the re-establishment of the EOTG, initialization joining, path calculation, and synchronization.Docket No. 6635 WO W1 / 376.2115WO01

[0088] The process of establishing communications with the second MU 801-1 through the second cable 845-2 may take some time, for example, up to five minutes. Upon establishing a connection through the second cable 845-2, the RU 807 may send an alarm to the second MU 801-2 to indicate that the connection through the first cable 845-1 was lost. The second MU 801-2 may then relay the alarm or related information to the service provider associated with the first MU 801-1 and the second MU 801-2. After switching to the second MU 801-2. if the RU 807 detects that the first SFP module 827-1 again indicates that there is an active connection, the RU 807 may notify the second MU 801-2 that the first cable 845-1 is available again for communication. In response to detecting the active C / S signal from the first SFP module 827-1, the RU 807 may also switch back to communicating through the first cable 845-1 and reestablish communications with the first MU 801-1. Alternatively, when notifying the second MU 801-1, the second MU 801-1 may notify a service provider that the first MU 801-1 is again available for communication. In response the service provider may notify the second MU 801-1 to direct the RU 807 to switch to communicating with the first MU 801-1 or continue communicating through the second cable 845-2 with the second MU 801-2. Thus, the RU 807 is able to maintain a redundant connection with multiple MUs 801.

[0089] FIG. 8C illustrates a block diagram of a portion of a DAS 800 that includes an MU 801 connected to an RU 807c through multiple connections. The RU 807c may monitor the status of the connections between the MU 801 and the RU 807c, where the RU 807c is able to switch between the different connections based on the status of the connections between the RU 807c and the MU 801. As shown, the MU 801 functions substantially as described in connection with FIG. 8A. Additionally, the MU 801 may be replaced with multiple MUs as described in connection with FIG. 8B.

[0090] In certain embodiments, the RU 807c may be designed to operate without an Ethernet switch (like Ethernet switch 833) that switches between the two paths that connect the RU 807c to the MU 801. In contrast, the RU 807c includes separate framer / deframers 839. In particular, the RU 807c includes a first framer / deframer 839-1 associated with the first Ethernet IP 831-1 and first cable 845-1. Also, the RU 807c includes a second framer / deframer 839-2 associated with the second Ethernet IP 831-2 and second cable 845-2.Docket No. 6635 WO W1 / 376.2115WO01

[0091] In some embodiments, the MU 801 transmits the same signals through both the first cable 845-1 and the second cable 845-2. As such, when both cables 845-1 and 845-2 are operational, the Ethernet IP 831-1 and the Ethernet IP 831-2 are both receiving Ethernet data from the MU 801. Additionally, as the RU 807c lacks an Ethernet switch, the signals received by the first Ethernet IP 831-1 and the second Ethernet IP 831-2 are provided directly to respective framer / deframers 839. In particular, the first ethemet IP 831-1 is coupled to a first framer / deframer 839-1 and the second ethemet IP 831-2 is coupled to a second framer / deframer 839-2. The first framer / deframer 839-1 and the second framer / deframer 839-2 work substantially similar to the framer / deframer 839 described above in connection FIG. 8 A. Thus, each of the first framer / deframer 839-1 and the second / deframer 839-2 function to convert downlink data from Ethemet data into RF data and to convert uplink data from RF data to Ethemet data.

[0092] When the first Ethemet IP 831-1 and the framer / deframer 839-1 receives data from the MU 801, the first Ethemet IP 831-1 and the framer / deframer 839-1 may perform the initialization processes discussed above (EOTG, joining, RF sync, path calibration, etc.). Also, the second Ethemet IP 831-1 and the framer / deframer 839-1 may also perform the initialization processes because they are also receiving data from the MU 801. The recovery clock 835, may receive the clock from both the first ethemet IP 831-1 and the second Ethemet IP 831-2. When the RU 807c is coupled to a single MU 801, the timing provided by the MU 801 is the same through both the first Ethemet IP 831-1 and the second Ethemet IP 831-2. Thus, the recovery clock 835 can use either signal to provide a reference clock for synchronizing communications. However, when the RU 807c is coupled to multiple MUs 801, the timing received by the recovery clock 835 may differ. As such, the RU 807c may perform some synchronization tasks when switching between different MUs 801. Alternatively, the RU 807c may store identified delay values for each connected MU 801. When switching, the processor 829 may use the stored delay value associated with the associated MU 801 to adjust the signal timing as needed.

[0093] In some embodiments, to control switching between the redundant paths, the RU 807c may include a downlink (DL) / uplink (UL) switch 847. The DL / UL switch 847 may be controlled by the processor 829 or other circuitry to connect to one of the redundant communication paths. For example, in the DL direction, the DL / UL switchDocket No. 6635 WO W1 / 376.2115WO01847 is connected to the currently active communication path. In the UL direction, a UL switch associated with the active communication path is opened and closed based on the timing of received UL messages. Accordingly, as the processor 829 controls the DL / UL switch 847, the processor 829 may also control which communication path from the MU 801 is active within the RU 807c.

[0094] In certain embodiments, to implement the redundancy afforded by the multiple cables 845 connected to the RU 807c, a first cable 845-1 may connect the MU 801 to the RU 807c through first SFP modules 825-1 and 827-1. Additionally, a second cable 845-2 may connect the MU 801 to the RU 807c through second SFP modules 825-2 and 827-1. The MU 801 then communicates IP data through both the first cable 845-1 and the second cable 845-1 with the RU 807c. Further, the MU 801 will establish IP communications along the first cable 845-1 with the first Ethernet IP 831-1 and first framer / deframer 839-1 and along the second cable 845-2 with the second Ethernet IP 831-2 and second framer / deframer 839-1. The MU 801 and RU 807c establish the IP communications along both communication paths by initializing Ethernet communications. As communications are established through both communication paths, the processor 829 controls the DL / UL switch 847 to select the first communication path through the first cable 845-1.

[0095] In the event the RU 807 loses communications with the MU 801 through the first cable 845-1, the first SFP module 827-1 provides a C / S signal indicating the loss of communications. As the processor 829 or other circuit device on the RU 807 monitors the C / S signal from the first SFP module 827-1, the processor 829 may determine that communication across the first cable 845-1 has failed. The processor 829 will then direct the DL / UL switch 847 to switch to the second communication path through the second cable 845-2. After switching, as communications are already initialized through the second Ethernet IP 831-2 and the second framer / deframer 839- 2, switching from the first communication path to the second communication path is faster than the embodiment described above with respect to FIGs. 8A and 8B. Further, the processor 829 may change the delay by retrieving a delay value stored in a register on the RU 807c.

[0096] Upon establishing a connection through the second cable 845-2, the RU 807c may send an alarm to the MU 801 to indicate that the connection through the first cable 845-1 was lost. If the RU 807c detects an active C / S signal again from the firstDocket No. 6635 WO W1 / 376.2115WO01SFP module 827-1, the RU 8O7c may then notify the MU 801 that the first cable 845- 1 is available again for communication. When the first cable 845-1 becomes available again, the MU 801 may send a command to the RU 807c to switch back to communicating through the first cable 845-1. Alternatively, the MU 801 and the RU 807c may continue communicating through the second cable 845-2, using the first cable 845-1 as a redundant cable. Thus, the two cables 845-1 and 845-2 can function together to provide a redundant connection between the MU 801 and the RU 807c. Additionally, as both paths are initialized at the beginning of operation, switching between the different communication paths may be performed quickly.

[0097] FIG. 8D illustrates a block diagram of a portion of a DAS 800 that includes an MU 801 connected to an RU 807d through multiple connections. The RU 807d may monitor the status of the connections between the MU 801 and the RU 807D. However, in contrast to the RU 807c, where the RU 807c controls a switch between different connections based on the status of the connections between the RU 807c and the MU 801, the RU 807d includes a combiner 849 that combines the signals received from the different communication paths between the RU 807d and the MU 801. As shown, the MU 801 functions substantially as described in connection with FIG. 8 A. Additionally, the MU 801 may be replaced with multiple MUs as described in connection with FIG. 8B.

[0098] In certain embodiments, the RU 807d includes a combiner 849. In the downlink direction, the combiner 849 may combine the RF data produced by the different framer / deframers 839 in the RU 807d for conversion to analog signals by the ADC / DAC 841 and transmission to UEs through the antenna 843. For example, a first framer / deframer 839-1 may provide a first digital RF signal to the combiner 849 and a second framer / deframer 839-2 may provide a second digital RF signal to the combiner 849, and the combiner 849 combines the two signals into a single signal. When the signals are received from multiple MUs 801 (as shown in FIG. 8B). the processor 829 may also apply timing delays to one or both of the signals so they correspond with one another in time. The processor 829 may acquire the timing delays from registers ono the RU 807d. Alternatively, the processor 829 may determine the delays using synchronization signals transmitted according to timing protocols. In the uplink direction, uplink signals bypass the combiner 849 and are coupled to bothDocket No. 6635 WO W1 / 376.2115WO01 framer / deframers 839 from the ADC / DAC 841. The uplink signals may then be transmitted to the MU 801 or multiple MUs 801 as described above.

[0099] In further embodiments, to implement the redundancy afforded by the multiple cables 845 connected to the RU 807d, a first cable 845-1 may connect the MU 801 to the RU 807d through first SFP modules 825-1 and 827-1. Additionally, a second cable 845-2 may connect the MU 801 to the RU 807d through second SFP modules 825-2 and 827-1. The MU 801 then communicates IP data through both the first cable 845-1 and the second cable 845-1 with the RU 807c. Further, the MU 801 will establish IP communications along the first cable 845-1 with the first Ethernet IP 831- 1 and first framer / deframer 839-1 and along the second cable 845-2 with the second Ethernet IP 831-2 and second framer / deframer 839-1. The MU 801 and RU 807c establish the IP communications along both communication paths by initializing Ethernet communications. The different downlink communications signals are also combined by the combiner 849.

[0100] In the event the RU 807d loses communications with the MU 801 through the first cable 845-1, the first SFP module 827-1 may provide a C / S signal indicating the failure. As the processor 829 or other circuit device on the RU 807 monitors the C / S signal from the first SFP module 827-1, the processor 829 may determine that communication across the first cable 845-1 has failed. As the signal from the second cable 845-2 is still present, the signal will still be provided through the RU 807d for transmission to a UE. The processor 829 may send an alarm to the MU 801 to indicate that the connection through the first cable 845-1 was lost. If the RU 807c detects the a C / S signal indicating an active connection again from the first SFP module 827-1, the RU 807c may then notify the MU 801 that the first cable 845-1 is available again for communication. As no switching occurs after a failure and initialization occurs at the beginning of operation, the redundancy provided may be near seamless with little time needed to implement the redundancy.

[0101] FIG. 9 is a flowchart diagram of a method 900 for implementing redundant features within a DAS. In particular, the method 900 proceeds at 901. where one or more master units in a distributed antenna system are configured to receive at least one signal from a signal source. Further, the method 900 proceeds at 903, where one or more remote units in the distributed antenna system are configured to communicate with the one or more master units. Additionally, the method 900 proceeds at 905.Docket No. 6635 WO W1 / 376.2115WO01 where one or more redundancy features are implemented within the distributed antenna system that incorporate at least one of one or more sets of redundant components and one or more sets of redundant connections.

[0102] In certain embodiments described herein, some of the functionality and components of the DAS 100, base stations 124, operators, and other external systems in communication with the DAS 100 may be or incorporate computation devices, such as a processor, that controls the operation of the DAS 100, monitors the performance of the DAS 100, and collects performance statistics for the DAS 100. The computation devices, that aid in performing the systems and methods described herein, may incorporate one or more computation devices, such as a processor, that implement some of the redundant functionality' described herein. The computation devices may be implemented using software, firmware, hardware, or an appropriate combinations thereof. A processor and other computational devices may be supplemented by, or incorporated in, specially-designed application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). The computational devices can also include or function with software programs, firmware, or other computer-readable instructions for carrying out various process tasks, calculations, and control functions used in the methods and systems described herein.

[0103] The methods described herein may be implemented by computer-executable instructions or code, such as program modules or components, which are executed by at least one processor. Generally, program modules include routines, programs, objects, data components, data structures, algorithms, and the like, which perform particular tasks or implement particular abstract data types.

[0104] Instructions for carrying out the various process tasks, calculations, and generation of other data used in the operation of the methods described herein can be implemented in software, firmware, or other computer-readable instructions. These instructions are typically stored on appropriate computer program products that include computer-readable media used to store computer-readable instructions or data structures. Such a computer-readable medium may be available media that can be accessed by a general-purpose or special-purpose computer or processor, or any programmable logic device.Docket No. 6635 WO W1 / 376.2115WO01

[0105] Suitable computer-readable storage media may include, for example, nonvolatile memory devices including semi-conductor memory devices such as Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory devices; magnetic disks such as internal hard disks or removable disks; optical storage devices such as compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs; or any other media that can be used to carry or store desired program code in the form of computer-executable instructions or data structures.Example Embodiments

[0106] Example 1 includes a system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; and one or more remote units in communication with the one or more master units; wherein the one or more redundancy features comprise at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.

[0107] Example 2 includes the system of Example 1, wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

[0108] Example 3 includes the system of Example 2, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

[0109] Example 4 includes the system of Example 3, wherein at least one of the remote unit and a component in the multiple components is configured to: detect a failure of an active connection in the one or more active connections; switch theDocket No. 6635 WO W1 / 376.2115WO01 communications associated with the active connection to the at least one redundant connection; and initialize the communications through the at least one redundant connection.

[0110] Example 5 includes the system of any of Examples 3-4, wherein the one or more second components comprise an active component and redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

[0111] Example 6 includes the system of Example 5, wherein the remote unit stores delay values associated with the one or more active connections between the remote unit and the active component and the at least one redundant connection between the remote unit and the redundant component.

[0112] Example 7 includes the system of any of Examples 3-6, wherein the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active; wherein at least one processor on the remote unit monitors the status signal and determines whether a connection is failed based on the status signal.

[0113] Example 8 includes the system of any of Examples 3-7, wherein the remote unit is configured to: simultaneously receive a transmission over the one or more active connections and the at least one redundant connection when both the one or more active connections and the at least one redundant connection are operational; and initialize the communications for both the one or more active connections and the at least one redundant connection.

[0114] Example 9 includes the system of Example 8, wherein the remote unit is configured to: couple to the one or more active connections; and upon determining that the one or more active connections has failed couple to the at least one redundant connection.

[0115] Example 10 includes the system of any of Examples 8-9, wherein the remote unit is configured to combine the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.Docket No. 6635 WO W1 / 376.2115WO01

[0116] Example 11 includes the system of any of Examples 1-10. wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel; wherein the at least one MIMO channel is split into different portions, wherein each portion is conveyed on different connections in the multiple connections between the one or more master units and the one or more remote units.

[0117] Example 12 includes the system of Example 11, wherein the different connections are between same devices.

[0118] Example 13 includes the system of any of Examples 11-12, wherein the different connections are between different devices.

[0119] Example 14 includes the system of any of Examples 1-13. wherein a remote unit in the one or more remote units is configured to receive a MIMO channel, where each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams, the remote unit is further configured to emit the portion of the available MIMO streams from more than one antenna in the multiple antennas.

[0120] Example 15 includes the system of any of Examples 1-14. wherein when a failure occurs within the distributed antenna system, the distributed antenna system is configured to prioritize communication traffic through the distributed antenna system, wherein the distributed antenna system is configured to at least one of: disable at least one communication channel through the distributed antenna system; disable communication bands through the distributed antenna system; wherein channels from multiple operators are conveyed through the distributed antenna system, give at least one channel associated with at least one operator in the multiple operators precedence over other channels; reduce MIMO order of the at least one communication channel; change a modulation and coding scheme for the at least one communication channel; and reduce bandwidth of the at least one communication channel.

[0121] Example 16 includes the system of any of Examples 1-15. wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the multiple components; where a component in the multiple components fails, assigning remote units in a simulcast group associated with the component to other simulcast groups.Docket No. 6635 WO W1 / 376.2115WO01

[0122] Example 17 includes the system of any of Examples 1-16. wherein the one or more redundancy features include at least one active component in the multiple components and at least one redundant component in the multiple components, wherein functionality of the at least one active component is performed by the at least one redundant component when the at least one active component experiences a failure.

[0123] Example 18 includes the system of Example 17, wherein the at least one active component and the at least one redundant component are switches.

[0124] Example 19 includes the system of any of Examples 17-18, wherein the at least one active component and the at least one redundant component each carry a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences a failure, routing the traffic through the at least one active component and the at least one redundant component that remains operational.

[0125] Example 20 includes the system of any of Examples 17-19, wherein the at least one active component and the at least one redundant component are redundant power supplies.

[0126] Example 21 includes the system of Example 20, wherein the redundant power supplies provide power to components within the distributed antenna system associated with higher traffic loads.

[0127] Example 22 includes the system of any of Examples 1-21, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

[0128] Example 23 includes a method comprising: configuring one or more master units in a distributed antenna system to receive at least one signal from a signal source; configuring one or more remote units in the distributed antenna system to communicate with the one or more master units; and implementing one or more redundancy features within the distributed antenna system that incorporate at least one of one or more sets of redundant components and one or more sets of redundant connections.

[0129] Example 24 includes the method of Example 23, wherein implementing the one or more redundancy features comprises: establishing one or more activeDocket No. 6635 WO W1 / 376.2115WO01 connections between a first component of the distributed antenna system and one or more second components of the distributed antenna system; maintaining at least one redundant connection between the first component and the one or more second components; and upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

[0130] Example 25 includes the method of Example 24, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

[0131] Example 26 includes the method of Example 25, further comprising: detecting a failure of an active connection in the one or more active connections; switching the communications associated with the active connection to the at least one redundant connection; and initializing the communications through the at least one redundant connection.

[0132] Example 27 includes the method of any of Examples 25-26. wherein the one or more second components comprise an active component and a redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

[0133] Example 28 includes the method of Example 27, further comprising storing delay values associated with the one or more active connections between the remote unit and the active component and the at least one redundant connection between the remote unit and the redundant component.

[0134] Example 29 includes the method of any of Examples 25-28, when the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active, further comprising: monitoring the status signal; and determining whether a connection is failed based on the status signal.

[0135] Example 30 includes the method of any of Examples 25-29, further comprising: simultaneously receiving a transmission over the one or more active connections and the at least one redundant connection w hen both the one or moreDocket No. 6635 WO WI / 376.2115WO01 active connections and the at least one redundant connection are operational; and initializing the communications for both the one or more active connections and the at least one redundant connection.

[0136] Example 31 includes the method of Example 30, further comprising: coupling the remote unit to the one or more active connections; determining that the one or more active connections has failed; and coupling the remote unit to the at least one redundant connection via an uplink / downlink switch.

[0137] Example 32 includes the method of any of Examples 30-31, further comprising combining the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.

[0138] Example 33 includes the method of any of Examples 23-32. wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel, further comprising: splitting the at least one MIMO channel into different portions; and conveying each portion in the different portions on different connections between the one or more master units and the one or more remote units.

[0139] Example 34 includes the method of Example 33, wherein the different connections are between same devices.

[0140] Example 35 includes the method of any of Examples 33-34. wherein the different connections are between different devices.

[0141] Example 36 includes the method of any of Examples 23-35, further comprising at least one of: receiving a MIMO channel by a remote unit in the one or more remote units, wherein each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams; and emitting the portion of the available MIMO streams from more than one antenna in the multiple antennas.

[0142] Example 37 includes the method of any of Examples 23-36, wherein when a failure occurs within the distributed antenna system, prioritizing communication traffic through the distributed antenna system, wherein prioritizing the communication traffic comprises at least one of: disabling at least one communication channel through the distributed antenna system; disabling communication bands through the distributed antenna system; wherein channels from multiple operators are conveyedDocket No. 6635 WO W1 / 376.2115WO01 through the distributed antenna system, giving at least one channel associated with at least one operator in the multiple operators precedence over other channels; reducing MIMO order of the at least one communication channel; changing a modulation and coding scheme for the at least one communication channel; and reducing bandwidth of the at least one communication channel.

[0143] Example 38 includes the method of any of Examples 23-37, wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the distributed antenna system, further comprising: detecting when a component in the distributed antenna system fails; and assigning remote units in a simulcast group associated with the component to other simulcast groups.

[0144] Example 39 includes the method of any of Examples 23-38, wherein the one or more redundancy features include at least one active component in multiple components and at least one redundant component in the multiple components, further comprising performing functionality of the at least one active component by the at least one redundant component when the at least one active component experiences a failure.

[0145] Example 40 includes the method of Example 39, wherein the at least one active component and the at least one redundant component are switches.

[0146] Example 41 includes the method of any of Examples 39-40, wherein the at least one active component and the at least one redundant component each carry a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences the failure further comprising routing the traffic through the at least one active component and the at least one redundant component that remains operational.

[0147] Example 42 includes the method of any of Examples 39-41, wherein the at least one active component and the at least one redundant component are redundant power supplies.

[0148] Example 43 includes the method of Example 42, wherein the redundant power supplies provide power to components within the distributed antenna system associated with higher traffic loads.Docket No. 6635 WO W1 / 376.2115WO01

[0149] Example 44 includes the method of any of Examples 23-43, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

[0150] Example 45 includes a system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; one or more intermediate nodes; and one or more remote units in communication with the one or more master units through the one or more intermediate nodes; wherein the one or more redundancy features incorporate at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.

[0151] Example 46 includes the system of Example 45. wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

[0152] Example 47 includes the system of any of Examples 45-46, wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel; wherein the at least one MIMO channel is split into different portions, wherein each portion is conveyed on different connections in the multiple connections between the one or more master units and the one or more remote units.

[0153] Example 48 includes the system of Example 47, wherein the different connections are between same devices.

[0154] Example 49 includes the system of any of Examples 47-48, wherein the different connections are between different devices.

[0155] Example 50 includes the system of any of Examples 45-49, wherein a remote unit in the one or more remote units is configured to receive a MIMO channel, whereDocket No. 6635 WO W1 / 376.2115WO01 each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams, the remote unit is further configured to emit the portion of the available MIMO streams from more than one antenna in the multiple antennas.

[0156] Example 51 includes the system of any of Examples 45-50, wherein when a failure occurs within the distributed antenna system, the distributed antenna system is configured to prioritize communication traffic through the distributed antenna system, wherein the distributed antenna system is configured to at least one of: disable at least one communication channel through the distributed antenna system; disable communication bands through the distributed antenna system; wherein channels from multiple operators are conveyed through the distributed antenna system, give at least one channel associated with at least one operator in the multiple operators precedence over other channels; reduce MIMO order of the at least one communication channel; change a modulation and coding scheme for the at least one communication channel; and reduce bandwidth of the at least one communication channel.

[0157] Example 52 includes the system of any of Examples 45-51, wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the multiple components; where a component in the multiple components fails, assigning remote units in a simulcast group associated with the component to other simulcast groups.

[0158] Example 53 includes the system of any of Examples 45-52, wherein the one or more redundancy features include at least one active component in the multiple components and at least one redundant component in the multiple components, wherein functionality of the at least one active component is performed by the at least one redundant component when the at least one active component expenences a failure.

[0159] Example 54 includes the system of Example 53, wherein the at least one active component and the at least one redundant component are switches.

[0160] Example 55 includes the system of any of Examples 53-54, wherein the at least one active component and the at least one redundant component each carry a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences aDocket No. 6635 WO W1 / 376.2115WO01 failure, routing the traffic through the at least one active component and the at least one redundant component that remains operational.

[0161] Example 56 includes the system of any of Examples 53-55, wherein the at least one active component and the at least one redundant component are redundant power supplies.

[0162] Example 57 includes the system of Example 56, wherein the redundant power supplies provide power to components within the distributed antenna system associated wi th higher traffic loads.

[0163] Example 58 includes the system of any of Examples 45-57, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

[0164] Example 59 includes a system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; and one or more remote units in communication with the one or more master units; wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

[0165] Example 60 includes the system of Example 59, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

[0166] Example 61 includes the system of Example 60. wherein the remote unit is configured to: detect a failure of an active connection in the one or more active connections; switch the communications associated with the active connection to theDocket No. 6635 WO W1 / 376.2115WO01 at least one redundant connection; and initialize the communications through the at least one redundant connection.

[0167] Example 62 includes the system of any of Examples 60-61, wherein the one or more second components comprise an active component and redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

[0168] Example 63 includes the system of Example 62, wherein the remote unit stores delay values associated with the one or more active connections between the remote unit and the active component and the at least one redundant connection between the remote unit and the redundant component.

[0169] Example 64 includes the system of any of Examples 60-63, wherein the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active; wherein at least one processor on the remote unit monitors the status signal and determines whether a connection is failed based on the status signal.

[0170] Example 65 includes the system of any of Examples 60-64, wherein the remote unit is configured to: simultaneously receive a transmission over the one or more active connections and the at least one redundant connection when both the one or more active connections and the at least one redundant connection are operational; and initialize the communications for both the one or more active connections and the at least one redundant connection.

[0171] Example 66 includes the system of Example 65, wherein the remote unit is configured to: couple to the one or more active connections; and upon determining that the one or more active connections has failed couple to the at least one redundant connection.

[0172] Example 67 includes the system of any of Examples 65-66, wherein the remote unit is configured to combine the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.Docket No. 6635 WO W1 / 376.2115WO01

[0173] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiments shown. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Claims

Docket No. 6635 WO W1 / 376.2115WO01CLAIMSWhat is claimed is:

1. A system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; and one or more remote units in communication with the one or more master units; wherein the one or more redundancy features comprise at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.

2. The system of claim 1, wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

3. The system of claim 2, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

4. The system of claim 3, wherein at least one of the remote unit and a component in the multiple components is configured to: detect a failure of an active connection in the one or more active connections; switch the communications associated with the active connection to the at least one redundant connection; andDocket No. 6635 WO W1 / 376.2115WO01 initialize the communications through the at least one redundant connection.

5. The system of claim 3, wherein the one or more second components comprise an active component and redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

6. The system of claim 5, wherein the remote unit stores delay values associated with the one or more active connections between the remote unit and the active component and the at least one redundant connection between the remote unit and the redundant component.

7. The system of claim 3, wherein the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active; wherein at least one processor on the remote unit monitors the status signal and determines whether a connection is failed based on the status signal.

8. The system of claim 3, wherein the remote unit is configured to: simultaneously receive a transmission over the one or more active connections and the at least one redundant connection when both the one or more active connections and the at least one redundant connection are operational; and initialize the communications for both the one or more active connections and the at least one redundant connection.

9. The system of claim 8, wherein the remote unit is configured to: couple to the one or more active connections; and upon determining that the one or more active connections has failed couple to the at least one redundant connection.

10. The system of claim 8, wherein the remote unit is configured to combine the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.Docket No. 6635 WO WI / 376.2115WO0111. The system of claim 1 , wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel; wherein the at least one MIMO channel is split into different portions, wherein each portion is conveyed on different connections in the multiple connections between the one or more master units and the one or more remote units.

12. The system of claim 11, wherein the different connections are between same devices.

13. The system of claim 11, wherein the different connections are between different devices.

14. The system of claim 1, wherein a remote unit in the one or more remote units is configured to receive a MIMO channel, where each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams, the remote unit is further configured to emit the portion of the available MIMO streams from more than one antenna in the multiple antennas.

15. The system of claim 1, wherein when a failure occurs within the distributed antenna system, the distributed antenna system is configured to prioritize communication traffic through the distributed antenna system, wherein the distributed antenna system is configured to at least one of disable at least one communication channel through the distributed antenna system; disable communication bands through the distributed antenna system; wherein channels from multiple operators are conveyed through the distributed antenna system, give at least one channel associated with at least one operator in the multiple operators precedence over other channels; reduce MIMO order of the at least one communication channel; change a modulation and coding scheme for the at least one communication channel; and reduce bandwidth of the at least one communication channel.Docket No. 6635 WO W1 / 376.2115WO0116. The system of claim 1 , wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the multiple components; where a component in the multiple components fails, assigning remote units in a simulcast group associated with the component to other simulcast groups.

17. The system of claim 1, wherein the one or more redundancy features include at least one active component in the multiple components and at least one redundant component in the multiple components, wherein functionality' of the at least one active component is performed by the at least one redundant component when the at least one active component experiences a failure.

18. The system of claim 17, wherein the at least one active component and the at least one redundant component are switches.

19. The system of claim 17, wherein the at least one active component and the at least one redundant component each carry' a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences a failure, routing the traffic through the at least one active component and the at least one redundant component that remains operational.

20. The system of claim 17, wherein the at least one active component and the at least one redundant component are redundant power supplies.

21. The system of claim 20, wherein the redundant power supplies provide power to components within the distributed antenna system associated with higher traffic loads.

22. The system of claim 1, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

23. A method comprising: configuring one or more master units in a distributed antenna system to receive at least one signal from a signal source;Docket No. 6635 WO W1 / 376.2115WO01 configuring one or more remote units in the distributed antenna system to communicate with the one or more master units; and implementing one or more redundancy features within the distributed antenna system that incorporate at least one of one or more sets of redundant components and one or more sets of redundant connections.

24. The method of claim 23, wherein implementing the one or more redundancy features comprises: establishing one or more active connections between a first component of the distributed antenna system and one or more second components of the distributed antenna system; maintaining at least one redundant connection between the first component and the one or more second components; and upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

25. The method of claim 24, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

26. The method of claim 25, further comprising: detecting a failure of an active connection in the one or more active connections; switching the communications associated with the active connection to the at least one redundant connection; and initializing the communications through the at least one redundant connection.

27. The method of claim 25, wherein the one or more second components comprise an active component and a redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

28. The method of claim 27, further comprising storing delay values associated with the one or more active connections between the remote unit and the activeDocket No. 6635 WO W1 / 376.2115WO01 component and the at least one redundant connection between the remote unit and the redundant component.

29. The method of claim 25, when the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active, further comprising: monitoring the status signal; and determining whether a connection is failed based on the status signal.

30. The method of claim 25, further comprising: simultaneously receiving a transmission over the one or more active connections and the at least one redundant connection when both the one or more active connections and the at least one redundant connection are operational; and initializing the communications for both the one or more active connections and the at least one redundant connection.

31. The method of claim 30, further comprising: coupling the remote unit to the one or more active connections; determining that the one or more active connections has failed; and coupling the remote unit to the at least one redundant connection via an uplink / downlink switch.

32. The method of claim 30, further comprising combining the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.

33. The method of claim 23, wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel, further comprising: splitting the at least one MIMO channel into different portions; and conveying each portion in the different portions on different connections between the one or more master units and the one or more remote units.

34. The method of claim 33, wherein the different connections are between same devices.Docket No. 6635 WO WI / 376.2115WO0135. The method of claim 33, wherein the different connections are between different devices.

36. The method of claim 23, further comprising at least one of: receiving a MIMO channel by a remote unit in the one or more remote units, wherein each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams; and emitting the portion of the available MIMO streams from more than one antenna in the multiple antennas.

37. The method of claim 23, wherein when a failure occurs within the distributed antenna system, prioritizing communication traffic through the distributed antenna system, wherein prioritizing the communication traffic comprises at least one of: disabling at least one communication channel through the distributed antenna system: disabling communication bands through the distributed antenna system; wherein channels from multiple operators are conveyed through the distributed antenna system, giving at least one channel associated with at least one operator in the multiple operators precedence over other channels; reducing MIMO order of the at least one communication channel; changing a modulation and coding scheme for the at least one communication channel; and reducing bandwidth of the at least one communication channel.

38. The method of claim 23, wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the distributed antenna system, further comprising: detecting when a component in the distributed antenna system fails; and assigning remote units in a simulcast group associated with the component to other simulcast groups.

39. The method of claim 23, wherein the one or more redundancy features include at least one active component in multiple components and at least one redundant component in the multiple components, further comprising performing functionalityDocket No. 6635 WO W1 / 376.2115WO01 of the at least one active component by the at least one redundant component when the at least one active component experiences a failure.

40. The method of claim 39, wherein the at least one active component and the at least one redundant component are switches.

41. The method of claim 39, wherein the at least one active component and the at least one redundant component each cany7a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences the failure further comprising routing the traffic through the at least one active component and the at least one redundant component that remains operational.

42. The method of claim 39, wherein the at least one active component and the at least one redundant component are redundant power supplies.

43. The method of claim 42, wherein the redundant power supplies provide power to components within the distributed antenna system associated with higher traffic loads.

44. The method of claim 23, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

45. A system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; one or more intermediate nodes; and one or more remote units in communication with the one or more master units through the one or more intermediate nodes;Docket No. 6635 WO W1 / 376.2115WO01 wherein the one or more redundancy features incorporate at least one of one or more sets of redundant components in the multiple components and one or more sets of redundant connections in the multiple connections.

46. The system of claim 45, wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

47. The system of claim 45, wherein the one or more remote units are configured to communicate with the one or more master units through at least one multiple input multiple output (MIMO) channel; wherein the at least one MIMO channel is split into different portions, wherein each portion is conveyed on different connections in the multiple connections between the one or more master units and the one or more remote units.

48. The system of claim 47, wherein the different connections are between same devices.

49. The system of claim 47, wherein the different connections are between different devices.

50. The system of claim 45, wherein a remote unit in the one or more remote units is configured to receive a MIMO channel, where each MIMO stream in the MIMO channel is associated with a different antenna in multiple antennas coupled to the remote unit and the remote unit receives a portion of available MIMO streams, the remote unit is further configured to emit the portion of the available MIMO streams from more than one antenna in the multiple antennas.

51. The system of claim 45, wherein when a failure occurs within the distributed antenna system, the distributed antenna system is configured to prioritizeDocket No. 6635 WO W1 / 376.2115WO01 communication traffic through the distributed antenna system, wherein the distributed antenna system is configured to at least one of disable at least one communication channel through the distributed antenna system; disable communication bands through the distributed antenna system; wherein channels from multiple operators are conveyed through the distributed antenna system, give at least one channel associated with at least one operator in the multiple operators precedence over other channels; reduce MIMO order of the at least one communication channel; change a modulation and coding scheme for the at least one communication channel; and reduce bandwidth of the at least one communication channel.

52. The system of claim 45, wherein the one or more remote units are associated with different simulcast groups, and each simulcast group is associated with a different component in the multiple components; where a component in the multiple components fails, assigning remote units in a simulcast group associated with the component to other simulcast groups.

53. The system of claim 45, wherein the one or more redundancy features include at least one active component in the multiple components and at least one redundant component in the multiple components, wherein functionality of the at least one active component is performed by the at least one redundant component when the at least one active component experiences a failure.

54. The system of claim 53, wherein the at least one active component and the at least one redundant component are switches.

55. The system of claim 53, wherein the at least one active component and the at least one redundant component each carry' a portion of traffic for the at least one active component, wherein when one of the at least one active component and the at least one redundant component experiences a failure, routing the traffic through the at least one active component and the at least one redundant component that remains operational.Docket No. 6635 WO W1 / 376.2115WO0156. The system of claim 53, wherein the at least one active component and the at least one redundant component are redundant power supplies.

57. The system of claim 56, wherein the redundant power supplies provide power to components within the distributed antenna system associated with higher traffic loads.

58. The system of claim 45, wherein multiple remote units in the one or more remote units are connected to a component in the distributed antenna system in a ring topology.

59. A system comprising: a distributed antenna system configured to implement one or more redundancy features, wherein the distributed antenna system comprises multiple components and multiple connections between the multiple components of the distributed antenna system, wherein the multiple components comprise: one or more master units configured to receive at least one signal from a signal source; and one or more remote units in communication with the one or more master units; wherein the one or more redundancy features comprises: one or more active connections between a first component in the multiple components and one or more second components; and at least one redundant connection between the first component and the one or more second components; wherein, upon detection of a failed connection in the one or more active connections, using the at least one redundant connection for transmission of signals associated with the failed connection.

60. The system of claim 59, wherein the first component is a remote unit in the one or more remote units configured to receive communications from the one or more second components through the at least one redundant connection.

61. The system of claim 60, wherein the remote unit is configured to: detect a failure of an active connection in the one or more active connections;Docket No. 6635 WO W1 / 376.2115WO01 switch the communications associated with the active connection to the at least one redundant connection; and initialize the communications through the at least one redundant connection.

62. The system of claim 60, wherein the one or more second components comprise an active component and redundant component, wherein the active component is connected to the remote unit through the one or more active connections and the redundant component is connected to the remote unit through the at least one redundant connection.

63. The system of claim 62, wherein the remote unit stores delay values associated with the one or more active connections between the remote unit and the active component and the at least one redundant connection between the remote unit and the redundant component.

64. The system of claim 60, wherein the remote unit is coupled to the one or more active connections and the at least one redundant connection through a small form factor pluggable module that emits a status signal when active; wherein at least one processor on the remote unit monitors the status signal and determines whether a connection is failed based on the status signal.

65. The system of claim 60, wherein the remote unit is configured to: simultaneously receive a transmission over the one or more active connections and the at least one redundant connection when both the one or more active connections and the at least one redundant connection are operational; and initialize the communications for both the one or more active connections and the at least one redundant connection.

66. The system of claim 65, wherein the remote unit is configured to: couple to the one or more active connections; and upon determining that the one or more active connections has failed couple to the at least one redundant connection.

67. The system of claim 65, wherein the remote unit is configured to combine the transmission received through the one or more active connections and the at least one redundant connection into a single transmission.

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