CN114978371A - Method, medium, and program product for detecting channel state and modem - Google Patents

Abstract

The present disclosure relates to a method, medium, and program product for detecting a channel state and a modem. In the method, for a plurality of codewords received by a modem from a central office device via a channel, determining, by the modem, a first amount associated with an error codeword that is not error-correctable and a second amount associated with codewords other than the error codeword; calculating, by the modem, a metric of the first quantity relative to the second quantity; and determining, by the modem, that the channel is impaired in response to determining that the metric exceeds the first threshold for a first predetermined time. By using the metric and the threshold, the channel state can be correctly identified, thereby avoiding the problem that the related art cannot identify the channel state under all conditions.

Description

Method, medium, and program product for detecting channel state and modem

Technical Field

The present disclosure relates to the field of network communications, and more particularly, to a method, medium, and program product for detecting a channel status in the field of network communications, and a modem.

Background

In communication networks with cable transmission, such as DOCSIS (Data Over cable Service Interface Specifications) networks, signals transmitted Over the cable may be affected by various sources of interference. For example, in a Cable between a CMTS (Cable Modem Termination System) as a local side device and a Modem as a subscriber side access device, a transmission signal may be interfered with by an LTE signal, a WCDMA signal, a QAM signal, an analog signal, or the like. These interfering signals act as noise that degrades the channel quality, making it difficult for the transmitted signals, including control messages and user data, to be properly received and decoded, thereby preventing proper communication between the CMTS and the modem.

Due to the influence of noise, physical layer/medium access control layer control messages (hereinafter, abbreviated as PHY/MAC control messages) such as SYNC (Synchronization) messages, MDD (media access control Domain Descriptor) messages, FEC (Forward Error Correction) signals, etc., transmitted by the CMTS to the modems may not be correctly received and decoded by the modem, thereby causing loss of the PHY/MAC control messages. After a certain period of PHY/MAC control message loss, the modem may determine that the downlink channel from the CMTS to it is impaired and thus no longer used. In some cases, the PHY/MAC control message may be lost briefly due to the noise level fluctuating continuously within a certain range, then locked by being received correctly by the modem when the period has not yet been reached, then lost briefly, and then locked by being received correctly by the modem, and so on, so that the PHY/MAC control message is continuously inverted (flipping).

The flipping of the PHY/MAC control message means that the channel quality of the corresponding channel is poor and is already unsuitable for continued use for transmitting data. More seriously, because the data sent by the CMTS to the modem is fragmented for common transmission over multiple channels between the CMTS and the modem, the modem needs to decode the fragmented data together based on the multiple channels to obtain the packet data. Since the fragmented data transmitted on the channel in which the PHY/MAC control message is continuously inverted has a high error code rate, when they are decoded together with the correct fragmented data on other channels, correct packet data cannot be obtained, and thus the throughput of the downstream is rapidly reduced.

In the current related art, only one specific PHY/MAC control message (i.e., FEC message) rollover in the primary channel (primary channel) between the CMTS and the modem is detected. The modem determines that the FEC message is in a flipped state by recording the number of times the FEC message in the main channel is lost and locked within a predetermined time, and stops using the main channel when the flipped state is detected. The multiple channels that exist between the CMTS and the modem can be divided into primary channels and non-primary channels. User data may be transmitted on both the primary channel and the non-primary channel. The primary channel is typically one through which the CMTS sends management information, including control information, configuration information, etc., to the modems for managing the modems. Since the modem is only concerned with the flipping of FEC messages in the primary channel, the modem cannot know whether there is a flipping phenomenon for other PHY/MAC control messages in the primary channel and for all types of PHY/MAC control messages in non-primary channels. This makes it impossible for the modem to recognize the degradation of the quality of the corresponding channel even if the above-mentioned roll-over occurs, and thus data transmission continues on the channel whose channel quality is not good, thereby causing a degradation in downstream throughput.

Therefore, in order to overcome the above-described problem in which the modem cannot correctly recognize the channel status in all cases, it is desirable to provide a way for the modem to correctly detect the channel status regardless of the channel type and the control message type.

Disclosure of Invention

Some aspects of the present disclosure relate to a modem. The modem may include: a memory storing instructions; and a processor configured to execute instructions stored in the memory to cause the modem to perform the following operations. The operations include: determining, for a plurality of codewords received by the modem from a central office device via a channel, a first amount associated with an error codeword that is not error-correctable and a second amount associated with codewords other than the error codeword; calculating a first measure of the first quantity relative to the second quantity; and determining that the channel is impaired in response to determining that the first metric exceeds the first threshold for a first predetermined time.

In some embodiments, in response to determining that the channel is corrupted, the modem may send a message to the office device to prevent the office device from sending user data on the channel.

In some embodiments, in response to determining that the channel is impaired, the modem may blacklist the channel to avoid using the channel as a channel via which to transmit management information for managing the modem.

In some embodiments, the first quantity associated with the non-error-correctable error codewords may be a number of non-error-correctable error codewords, the second quantity associated with the other codewords other than said error codewords may be a number of correct codewords after the error correction processing, and the first metric may be a ratio of the first quantity with respect to the second quantity or a ratio of the first quantity with respect to a sum of the first quantity and the second quantity.

In some embodiments, in the case where the channel is a channel through which the office device transmits management information for managing the modem, the modem may reestablish a connection between the office device and the modem in response to determining that the channel is damaged.

In some embodiments, in a case where the channel is not a channel through which the central office device transmits management information for managing the modem, for a plurality of test codewords received by the modem from the central office device via the channel, the modem may determine a third amount associated with an incorrect test codeword that is not error-correctable and a fourth amount associated with test codewords other than the incorrect test codeword; calculating a second measure of the third quantity relative to the fourth quantity; and determining that the channel is available in response to determining that the second metric is below the second threshold for a second predetermined time.

In some embodiments, the second predetermined time is greater than the first predetermined time, the first threshold is higher than the second threshold, and the second threshold is not higher than 2%.

Other aspects of the disclosure relate to a method, non-transitory computer-readable medium, and computer program product for setting a modulation mode. Each of which may implement the operations performed by the modem described above.

Drawings

For a better understanding of the present disclosure, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

fig. 1 is a schematic diagram of a network including a modem and a local side device according to an embodiment of the present disclosure.

Fig. 2 is a block diagram of an exemplary configuration of the modem of fig. 1 according to an embodiment of the disclosure.

Fig. 3 is a diagram illustrating a change in downstream data throughput when any one PHY/MAC control message is flipped in the related art.

Fig. 4 is a flowchart of a method for detecting a channel state according to an embodiment of the present disclosure.

Fig. 5 is a flow chart of a method for determining impaired non-primary channel recovery in accordance with an embodiment of the present disclosure.

Fig. 6 is another flowchart of a method for detecting a channel state according to an embodiment of the present disclosure.

Fig. 7 is a schematic diagram of an example of detecting a channel state using a method according to an embodiment of the present disclosure.

Detailed Description

The following detailed description is made with reference to the accompanying drawings and is provided to assist in a comprehensive understanding of various exemplary embodiments of the disclosure. The following description includes various details to aid understanding, but these details are to be regarded as examples only and are not intended to limit the disclosure, which is defined by the appended claims and their equivalents. The words and phrases used in the following description are used only to provide a clear and consistent understanding of the disclosure. In addition, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness. Those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made without departing from the spirit and scope of the disclosure.

Referring initially to fig. 1, a schematic diagram of a network 100 including a modem 110 and a local side device 120, such as a CMTS, is depicted in accordance with an embodiment of the present disclosure.

The modem 110 is connected to the office device 120 through a cable, and the office device 120 is connected to an external network such as the internet through an optical fiber or the like. Modem 110 may be a DOCSIS based modem and it may contain a cable modem (cable modem) based multimedia adapter (MTA), gateway, WiFi gateway, etc. The user devices 130 and 140 may be connected to the modem 110 in a wireless manner or a wired manner. The modem 110 sends the user data received from the user devices 130 and 140 to the CMTS 120 for transmission to an external network. The office side device 120 transmits data destined for the user devices 130 and 140 received from the external network to the modem 110 for forwarding to the user devices 130 and 140. Although only two user devices are shown in fig. 1, there may be more user devices. Further, although only one modem 110 is shown in fig. 1, the office device 120 may be connected to a plurality of modems.

In the downlink direction from the office side device 120 to the modem 110, the office side device 120 may transmit data to the modem 110 through a plurality of downlink channels. In each downlink channel, the office device 120 may send PHY/MAC control messages such as SYNC, MDD, FEC to the modem 110. When the modem 110 is able to correctly lock onto (i.e., correctly receive and decode) the PHY/MAC control message, the modem 110 determines that the channel quality is good and continues to receive user data from the office device 120 via the corresponding downlink channel. When the modem 110 fails to lock the PHY/MAC control message for a long time (i.e., the PHY/MAC control message is lost for a long time), the modem 110 determines that the corresponding channel is impaired. In the event that a downlink channel is impaired, the use of that channel can affect the downstream data throughput.

The plurality of downlink channels between the office device 120 and the modem 110 may include a primary channel 150 and one or more non-primary channels 160. Data transmitted in the main channel 150 and the non-main channel 160 may be modulated by OFDM (Orthogonal Frequency Division Multiplexing) or SC-QAM (Single-Carrier Quadrature Amplitude Modulation). The primary channel 150 and the non-primary channel 160 occupy different frequency bins and do not overlap each other. When the office device 120 and the modem 110 establish a connection, the primary channel 150 is established first, then the non-primary channel 160 is established, and management information is transmitted only on the primary channel 150. Both primary channel 150 and non-primary channel 160 may be used to transmit user data, e.g., data of different portions of a user packet may be transmitted simultaneously.

The modem 110 may be configured using the exemplary architecture shown in fig. 2.

Although referred to herein as a modem, the modem 110 may be, for example, a hardware electronic device that may combine the functionality of a modem, an access point, and/or a router. The present disclosure also contemplates that modem 110 may include, but is not limited to, the functionality of a Smart Media Device (SMD) or IP/QAM Set Top Box (STB) capable of decoding audio/video content and playing out OTT or MSO provided content.

As shown in fig. 2, the modem 110 includes a user interface 20, a network interface (e.g., LAN interface) 21, a power supply 22, a WAN interface 23, a memory 24, and a controller 26. The user interface 20 may include, but is not limited to, push buttons, a keyboard, a keypad, an LCD, a CRT, TFTs, LEDs, HD, or other similar display device, including a display device with touch screen capability to allow interaction between a user and the modem 110. The network interface 21 may include various network cards and circuitry implemented in software and/or hardware to enable communication with wireless extender devices and user devices using one or more wireless protocols, such as any IEEE 802.11Wi-Fi protocol, Bluetooth Low Energy (BLE), or any short range protocol operating according to a wireless technology standard to exchange data over short distances using any licensed or unlicensed frequency band, such as the Civic Broadband Radio Service (CBRS) band, the 2.4GHz band, the 5GHz band, or the 6GHz band, RF4CE protocol, ZigBee protocol, Z-wave protocol, or IEEE802.15.4 protocol.

The power supply 22 supplies power to the internal components of the modem 110 through the internal bus 27. The power source 22 may be a stand alone power source, such as a battery pack, having an interface that is powered by an electrical charger connected to an outlet (e.g., directly or through other equipment). The power source 22 may also include a rechargeable battery, such as a NiCd, NiMH, Li-ion, or Li-polymer battery, which may be removable to allow replacement. If modem 110 is a modem or gateway device, it may include a WAN interface 23, and WAN interface 23 may include various network cards and circuitry implemented in software and/or hardware to enable communication between the gateway device and an Internet service provider or Multiple System Operators (MSOs).

Memory 24 comprises a single memory or one or more memories or memory locations including, but not limited to, Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Read Only Memory (ROM), EPROM, EEPROM, ROM, flash memory, logic blocks of an FPGA, a hard disk, or any other layer of a hierarchy of memories. Memory 24 may be used to store any type of instructions, software, or algorithms, including software 25 for controlling the general function and operation of modem 110.

Controller 26 controls the general operation of modem 110 and performs management functions related to other devices in the network, such as expanders and user equipment. Controller 26 may include, but is not limited to, a CPU, hardware microprocessor, hardware processor, multi-core processor, single-core processor, microcontroller, Application Specific Integrated Circuit (ASIC), DSP, or other similar processing device capable of executing any type of instructions, algorithms, or software for controlling the operation and function of modem 110 in accordance with embodiments described in this disclosure. The processor 26 may include various implementations of digital circuitry, analog circuitry, or mixed-signal (a combination of analog and digital) circuitry that performs functions in a computing system. Controller 26 may include, for example, circuitry such as an Integrated Circuit (IC), a portion or circuitry of a single processor core, the entire processor core, a single processor, a programmable hardware device such as a Field Programmable Gate Array (FPGA), and/or a system including multiple processors.

Communications may be established between components of modem 110 (e.g., 20-22, 24, and 26) using internal bus 27.

Returning to fig. 1, due to the effect of channel noise, the PHY/MAC control message may not experience a long loss, but may be briefly lost, locked by the modem 110, then briefly lost and locked again, and so on, thereby causing a rollover phenomenon.

Flipping of the PHY/MAC control message may result in a change in downstream data throughput as shown in fig. 3. In fig. 3, the PHY/MAC control message is flipped from time t 1. Since modem 110 may not recognize the PHY/MAC control message toggling, modem 110 and office device 120 may not know that the corresponding channel is no longer suitable for transmitting user data and may continue to transmit on that channel. The erroneous transmission data is used for decoding together with the correct data of other channels, resulting in a rapid decrease in the downstream data throughput and maintained at a low level. At time t2, after the rollover phenomenon has disappeared, the downstream data throughput may return to normal.

To avoid the serious impact on downstream data throughput due to the inability of the modem 110 to correctly identify the channel conditions, embodiments of the present disclosure provide a method 400 as shown in fig. 4 to correctly detect the channel conditions. The method 400 may be performed by the modem 110.

In S410, for a plurality of codewords received by the modem from the central office device via the channel, the modem determines a first amount associated with an error codeword that is not error-correctable and a second amount associated with codewords other than the error codeword.

A first quantity associated with the non-error-correctable error codeword among the codewords and a second quantity associated with other codewords except the non-error-correctable error codeword among the codewords may be determined for all codewords received by the modem 110 from the central office device 120 via a certain channel (hereinafter, denoted as channel a) within a predetermined time (e.g., 10 seconds, 30 seconds, 60 seconds, etc.).

For example, the first quantity may be the number of error codewords that are not error-correctable and the second quantity may be the number of correct codewords. The correct code words include code words which themselves have no errors and code words which can be correctly corrected by the error correction process of the modem. Embodiments of the present disclosure characterize the number information of non-error-correctable error codewords by a first quantity and the number information of correct codewords by a second quantity. For example, the modem may count the codewords it receives from the office device 120 via channel a in 10 seconds, assuming a total of 500. After the error correction process, the number of error code words that cannot be corrected is 100, and the number of correct code words is 400. The first amount may be equal to 100 and the second amount may be equal to 400.

A time window having a certain length of time for counting the number of code words may slide with the lapse of time to contain a new code word received from the central office device 120 via the channel a each time the first amount and the second amount are determined. The size of the time window may be fixed or may vary, as long as different code words are included in the two adjacent determinations of the first quantity and the second quantity.

In S420, the modem calculates a first metric of the first quantity relative to the second quantity.

Each time after determining the first and second quantities from the code words received within the time window, the modem 110 may calculate a ratio of the first quantity to the second quantity as the first metric, i.e. "first quantity equals first quantity/second quantity", or the modem 110 may calculate a ratio of the first quantity to a sum of the first and second quantities as the first metric, i.e. "first quantity equals first quantity/(first quantity + second quantity)". More specifically, "first metric" is the number of error codes that cannot be corrected/the number of correct code words, "or" first metric "is the number of error codes that cannot be corrected/the number of total code words.

In S430, in response to determining that the first metric exceeds the first threshold for a first predetermined time, the modem determines that the channel is impaired.

Since the modem 110 is able to continuously determine the first and second quantities of codewords received via channel a within the respective time windows over time and calculate a metric R1 of the first quantity relative to the second quantity, the modem is able to obtain a series of metrics R1 over time. If the metric R1 remains above the first threshold Th1 for the first predetermined time T1, it may be determined that the number of error code words that are uncorrectable is relatively high, and thus the quality of the channel a is poor, the channel is no longer suitable for transmitting user data, and the modem 110 determines that the channel status of the channel a is a corrupted status.

In the above method 400, by introducing a first quantity, such as the number of error codewords that are not error-correctable, and a second quantity, such as the number of correct codewords or the number of total codewords after error correction processing, a first metric of the first quantity relative to the second quantity can be utilized to assist in determining the channel state. In case that the first quantity counted by the modem in time sequence relative to the first measure of the second quantity exceeds the first threshold value within the first predetermined time, the modem can determine that the channel is damaged, thereby avoiding the problem that the channel state cannot be known in any situation as in the related art, and further facilitating the modem to take more appropriate operation based on the channel state.

According to an embodiment of the present disclosure, after the modem 110 determines that channel a is damaged, the modem 110 may directly transmit a message to the central office device through a normal uplink channel to prevent the central office device 120 from transmitting user data on channel a. Alternatively, the modem 110 may send such a message to the user equipment 130 or 140, and the message is sent by the user equipment 130 or 140 to other devices (e.g., other modems or gateway devices connected to the office equipment 120) in connection with the office equipment 120, and is further forwarded to the office equipment 120. After receiving the message, the central office device 120 determines that the channel a indicated by the message is damaged, and then stops transmitting downstream data on the channel a.

Since only the impaired downlink channel is out of service and the other normal downlink channels are in continued service, although the amount of data transmitted by the office device 120 through all channels between itself and the modem 110 per unit time is reduced, the transmission efficiency of packet data is improved instead, compared to the case of continuing to transmit data using the impaired channel with poor quality, since the fragmented data that needs to be decoded together to obtain packet data is substantially correct, so that the downstream data throughput is improved and can be maintained at a higher level.

According to an embodiment of the present disclosure, in response to determining that channel a is corrupted in S430, modem 110 may blacklist channel a to avoid having channel a as the primary channel.

Since the main channel transmits management information for managing the modem 110, the channel is an important channel for maintaining normal connection and communication between the modem 110 and the office equipment 120. When the channel A is determined to be damaged, it is indicated that the frequency point corresponding to the channel A is easily subjected to strong interference in the current environment, and is not suitable for being used as a main channel. Therefore, the frequency point corresponding to the channel a can be prevented from being used as the main channel by adding the information of the channel a into the blacklist, so that the success rate and stability of the subsequent connection process between the modem 110 and the office end device 120 can be improved.

The impaired channel a may be the primary channel. In this case, the modem 110 may re-establish a connection between the office device 120 and the modem 110 in response to determining that channel a is impaired. For example, modem 110 may perform a reinit-MAC operation to reinitialize a MAC (media access control) module, thereby triggering modem 110 to rescan frequency bins to lock the frequency. In the process of rescanning the available frequency points by the modem 110, the modem 110 may prevent the frequency point corresponding to the channel a from being used as a channel, and particularly prevent the frequency point corresponding to the channel a from being used as a main channel. Of course, the modem 110 may also re-establish the connection by restarting itself. Compared with the restarting operation, the reinit-mac operation takes less time and the connection is restored more quickly.

The impaired channel a may also be a non-primary channel. Since the non-primary channel is used for transmitting user data, its consequences of corruption are less severe than those of the primary channel that still needs to transmit management information. Thus, modem 110 may not perform reinit-mac or restart operations after a non-primary channel is corrupted, but instead wait for the corrupted non-primary channel to recover. Whether the non-primary channel is recovered may be detected by method 500 of fig. 5.

In S510, for a plurality of test codewords received by the modem from the central office device via the damaged channel, the modem determines a third quantity associated with the non-error-correctable erroneous test codewords and a fourth quantity associated with test codewords other than the erroneous test codewords.

Although downlink channel a is in a corrupted state, downlink channel a still exists. On this channel, the office device 120 may actively send test data to the modem 110 to test whether channel a can properly transmit data. The test data for testing the channel a may be randomly generated, may be data being transmitted by other channels or a part thereof, may be predetermined data designed in advance, and the like. It may be transmitted periodically or continuously by the office device 120.

Similar to S410, the modem 110 may count a third amount associated with an uncorrectable erroneous test codeword and a fourth amount associated with a correct test codeword after error correction care among all test codewords received from the central office device 120 via the channel a within a predetermined time. The predetermined time may be fixed or variable. The predetermined time may be equal to the predetermined time in S410, or may be greater than the predetermined time in S410, for example, 1 minute, 3 minutes, 8 minutes, or the like. The third quantity may be the number of error test codewords that are not error-correctable and the fourth quantity may be the number of correct test codewords after the error-correction process.

For example, the modem 110 may prevent the office device 120 from continuing to transmit user data on channel a after determining that channel a is corrupted. Although the station-side device 120 cannot continue to transmit user data on channel a, the station-side device 120 may transmit a small amount of test data for testing channel quality on channel a. The modem 110 may determine the number of codewords received from the office device 120 via channel a within the time window for counting the test codewords, e.g., determine that 50 codewords are received in 3 minutes. After the error correction process of the modem 110, the modem 110 determines that the number of error code words that cannot be corrected is 5, and the number of correct code words is 45. Thus, it may be determined that the third amount is equal to 5 and the fourth amount is equal to 45.

In S520, the modem calculates a second metric of the third quantity relative to the fourth quantity.

Each time after determining the third quantity and the fourth quantity from the codewords received within the time window for counting the test codewords, the modem 110 may calculate a ratio of the third quantity to the fourth quantity as the second metric, i.e., "second metric ═ third quantity/fourth quantity", or the modem 110 may calculate a ratio of the third quantity to a sum of the third quantity and the fourth quantity as the second metric, i.e., "second metric ═ third quantity/(third quantity + fourth quantity)". More specifically, "second metric" is the number of error test codewords that cannot be corrected/the number of correct test codewords ", or" second metric "is the number of error test codewords that cannot be corrected/the number of total test codewords".

In S530, in response to determining that the second metric is below the second threshold for a second predetermined time, the modem determines that the impaired channel is restored as available.

Since modem 110 is able to continuously determine over time a third quantity and a fourth quantity of codewords received via channel a within a time window of statistical test codewords and calculate a metric R2 of the third quantity relative to the fourth quantity, modem 110 is able to obtain a series of metrics R2 over time. If the metric R2 remains below the second threshold Th2 for the second predetermined time T2, then it may be determined that the number of correct test codewords is relatively high and that the channel quality is good and suitable for transmitting user data, and the modem 110 determines that channel a is back up as being usable.

The second predetermined time T2 in S530 and the first predetermined time T1 in S430 may be the same or different. Preferably, the second predetermined time T2 is greater than the first predetermined time T1, the first threshold Th1 is higher than the second threshold Th2, and the second threshold Th2 is not higher than 2%. Therefore, the channel state can be prevented from being switched back and forth between the damaged state and the available state due to the influence of jitter noise (jitter noise), and meanwhile, the channel can be ensured to be recovered to be available when the quality of the damaged channel becomes good enough, so that the correct transmission of data is further ensured, and the throughput of the downstream data is more reliably improved.

The parameters T1, T2, Th1 and Th2 can be flexibly set as required. For example, T1 may be set in the range of 10 seconds to 2 minutes, and its default value may be 60 seconds; t2 may be set in the range of 2 minutes to 10 minutes, and its default value may be 300 seconds; th1 may be set in the range of 10% to 50%, and its default value may be 30%; th2 may be set in the range of 0.01% to 2%, and its default value may be 0.1%. The values of these parameters may be set by modem 110 by automatically reading a configuration file at startup, or may be set by an administrator through a remote control, for example, via a MIB (Management Information Base) message. Similarly, the time window for counting the number of code words can be flexibly set according to the requirement, for example, the time window for counting in S410 and S510 is 20 seconds.

Fig. 6 shows a flowchart of an example method 600 for detecting channel conditions in accordance with an embodiment of the present disclosure.

In S610, the modem 110 determines the number of error codewords that are not error-correctable (which is the first amount) and the number of correct codewords (which is the second amount) for a plurality of codewords that it receives from the central office device 120 via the channel a. This step is substantially the same as S410.

In S620, the modem 110 calculates a metric R1 of the first quantity relative to the second quantity in S610. This step is substantially the same as S420.

In S630, the modem 110 determines that channel a is impaired in response to determining that the metric R1 exceeds the first threshold Th1 for the first predetermined time T1. This step is substantially the same as S430.

In S633, the modem 110 sends a message to the central office device 120 to prevent the central office device from sending user data on channel a.

In S636, the modem 110 adds the channel a to the blacklist to avoid using the frequency point corresponding to the channel a as the main channel in the subsequent connection process.

Although S633 is performed before S636 in the above description, S633 may also be performed after S636, or S633 may be performed in parallel with S636.

In S640, the modem 110 determines whether the impaired channel a is a primary channel or a non-primary channel.

In the event that it is determined that impaired channel a is the primary channel, method 600 proceeds to S650. In the event that it is determined that impaired channel a is a non-primary channel, method 600 proceeds to S660.

In S650, the modem 110 performs a reinit-mac operation to re-establish a connection with the office device 120.

In S660, the modem 110 determines the number of error test codewords that it cannot correct (which is the third quantity) and the number of correct test codewords (which is the fourth quantity) for the plurality of test codewords it receives from the central office device 120 via the impaired channel a. This step is substantially the same as S510.

In S670, the modem 110 calculates a metric R2 of the third quantity relative to the fourth quantity. This step is substantially the same as S520.

In S680, the modem 110 determines that the impaired channel a is restored to be usable in response to determining that the metric R2 is below the second threshold Th2 for a second predetermined time T2. This step is substantially the same as S530.

The method 600 then returns to S610 to continue monitoring the status of the recovered channel a.

Fig. 7 shows a schematic diagram of detecting the state of channel a by method 600, taking T1 ═ 60 seconds, T2 ═ 300 seconds, Th1 ═ 30% and Th2 ═ 0.1% as examples.

Initially, channel a is available and the office device 120 transmits downlink data to the modem 110 using channel a. The modem derives a series of metrics R1 according to steps S610 and S620. The modem determines that R1 has been below Th2 for t1-t2, exceeded Th1 for 40s at t2-t3 and dropped below Th2 again until t 4. Since the duration of T2-T3 does not reach T1, the channel status remains unchanged.

Next, the modem determines from the series of metrics R1 obtained in steps S610 and S620 that R1 starts to exceed Th1 at t 4. When R1 exceeds Th1 for T1 time to T5, the modem determines that the channel status is a corrupted status. Since channel a in this example is a non-primary channel, the modem maintains channel a and begins testing whether channel a has recovered as being available.

The modem then derives a series of metrics R2 according to steps S660 and S670. The modem determines that R2 remains above Th1 at t5-t6, falls below Th2 for 100s at t6-t7 and again exceeds Th 1. Since the duration of T6-T7 does not reach T2, the channel status remains unchanged.

Next, R2 exceeded Th1 from t7-t8 and fell below Th2 from t 8. When T9 is reached for a time T2 below Th2, the modem determines that the channel status is restored to the available state.

Next, the modem derives a series of metrics R1 according to steps S610 and S620. R1 remained below Th2 at t9-t10 and exceeded Th1 from t 10. Then, if R1 exceeds Th1 for the T1 time period, the channel state switches to the impaired state again.

According to the technical scheme, the channel state can be correctly determined by utilizing the relationship between the first metric of the first quantity and the second metric of the third quantity and the fourth quantity and the threshold value within the preset time, so that the problem that the channel state cannot be correctly identified in the related technology is solved. By correctly identifying the channel condition, the modem is further assisted to take appropriate action to deal with the problem of the damaged channel, thereby improving the downstream data throughput.

The present disclosure may be implemented as any combination of apparatus, systems, integrated circuits, and computer programs on non-transitory computer readable media. One or more processors may be implemented as an Integrated Circuit (IC), an Application Specific Integrated Circuit (ASIC), or a large scale integrated circuit (LSI), a system LSI, or a super LSI, or as an ultra LSI package that performs some or all of the functions described in this disclosure.

The present disclosure includes the use of software, applications, computer programs or algorithms. Software, applications, computer programs, or algorithms may be stored on a non-transitory computer readable medium to cause a computer, such as one or more processors, to perform the steps described above and depicted in the figures. For example, the one or more memories store software or an algorithm as executable instructions, and the one or more processors may associate a set of instructions to execute the software or algorithm to correctly identify a channel state by utilizing a relation of a metric related to a number of codewords to a threshold value within a predetermined time according to embodiments described in the present disclosure, thereby avoiding a problem that the related art cannot identify the channel state in all cases.

Software and computer programs (which may also be referred to as programs, software applications, components, or code) include machine instructions for a programmable processor, and may be implemented in a high-level procedural, object-oriented, functional, logical, or assembly or machine language. The term "computer-readable medium" refers to any computer program product, apparatus or device, such as magnetic disks, optical disks, solid state storage devices, memories, and Programmable Logic Devices (PLDs), used to provide machine instructions or data to a programmable data processor, including a computer-readable medium that receives machine instructions as a computer-readable signal.

By way of example, computer-readable media can comprise Dynamic Random Access Memory (DRAM), Random Access Memory (RAM), Read Only Memory (ROM), electrically erasable read only memory (EEPROM), compact disk read only memory (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired computer-readable program code in the form of instructions or data structures and which can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Disk or disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

In one or more embodiments, use of the terms "can," "operable" or "configured" refer to some apparatus, logic, hardware, and/or element that is designed to be used in a specified manner. The subject matter of the present disclosure is provided as examples of apparatus, systems, methods, and programs for performing the features described in the present disclosure. However, other features or variations are contemplated in addition to the features described above. It is contemplated that the implementation of the components and functions of the present disclosure may be accomplished with any emerging technology that may replace the technology of any of the implementations described above.

Additionally, the above description provides examples, and does not limit the scope, applicability, or configuration set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the spirit and scope of the disclosure. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For example, features described with respect to certain embodiments may be combined in other embodiments.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous.

Claims (20)

1. A modem, comprising:

a memory storing instructions; and

a processor configured to execute instructions stored in memory to cause the modem to:

determining, for a plurality of codewords received by the modem from a central office device via a channel, a first amount associated with an error codeword that is not error-correctable and a second amount associated with codewords other than the error codeword;

calculating a first measure of the first quantity relative to the second quantity; and

determining that the channel is impaired in response to determining that the first metric exceeds the first threshold for a first predetermined time.

2. The modem of claim 1, wherein the processor is further configured to execute instructions stored in memory to cause the modem to:

and responding to the determined damage of the channel, and sending a message for preventing the central office side equipment from sending user data on the channel to the central office side equipment.

3. The modem of claim 1, wherein the processor is further configured to execute instructions stored in memory to cause the modem to:

in response to determining that the channel is corrupted, the channel is blacklisted to avoid using the channel as a channel via which to transmit management information for managing modems.

4. The modem of claim 1,

the first amount associated with the non-error-correctable error codewords is the number of non-error-correctable error codewords,

the second quantity related to the other code words than the erroneous code word is the number of correct code words after the error correction process, and

the first metric is a ratio of the first quantity to the second quantity or a ratio of the first quantity to a sum of the first quantity and the second quantity.

5. The modem of claim 1, wherein the processor is further configured to execute instructions stored in memory to cause the modem to:

in a case where the channel is a channel through which the office device transmits management information for managing the modem, in response to determining that the channel is damaged, a connection is re-established between the office device and the modem.

6. The modem of claim 1, wherein the processor is further configured to execute instructions stored in memory to cause the modem to:

in a case where the channel is not a channel through which the central office device transmits management information for managing the modem, determining, for a plurality of test codewords received by the modem from the central office device via the channel, a third amount related to an incorrect test codeword that is not error-correctable and a fourth amount related to test codewords other than the incorrect test codeword;

calculating a second measure of the third quantity relative to the fourth quantity; and

determining that the channel is available in response to determining that the second metric is below the second threshold for a second predetermined time.

7. The modem of claim 6, wherein the second predetermined time is greater than the first predetermined time, the first threshold is higher than the second threshold, and the second threshold is not higher than 2%.

8. A method for detecting channel conditions, comprising:

determining, by the modem, for a plurality of codewords received by the modem from the office device via the channel, a first amount associated with an uncorrectable erroneous codeword and a second amount associated with codewords other than the erroneous codeword;

calculating, by the modem, a first metric of the first quantity relative to the second quantity; and

determining, by the modem, that the channel is impaired in response to determining that the first metric exceeds the first threshold for a first predetermined time.

9. The method of claim 8, further comprising:

and sending, by the modem, a message for preventing the central office device from sending user data on the channel to the central office device in response to determining that the channel is damaged.

10. The method of claim 8, further comprising:

adding, by the modem, the channel to a blacklist in response to determining that the channel is corrupted to avoid using the channel as a channel for transmitting management information for managing the modem therethrough.

11. The method of claim 8, wherein,

the first amount associated with a non-error-correctable error codeword is the number of non-error-correctable error codewords,

the second quantity related to the other code words than the erroneous code word is the number of correct code words after the error correction process, and

the first metric is a ratio of the first quantity to the second quantity or a ratio of the first quantity to a sum of the first quantity and the second quantity.

12. The method of claim 8, further comprising:

in a case where the channel is a channel through which the office device transmits management information for managing the modem, a connection is reestablished between the office device and the modem by the modem in response to determining that the channel is damaged.

13. The method of claim 8, further comprising:

in a case where the channel is not a channel via which the central office side device transmits management information for managing the modem, determining, by the modem, for a plurality of test codewords received by the modem from the central office side device via the channel, a third amount related to an uncorrectable erroneous test codeword and a fourth amount related to other test codewords except the erroneous test codeword;

calculating, by the modem, a second metric of the third quantity relative to the fourth quantity; and

determining, by the modem, that the channel is available in response to determining that the second metric is below the second threshold for a second predetermined time.

14. The method of claim 13, wherein the second predetermined time is greater than the first predetermined time, the first threshold is higher than the second threshold, and the second threshold is not higher than 2%.

15. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations comprising:

determining, for a plurality of codewords received by a modem from a central office device via a channel, a first amount associated with an error codeword that is not error-correctable and a second amount associated with codewords other than the error codeword;

calculating a first measure of the first quantity relative to the second quantity; and

determining that the channel is impaired in response to determining that the first metric exceeds the first threshold for a first predetermined time.

16. The non-transitory computer readable medium of claim 15, wherein the instructions, when executed by a processor, cause the processor to further perform operations comprising:

and responding to the determined damage of the channel, and sending a message for preventing the central office side equipment from sending user data on the channel to the central office side equipment.

17. The non-transitory computer readable medium of claim 15, wherein the instructions, when executed by a processor, cause the processor to further perform operations comprising:

in response to determining that the channel is corrupted, the channel is blacklisted to avoid using the channel as a channel via which to transmit management information for managing modems.

18. The non-transitory computer readable medium of claim 15, wherein the instructions, when executed by a processor, cause the processor to further perform operations comprising:

in a case where the channel is a channel through which the office device transmits management information for managing the modem, in response to determining that the channel is damaged, a connection is re-established between the office device and the modem.

19. The non-transitory computer readable medium of claim 15, wherein the instructions, when executed by a processor, cause the processor to further perform operations comprising:

in a case where the channel is not a channel through which the central office device transmits management information for managing the modem, determining, for a plurality of test codewords received by the modem from the central office device via the channel, a third amount related to an incorrect test codeword that is not error-correctable and a fourth amount related to test codewords other than the incorrect test codeword;

calculating a second measure of the third quantity relative to the fourth quantity; and

determining that the channel is available in response to determining that the second metric is below the second threshold for a second predetermined time.

20. A computer program product comprising computer instructions, characterized in that the computer instructions, when executed by a processor, implement the method according to any of claims 8-14.

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