Network Devices, Methods, and Systems

Abstract

The transmitter transmits a first signal at a first communication rate over a first cable. The receiver receives a second signal over the first cable simultaneously with transmitting the first signal over the first cable. The second signal is transmitted by another device at a second communication rate that is lower than both (i) the first communication rate and (ii) a third communication rate at which a third signal is being transmitted over the second cable that causes crosstalk in the second signal received over the first cable. Receiving the second signal at a second communication rate that is lower than the third communication rate facilitates mitigating crosstalk in the second signal caused by transmission of the third signal at the third communication rate over the second cable.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 124,510, filed December 11, 2020, entitled "Asymmetric Enterprise Network," the disclosure of which is expressly incorporated herein by reference in its entirety.

[0002] TECHNICAL FIELD This disclosure relates generally to communication networks, and more particularly to Ethernet communications over twisted pair cables. [Background technology]

[0003] Over the past two decades, there has been a proliferation of 1 Gigabit per second (1G) and slower Ethernet networks in office buildings, schools, homes, etc. 1G and slower Ethernet networks often utilize Category 5 (Cat5) or Category 5e (Cat5e) twisted-pair copper cabling, which contains multiple twisted wire pairs. As a result, there is now a large installed base of 1G and slower Ethernet networks using Cat5 and Cat5e cabling.

[0004] The Institute for Electrical and Electronics Engineers (IEEE) published several standards for Ethernet networks using 10 Gigabit per second (10G) communications over optical and copper cables in the early to mid-2000s. For example, the IEEE 802.3ae standard (2002) defines a communication protocol for 10G Ethernet over optical fiber, the IEEE 802.3ak standard (2004) defines a communication protocol for 10G Ethernet over twin-axial cable, and the IEEE 802.3an standard (2006) defines a communication protocol for 10G Ethernet over copper twisted pair cable.

[0005] The higher communication speed of 10G Ethernet compared to 1G and slower Ethernet tends to result in more crosstalk between twisted-pair copper cables. Cat5 and Cat5e cables are generally not rated for use with 10G Ethernet. This is primarily due to the performance degradation caused by increased crosstalk between cables as 10G Ethernet communication speeds increase. For example, Cat5 and Cat5e cables are rated up to 100 MHz, while 10G Ethernet over copper twisted-pair cable (IEEE 802.3an standard) utilizes a communication speed of 800 megasymbols per second (MSps). The minimum bandwidth required for a given communication speed is at least twice that communication speed. Thus, for 10G Ethernet, the minimum required bandwidth is 400 MHz. However, as discussed above, Cat5 and Cat5e are rated only up to 100 MHz.

[0006] On the other hand, Category 6 (Cat6) and Category 6A (Cat6A) cables are designed for higher communication speeds (and they reduce crosstalk at higher communication speeds) and are rated up to 250 MHz and 500 MHz, respectively. Therefore, it is common for 10G Ethernet network deployments to use Cat6 or Cat6A (or even Category 7 (Cat7)) cables.

[0007] Relatively few 10G Ethernet networks currently exist in office buildings, schools, homes, etc., partly as a result of the high cost of replacing the existing large installed base of Cat5 and Cat5e cabling with Cat6 or Cat6A (or even Cat7) cabling. Summary of the Invention

[0008] In one embodiment, a first network device for communicating over a first cable includes a first transmitter configured to transmit a first signal over the first cable at a first communication rate corresponding to a first minimum required bandwidth, the first minimum required bandwidth exceeding a maximum bandwidth rating of the first cable; and a first receiver configured to receive a second signal over the first cable simultaneously with transmitting the first signal over the first cable, the second signal being (i) at the first communication rate, and (ii) at a third signal over the second cable that causes crosstalk in the second signal received over the first cable. and a third communication rate being transmitted by the second network device at a second communication rate that is lower than both the first communication rate and the third communication rate being transmitted by the second network device, wherein the second communication rate corresponds to a second required minimum bandwidth that does not exceed a maximum bandwidth rating of the first cable, and the third communication rate corresponds to a third required minimum bandwidth that exceeds the maximum bandwidth rating of the second cable, and receiving the second signal at a second communication rate that is (i) lower than the third communication rate and (ii) does not exceed the maximum bandwidth rating of the first cable facilitates mitigation of crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable.

[0009] In another embodiment, a method for communicating over a first cable includes transmitting, by a first transceiver of a first network device, a first signal over the first cable at a first communication rate corresponding to a first minimum required bandwidth, the first minimum required bandwidth exceeding a maximum bandwidth rating of the first cable; and, concurrently with transmitting the first signal over the first cable, receiving, by the first transceiver, a second signal over the first cable, the second signal being (i) at the first communication rate and (ii) at a third signal over the second cable that causes crosstalk in the second signal received over the first cable. and a third communication rate being transmitted by the second network device at a second communication rate lower than both the first communication rate and the third communication rate being transmitted on the second cable, wherein the second communication rate corresponds to a second required minimum bandwidth not exceeding a maximum bandwidth rating of the first cable, and the third communication rate corresponds to a third required minimum bandwidth that exceeds the maximum bandwidth rating of the second cable, and receiving the second signal at a second communication rate that is (i) lower than the third communication rate and (ii) not exceeding the maximum bandwidth rating of the first cable facilitates mitigation of crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable.

[0010] In yet another embodiment, a first network interface for communicating via a first cable comprises: a receiver configured to receive a first signal via the first cable, the first signal being transmitted by a second network device at a first communication rate; and a transmitter configured to transmit a second signal via the first cable at a second communication rate lower than the first communication rate to reduce crosstalk to one or more second cables caused by transmitting a second signal on the first cable simultaneously with the receiver receiving the first signal at the first communication rate.

[0011] In yet another embodiment, a method for communicating over a first cable includes receiving a first signal over the first cable at a transceiver unit of a first network device, the first signal being transmitted by a second network device at a first communication rate; and simultaneously receiving the first signal over the first cable, transmitting a second signal over the first cable by the transceiver unit at a second communication rate that is lower than the first communication rate, to reduce crosstalk to one or more second cables caused by transmitting the second signal over the first cable. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a simplified diagram of an exemplary communication system that uses asymmetric uplink and downlink transmission rates to reduce crosstalk between multiple cables, according to one embodiment.

[0013] [Figure 2] A plot of the power spectral density (PSD) of alien crosstalk between multiple Cat5e cables versus frequency.

[0014] [Figure 3] FIG. 1 is a simplified block diagram of an exemplary transceiver configured to transmit at a first communication rate while simultaneously receiving at a second communication rate that is lower than the first communication rate, according to one embodiment.

[0015] [Figure 4] FIG. 1 is a simplified block diagram of an exemplary transceiver configured to receive at a first communication rate while simultaneously transmitting at a second communication rate that is lower than the first communication rate, according to one embodiment.

[0016] [Figure 5] 1 is a flow diagram of an exemplary method for communicating over a first cable according to one embodiment.

[0017] [Figure 6] FIG. 10 is a flow diagram of an exemplary method for communicating over a cable according to another embodiment.

[0018] [Figure 7] FIG. 10 is a flow diagram of another exemplary method for communicating over a first cable according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] As mentioned above, there is currently a large installed base of 1G and slower Ethernet networks using Cat5 and Cat5e cables. However, over the past few years, both the need for higher data rates and the availability of 10 Gigabit per second (10G) Ethernet ports have increased significantly. Therefore, there is a growing desire to upgrade existing 1G and slower Ethernet networks. However, one of the obstacles to upgrading existing 1G and slower Ethernet networks is the cost of upgrading the cables required for 10G Ethernet. Cat6 and Cat6a cables are more expensive than Cat5 and Cat5e cables. More importantly, the labor costs of replacing Cat5 and Cat5e cables with Cat6 or Cat6a cables are very significant, and the cable replacement process can be very disruptive to, for example, Ethernet network users, office building employees, apartment building residents, etc.

[0020] In many existing Ethernet networks, the amount of data traveling in a first direction (e.g., from a router, switch, hub, etc. to an endpoint) is much greater than the amount of data traveling in a second direction (e.g., from an endpoint to a router, switch, hub, etc.). Thus, in many Ethernet networks, the need for high-speed data in the first direction is greater than in the second direction. This application describes embodiments of devices and methods that enable higher-speed transmission in the first direction (e.g., 10 Gigabits per second (Gbps)) using existing cables that are not rated for higher speeds (e.g., Cat5 and Cat5e cables, or even Cat3 cables). The higher-speed transmission in the first direction over existing cables is facilitated at least in part by lower-speed transmission in the second direction (e.g., 0.1 Gbps, 1 Gbps, 2.5 Gbps, 5 Gbps). As further described below, using asymmetric transmission rates mitigates the adverse effects of crosstalk between multiple cables (e.g., Cat5 and Cat5e cables). Thus, higher speed transmission in the first direction can be achieved over existing, already installed cables (e.g., Cat5 and Cat5e cables, or even Cat3 cables), i.e., without the need to install new cables.

[0021] 1 is a simplified diagram of an exemplary communication system 100, according to one embodiment. The communication system 100 includes a network device 104, such as a router, switch, or hub, communicatively coupled to a plurality of endpoint devices 108 (e.g., computers, televisions, gaming systems, medical equipment, etc.) via respective cables 112. As an illustrative example, the communication system 100 is located in an office building, and the endpoint devices 108 correspond to computers in different workstations (e.g., offices, cubicles, etc.). As another illustrative example, the communication system 100 is located in an apartment building, and the endpoint devices 108 correspond to computers, televisions, gaming systems, etc. throughout the building. As another illustrative example, the communication system 100 is located in a healthcare facility, and the endpoint devices 108 correspond to medical equipment, computers, and televisions throughout the healthcare facility.

[0022] The network device 104 includes multiple transceivers 120, each communicatively coupled to a respective cable 112. Similarly, each endpoint 108 includes a respective transceiver 124, communicatively coupled to a respective cable 112. Although three transceivers 120 and three endpoints 108 are shown in FIG. 1 , the communication system 100 includes other suitable numbers of transceivers 120 and endpoints 108, such as two or more than three. In some embodiments, a single endpoint 108 includes multiple transceivers 124 communicatively coupled to multiple respective cables 112.

[0023] According to one embodiment, one or more of the cables 112 are Class C cables (sometimes called Category 3 (Cat3) cables) or Class D cables (sometimes called Category 5e (Cat5e) cables) as specified by the ISO / IEC 11801 standard. Class C (Cat3) cables contain multiple twisted copper wire pairs and are typically rated for specific performance and test requirements up to 16 MHz. Class D (Cat5e) cables contain multiple twisted copper wire pairs and are typically rated for specific performance and test requirements up to 100 MHz. One or more of the cables 112 are Category 5 (Cat5) cables as specified by older versions of the ISO / IEC 11801 standard and, like Cat5e cables, are rated for specific performance and test requirements up to 100 MHz (according to older versions of the ISO / IEC 11801 standard). Category 3 cables, Category 5 cables, and Category 5E cables are sometimes referred to herein as "legacy cables."

[0024] By comparison, Class E cable (sometimes called Category 6 (Cat6) cable) as specified by the ISO / IEC 11801 standard and Class E cable as specified by the ISO / IEC 11801 standard A Cables (sometimes called Category 6A (Cat6A) cables) are rated for specific performance and test requirements up to 250 MHz and 500 MHz, respectively. Class F cables (sometimes called Category 7 (Cat7) cables) specified by the ISO / IEC 11801 standard are rated for specific performance and test requirements up to 600 MHz. Meanwhile, according to some embodiments, legacy cables may not be rated for any performance or test requirements above 100 MHz according to the ISO / IEC 11801 standard.

[0025] In some embodiments, one or more other cables 112 are legacy cables that are not rated for any performance or testing requirements above 100 MHz. In some embodiments, one or more other cables 112 are rated for performance or testing requirements above 100 MHz. For example, in one embodiment, one or more other cables 112 are Cat6, Cat6A, or Cat7 cables.

[0026] As described in more detail below, at least some of the plurality of transceivers 120 (e.g., at least transceivers 120-1, 120-2, and 120-3) are configured to transmit at a first communication rate but simultaneously receive at a second communication rate that is lower than the first communication rate. Similarly, at least some of the plurality of transceivers 124 (e.g., at least transceivers 124-1, 124-2, and 124-3) are configured to receive at the first communication rate but simultaneously transmit at a second communication rate.

[0027] 1, at least cables 112-1, 112-2, and 112-3 are bundled together for cable management. Bundling cables 112-1, 112-2, and 112-3 generally increases crosstalk between cables 112-1, 112-2, and 112-3. For example, transmissions in cable 112-1 and in cable 112-3 both cause crosstalk into cable 112-2. Similarly, transmissions in cable 112-2 cause crosstalk into cables 112-1 and 112-3. Such crosstalk is sometimes referred to as "alien crosstalk" because the crosstalk experienced by one cable 112 is caused by transmissions in another cable 112, as opposed to crosstalk between different twisted pairs within a single cable 112.

[0028] In other embodiments, at least some of the cables 112 (e.g., at least cables 112-1, 112-2, and 112-3) are not bundled but are otherwise deployed in a configuration that causes alien crosstalk between the multiple cables 112. For example, multiple cables 112 that run together in close proximity for a span (but are not bundled with straps or ties) may experience alien crosstalk. In other embodiments, at least some of the alien crosstalk occurs due to the close proximity between the ports of the network devices to which each cable 112 is connected, as opposed to bundling the multiple cables 112 or the close proximity of the multiple cables 112.

[0029] Generally, legacy cables tend to induce and / or experience more alien crosstalk in 10G Ethernet transmissions compared to Cat6, Cat6A, and Cat7 cables.

[0030] The largest component of alien crosstalk is typically crosstalk experienced by a receiver circuit within a first transceiver unit (e.g., transceiver unit 120 or transceiver unit 124) caused by transmissions by one or more second transceivers located proximate to the first transceiver unit, and is sometimes referred to as "near-end alien crosstalk." For example, the receiver circuit of transceiver unit 120-1 experiences near-end alien crosstalk caused by transmissions by transceiver unit 120-2 within cable 112-2. As another example, the receiver circuit of transceiver unit 120-2 experiences near-end alien crosstalk caused by transmissions by transceiver unit 120-1 within cable 112-1 and by transceiver unit 120-3 within cable 112-3. As another example, the receiver circuit of transceiver unit 120-3 experiences near-end alien crosstalk caused by transmissions by transceiver unit 120-2 within cable 112-2.

[0031] Other examples of alien crosstalk include: the receive circuit of transceiver unit 124-1 experiences near-end alien crosstalk caused by transmissions by transceiver unit 124-2 in cable 112-2; the receive circuit of transceiver unit 124-2 experiences near-end alien crosstalk caused by transmissions by transceiver unit 124-1 in cable 112-1 and by transceiver unit 124-3 in cable 112-3; and the receive circuit of transceiver unit 124-3 experiences near-end alien crosstalk caused by transmissions by transceiver unit 124-2 in cable 112-2.

[0032] Cat5e cable (or even Cat5 cable) can be used for 10G Ethernet links when the cable length is relatively short and alien crosstalk is not an issue, for example, when the cable is not bundled with any other Ethernet cables. However, in networks such as that shown in FIG. 1 where multiple network cables 112 are bundled, or in deployments where alien crosstalk is otherwise significant, standard 10G Ethernet transmission over Cat5e or Cat5 cable will typically result in alien crosstalk that significantly degrades performance.

[0033] Figure 2 plots the power spectral density (PSD) of alien crosstalk between multiple Cat5e cables versus frequency in a specific experimental network configuration. In particular, Figure 2 shows the PSD of alien crosstalk caused by 10G Ethernet transmissions and 1G Ethernet transmissions in a specific experimental network configuration. Alien crosstalk is highly dependent on the physical implementation and traffic characteristics, and a general model for alien crosstalk has not been clearly defined. Therefore, Figure 2 is merely intended to illustrate the general behavior of alien crosstalk in a specific experimental setting.

[0034] In the experimental network configuration corresponding to Figure 2, the PSD of alien crosstalk ("1G alien crosstalk") caused by 1G Ethernet remains at a level that does not adversely affect other 1G Ethernet transmissions to a significant extent. Additionally, the PSD of 1G alien crosstalk generally decreases with increasing frequency. Thus, in the experimental network configuration corresponding to Figure 2, alien crosstalk caused by 1G Ethernet transmissions tends not to adversely affect other 1G Ethernet transmissions or other 10G Ethernet transmissions.

[0035] The PSD of alien crosstalk caused by 10G Ethernet ("10G alien crosstalk") is generally constant (e.g., approximately -152.5 dB) for frequencies corresponding to 1G Ethernet, but generally increases with increasing frequency. Thus, in contrast to the PSD of 1G alien crosstalk, the PSD of 10G alien crosstalk generally increases with frequency, generally at frequencies that overlap with 10G Ethernet transmissions.

[0036] Additionally, as can be seen in FIG. 2, the PSD of 10G alien crosstalk is much larger than the PSD of 1G alien crosstalk for higher frequencies.

[0037] Referring again to FIG. 1 , if transceiver 124-2 transmits at a communication rate corresponding to 1G Ethernet, alien crosstalk will be generated on cables 112-1 and 112-3. Similarly, if transceivers 124-1 and 124-3 transmit at a communication rate corresponding to 1G Ethernet, alien crosstalk will be generated on cable 112-2. However, the PSD of such alien crosstalk remains at a level that does not appreciably adversely affect other Ethernet transmissions at higher communication rates. For example, as discussed above with reference to FIG. 2 , the PSD of 1G alien crosstalk caused by the transmissions of transceiver 124 generally decreases with increasing frequency. Therefore, near-end alien crosstalk caused by transceiver 124 transmitting at a communication rate corresponding to 1G Ethernet will not appreciably adversely affect the reception by other transceivers 124 of Ethernet transmissions at higher communication rates (e.g., corresponding to 10G).

[0038] If transceiver 120-2 transmits at a communication rate corresponding to 10G Ethernet, alien crosstalk will be induced on cables 112-1 and 112-3. Similarly, if transceivers 120-1 and 120-3 transmit at a communication rate corresponding to 10G Ethernet, alien crosstalk will be induced on cable 112-2. At frequencies generally corresponding to 1G Ethernet, the PSD of such alien crosstalk remains at a level that does not itself significantly adversely affect other Ethernet transmissions. Additionally, because transmissions by transceivers 124 are at a lower communication rate (e.g., corresponding to 1G Ethernet), signals received at each transceiver 120 can be low-pass filtered to remove higher frequency components of the 10G alien crosstalk. Thus, the PSD of the 10G alien crosstalk caused by the transmissions of transceivers 120 can be kept below a level that does not significantly adversely affect reception of 1G Ethernet transmissions from transceivers 124.

[0039] Thus, a transceiver 120 transmitting at a first communication rate but simultaneously receiving at a second communication rate can mitigate (e.g., using a low-pass filter) near-end alien crosstalk caused by the transmissions of other transceivers 120. Additionally, a transceiver 124 receiving at a higher first communication rate but simultaneously transmitting at a lower second communication rate may experience near-end alien crosstalk (e.g., 1G alien crosstalk) caused by the transmissions of other transceivers 124, but such near-end alien crosstalk remains at a PSD level that does not adversely affect reception at the transceiver 124 to any appreciable extent.

[0040] In some embodiments, at least some of the plurality of transceivers 120 are each configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the respective cable 112. In some embodiments, at least some of the plurality of transceivers 120 are each configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the respective cable 112 by at least 75 MHz. In other embodiments, at least some of the plurality of transceivers 120 are each configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the respective cable 112 by at least 100 MHz. In other embodiments, at least some of the plurality of transceivers 120 are each configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the respective cable 112 by at least 250 MHz.

[0041] In some embodiments, each of at least some of the transceivers 120 is additionally configured to receive at a communication rate corresponding to a minimum bandwidth less than or equal to the maximum bandwidth rating of the respective cable 112 .

[0042] In some embodiments, at least some of the plurality of transceivers 124 are each configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112. In some embodiments, at least some of the plurality of transceivers 124 are each configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 75 MHz. In other embodiments, at least some of the plurality of transceivers 124 are each configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 100 MHz. In other embodiments, at least some of the plurality of transceivers 124 are each configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 250 MHz.

[0043] In some embodiments, at least some of the transceivers 124 are each additionally configured to transmit at a communication rate corresponding to a minimum bandwidth less than or equal to the maximum bandwidth rating of the cable 112 .

[0044] 1 has been discussed in the context of downlink direction transmissions at a first, higher communication rate and uplink direction transmissions at a second, lower communication rate, in other embodiments it is useful to have downlink direction transmissions at a second, lower communication rate and uplink direction transmissions at a higher, first communication rate. For example, in one embodiment, endpoint 108 corresponds to a video camera (e.g., communication system 100 corresponds to a security system) that transmits video data in the uplink direction to network device 104, while network device 104 transmits a relatively small amount of data in the downlink direction to endpoint 108. In such an embodiment, the amount of data traveling in the uplink direction is much greater than the amount of data traveling in the downlink direction.

[0045] Thus, in some embodiments, each transceiver 120 is configured to transmit at a lower second communication rate and receive at a higher first communication rate, and each transceiver 124 is configured to transmit at the higher first communication rate and receive at the lower second communication rate.

[0046] In some embodiments, network device 104 includes controller 140 configured to determine the direction of communication rate asymmetry utilized in network 100. For example, according to one embodiment, controller 140 monitors the amount of network traffic in the downlink direction compared to the uplink direction to determine in which direction (e.g., downlink or uplink) a higher communication rate should be utilized. In one such embodiment, controller 140 informs at least transceiver 120 (and optionally transceiver 124) of the direction (e.g., downlink or uplink) in which a higher communication rate should be utilized. Although controller 140 is shown as a component of network device 104, in some embodiments, controller 140 is separate from and communicatively coupled to network device 104. In some embodiments, controller 140 is omitted from communication system 100.

[0047] In some embodiments, the transceivers 120 and 140 are capable of using multiple different communication rates in the downlink direction and / or multiple different communication rates in the uplink direction. In some such embodiments, the transceivers 120 and 140 are configured to negotiate with each other regarding the communication rates to use in the uplink and downlink directions, subject to one or more constraints, such as, for example, one or more of: (i) the communication rate in the downlink direction must exceed the communication rate in the uplink direction, or vice versa; (ii) all transceivers 120 must use the same transmission communication rate; (iii) all transceivers 120 must use at least a minimum transmission communication rate; (iv) all transceivers 120 must use at most a maximum transmission communication rate; (v) all transceivers 124 must use the same transmission communication rate; (vi) all transceivers 124 must use at least a minimum transmission communication rate; (vii) all transceivers 124 must use at most a maximum transmission communication rate; etc.

[0048] In other embodiments, each of the one or more transceivers 120 is capable of transmitting only at a first, higher communication rate and / or receiving only at a second, lower communication rate, or vice versa. Similarly, in some embodiments, each of the one or more transceivers 124 is capable of receiving only at a first, higher communication rate and / or transmitting only at a second, lower communication rate, or vice versa.

[0049] Figure 3 is a simplified block diagram of an exemplary transceiver 300 configured to transmit at a first communication rate while simultaneously receiving at a second communication rate that is lower than the first communication rate, according to one embodiment. The transceiver 300 may, according to some embodiments, be utilized in each of at least some of the plurality of transceivers 120 of Figure 1, and Figure 3 is described with reference to Figure 1 for illustrative purposes. In other embodiments, the transceiver 300 may be utilized in another suitable communication system different from the communication system 100 of Figure 1, and / or some or all of the plurality of transceivers 120 of Figure 1 may correspond to a suitable transceiver different from the exemplary transceiver 300 of Figure 3.

[0050] According to one embodiment, the transceiver 300 is coupled to the cable 112, for example, by suitable cable connectors (not shown), such as male and female RJ45 connectors, male and female M12 connectors, or the like.

[0051] The transceiver 300 includes a transmitter circuit 304 configured to transmit at a first communication rate. In some embodiments, the first communication rate corresponds to a signal bandwidth that exceeds the maximum frequency rating of the cable 112. In one embodiment, the first communication rate is approximately 800 megasymbols per second (MSps) (i.e., 800 MSps ± 8 MSps). In another embodiment, the first communication rate is approximately 400 MSps (i.e., 400 MSps ± 4 MSps). More generally, according to some embodiments, the minimum required bandwidth corresponding to the first communication rate exceeds the maximum frequency rating of the cable 112. For example, according to some embodiments, the cable 112 is a legacy cable with a maximum frequency rating that is less than the minimum required bandwidth corresponding to the first communication rate.

[0052] The transceiver 300 also includes a receiver circuit 308 configured to receive at a second communication rate lower than the first communication rate. In one embodiment, the second communication rate is approximately 125 MSps (i.e., 125 MSps ± 1 MSps). In another embodiment, the second communication rate is approximately 200 MSps (i.e., 200 MSps ± 2 MSps). In another embodiment where the first communication rate is approximately 800 MSps, the second communication rate is approximately 400 MSps (i.e., 400 MSps ± 4 MSps). In some embodiments, the minimum required bandwidth corresponding to the second communication rate is less than or equal to the maximum frequency rating of the cable 112 according to some embodiments. For example, according to some embodiments, the cable 112 is a legacy cable with a maximum frequency rating greater than or equal to the minimum required bandwidth corresponding to the second communication rate.

[0053] Transmit circuitry 304 transmits at a first communication rate simultaneously with receive circuitry 308 receiving at a second communication rate.

[0054] 3 shows one transmit circuit block 304 and one receive circuit block 308. However, in embodiments in which the cable 112 includes multiple twisted wire pairs, the transceiver unit 300 includes a respective transmit circuit block 304 and a respective receive circuit block 308 for each twisted wire pair in the cable 112. For example, each transmit circuit block 304 generates a respective transmit signal for each twisted wire pair, and each receive circuit block 308 processes a respective receive signal for each twisted wire pair. Thus, according to one embodiment, for a cable 112 including four twisted wire pairs, the transceiver unit 300 includes four transmit circuit blocks 304 and four receive circuit blocks 308.

[0055] The transmit circuit 304 is coupled to the cable 112 via a hybrid circuit 312, and the receive circuit 308 is coupled to the cable 112 via the hybrid circuit 312. The hybrid circuit 312 is configured to pass transmit signals generated by the transmit circuit 304 to the cable 112 and to block the transmit signals from passing to the receive circuit 308. Additionally, the hybrid circuit 312 is configured to pass receive signals received from the cable 112 to the receive circuit 308. In one embodiment, the hybrid circuit 312 is configured to block the receive signals from passing to the transmit circuit 304.

[0056] The transceiver 300 includes an echo canceller 316 configured to reduce echoes associated with full-duplex communication. In one embodiment, the echo canceller 316 is configured to generate a respective correction signal for each receive circuit block 308. In one embodiment, the echo canceller 316 is configured to generate one or more correction signals using respective signals generated by each transmit circuit block 304.

[0057] The transmit circuit 304 includes an error correction encoder 332 that encodes information bits ("transmit bits") to be transmitted over the cable 112 according to an appropriate error correction code to generate encoded transmit bits. In an exemplary embodiment, the error correction encoder 332 is configured to encode the transmit bits according to a low-density parity-check (LDPC) code. In other embodiments, the error correction encoder 332 is configured to encode the transmit bits according to another appropriate error correction code.

[0058] The transmit circuitry 304 also includes a modulation symbol mapper 336 configured to map the coded transmit bits to modulation symbols. In some embodiments, the modulation symbol mapper 336 is also configured to implement Tomlinson-Harashima Precoding (THP) (“Modulation Symbol Mapper / THP 336”). In one embodiment, the modulation symbol mapper 336 outputs modulation symbols at the first communication rate.

[0059] The transmit circuitry 304 further comprises a digital-to-analog converter (DAC) 340 configured to convert the output of the modulation symbol mapper 336 into an analog transmit signal for transmission over the cable 112 .

[0060] The receive circuit 308 includes an analog low-pass filter 354 coupled to the hybrid circuit 512. The receive circuit 308 also includes an analog-to-digital converter (ADC) 360 coupled to the low-pass filter 354. The ADC 360 is configured to convert the analog receive signal (received via the cable 112) to a digital receive signal. In one embodiment, the analog low-pass filter 354 is an anti-aliasing filter configured to attenuate high-frequency components of the receive signal prior to sampling by the ADC 360 to attenuate aliasing of high-frequency components caused by the sampling process.

[0061] The receive circuit 308 also includes an adder circuit 364 configured to add the correction signal generated by the echo canceller 316 to the digital receive signal to mitigate crosstalk from one or more transmit signals generated by the transmit circuit block 304.

[0062] The receiver circuitry 308 further comprises a demodulator / equalizer 368 configured to equalize the digital received signal and convert modulation symbols into coded information bits.

[0063] The receiver circuit 308 also includes an error correction decoder 372 that generates received bits by decoding the coded information bits output by the demodulator / equalizer 368 according to the error correction code used by the transmitter. In an exemplary embodiment, the error correction encoder 372 is configured to decode the coded received bits according to an LDPC code. In other embodiments, the error correction decoder 372 is configured to decode the coded received bits according to another suitable error correction code.

[0064] Receive circuit 308 further includes digital low-pass filter 384 configured to attenuate high-frequency alien crosstalk components caused by transmissions at the first communication rate on other cable 112. Referring to FIGS. 1 and 3, if transceiver 300 (FIG. 3) corresponds to transceiver 120-2 (FIG. 1), digital low-pass filter 384 is configured, according to an exemplary embodiment, to attenuate high-frequency alien crosstalk components caused by transmissions at the first communication rate by transceiver 120-1 and transceiver 120-3 on cables 112-1 and 112-3, respectively. Similarly, if transceiver 300 (FIG. 3) corresponds to transceiver 120-1 (FIG. 1), digital low-pass filter 384 is configured, according to another exemplary embodiment, to attenuate high-frequency alien crosstalk components caused by transmissions at the first communication rate by transceiver 120-2 on cable 112-2. Similarly, if transceiver 300 (FIG. 3) corresponds to transceiver 120-3 (FIG. 1), digital low-pass filter 384, according to another exemplary embodiment, is configured to attenuate high-frequency alien crosstalk components in cable 112-2 caused by transmissions by transceiver 120-2 at at least the first communication speed.

[0065] In one embodiment, the digital low-pass filter 384 is configured to provide significant attenuation (i.e., by at least −6 dB) at frequencies above an appropriate cutoff frequency. In some embodiments, the cutoff frequency will vary depending on the first and second communication rates used by the transceiver 300. In other embodiments, the cutoff frequency will vary depending on (i) the second communication rate and (ii) a third communication rate of another signal transmitted on another cable (not shown) that is causing crosstalk in the received signal received by the receiver circuitry 308. The other signal is transmitted by another transceiver (not shown) at the third communication rate. In some embodiments where multiple low-pass filters are provided (described further below), the multiple low-pass filters together provide significant attenuation at frequencies above the cutoff frequency.

[0066] In some embodiments, digital low-pass filter 384 is coupled between summing circuit 364 and demodulator / equalizer 368 to filter the digital received signal before it is processed by demodulator / equalizer 368. In some embodiments, digital low-pass filter 384 is coupled between demodulator / equalizer 368 and error correction decoder 372 to filter the digital received signal before it is processed by error correction decoder 372. In some embodiments, digital low-pass filter 384 is coupled between ADC 360 and summing circuit 364 to filter the digital received signal before it is processed by summing circuit 364. In some embodiments, the digital low-pass filter 384 is implemented as multiple digital low-pass filters located in two or more of the following locations: (i) between the ADC 360 and the summing circuit 364, (ii) between the summing circuit 364 and the demodulator / equalizer 368, (iii) between the demodulator / equalizer 368 and the error correction decoder 372, etc.

[0067] In some embodiments, digital lowpass filter 384 is omitted. For example, in at least some network implementations, analog lowpass filter 354 is configured to attenuate high-frequency alien crosstalk components to a sufficient degree. As another example, in some network implementations, the level of high-frequency alien crosstalk components, combined with the greater robustness of the received signal at a slower second communication rate (compared to the transmitted signal at a faster first communication rate), is at a level that provides an adequate error rate for the received signal without requiring the use of digital lowpass filter 384.

[0068] During operation (in the exemplary network 100 of FIG. 1 , where the transceiver 300 is located in the network device 104, according to one embodiment), the transmit circuitry 304 generates a transmit signal at a first communication rate for transmission over the cable 112, while the receive circuitry 308 simultaneously receives and processes a receive signal transmitted over the cable 112 at a second communication rate that is slower than the first communication rate. As discussed above, the largest component of alien crosstalk experienced by the receive circuitry 308 is typically near-end alien crosstalk caused by the transmissions of one or more other transceivers located near the transceiver 300. However, because the receive signal is transmitted at the lower second communication rate, the one or more low-pass filters 384 can remove higher frequency components of the near-end alien crosstalk, while the lower frequency components of the near-end alien crosstalk are at a lower PSD (compared to the higher frequency components of the near-end alien crosstalk) and therefore do not adversely affect decoding of the receive signal to a significant extent. In some embodiments in which digital lowpass filter 384 is omitted, analog lowpass filter 354 is configured to attenuate high frequency components of alien crosstalk to a sufficient degree, while in other embodiments in which digital lowpass filter 384 is omitted, the level of high frequency components of alien crosstalk is at a level that, combined with the greater robustness of the received signal at the slower second communication rate (compared to the transmitted signal at the faster first communication rate), provides an adequate error rate for the received signal.

[0069] In some embodiments, the transmit circuitry 304 is configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112. In some embodiments, the transmit circuitry 304 is configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 75 MHz. In other embodiments, the transmit circuitry 304 is configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 100 MHz. In other embodiments, the transmit circuitry 304 is configured to transmit using a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 250 MHz.

[0070] In some embodiments, the receive circuitry 308 is additionally configured to receive at a communication rate corresponding to a minimum bandwidth less than or equal to the maximum bandwidth rating of the cable 112 .

[0071] In some embodiments, one or more (or all) of the error correction encoder 332, modulation symbol mapper / THP 336, echo canceller 316, digital low pass filter 384 (if present), summing circuit 364, demodulator / equalizer 368, and error correction decoder 372 are implemented using respective digital circuitry; and / or one or more (or all) of the error correction encoder 332, modulation symbol mapper / THP 336, echo canceller 316, digital low pass filter 384 (if present), summing circuit 364, demodulator / equalizer 368, and error correction decoder 372 are implemented by one or more digital signal processors (DSPs) (not shown) executing machine-readable instructions stored in one or more memories (not shown) coupled to the one or more DSPs.

[0072] In some embodiments, the transmit circuitry 304 may be capable of transmitting at multiple different communication rates and / or the receive circuitry 308 may be capable of receiving at multiple different communication rates. In some such embodiments, the digital low pass filter 384 may be configured to implement low pass filters with multiple different cutoff frequencies appropriate for the multiple communication rates used by the transmit circuitry 304 and the receive circuitry 308.

[0073] In embodiments in which the transmit circuitry 304 is capable of transmitting at a second communication rate that is lower than the first communication rate at which the receive circuitry 308 receives, the receive circuitry 308 can be configured to deactivate the digital low-pass filter 384 (e.g., so that the signal passes through the digital low-pass filter 384 without being modified) or to bypass the digital low-pass filter 384 (e.g., so that the signal passes around the digital low-pass filter 384 without being modified).

[0074] Figure 4 is a simplified block diagram of an exemplary transceiver 400 configured to receive at a first communication rate while simultaneously transmitting at a second communication rate that is lower than the first communication rate, according to one embodiment. The transceiver 400, according to some embodiments, may be utilized in each of at least some of the plurality of transceivers 124 in the endpoint device 108 of Figure 1, and Figure 4 is described with reference to Figure 1 for illustrative purposes. In other embodiments, the transceiver 400 may be utilized in another suitable communication system different from the communication system 100 of Figure 1, and / or some or all of the plurality of transceivers 124 of Figure 1 may correspond to a suitable transceiver different from the exemplary transceiver 400 of Figure 4.

[0075] According to one embodiment, the transceiver 400 is coupled to the cable 112, for example, by suitable cable connectors (not shown), such as male and female RJ45 connectors, male and female M12 connectors, or the like.

[0076] The transceiver 400 includes a transmitter circuit 404 configured to transmit at a second communication rate that is lower than the first communication rate. For example, the second communication rate is approximately 125 MSps (i.e., 125 MSps±1 MSps).

[0077] The transceiver 400 also includes receiver circuitry 408 configured to receive at a first communication rate corresponding to a signal bandwidth that exceeds the maximum frequency rating of the cable 112. For example, according to one embodiment, the first communication rate is approximately 800 MSps (i.e., 800 MSps ±8 MSps).

[0078] Transmit circuitry 404 transmits at a second communication rate while receive circuitry 408 receives at a first communication rate.

[0079] 4 shows one transmit circuit block 404 and one receive circuit block 408. However, in embodiments in which the cable 112 includes multiple twisted wire pairs, the transceiver 400, according to one embodiment, includes a respective transmit circuit block 404 and a respective receive circuit block 408 for each twisted wire pair in the cable 112. For example, each transmit circuit block 404 generates a respective transmit signal for each twisted wire pair, and each receive circuit block 408 processes a respective receive signal for each twisted wire pair. Thus, according to one embodiment, for a cable 112 including four twisted wire pairs, the transceiver 400 includes four transmit circuit blocks 404 and four receive circuit blocks 408.

[0080] The transmit circuitry 404 is coupled to the cable 112 via a hybrid circuit 412, and the receive circuitry 408 is coupled to the cable 112 via the hybrid circuit 412. The hybrid circuit 412 is configured to pass transmit signals generated by the transmit circuitry 404 to the cable 112 and to block the transmit signals from passing to the receive circuitry 408. Additionally, the hybrid circuit 412 is configured to pass receive signals received from the cable 112 to the receive circuitry 408. In one embodiment, the hybrid circuit 412 is configured to block the receive signals from passing to the transmit circuitry 404.

[0081] The transceiver 400 includes an echo canceller 416 configured to reduce echoes associated with full-duplex communication. In one embodiment, the echo canceller 416 is configured to generate a respective correction signal for each receive circuit block 408. In one embodiment, the echo canceller 416 is configured to generate one or more correction signals using respective signals generated by each transmit circuit block 404.

[0082] The transmit circuit 404 includes an error correction encoder 432 that encodes information bits to be transmitted over the cable 112 ("transmit bits") according to an appropriate error correction code to generate encoded transmit bits. In an exemplary embodiment, the error correction encoder 432 is configured to encode the transmit bits according to an LDPC code. In other embodiments, the error correction encoder 432 is configured to encode the transmit bits according to a Reed-Solomon code or another appropriate error correction code.

[0083] The transmit circuitry 404 also includes a modulation symbol mapper 436 configured to map the coded transmission bits to modulation symbols. In some embodiments, the modulation symbol mapper 436 is also configured to implement a THP ("Modulation Symbol Mapper / THP 436"). In one embodiment, the modulation symbol mapper 436 outputs modulation symbols at the second communication rate.

[0084] The transmit circuitry 404 further comprises a DAC 440 configured to convert the output of the modulation symbol mapper 436 into an analog transmit signal for transmission over the cable 112 .

[0085] The receive circuitry 408 includes an ADC 460 configured to convert an analog receive signal (received via cable 112) to a digital receive signal.

[0086] The receive circuit 408 also includes a summing circuit 464 configured to add the correction signal generated by the echo canceller 416 to the digital receive signal to mitigate crosstalk from one or more transmit signals generated by the transmit circuit block 404.

[0087] The receiver circuitry 408 further comprises a demodulator / equalizer 468 configured to equalize the digital received signal and convert modulation symbols into coded information bits.

[0088] The receiver circuit 408 also includes an error correction decoder 472 that generates received bits by decoding the coded information bits output by the demodulator / equalizer 468 according to an error correction code used by the transmitter. In an exemplary embodiment, the error correction encoder 472 is configured to decode the coded received bits according to an LDPC code. In another exemplary embodiment, the error correction encoder 472 is configured to decode the coded received bits according to a Reed-Solomon code. In other embodiments, the error correction decoder 472 is configured to decode the coded received bits according to another suitable error correction code.

[0089] During operation, the transmit circuitry 404 generates transmit signals at a second communication rate (slower than the first communication rate) for transmission over the cable 112, while the receive circuitry 408 simultaneously receives and processes receive signals transmitted over the cable 112 at the first communication rate. As discussed above, the largest component of alien crosstalk experienced by the receive circuitry 408 is typically near-end alien crosstalk caused by the transmissions of one or more other transceivers located near the transceiver unit 400. However, because the signals transmitted by the other transceivers located near the transceiver unit 400 are transmitted at the lower second communication rate, the alien crosstalk caused by such signals does not appreciably adversely affect the decoding of the received signals. Additionally, because the transmit signals are generated and transmitted by the transmit circuitry 404 at the lower second communication rate, the alien crosstalk caused by the transmit signals does not appreciably adversely affect the decoding of the received signals at the other transceivers located near the transceiver unit 400.

[0090] In some embodiments, one or more (or all) of the error correction encoder 432, the modulation symbol mapper / THP 436, the echo canceller 416, the summing circuit 464, the demodulator / equalizer 468, and the error correction decoder 472 are implemented using respective digital circuitry; and / or one or more (or all) of the error correction encoder 432, the modulation symbol mapper / THP 436, the echo canceller 416, the summing circuit 464, the demodulator / equalizer 468, and the error correction decoder 472 are implemented by one or more DSPs (not shown) executing machine-readable instructions stored in one or more memories (not shown) coupled to the one or more DSPs.

[0091] In some embodiments, the receive circuitry 408 is configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112. In some embodiments, the receive circuitry 408 is configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 75 MHz. In other embodiments, the receive circuitry 408 is configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 100 MHz. In other embodiments, the receive circuitry 408 is configured to receive at a communication rate corresponding to a minimum bandwidth that exceeds the maximum bandwidth rating of the cable 112 by at least 250 MHz.

[0092] In some embodiments, the transmit circuitry 404 is additionally configured to transmit at a communication rate corresponding to a minimum bandwidth less than or equal to the maximum bandwidth rating of the cable 112 .

[0093] In some embodiments, the transmit circuitry 404 is capable of transmitting at a plurality of different communication rates, and / or the receive circuitry 408 is capable of receiving at a plurality of different communication rates. In some such embodiments, the transceiver 400 includes one or more digital low-pass filters (not shown), similar to the digital low-pass filter 384 discussed above with reference to FIG. 3. In a scenario in which the transmit circuitry 404 transmits at a second communication rate that is lower than the first communication rate at which the receive circuitry 408 receives, the receive circuitry 408 can be configured to deactivate the one or more digital low-pass filters (e.g., so that signals pass through the digital low-pass filters unmodified) or to bypass the one or more digital low-pass filters (e.g., so that signals pass around the digital low-pass filter 384 unmodified). Similarly, in a scenario where the transmit circuitry 404 transmits at a first communication rate that exceeds a second communication rate received by the receive circuitry 408, the receive circuitry 408 can be configured to activate one or more digital low-pass filters to reduce alien crosstalk in a manner similar to the digital low-pass filter 354 discussed above with reference to alien crosstalk FIG. 3.

[0094] FIG. 5 is a flow diagram of an exemplary method 500 for communicating over a first cable, according to one embodiment. In one embodiment, method 500 is implemented by network device 104 of FIG. 1, and method 500 will be described with reference to FIG. 1 for ease of explanation. In another embodiment, method 500 is implemented by one of endpoint devices 108 of FIG. 1. In other embodiments, method 500 is implemented by a suitable network device other than network device 104 and endpoint device 108 of FIG. 1. In one embodiment, method 500 is implemented using transceiver 300 of FIG. 3, and method 500 will be described with reference to FIG. 3 for ease of explanation. However, in other embodiments, method 500 is implemented using a suitable transceiver other than transceiver 300 of FIG. 3.

[0095] In some embodiments where the amount of data transmitted in a downlink direction within a communications network exceeds the amount of data transmitted in an uplink direction within the communications network, method 500 is implemented in a transceiver transmitting in the downlink direction. In some embodiments where the amount of data transmitted in an uplink direction within a communications network exceeds the amount of data transmitted in a downlink direction within the communications network, method 500 is implemented in a transceiver transmitting in the uplink direction.

[0096] At block 504, a first transceiver of the first network device transmits a first signal at a first communication rate over a first cable. According to one embodiment, the first transceiver transmitting the first signal at block 504 comprises transceiver 120-2 (FIG. 1) transmitting the first signal at the first communication rate over cable 112-2. According to another embodiment, the first transceiver transmitting the first signal at block 504 comprises transceiver 300 (FIG. 3) transmitting the first signal at the first communication rate over cable 112.

[0097] In one embodiment, the first cable is a first legacy cable that is not rated to support the minimum required bandwidth corresponding to the first communications speed, at least for the length of the first legacy cable and / or for deployments where alien crosstalk is an issue. In one embodiment, the first cable is a first legacy cable having a maximum frequency rating that is at most 50% of the minimum required bandwidth corresponding to the first communications speed (i.e., the minimum required bandwidth corresponding to the first communications speed is at least 200% greater than the maximum frequency rating of the first legacy cable). In other respective embodiments, the first cable is a first legacy cable having a maximum frequency rating that is at most 25% or at most 60% of the minimum required frequency corresponding to the first communications speed (i.e., the first communications speed is at least 400% or 167%, respectively, of the maximum frequency rating of the first legacy cable). In one embodiment, the first cable is a Class D cable according to the current ISO / IEC 11801 standard or a non-current version of the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class C cable according to the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class E cable according to the ISO / IEC 11801 standard.

[0098] In one embodiment, the first communication speed is approximately 800 MSps. In one embodiment, the first communication speed corresponds to a first data rate of 10 Gbps. In another embodiment, the first communication speed is approximately 400 MSps. In one embodiment, the first communication speed corresponds to a first data rate of 5 Gbps.

[0099] At block 508, concurrent with the transmission of the first signal at block 504, the first transceiver receives a second signal over the first cable, the second signal being transmitted by the second network device at a second communication rate that is lower than both (i) the first communication rate and (ii) a third communication rate (discussed further below). According to one embodiment, the first transceiver receiving the second signal at block 508 comprises transceiver 120-2 (FIG. 1) receiving the second signal at the second communication rate over cable 112-2. According to another embodiment, the first transceiver receiving the second signal at block 508 comprises transceiver 300 (FIG. 3) receiving the second signal at the second communication rate over cable 112.

[0100] In one embodiment, the first cable has a maximum frequency rating that is greater than or equal to the minimum required bandwidth of the second communication speed.

[0101] In one embodiment, the second communication rate is approximately 100 MSps (i.e., 100 MSps ± 1 MSps). In another embodiment, the second communication rate is approximately 200 MSps (i.e., 200 MSps ± 2 MSps). In another embodiment, where the first communication rate is approximately 800 MSps and the third communication rate is also approximately 800 MSps, the second communication rate is approximately 400 MSps (i.e., 400 MSps ± 4 MSps).

[0102] In one embodiment, the third communication rate is approximately 800 MSps. In one embodiment, the third communication rate corresponds to a second data rate of 10 Gbps over the second plurality of pairs of twisted wires of the second cable. In another embodiment, the third communication rate is approximately 400 MSps. In one embodiment, the third communication rate corresponds to a second data rate of 5 Gbps over the second plurality of pairs of twisted wires of the second cable.

[0103] In some embodiments, the third communication rate is the same as the first communication rate. In other embodiments, the third communication rate is different from the first communication rate.

[0104] At block 516, the first transceiver low-pass filters the second signal received at block 508 to attenuate crosstalk in the second signal caused by transmission of the third signal on the second cable at the third communication rate. According to one embodiment, the first transceiver low-pass filters the second signal at block 516 comprises transceiver 120-2 (FIG. 1) that low-pass filters the second signal. According to one embodiment, the first transceiver low-pass filters the second signal at block 516 comprises transceiver 300 (FIG. 1) that low-pass filters the second signal using one or both of: (i) analog low-pass filter 380; and (ii) digital low-pass filter 384.

[0105] In one embodiment, the second cable is a second legacy cable that is not rated to support the minimum required bandwidth corresponding to the third communications rate, at least for the length of the second legacy cable and / or for deployments where alien crosstalk is an issue. In one embodiment, the second cable is a second legacy cable having a maximum frequency rating that is at most 50% of the minimum required bandwidth corresponding to the third communications rate (i.e., the minimum required bandwidth corresponding to the third communications rate is at least 200% of the maximum frequency rating of the second legacy cable). In other respective embodiments, the second cable is a second legacy cable having a maximum frequency rating that is at most 25% or at most 60% of the minimum required bandwidth corresponding to the third communications rate (i.e., the minimum required bandwidth corresponding to the third communications rate is at least 400% or 167%, respectively, of the maximum frequency rating of the second legacy cable). In one embodiment, the second cable is a Class D cable according to the current ISO / IEC 11801 standard or a non-current version of the ISO / IEC 11801 standard. In another embodiment, the second cable is a Class C cable according to the ISO / IEC 11801 standard. In another embodiment, the second cable is a Class E cable according to the ISO / IEC 11801 standard.

[0106] In some embodiments, the third signal is transmitted on the second cable by another communication device, separate from the first communication device. In other embodiments, the first communication device transmits the third signal on the second cable. For example, in some embodiments, method 500 further includes: simultaneously transmitting the first signal at block 504 and receiving the second signal at block 508, a second transceiver of the first network device transmitting the third signal at a third communication rate at 512, and the second transceiver receiving a fourth signal via the second cable. According to one embodiment, the fourth signal is transmitted by the third network device at a fourth communication rate that is lower than both (i) the first communication rate and (ii) the third communication rate, and the second transceiver low-pass filters the fourth signal to attenuate crosstalk in the fourth signal caused by the transmission of the first signal on the first cable at block 504.

[0107] In one embodiment in which method 500 comprises a second transceiver of the first network device receiving the fourth signal, transceiver 120-1 (FIG. 1) receives the fourth signal at a fourth communication rate over cable 112-1, according to one embodiment. According to another embodiment, the second transceiver receiving the fourth signal comprises transceiver 300 (FIG. 3) receiving the fourth signal at the fourth communication rate over cable 112.

[0108] In one embodiment, the fourth communication rate is approximately 100 MSps (i.e., 100 MSps ± 1 MSps). In another embodiment, the fourth communication rate is approximately 200 MSps (i.e., 200 MSps ± 2 MSps). In another embodiment where the first communication rate is approximately 800 MSps and the third communication rate is also approximately 800 MSps, the fourth communication rate is approximately 400 MSps (i.e., 400 MSps ± 4 MSps).

[0109] In some embodiments, the fourth communication rate is the same as the second communication rate. In other embodiments, the fourth communication rate is different from the second communication rate.

[0110] According to one embodiment, the second transceiver that low-pass filters the fourth signal comprises transceiver 120-1 (FIG. 1) that low-pass filters the fourth signal. According to one embodiment, the second transceiver that low-pass filters the fourth signal comprises transceiver 300 (FIG. 1) that low-pass filters the fourth signal using one or both of (i) analog low-pass filter 380 and (ii) digital low-pass filter 384.

[0111] In some embodiments, transmitting the first signal at block 504 includes transmitting the first signal to the second network device in a downlink direction; receiving the second signal at block 508 includes receiving the second signal from the second network device in an uplink direction; and transmitting the third signal to the third network device in a downlink direction.

[0112] In another embodiment, transmitting the first signal in block 504 includes transmitting the first signal to the second network device in an uplink direction; receiving the second signal in block 508 includes receiving the second signal from the second network device in a downlink direction; and transmitting the third signal to the third network device in an uplink direction.

[0113] FIG. 6 is a flow diagram of an exemplary method 600 for communicating over a first cable, according to one embodiment. In one embodiment, method 600 is implemented by endpoint device 108-2 of FIG. 1, and method 600 will be described with reference to FIG. 1 for ease of explanation. In another embodiment, method 600 is implemented by network device 104 of FIG. 1. In other embodiments, method 600 is implemented by a suitable network device other than network device 104 and endpoint device 108 of FIG. 1. In one embodiment, method 600 is implemented using transceiver 400 of FIG. 4, and method 600 will be described with reference to FIG. 4 for ease of explanation. However, in other embodiments, method 600 is implemented using a suitable transceiver other than transceiver 400 of FIG. 4.

[0114] In some embodiments where the amount of data transmitted in a downlink direction within a communications network exceeds the amount of data transmitted in an uplink direction within the communications network, method 600 is implemented in a transceiver transmitting in the uplink direction. In some embodiments where the amount of data transmitted in an uplink direction within a communications network exceeds the amount of data transmitted in a downlink direction within the communications network, method 600 is implemented in a transceiver transmitting in the downlink direction.

[0115] At block 604, a transceiver of the first network device receives a first signal over a first cable, the first signal being transmitted by a second network device at a first communication rate. According to one embodiment, the transceiver receiving the first signal at block 604 comprises transceiver 124-2 (FIG. 1) receiving the first signal over cable 112-2 at the first communication rate. According to another embodiment, the transceiver receiving the first signal at block 604 comprises transceiver 400 (FIG. 4) receiving the first signal over cable 112 at the first communication rate.

[0116] In one embodiment, the first cable is a first legacy cable that is not rated to support the first communications speed, at least for the length of the first legacy cable and / or for deployments where alien crosstalk is an issue. In one embodiment, the first cable is a first legacy cable that has a maximum frequency rating that is at most 25% of the first communications speed (i.e., the first communications speed is at least 400% of the maximum frequency rating of the first legacy cable). In other respective embodiments, the first cable is a first legacy cable that has a maximum frequency rating that is at most 33%, at most 15%, at most 12.5%, or at most 5% of the first communications speed (i.e., the first communications speed is at least 300%, 667%, 800%, or 2000%, respectively, of the maximum frequency rating of the first legacy cable). In one embodiment, the first cable is a Class D cable according to the current ISO / IEC 11801 standard or a non-current version of the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class C cable according to the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class E cable according to the ISO / IEC 11801 standard.

[0117] In one embodiment, the first communication rate is approximately 800 MSps. In one embodiment, the first communication rate corresponds to a first data rate of 10 Gbps over the first plurality of pairs of the twisted wires of the first cable. In another embodiment, the first communication rate is approximately 400 MSps. In one embodiment, the first communication rate corresponds to a first data rate of 5 Gbps over the first plurality of pairs of the twisted wires of the first cable.

[0118] At block 608, simultaneously with receiving the first signal at block 604, the transceiver transmits a second signal over the first cable at a second communication rate that is lower than the first communication rate to reduce crosstalk from the first cable to one or more second cables. According to one embodiment, the first transceiver transmitting the second signal at block 608 comprises transceiver 120-2 (FIG. 1) transmitting the second signal at the second communication rate over cable 112-2. According to another embodiment, the transceiver transmitting the second signal at block 608 comprises transceiver 400 (FIG. 4) transmitting the second signal at the second communication rate over cable 112.

[0119] In one embodiment, the second communication rate is approximately 100 MSps (i.e., 100 MSps±1 MSps). In another embodiment, the second communication rate is approximately 200 MSps (i.e., 200 MSps±2 MSps). In another embodiment where the first communication rate is approximately 800 MSps, the second communication rate is approximately 400 MSps (i.e., 400 MSps±4 MSps).

[0120] In one embodiment, the first cable is rated to support the second communication speed.

[0121] In some embodiments, receiving a first signal at block 604 includes receiving the first signal from the second network device in a downlink direction; and transmitting a second signal at block 608 includes transmitting the second signal to the second network device in an uplink direction. In other embodiments, receiving a first signal at block 604 includes receiving the first signal from the second network device in an uplink direction; and transmitting a second signal at block 608 includes transmitting the second signal to the second network device in a downlink direction.

[0122] As discussed above, transmitting a second signal at a second communication rate over the first cable reduces crosstalk from the first cable to one or more second cables. In some embodiments, at least one of the plurality of second cables is coupled to a second network device. In other embodiments, at least one of the plurality of second cables is not coupled to the second network device, but instead is coupled to a third network device.

[0123] FIG. 7 is a flow diagram of another exemplary method 700 for communicating over a first cable, according to one embodiment. In one embodiment, method 700 is implemented by network device 104 of FIG. 1, and method 700 will be described with reference to FIG. 1 for ease of explanation. In another embodiment, method 700 is implemented by one of multiple endpoint devices 108 of FIG. 1. In other embodiments, method 700 is implemented by a suitable network device other than network device 104 and endpoint device 108 of FIG. 1. In one embodiment, method 700 is implemented using transceiver 300 of FIG. 3, and method 700 will be described with reference to FIG. 3 for ease of explanation. However, in other embodiments, method 700 is implemented using a suitable transceiver other than transceiver 300 of FIG. 3.

[0124] In some embodiments where the amount of data transmitted in a downlink direction within a communications network exceeds the amount of data transmitted in an uplink direction within the communications network, method 700 is implemented in a transceiver transmitting in the downlink direction. In some embodiments where the amount of data transmitted in an uplink direction within a communications network exceeds the amount of data transmitted in a downlink direction within the communications network, method 700 is implemented in a transceiver transmitting in the uplink direction.

[0125] At block 704, a first transceiver of the first network device transmits a first signal over a first cable at a first communication rate corresponding to a first minimum required bandwidth, where the first minimum required bandwidth exceeds a maximum bandwidth rating of the first cable. According to one embodiment, the first transceiver transmitting the first signal at block 704 comprises transceiver 120-2 (FIG. 1) transmitting the first signal at the first communication rate over cable 112-2. According to another embodiment, the first transceiver transmitting the first signal at block 704 comprises transceiver 300 (FIG. 3) transmitting the first signal at the first communication rate over cable 112.

[0126] In one embodiment, the first cable is a first legacy cable that is not rated to support the minimum required bandwidth corresponding to the first communications speed, at least for the length of the first legacy cable and / or for deployments where alien crosstalk is an issue. In one embodiment, the first cable is a first legacy cable having a maximum frequency rating that is at most 50% of the minimum required bandwidth corresponding to the first communications speed (i.e., the minimum required bandwidth corresponding to the first communications speed is at least 200% greater than the maximum frequency rating of the first legacy cable). In other respective embodiments, the first cable is a first legacy cable having a maximum frequency rating that is at most 25% or at most 60% of the minimum required frequency corresponding to the first communications speed (i.e., the first communications speed is at least 400% or 167%, respectively, of the maximum frequency rating of the first legacy cable). In one embodiment, the first cable is a Class D cable according to the current ISO / IEC 11801 standard or a non-current version of the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class C cable according to the ISO / IEC 11801 standard. In another embodiment, the first cable is a Class E cable according to the ISO / IEC 11801 standard.

[0127] In one embodiment, the first communication speed is approximately 800 MSps. In one embodiment, the first communication speed corresponds to a first data rate of 10 Gbps. In another embodiment, the first communication speed is approximately 400 MSps. In one embodiment, the first communication speed corresponds to a first data rate of 5 Gbps.

[0128] At block 708, concurrent with transmitting the first signal at block 504, the first transceiver receives a second signal over the first cable, the second signal being transmitted by the second network device at a second communication rate that is lower than both (i) the first communication rate and (ii) a third communication rate at which a third signal is being transmitted over the second cable, causing crosstalk in the second signal received over the first cable. In one embodiment, the second communication rate corresponds to a second minimum required bandwidth that does not exceed the maximum bandwidth rating of the first cable. According to one embodiment, the third communication rate corresponds to a third minimum required bandwidth that exceeds the maximum bandwidth rating of the second cable. In another embodiment, the third minimum required bandwidth exceeds the maximum bandwidth rating of the first cable in addition to or instead of exceeding the maximum bandwidth rating of the second cable.

[0129] Receiving the second signal at a second communication rate that is (i) lower than the third communication rate and (ii) does not exceed the maximum bandwidth rating of the first cable facilitates mitigating crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable.

[0130] According to one embodiment, the first transceiver that receives the second signal at block 708 comprises transceiver 120-2 (FIG. 1) that receives the second signal at the second communication rate via cable 112-2. According to another embodiment, the first transceiver that receives the second signal at block 708 comprises transceiver 300 (FIG. 3) that receives the second signal at the second communication rate via cable 112.

[0131] In one embodiment, the second communication rate is approximately 100 MSps (i.e., 100 MSps ± 1 MSps). In another embodiment, the second communication rate is approximately 200 MSps (i.e., 200 MSps ± 2 MSps). In another embodiment, where the first communication rate is approximately 800 MSps and the third communication rate is also approximately 800 MSps, the second communication rate is approximately 400 MSps (i.e., 400 MSps ± 4 MSps).

[0132] In one embodiment, the third communication rate is approximately 800 MSps. In one embodiment, the third communication rate corresponds to a second data rate of 10 Gbps over the second plurality of pairs of twisted wires of the second cable. In another embodiment, the third communication rate is approximately 400 MSps. In one embodiment, the third communication rate corresponds to a second data rate of 5 Gbps over the second plurality of pairs of twisted wires of the second cable.

[0133] In some embodiments, the third communication rate is the same as the first communication rate. In other embodiments, the third communication rate is different from the first communication rate.

[0134] 5, the first transceiver unit low-pass filtering the second signal received in block 708 to attenuate crosstalk in the second signal caused by transmission of the third signal at the third communication rate on the second cable. In other embodiments, the method 700 does not require the first transceiver unit low-pass filtering the second signal received in block 708 to attenuate crosstalk in the second signal caused by transmission of the third signal at the third communication rate on the second cable.

[0135] In one embodiment, the second cable is a second legacy cable that is not rated to support the minimum required bandwidth corresponding to the third communications rate, at least for the length of the second legacy cable and / or for deployments where alien crosstalk is an issue. In one embodiment, the second cable is a second legacy cable having a maximum frequency rating that is at most 50% of the minimum required bandwidth corresponding to the third communications rate (i.e., the minimum required bandwidth corresponding to the third communications rate is at least 200% of the maximum frequency rating of the second legacy cable). In other respective embodiments, the second cable is a second legacy cable having a maximum frequency rating that is at most 25% or at most 60% of the minimum required bandwidth corresponding to the third communications rate (i.e., the minimum required bandwidth corresponding to the third communications rate is at least 400% or 167%, respectively, of the maximum frequency rating of the second legacy cable). In one embodiment, the second cable is a Class D cable according to the current ISO / IEC 11801 standard or a non-current version of the ISO / IEC 11801 standard. In another embodiment, the second cable is a Class C cable according to the ISO / IEC 11801 standard. In another embodiment, the second cable is a Class E cable according to the ISO / IEC 11801 standard.

[0136] In some embodiments, the third signal is transmitted on the second cable by another communication device, separate from the first communication device. In other embodiments, the first communication device transmits the third signal on the second cable. For example, in some embodiments, method 700 further includes: simultaneously transmitting the first signal at block 704 and receiving the second signal at block 708, a second transceiver of the first network device transmitting the third signal at a third communication rate, and the second transceiver receiving a fourth signal via the second cable. According to one embodiment, the fourth signal is transmitted by the third network device at a fourth communication rate that is lower than both (i) the first communication rate and (ii) the third communication rate. In some embodiments, method 700 further includes the second transceiver low-pass filtering the fourth signal to attenuate crosstalk in the fourth signal caused by transmitting the first signal on the first cable at block 704.

[0137] In some embodiments, transmitting the first signal at block 704 includes transmitting the first signal to the second network device in a downlink direction; receiving the second signal at block 708 includes receiving the second signal from the second network device in an uplink direction; and transmitting the third signal to the third network device in a downlink direction.

[0138] In another embodiment, transmitting the first signal in block 704 includes transmitting the first signal to the second network device in an uplink direction; receiving the second signal in block 708 includes receiving the second signal from the second network device in a downlink direction; and transmitting the third signal to the third network device in an uplink direction.

[0139] While the embodiments described above utilize cables including one or more twisted pairs, other embodiments utilize other suitable cables having a metallic transmission medium, such as, for example, a coaxial cable. In embodiments where a coaxial cable is used, a transceiver, such as those described above, is coupled to the coaxial cable via a suitable cable connector (not shown), such as, for example, a Bayonet-Neill-Concelman (BNC) connector.

[0140] Embodiment 1: A first network device for communicating over a first cable, comprising: a first transmitter configured to transmit a first signal over the first cable at a first communication rate corresponding to a first minimum required bandwidth, the first minimum required bandwidth exceeding a maximum bandwidth rating of the first cable; and a first receiver configured to transmit the first signal over the first cable and simultaneously receive a second signal over the first cable, the second signal being at (i) the first communication rate and (ii) a third communication rate being transmitted over a second cable that causes crosstalk in the second signal received over the first cable. a first network device receiving the second signal at the second communication rate that is lower than both the first and second communication rates, the second communication rate corresponding to a second required minimum bandwidth that does not exceed a maximum bandwidth rating of the first cable, and the third communication rate corresponding to a third required minimum bandwidth that exceeds the maximum bandwidth rating of the second cable, wherein the first network device facilitates mitigating the crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable by receiving the second signal at the second communication rate that is lower than the third communication rate and (ii) does not exceed the maximum bandwidth rating of the first cable.

[0141] Embodiment 2: The first network device of embodiment 1, wherein the third required minimum bandwidth exceeds the maximum bandwidth rating of the first cable.

[0142] Embodiment 3: The first network device of either embodiment 1 or 2, further comprising a low-pass filter configured to attenuate the crosstalk in the second signal caused by transmitting the third signal at the third communication rate in the second cable.

[0143] Embodiment 4: The first network device of embodiment 3, wherein the low pass filter includes one or both of: (i) one or more digital low pass filters; and (ii) an analog low pass filter.

[0144] Embodiment 5: The first network device of any of embodiments 1-3 further comprises: a second transmitter configured to (i) transmit the first signal via the first cable and (ii) receive the second signal via the first cable, and simultaneously transmit the third signal via the second cable at the third communication speed; and a second receiver configured to (i) transmit the first signal via the first cable, (ii) receive the second signal via the first cable, and (iii) transmit the third signal via the second cable, and simultaneously receive a fourth signal via the second cable, the fourth signal being transmitted by a third network device at a fourth communication speed that is lower than both (i) the first communication speed and (ii) the third communication speed.

[0145] Embodiment 6: The first network device of embodiment 5, further comprising: a first low-pass filter configured to attenuate the crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable; and a second low-pass filter configured to attenuate the crosstalk in the fourth signal caused by transmitting the first signal at the first communication rate on the first cable.

[0146] Embodiment 7: A first network device of any of embodiments 1-6, wherein the first transmitter is configured to transmit the first signal at a communication rate of approximately 800 megasymbols per second (MSps); the first receiver is configured to receive the second signal at a communication rate of at most 400 MSps; and the third signal is transmitted at the communication rate of approximately 800 MSps.

[0147] Embodiment 8: A first network device of any of embodiments 1-7, wherein the first transmitter is configured to transmit the first signal to the second network device via the first cable in a downlink direction; the first receiver is configured to receive the second signal from the second network device via the first cable in an uplink direction; and the third signal is transmitted via the second cable in the downlink direction.

[0148] Embodiment 9: A first network device of any of embodiments 1-7, wherein the first transmitter is configured to transmit the first signal to the second network device via the first cable in an uplink direction; the first receiver is configured to receive the second signal from the second network device via the first cable in a downlink direction; and the third signal is transmitted via the second cable in the uplink direction.

[0149] Embodiment 10: A method for communicating over a first cable, comprising: transmitting, by a first transceiver of a first network device, a first signal over the first cable at a first communication rate corresponding to a first minimum required bandwidth, the first minimum required bandwidth exceeding a maximum bandwidth rating of the first cable; and receiving, by the first transceiver, a second signal over the first cable simultaneously with transmitting the first signal over the first cable, the second signal being (i) at the first communication rate and (ii) a third signal being transmitted over the second cable that causes crosstalk in the second signal received over the first cable. a third communication rate associated with a first cable, the third communication rate being transmitted by a second network device at a second communication rate lower than both the first and second communication rates, the second communication rate corresponding to a second required minimum bandwidth not exceeding the maximum bandwidth rating of the first cable, and the third communication rate corresponding to a third required minimum bandwidth exceeding the maximum bandwidth rating of the second cable, wherein receiving the second signal at the second communication rate that is (i) lower than the third communication rate and (ii) not exceeding the maximum bandwidth rating of the first cable facilitates mitigation of crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable.

[0150] Embodiment 11: The method of embodiment 10, wherein the third required minimum bandwidth exceeds the maximum bandwidth rating of the first cable.

[0151] Embodiment 12: The method of either embodiment 10 or 11, further comprising a step of low-pass filtering the second signal in the first transceiver unit to attenuate the crosstalk in the second signal caused by transmitting the third signal at the third communication speed on the second cable.

[0152] Embodiment 13: The method of embodiment 12, wherein the step of low-pass filtering the second signal to attenuate the crosstalk in the second signal caused by transmitting the third signal at the third communication rate on the second cable includes one or both of: (i) low-pass filtering a digital signal corresponding to the second signal using one or more digital low-pass filters; and (ii) low-pass filtering an analog signal corresponding to the second signal using an analog low-pass filter.

[0153] Embodiment 14: A method of any of embodiments 10-12, further comprising: (i) transmitting the first signal via the first cable and (ii) receiving the second signal via the first cable, while simultaneously transmitting the third signal via the second cable at the third communication speed by a second transceiver of the first network device; and (i) transmitting the first signal via the first cable, (ii) receiving the second signal via the first cable, and (iii) transmitting the third signal via the second cable, while simultaneously receiving a fourth signal via the second cable by the second transceiver, the fourth signal being transmitted by a third network device at a fourth communication speed that is lower than both (i) the first communication speed and (ii) the third communication speed.

[0154] Embodiment 15: The method of embodiment 14, further comprising: in the first transceiver unit, low-pass filtering the second signal to attenuate the crosstalk in the second signal caused by transmitting the third signal at the third communication speed on the second cable; and in the second transceiver unit, low-pass filtering the fourth signal to attenuate the crosstalk in the fourth signal caused by transmitting the first signal at the first communication speed on the first cable.

[0155] Embodiment 16: A method of any of embodiments 10-15, wherein the step of transmitting the first signal via the first cable includes transmitting the first signal at a communication rate of approximately 800 megasymbols per second (MSps); the step of receiving the second signal via the first cable includes receiving the second signal at a communication rate of at most 400 MSps; and the third signal is transmitted via the second cable at the communication rate of approximately 800 MSps.

[0156] Embodiment 17: A method of any of embodiments 10-16, wherein the step of transmitting the first signal via the first cable includes the step of transmitting the first signal to the second network device via the first cable in a downlink direction; the step of receiving the second signal via the first cable includes the step of receiving the second signal from the second network device in an uplink direction; and the third signal is transmitted via the second cable in the downlink direction.

[0157] Embodiment 18: A method of any of embodiments 10-16, wherein the step of transmitting the first signal via the first cable includes the step of transmitting the first signal to the second network device via the first cable in an uplink direction; the step of receiving the second signal via the first cable includes the step of receiving the second signal from the second network device via the first cable in a downlink direction; and the third signal is transmitted via the second cable in the uplink direction.

[0158] Embodiment 19: A first network interface for communicating via a first cable, comprising: a receiver configured to receive a first signal via the first cable, the first signal being transmitted by a second network device at a first communication rate; and a transmitter configured to transmit a second signal via the first cable at a second communication rate lower than the first communication rate simultaneously with the receiver receiving the first signal at the first communication rate, to reduce crosstalk to one or more second cables caused by transmitting the second signal on the first cable.

[0159] Embodiment 20: The first network interface of embodiment 19, wherein the receiver is configured to receive the first signal at a first communication rate corresponding to a minimum required bandwidth that exceeds a maximum frequency rating of the first cable; and the transmitter is configured to transmit the second signal at a second communication rate corresponding to a minimum required bandwidth that is less than or equal to the maximum frequency rating of the first cable simultaneously with the receiver receiving the first signal at the first communication rate.

[0160] Embodiment 21: The first network device of either embodiment 19 or 20, wherein the receiver is configured to receive the first signal at a communication rate of approximately 800 megasymbols per second (MSps); and the transmitter is configured to transmit the second signal at a communication rate of at most 400 MSps simultaneously with the receiver receiving the first signal at the first communication rate.

[0161] Embodiment 22: A first network device of any of embodiments 19-21, wherein the receiving unit is configured to receive the first signal from the second network device via the first cable in the downlink direction; and the transmitting unit is configured to transmit the second signal to the second network device via the first cable in the uplink direction.

[0162] Embodiment 23: A first network device of any of embodiments 19-21, wherein the receiving unit is configured to receive the first signal from the second network device via the first cable in the uplink direction; and the transmitting unit is configured to transmit the second signal to the second network device via the first cable in the downlink direction.

[0163] Embodiment 24: A method for communicating via a first cable, comprising: receiving, at a transceiver unit of a first network device, a first signal via the first cable, the first signal being transmitted by a second network device at a first communication speed; and, simultaneously with receiving the first signal via the first cable, transmitting, by the transceiver unit, a second signal via the first cable at a second communication speed lower than the first communication speed, to reduce crosstalk to one or more second cables caused by transmitting the second signal on the first cable.

[0164] Embodiment 25: The method of embodiment 24, wherein receiving the first signal via the first cable includes receiving the first signal at a first communication rate corresponding to a minimum required bandwidth that exceeds a maximum frequency rating of the first cable; and transmitting the second signal via the first cable includes transmitting the second signal at a second communication rate corresponding to a minimum required bandwidth that is less than or equal to the maximum frequency rating of the first cable.

[0165] Embodiment 26: The method of either embodiment 24 or 25, wherein the step of receiving the first signal via the first cable includes receiving the first signal via a first Class D cable that (i) complies with the ISO / IEC 11801 standard for 100 MHz applications and (ii) does not comply with the ISO / IEC 11801 standard for applications at frequencies above 100 MHz; and the step of transmitting the second signal via the first cable includes transmitting the second signal via the first Class D cable at the second communication speed that is lower than the first communication speed, thereby reducing crosstalk from the first Class D cable to one or more second Class D cables.

[0166] Embodiment 27: A method of any of embodiments 24-26, wherein the step of receiving the first signal via the first cable includes receiving the first signal at a communication rate of approximately 800 megasymbols per second (MSps); and the step of transmitting the second signal via the first cable includes receiving the first signal at the communication rate of approximately 800 MSps and simultaneously transmitting the second signal at a communication rate of at most 400 MSps.

[0167] Embodiment 28: A method of any of embodiments 24-26, wherein the step of receiving the first signal via the first cable includes receiving the first signal at a communication rate of approximately 400 megasymbols per second (MSps); and the step of transmitting the second signal via the first cable includes receiving the first signal at the communication rate of approximately 400 MSps and transmitting the second signal at a communication rate of at most 100 MSps simultaneously.

[0168] Embodiment 29: A method of any of embodiments 24-28, wherein the step of receiving the first signal via the first cable includes the step of receiving the first signal from the second network device via the first cable in a downlink direction; and the step of transmitting the second signal via the first cable includes the step of transmitting the second signal to the second network device via the first cable in an uplink direction.

[0169] Embodiment 30: A method of any of embodiments 24-28, wherein the step of receiving the first signal via the first cable includes the step of receiving the first signal from the second network device via the first cable in an uplink direction; and the step of transmitting the second signal via the first cable includes the step of transmitting the second signal to the second network device via the first cable in a downlink direction.

[0170] At least some of the various blocks, operations, and techniques described above may be implemented using hardware, a processor executing firmware instructions, a processor executing software instructions, or any combination thereof. When implemented using a processor executing software or firmware instructions, the software or firmware instructions may be stored in any computer-readable memory coupled to the processor, such as RAM, ROM, flash memory, etc. The software or firmware instructions may include machine-readable instructions that, when executed by one or more processors, cause the one or more processors to perform various operations.

[0171] If implemented in hardware, the hardware may comprise one or more of discrete components, an integrated circuit, an application specific integrated circuit (ASIC), a programmable logic device (PLD), and so on.

[0172] While the present invention has been described with reference to particular examples, these examples are intended to be illustrative rather than limiting of the invention, and modifications, additions and / or deletions may be made to the disclosed embodiments without departing from the scope of the invention.

Claims

1. 1. A first network device for communicating over a first cable and a second cable separate from the first cable, comprising: a first transmitter configured to transmit a first Ethernet signal over the first cable at a first communication speed (Sps) corresponding to a first bandwidth, the first bandwidth exceeding a maximum bandwidth rating of the first cable; a second transmitter configured to transmit a second Ethernet signal over the second cable at a second communication rate (Sps) concurrently with the transmission of the first Ethernet signal over the first cable, the second communication rate corresponding to a second bandwidth that exceeds a maximum bandwidth rating of the second cable; and a first receiver configured to receive a third Ethernet signal via the first cable simultaneously with the transmission of the first Ethernet signal via the first cable and the transmission of the second Ethernet signal via the second cable, the third Ethernet signal being transmitted by a second network device at a third communication speed (Sps) that is lower than both (i) the first communication speed and (ii) the second communication speed; Equipped with the third communication rate corresponds to a third bandwidth not exceeding the maximum bandwidth rating of the first cable; receiving the third Ethernet signal at the third communications rate corresponding to the third bandwidth that is (i) lower than the second communications rate and (ii) not exceeding the maximum bandwidth rating of the first cable, thereby facilitating mitigation of first crosstalk in the third Ethernet signal caused by transmitting the second Ethernet signal at the second communications rate on the second cable compared to when the first receiver receives the third Ethernet signal at a communications rate that exceeds the third communications rate; the first receiver having circuitry configured to process the third Ethernet signal to mitigate second crosstalk in the third Ethernet signal caused by the transmission of the first Ethernet signal on the first cable; A first network device.

2. the second bandwidth exceeds the maximum bandwidth rating of the first cable; The first network device of claim 1 .

3. a low pass filter configured to attenuate the first crosstalk in the first cable caused by transmitting the second Ethernet signal at the second communication rate in the second cable. The first network device of claim 1 .

4. The low pass filter: (i) one or more digital low-pass filters; and (ii) an analog low-pass filter; including one or both of The first network device of claim 3 .

5. A second receiver configured to receive a fourth Ethernet signal via the second cable simultaneously with (i) transmitting the first Ethernet signal via the first cable, (ii) receiving the third Ethernet signal via the first cable, and (iii) transmitting the second Ethernet signal via the second cable, the fourth Ethernet signal being transmitted by a third network device at a fourth communication rate lower than both (i) the first communication rate and (ii) the second communication rate. Further comprising: The first network device of claim 1 .

6. a first low pass filter configured to attenuate the first crosstalk in the first cable caused by transmitting the second Ethernet signal at the second communication rate in the second cable; and a second low pass filter configured to attenuate third crosstalk in the second cable caused by transmitting the first Ethernet signal at the first communication rate in the first cable; Further comprising: The first network device of claim 5 .

7. the first transmitter is configured to transmit the first Ethernet signal at a communication rate of 800 mega symbols per second (MSps) ±8 MSps; the first receiver is configured to receive the third Ethernet signal at a communication rate of at most 400 MSps ± 4 MSps; and the second Ethernet signal is transmitted at the communication speed of 800 MSps ± 8 MSps; The first network device of claim 1 .

8. the first transmitter is configured to transmit the first Ethernet signal over the first cable to the second network device in a downlink direction; the first receiver is configured to receive the third Ethernet signal from the second network device via the first cable in an uplink direction; and the second transmitter is configured to transmit the second Ethernet signal over the second cable in the downlink direction. A first network device according to any one of claims 1 to 7.

9. the first transmitter is configured to transmit the first Ethernet signal over the first cable to the second network device in an uplink direction; the first receiver is configured to receive the third Ethernet signal from the second network device via the first cable in a downlink direction; and the second transmitter is configured to transmit the second Ethernet signal over the second cable in the uplink direction. A first network device according to any one of claims 1 to 7.

10. 1. A method for communicating over a first cable and a second cable separate from the first cable, comprising: transmitting, by a first transceiver of a first network device, a first Ethernet signal over the first cable at a first communication speed (Sps) corresponding to a first bandwidth, the first bandwidth exceeding a maximum bandwidth rating of the first cable; transmitting, by a second transceiver of the first network device, a second Ethernet signal over the second cable at a second communication speed (Sps) simultaneously with transmitting the first Ethernet signal over the first cable, the second communication speed corresponding to a second bandwidth that exceeds a maximum bandwidth rating of the second cable; receiving, by the first transceiver unit, a third Ethernet signal via the first cable simultaneously with transmitting the first Ethernet signal via the first cable and transmitting the second Ethernet signal via the second cable, the third Ethernet signal being transmitted by a second network device at a third communication speed (Sps) that is lower than both (i) the first communication speed and (ii) the second communication speed, the third communication speed corresponding to a third bandwidth that does not exceed the maximum bandwidth rating of the first cable; receiving the third Ethernet signal at the third communication speed that is (i) lower than the second communication speed and (ii) does not exceed the maximum bandwidth rating of the first cable, facilitates mitigation of first crosstalk in the third Ethernet signal caused by transmitting the second Ethernet signal at the second communication speed on the second cable compared to when the first transceiver unit receives the third Ethernet signal at a communication speed that exceeds the third communication speed; and processing the third Ethernet signal by the first transceiver unit to mitigate second crosstalk in the third Ethernet signal caused by the transmission of the first Ethernet signal on the first cable; Equipped with method.

11. the second bandwidth exceeds the maximum bandwidth rating of the first cable; The method of claim 10.

12. and low-pass filtering the third Ethernet signal in the first transceiver to attenuate the first crosstalk in the third Ethernet signal caused by transmitting the second Ethernet signal at the second communication speed on the second cable. The method of claim 10.

13. The step of low-pass filtering the third Ethernet signal to attenuate the first crosstalk in the third Ethernet signal caused by transmitting the second Ethernet signal at the second communication rate on the second cable includes: (i) low-pass filtering a digital signal corresponding to the third Ethernet signal using one or more digital low-pass filters; and (ii) low-pass filtering an analog signal corresponding to the third Ethernet signal using an analog low-pass filter; including one or both of The method of claim 12.

14. A step of (i) transmitting the first Ethernet signal via the first cable, (ii) receiving the third Ethernet signal via the first cable, and (iii) transmitting the second Ethernet signal via the second cable, and simultaneously receiving a fourth Ethernet signal via the second cable by the second transceiver, the fourth Ethernet signal being transmitted by a third network device at a fourth communication speed lower than both (i) the first communication speed and (ii) the second communication speed. Further comprising: The method of claim 10.

15. low-pass filtering the third Ethernet signal in the first transceiver unit to attenuate the first crosstalk in the third Ethernet signal caused by transmitting the second Ethernet signal at the second communication speed on the second cable; and low-pass filtering the fourth Ethernet signal in the second transceiver unit to attenuate third crosstalk in the fourth Ethernet signal caused by transmitting the first Ethernet signal at the first communication speed on the first cable; Further comprising:

15. The method of claim 14.

16. Transmitting the first Ethernet signal over the first cable includes transmitting the first Ethernet signal at a communication rate of 800 mega symbols per second (MSps) ±8 MSps; receiving the third Ethernet signal via the first cable includes receiving the third Ethernet signal at a communication rate of at most 400 MSps ± 4 MSps; and transmitting the second Ethernet signal over the second cable includes transmitting the second Ethernet signal over the second cable at the communication rate of 800 MSps±8 MSps; The method of claim 10.

17. Transmitting the first Ethernet signal over the first cable includes transmitting the first Ethernet signal over the first cable in a downlink direction to the second network device; Receiving the third Ethernet signal via the first cable includes receiving the third Ethernet signal from the second network device in an uplink direction; and transmitting the second Ethernet signal over the second cable includes transmitting the second Ethernet signal over the second cable in the downlink direction.

17. The method according to any one of claims 10 to 16.

18. Transmitting the first Ethernet signal over the first cable includes transmitting the first Ethernet signal over the first cable in an uplink direction to the second network device; Receiving the third Ethernet signal via the first cable includes receiving the third Ethernet signal from the second network device via the first cable in a downlink direction; and transmitting the second Ethernet signal over the second cable includes transmitting the second Ethernet signal over the second cable in the uplink direction.

17. The method according to any one of claims 10 to 16.

19. A system comprising the first network device of any one of claims 1 to 7, the system further comprising a second network device for communicating via the first cable; the second network device: a third receiver configured to receive the first Ethernet signal via the first cable; and a third transmitter configured to transmit the third Ethernet signal over the first cable at the third communication speed lower than the first communication speed while the third receiver receives the first Ethernet signal at the first communication speed; Equipped with system.

20. the third receiver configured to receive the first Ethernet signal from the first network device via the first cable in a downlink direction; and the third transmitter is configured to transmit the third Ethernet signal to the first network device via the first cable in an uplink direction.

20. The system of claim 19.

21. the third receiver configured to receive the first Ethernet signal from the first network device via the first cable in an uplink direction; and the third transmitter is configured to transmit the third Ethernet signal to the first network device via the first cable in a downlink direction.

20. The system of claim 19.

22. A method for receiving, at a third transceiver unit of the second network device, the first Ethernet signal via the first cable; and receiving the first Ethernet signal via the first cable and, simultaneously, transmitting a third Ethernet signal via the first cable by the third transceiver at the third communication speed lower than the first communication speed; Further comprising:

17. The method according to any one of claims 10 to 16.

23. Receiving the first Ethernet signal over the first cable includes receiving the first Ethernet signal over a first Class D cable that (i) complies with the ISO / IEC 11801 standard for 100 MHz applications, and (ii) does not comply with the ISO / IEC 11801 standard for applications at frequencies above 100 MHz; and transmitting the third Ethernet signal over the first cable includes transmitting the third Ethernet signal over the first Class D cable at the second communication rate that is lower than the first communication rate to reduce crosstalk from the first Class D cable to one or more second Class D cables.

23. The method of claim 22.

24. Receiving the first Ethernet signal via the first cable includes receiving the first Ethernet signal from the first network device via the first cable in a downlink direction; and transmitting the third Ethernet signal over the first cable includes transmitting the third Ethernet signal over the first cable to the first network device in an uplink direction.

23. The method of claim 22.

25. Receiving the first Ethernet signal over the first cable includes receiving the first Ethernet signal from the first network device over the first cable in an uplink direction; and transmitting the third Ethernet signal over the first cable includes transmitting the third Ethernet signal over the first cable to the first network device in a downlink direction.

23. The method of claim 22.

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