Striping of signal to groups of nodes for flexible service group sizing

In one embodiment, a first group of splitters receives a group of signals from a group of transmitters. Each splitter in the first group of splitters splits a signal into a plurality of signals that are sent to a plurality of multiplexers. A multiplexer in the plurality of multiplexers receives one of the plurality of signals from each splitter in the group of splitters and multiplexes the received one of the plurality of signals into a multiplexed signal. The multiplexer sends the multiplexed signal through a single connection in which upstream signals are sent to a group of nodes and downstream signals are received from the group of nodes. A de-multiplexer de-multiplexes the multiplexed signal into the group of signals and sends the group of signals to the group of nodes via a second group of splitters that are connected to the group of nodes.

BACKGROUND

In network architecture upgrades, two criteria that are often considered and traded off one against another include: a) proper sizing of “service groups” to enable enough capacity to meet eventual customers' demand (even at the later stage of life of the proposed upgrade) and b) enabling a cost-effective start (e.g., with just the right amount of capacity to serve customers demand in the early stage of life). The networks are organized into “service groups” to which a certain bandwidth capacity is assigned to, both in downstream (DS) and upstream (US) directions. For example, a service group may start at 200 users or 400 homes passed (if it is assumed only 50% of homes passed may subscribe to the service). As the bandwidth capacity is expected to grow in time, the service groups may be split into additional service groups, such as two, four, eight, etc. service groups, to meet the growing demand. For example, the service group may be split into two service groups of 100, and then four service groups of 50. However, delaying those service group splits will save the cost needed to perform the “split” until the time the additional service groups are necessary.

A network may include 16 fiber deep (FD) nodes that may each feed a number of homes, such as 20-80 homes, via a single fiber link for both the downstream and the upstream directions. To transition to this type of network, a network provider may want to develop the network in phases. An end goal may be a maximum of eight dense wavelength division multiplexing (DWDM) downstream transmitters (TXs) and a maximum of 16 coarse wavelength division multiplexing (CWDM) upstream receivers (RXs). Also, the end goal may be two FD nodes per transmitter in the downstream and one FD node per receiver in the upstream. However, the network provider may convert the network using multiple phases before reaching the end goal.

A possible phase1configuration may be eight FD nodes per transmitter in the downstream and four FD nodes per receiver in the upstream. A possible phase2configuration may include four FD nodes per transmitter in the downstream and two FD nodes per receiver in the upstream. Changing from phase1to phase2, and then to the end goal (e.g., phase3) requires both head end and field changes. For example, at the head end, when the transmitter and receiver additions are made, the multiplexer in the head end upstream path needs to be replaced at every phase-to-phase conversion, such as from a four output CWDM de-multiplexer in phase1to an eight output CWDM de-multiplexer in phase2, and eventually to a 16 output CWDM de-multiplexer in phase3. The 4-CWDM and 8-CWDM de-multiplexers may not be standard de-multiplexers and may have to be custom-manufactured, which increases the cost.

In the field, in the downstream direction, splitters will require reconfiguration at each phase conversion. For example, phase1may require three levels of splitters; phase2will require two levels of splitters; and phase3will require only one level of splitters. This will require that a network provider go out into the field (e.g., truck rolls) to access the splitters and reconfigure the splitters in the field. The reconfiguration may also require service outages in addition to the cost for the service provider to go into the field.

DETAILED DESCRIPTION

In a downstream direction, some embodiments split signals from downstream transmitters via a striping configuration on a per-wavelength basis at the head end side starting at a phase1configuration. Also, in an upstream direction, the signal may be combined via a striping configuration also. While the phase3configuration may be the same as that described in the Background, which is two fiber deep (FD) nodes per transmitter in the downstream direction and one FD node per receiver in the upstream direction, the configuration in phase1improves the conversion to phase2, and also from phase2to phase3. For example, the configuration in phase1eliminates the need to change the configuration in the field (e.g., components located after the fiber connection). For example, one level of splitters is used in the field in phases1,2, and3, which eliminates the need to change the splitter configuration in the field when the configurations are changed in between phases.

The use of striping also allows the same 16 coarse wavelength division multiplexer (CWDM) de-multiplexer to use in all phases in the upstream direction. This eliminates need to use the 4-CWDM de-multiplexer and 8-CWDM de-multiplexer. Accordingly, the use of striping saves cost in that custom CWDM de-multiplexers do not need to be manufactured and changed.

Stripping Configuration

FIG. 1depicts a simplified system100showing a phase1configuration of a network according to some embodiments. A head end102may transmit signals in a downstream direction to nodes112(e.g., signals destined for customer premise equipment) that are located remotely in “the field”. The field may be located remotely from head end102, such as after a fiber connection115. Also, signals are transmitted in an upstream direction that originate at the customer premise, and travel upstream via nodes112, to head end102. The upstream and downstream directions may be served via a single fiber link115in both the upstream and downstream directions. That is, both the upstream signal and the downstream signal may be transmitted on the same fiber link. Other types of networks may also be used. There could be a dedicated/separate fiber to each downstream TX/node link and to each upstream Node/RX link. Also, all of the downstream and upstream links can go over the same fiber, as described herein. The fewer fiber strands means less cost, but is traded-off with cost/complexity of the de-multiplexers and multiplexers filtering. Other options use one fiber for all downstream signals and another fiber for all upstream signals, or to use a few fiber connections, with a fewer number of downstream wavelengths per fiber for downstream, upstream, and/or a combination of.

Each node may service a number of “homes passed” (HP) or “HouseHolds Passed” (HHP). The homes passed may be connected to the nodes, but some percentage of subscribers may subscribe to a service, such as subscribe to receive cable television service. The number of homes passed may be between 20 to 80 subscribers and the number of subscribers served by a set of nodes may be referred to as a service group.

In the downstream direction, head end102includes eight transmitters103denoted as TX01to TX08that transmit signals downstream. Also, 16 nodes112are shown as node01to node16. These nodes may be fiber deep (FD) nodes, which are nodes located closer to subscriber premises where there are no amplifiers after the node (also called Node+zero (N+0)). In the upstream direction, 16 receivers120, shown as RX01to RX16, receive the upstream signals from nodes112in head end102. In phase1, all transmitters, nodes, and receivers are active.

In the downstream direction, a transmitter103may transmit a signal to a 1:4 splitter104. For example, eight splitters104-1to104-8correspond, respectively, to the eight transmitters TX01to TX08. Splitters104may split the signal into four signals that are destined for four different multiplexers. For example, each signal may be sent to a different 8-dense wavelength division multiplexer (DWDM)106. That is, a single signal from transmitter TX01may be split by a 1:4 splitter104into four signals that are sent to four different 8-DWDM multiplexers A to D. Sending the signal to four different-DWDM multiplexers A to D stripes the signal to a different set of nodes. That is, the 8-DWDM multiplexer D shown inFIG. 1may send a first signal that is destined for the set of 16 nodes112. Then, a 8-DWDM multiplexer A (not shown) sends a second signal of the four signals to another set of 16 nodes, a 8-DWDM multiplexer B (not shown) sends a third signal of the four signals to another set of 16 nodes, and a 8-DWDM multiplexer C (not shown) sends a fourth signal to another set of 16 nodes. That is, a single signal from TX01may service four different sets of 16 nodes (e.g., 48 nodes in total). As described in the Background, just 16 nodes are connected with one set of multiplexers and de-multiplexers, but with only two transmitters being active. However, in some embodiments, by adding three more groups of 16 nodes, with set of multiplexers and de-multiplexers A, B, C, “striping” among the set of multiplexers and de-multiplexers A, B, C, and D to achieve the same ratio of eight nodes to a transmitter.

InFIG. 1, a single 8-DWDM multiplexer D106is shown that receives one of the signals from splitter 1:4 and multiplexes the signal with other signals from other transmitters into a single signal. For example, 8-DWDM multiplexer D106may multiplex a number of signals using different wavelengths into a signal for transmission over fiber connection115. That is, 8-DWDM multiplexer106includes eight inputs to receive signals from eight transmitters and one output to output the multiplexed signal. The following will describe the signal communication for multiplexer D, but a similar signal communication may be appreciated for multiplexers A, B, and C.

8-DWDM multiplexer D106outputs the signal to an amplifier107, which amplifies the signal. Although amplifier107is described, it may not be used if not needed.

A DWDM bypass port of 16-CWDM-channel de-multiplexer D receives the signal from amplifier107and then sends the signal over fiber115to a 16-CWDM multiplexer114. The bypass port passes the signal through 16-CWDM de-multiplexer. In some embodiments, the signal does not need to pass through 16-CWDM de-multiplexer and additional fiber connections may be used to send signals. Fiber115may send signals in both the downstream and the upstream direction as described herein, but additional fiber connections may be used.

At the field side, 16-CWDM multiplexer114receives the signal and sends the signal to an 8-DWDM de-multiplexer108, which de-multiplexes the signal to eight signals. For example, 8-DWDM multiplexer108includes one input and eight outputs to output eight signals that are de-multiplexed from the signal. Given that there are 16 nodes, 1:2 splitters110-1to110-8are used to split the eight signals from 8-DWDM de-multiplexer108into 16 signals, which are sent to nodes01to nodes16. For example, a splitter110-1may split a signal to node01and node02, and so forth.

In the upstream direction, at the field side, each node01to node16transmits a signal to 16-CWDM multiplexer D114, which multiplexes the signals into a multiplexed signal onto fiber115to 16-CWDM de-multiplexer D116. For example, 16-CWDM multiplexer114includes 16 inputs to receive signals from 16 nodes and one output to output the multiplexed signal.

16-CWDM de-multiplexer D116includes one input to receive the signal and 16 outputs to output the de-multiplexed signal. 16-CWDM de-multiplexer D116may de-multiplex a signal into 16 signals at different wavelengths. At 16-CWDM de-multiplexer D116, different configurations to send the upstream signals from 16-CWDM de-multiplexer D116to receivers RX01to RX16may be appreciated. In this example, the upstream signals are sent to 4:1 combiners118-1to118-16, which also receive upstream signals from 16-CWDM de-multiplexers A, B, and C. Each 4:1 combiner118combines the signals from de-multiplexers A, B, C, and D into a single signal, and sends the signal to a receiver. For example, the signals from four different node01sin groups A, B, C, and D are sent to receiver RX01.

In the above, the configuration in the field does not need to be changed when the striping is changed when converting between different phases. That is, 1:2 splitters110-1to110-8are not reconfigured throughout all the phase changes, such as the number of 1:2 splitters, the number of levels of 1:2 splitters, or the connections of the 1:2 splitters to nodes are not changed. This improves the network because no down time in the field occurs and additional cost to reconfigure the splitters is not incurred by having to change the configuration in the field. Additionally, the 16-CWDM de-multiplexer D does not need to be changed when phases change. That is, the 16 output de-multiplexer stays the same, which improves cost as a 4-CWDM de-multiplexer and a 8-CWDM de-multiplexer are not used.

Specific numbers for the transmitters, nodes, multiplexers, de-multiplexers, splitters, and combiners are used. However, the numbers may be altered or scaled within some embodiments.

Phase3Example Network Configuration

FIG. 2depicts an example of the network configuration in phase3according to some embodiments. In phase3, as mentioned above, two FD nodes per transmitter are found in the downstream direction and one FD node per receiver is found in the upstream direction. As shown, splitters110-1to110-8remain the same from phase1to phase3.

16-CWDM de-multiplexer116includes the same 16 outputs as in phase1. However, the 16 outputs of 16-CWDM de-multiplexer116is 1:1 with receivers RX01to RX16. That is, no combiners are needed unlike in phase1. Additionally, transmitters TX01to TX08do not use a striping configuration. That is, each transmitter TX01to TX08sends a signal to 8-DWDM multiplexer106. 8-DWDM multiplexer106then multiplexes the eight signals to a single output that can be sent on fiber115through 16-CWDM de-multiplexer116. In phase3, striping is removed and 16 nodes receive signals from eight transmitters. In the upstream, 16 nodes send signals to 16 receivers. The conversion changes from phase1in which four sets of nodes A, B, C, and D being serviced by the eight transmitters to phase3in which the four sets of nodes are now serviced by four different sets of 8 transmitters. Also, four sets of 16 nodes sending signals to a single set of 16 receivers in phase1now send signals to four different sets of 16 receivers in phase3.

Striping

FIG. 3depicts a more detailed example of striping in the downstream direction according to some embodiments. Transmitters103-1to103-8may transmit at different wavelengths λ1to λ8. The signals may be striped across four 8-DWDM multiplexers A, B, C, and D106-1,106-2,106-3, and106-4. For example, a transmitter103-1may transmit to a splitter104-1, which splits the signal into four signals. A first signal is sent to 8-DWDM multiplexer A106-1; a second signal is sent to 8-DWDM multiplexer B106-2; a third signal is sent to 8-DWDM multiplexer C106-3; and a fourth signal is sent to 8-DWDM multiplexer D106-4. This is the forward stripping configuration where a single signal from a transmitter is striped to multiple 8-DWDM multiplexers that service different sets of nodes. Each 8-DWDM multiplexer may output a single signal to an amplifier107-1to107-4, respectively. Amplifier107may be an erbium-doped fiber amplifier (EDFA), but may be other types of optical amplifiers, or not needed at all.

FIG. 4depicts the striping in the upstream direction according to some embodiments. Although this configuration of striping is described, other striping configurations in the upstream direction may be appreciated as will be described in more detail below. In this configuration, 16-CWDM de-multiplexers A, B, C, and D,116-1,116-2,116-3, and116-4receive signals from four different sets of 16 nodes, respectively. A single signal from each of the four 16-CWDM de-multiplexer is then input into a 4:1 combiner, which then outputs the four signals via a single output to a receiver, such as combiner118-1outputs a signal to RX01120-1.

FIG. 5depicts the striping in both the upstream and downstream directions where the same wavelength striping is used according to some embodiments. This example is a more detailed example of the system shown inFIG. 1. For example, in this embodiment, the same wavelength signal from transmitters TX01to TX08is sent to 8-DWDM de-multiplexers A, B, C, and D in the downstream direction.

In the upstream direction, the same wavelength signals are sent to a 4:1 combiner118. Sending the same wavelength from multiple nodes to a single receiver may result in interference, such as optical beat interference (OBI). Optical beat interference occurs when multiple transmitters transmit at the same wavelength to a single receiver at the same time and when a receiver receives the multiple signals at a similar wavelength at the same time. In some embodiments, to remove the possibility of any interference, different wavelengths from different 16-CWDM de-multiplexers A, B, C, and D are sent.FIG. 6depicts an example of using different wavelengths in the upstream direction according to some embodiments. In some examples, a first wavelength λ01is sent from 16-CWDM de-multiplexer D; a second wavelength λ02is sent from 16-CWDM de-multiplexer C; a third wavelength λ03is sent from 16-CWDM de-multiplexer B; and a fourth wavelength λ04is sent from 16-CWDM de-multiplexer A to receiver01. Because receiver01is receiving signals at different wavelengths at the same time, the signals do not interfere with one another if received at the same time. The same configuration is used at the other receivers.

Phase Conversion Examples

FIG. 7-FIG. 10depict the configurations for different phases according to some embodiments. In each of the phases, the field size is configured once and unchanged through phases1,2, and3. That is, the nodes, splitters, 8-DWDM de-multiplexer, and 16-CWDM multiplexer are not changed when a phase conversion occurs.

The configuration ofFIG. 7is similar to the configuration described above inFIG. 1, but shows all the 8-DWDM multiplexers A, B, C, and D106-1to106-4. In head end102, eight transmitters103send signals to eight 1:4 splitters104. Then, 8-DWDM multiplexers A, B, C, and D106-1to106-4each receive one of the four signals from each 1:4 splitter104.

In the upstream direction, four 16-CWDM de-multiplexers A, B, C, and D116-1to116-4receive signals from four sets of 16 nodes A, B, C, and D. Sixteen 4:1 combiners118receive signals from the four de-multiplexers and output a single signal to 16 receivers120respectively.

In the above configuration, the return receiver input level may be below a desired power level. To rectify this, receivers that are receiving an optical input that is below the desired power level threshold may be “doubled up”—e.g., instead of one 4:1 combiner being input into one receiver, two 2:1 combiners are input into two separate receivers. Optical levels input into receivers will be ˜3 dB higher and the radio frequency (RF) outputs from those pairs of the receivers can then be RF combined, to preserve the right “phasing/service group sizing”.FIG. 8depicts such an arrangement on receivers RX01to RX06according to some embodiments.

At802-1, receivers RX01to RX06are used in addition to 6 additional receivers RX01to RX06at802-2. This increases the cost as the number of receivers increases. However, the power level may be increased because the combiners used for these two sets of receivers are 2:1 combiners. That is, each combiner receives two signals from two of the 16-CWDM de-multiplexers and outputs a single signal to a receiver. The loss at each of the 2:1 combiners may be less than the loss at 4:1 combiners, which increases the return receiver input level for these 12 receivers. The remaining combiners for receivers RX08to RX16are still 4:1 combiners.

FIG. 9depicts an example configuration for a phase2according to some embodiments. In this example, one downstream transmitter feeds two of the downstream nodes and one upstream receiver receives signals from two of the downstream nodes. In the downstream direction, two sets of transmitters TX01to TX08at902-1and902-2are used. Each transmitter outputs a signal to a 1:2 splitter shown at904-1and904-2. Each 1:2 splitter may split the signal into two signals, which are then sent to two 8-DWDM multiplexers. For example, a first transmitter TX01in902-1may send a signal for 8-DWDM multiplexers A and B, and a second transmitter TX01in902-2may send a signal for 8-DWDM multiplexers C and D.

In the upstream direction, receivers RX01to RX16are included in two sets shown at906-1and906-2. Also, two sets of 2:1 combiners are then shown at908-1and908-2. Each 2:1 combiner receives signals from two 16-CWDM de-multiplexers. For example, a first 2:1 combiner receives signals from 16-CWDM de-multiplexers A and B, and a second 2:1 combiner receives signals from 16-CWDM de-multiplexers C and D. Then, a first receiver RX01at906-1may receive signals from 16-CWDM de-multiplexers A and B, and a second receiver RX01at906-2may receive signals from 16-CWDM de-multiplexers C and D.

FIG. 10depicts an example of the configuration in phase3according to some embodiments. In this example, one downstream transmitter feeds one de-multiplexer and one upstream receiver receives signals from one de-multiplexer. For example, four sets of transmitters are shown at1002-1to1002-4. Each respective set of transmitters sends signals to a specific 8-DWDM multiplexer. For example, a first transmitter TX01at1002-1sends a signal to 8-DWDM multiplexer A; a second transmitter TX01at1002-2sends a signal to 8-DWDM multiplexer B; a third transmitter TX01at1002-3sends a signal to 8-DWDM multiplexer C; and a fourth transmitter TX01at1002-4sends a signal to 8-DWDM multiplexer D.

In the upstream direction, one receiver receives a signal from a single 16-CWDM de-multiplexer. For example, four sets of 16 receivers are shown at1004-1to1004-4. A first receiver RX01at1004-1receives a signal from 16-CWDM de-multiplexer A; a second receiver RX01at1004-2receives a signal from 16-CWDM de-multiplexer B; a third receiver RX01at1004-3receives a signal from 16-CWDM de-multiplexer C; and a fourth receiver RX01at1004-4receives a signal from 16-CWDM de-multiplexer D.

Alternative Upstream Striping Configuration

FIG. 11depicts an alternative upstream striping configuration according to some embodiments. In this example, a one FD node per receiver configuration is used in phase1. Accordingly, four sets of 16 receivers RX01to RX16are associated with the four 16-CWDM de-multiplexers A, B, C, and D116-1to116-4. Only 16-CWDM de-multiplexer D116is shown in this example, however. Different from the configuration shown inFIG. 1, additional receivers are required because the striping happens after the receivers using RF 4:1 combiners1102-1to1102-16. For example, an RF 4:1 combiner1102-1receives signals from receivers RX01that are connected to 16-CWDM de-multiplexers A, B, C, and D, combines the signals, and outputs a single signal. The combining is performed in RF instead of optical because the receivers output RF.

The use of a single receiver for a single node eliminates the possibility of optical beat interference because multiple transmitters are not transmitting to a single receiver. Rather, only one node is transmitting to one receiver.

Splitter Configuration

The above changes between phases may change the splitters used in the downstream direction at head end102(not in the field). That is, a 1:4 splitter may be changed to a 1:2 splitter when the phase1to phase2conversion occurs. This may cause total replacement of the 1:4 splitters. However, some embodiments use a 1:4 splitter that can be converted to two 1:2 splitters.FIGS. 12A and 12Bdepict the re-use of a 1:4 splitter according to some embodiments. Phase1requires a 1:4 splitter after the downstream transmitters.FIG. 12Ashows an example of a 1:4 splitter according to some embodiments. Splitter104includes three 1:2 splitters1202-1,1202-2, and1202-3that are included in a single housing.

The configuration for the splitter104is one input and four outputs. For example, a 1:4 input is input into a 1:2 splitter1202-1. 1:2 splitter1202-1then splits the input into two signals that are output to a 1:2 splitter1202-2and a 1:2 splitter1202-3. Splitter1202-2splits the signal into two signals, which can be sent to an 8-DWDM multiplexer A and an 8-DWDM multiplexer B. A 1:2 splitter1202-3can split the signal into two signals and send the signals to an 8-DWDM multiplexer C and an 8-DWDM multiplexer D. Accordingly, the single input is split into four outputs.

FIG. 12Bshows an example of a splitter that can be converted from a 1:4 splitter to two 1:2 splitters according to some embodiments. Phase2requires two 1:2 splitters after a transmitter. Instead of replacing a 1:4 splitter with two 1:2 splitters, the 1:4 splitter inFIG. 12Acan be re-used by adding 2 inputs to the original 1:4 housing. The housing thus has three inputs and four outputs.

InFIG. 12B, the 1:4 input is not used in this example. Rather, a 1:2 input at1204-1and a 1:2 input at1204-2is used to receive inputs from two transmitters. At 1:2 input at1204-1, splitter1202-1receives a signal from a transmitter, and splits the signal into two signals at the two outputs, which then sends a signal to 8-DWDM multiplexer A and a signal to 8-DWDM multiplexer B. At 1:2 input at1204-2, splitter1202-3receives a signal from a transmitter, and splits the signal into two signals at the two outputs, which then sends a signal to 8-DWDM multiplexer C and a signal to 8-DWDM multiplexer D. In this example, the 1:4 input may be disconnected from 1:2 splitter1202-1and reconnected to 1:2 splitter1202-2at input1204-1. Then, another input from another transmitter may be connected to 1:2 splitter1202-3at input1204-2. In this case, 1:2 splitter1202-1and the corresponding input are not used.

The above configuration does not require a splitter to be replaced when the conversion between phases occurs. Rather, only the inputs need to be reconfigured. This may save cost as an additional splitter does not need to be purchased. To provide the reconfigurable splitter, two additional inputs may be added to the housing that can be input to splitters1202-2and1202-3, respectively. It is noted that splitter104may operate at a 1:4 configuration or the 2:4 configuration. That is, two inputs are split into four outputs when converted to the two 1:2 splitters. Splitter104may include logic such that if three inputs are connected at the same time, such as the 1:4 input, the 1:2 input, and the other 1:2 input at the same time, splitter104may select either the 1:4 input or the two 1:2 inputs individually or either of them. That is, splitter104will not transmit signals from all three inputs simultaneously.

In the upstream direction, the configuration of combiner118may be converted to two 2:1 combiners between a phase conversion. For example, the four inputs of a 4:1 combiner may receive signals from 16-CWDM de-multiplexers A, B, C, and D. When a 4:1 combiner is used, a single output from combiner104may be used. However, when a 2:1 combiner is used, then the 4:1 combiner may use two outputs to provide two 2:1 combiners.FIGS. 13A and 13Bshow the 4:1 re-usable combiner according to some embodiments.FIG. 13Ashows a 4:1 combiner118according to some embodiments. A 4:1 combiner includes 2:1 combiners1302-1,1302-2, and1302-3in a single housing.

Combiner118includes four inputs from four 16-CWDM de-multiplexers A, B, C, and D. Two of the inputs from 16-CWDM de-multiplexers A and B are input into a 2:1 combiner1302-2and two inputs from 16-CWDM de-multiplexers C and D are input into a 2:1 combiner1302-3. Combiner1302-2and combiner1302-3combine the respective signals and each output a single signal that is input into a 2:1 combiner1302-1. Combiner1302-1combines the signals and then outputs a single signal at a 4:1 output that is sent to a single receiver.

FIG. 13Bdepicts an example of converting a 4:1 combiner to two 2:1 combiners according to some embodiments. In this example, instead of using a single 4:1 output from 2:1 combiner1302-1, two outputs from combiners1302-2and1302-3are used. For example, 2:1 combiner1302-2receives signals from 16-CWDM de-multiplexers A and B; and 2:1 combiner1302-3receives signals from 16-CWDM de-multiplexers C and D. Each 2:1 combiner combines the respective signals, and outputs a single signal. For example, 2:1 combiner1302-2outputs a 2:1 output at an output1304-1and combiner1302-3outputs a 2:1 output at output1304-2. It is noted that combiner118may operate at a 4:1 configuration or the 4:2 configuration. That is, four inputs are combined into two inputs when converted to the two 2:1 combiners. Combiner118may include logic such that if three outputs are connected at the same time, such as the 4:1 output, the 2:1 output, and the other 2:1 output at the same time, splitter104may select either the 4:1 output or the two 2:1 outputs. That is, splitter104will not transmit signals from all three inputs simultaneously.

Because each 2:1 combiner1302-1and1302-2outputs a single output at1304-1and1304-2, respectively, 2:1 combiner1302-1are the 4:1 output are not used to output a signal inFIG. 12B. Accordingly, a 4:1 combiner has been converted to two 2:1 combiners. Instead of replacing the 4:1 combiners with two 2:1 combiners, the same 4:1 combiner may be used as two 2:1 combiners. This saves costs as only outputs need to be reconfigured rather than the replacement of the combiners.

Method Flows

FIG. 14depicts a simplified flowchart1400of a method for striping according to some embodiments. At1402, 1:4 splitter104receives a signal from a transmitter in head end102. At1404, 1:4 splitter104splits the signal into four signals. Then, at1406, 1:4 splitter sends each respective signal to different 8-DWDM multiplexers.

At1408, each 8-DWDM multiplexer106sends the respective signal to a 16-CWDM de-multiplexer116. At1410, each 16-CWDM de-multiplexer114sends a signal through a single fiber to a 16-CWDM multiplexer114. At1412, each 16-CWDM de-multiplexer114sends a signal to 8-DWDM de-multiplexer108. At1414, each 8-DWDM de-multiplexer108sends a signal to a 1:2 splitter110-1. At1416, each 1:2 splitter110splits the signal and sends the two signals to two nodes112.

The upstream direction goes from nodes112to 16-CWDM de-multiplexer114to fiber connection115. Then, 16-CWDM de-multiplexer116sends the signal to optical combiner118, which receives the signals from four 16-CWDM de-multiplexers116, and combines them. A receiver120receives the combined signal.

Conclusion

Accordingly, the use of striping may allow the configuration of the field components once and not need any reconfiguration thereafter as the configuration of head end102is changed. This saves costs as the field does not have to be reconfigured. Additional cost savings may be provided by using a splitter and combiner in the head end that can be converted from a 1:4 splitter to a 1:2 splitter and from a 4:1 combiner to 2 1:2 combiners.

System

FIG. 15illustrates an example of special purpose computer systems1500configured with components in the network described above according to one embodiment. Computer system1500includes a bus1502, network interface1504, a computer processor1506, a memory1508, a storage device1510, and a display1512.

Bus1502may be a communication mechanism for communicating information. Computer processor1506may execute computer programs stored in memory1508or storage device1508. Any suitable programming language can be used to implement the routines of some embodiments including C, C++, Java, assembly language, etc. Different programming techniques can be employed such as procedural or object oriented. The routines can execute on a single computer system1500or multiple computer systems1500. Further, multiple computer processors1506may be used.

Memory1508may store instructions, such as source code or binary code, for performing the techniques described above. Memory1508may also be used for storing variables or other intermediate information during execution of instructions to be executed by processor1506. Examples of memory1508include random access memory (RAM), read only memory (ROM), or both.

Storage device1510may also store instructions, such as source code or binary code, for performing the techniques described above. Storage device1510may additionally store data used and manipulated by computer processor1506. For example, storage device1510may be a database that is accessed by computer system1500. Other examples of storage device1510include random access memory (RAM), read only memory (ROM), a hard drive, a magnetic disk, an optical disk, a CD-ROM, a DVD, a flash memory, a USB memory card, or any other medium from which a computer can read.

Memory1508or storage device1510may be an example of a non-transitory computer-readable storage medium for use by or in connection with computer system1500. The non-transitory computer-readable storage medium contains instructions for controlling a computer system1500to be configured to perform functions described by some embodiments. The instructions, when executed by one or more computer processors1506, may be configured to perform that which is described in some embodiments.

Computer system1500includes a display1512for displaying information to a computer user. Display1512may display a user interface used by a user to interact with computer system1500.

Computer system1500also includes a network interface1504to provide data communication connection over a network, such as a local area network (LAN) or wide area network (WAN). Wireless networks may also be used. In any such implementation, network interface1504sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

Computer system1500can send and receive information through network interface1504across a network1514, which may be an Intranet or the Internet. Computer system1500may interact with other computer systems1500through network1514. In some examples, client-server communications occur through network1514. Also, implementations of some embodiments may be distributed across computer systems1500through network1514.

Some embodiments may be implemented in a non-transitory computer-readable storage medium for use by or in connection with the instruction execution system, apparatus, system, or machine. The computer-readable storage medium contains instructions for controlling a computer system to perform a method described by some embodiments. The computer system may include one or more computing devices. The instructions, when executed by one or more computer processors, may be configured to perform that which is described in some embodiments.