WO2008086670A1 - Dispositif de réception et d'émission par ethernet à base de réseau à câble coaxial et procédé de transmission par ethernet - Google Patents

Dispositif de réception et d'émission par ethernet à base de réseau à câble coaxial et procédé de transmission par ethernet Download PDF

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Publication number
WO2008086670A1
WO2008086670A1 PCT/CN2007/002153 CN2007002153W WO2008086670A1 WO 2008086670 A1 WO2008086670 A1 WO 2008086670A1 CN 2007002153 W CN2007002153 W CN 2007002153W WO 2008086670 A1 WO2008086670 A1 WO 2008086670A1
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Prior art keywords
unit
analog
ethernet
signal
interface unit
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PCT/CN2007/002153
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English (en)
French (fr)
Inventor
Yang Yu
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Hangzhou H3C Technologies Co., Ltd.
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Publication of WO2008086670A1 publication Critical patent/WO2008086670A1/zh
Priority to US12/502,871 priority Critical patent/US20090274201A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2801—Broadband local area networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/407—Bus networks with decentralised control
    • H04L12/413—Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Definitions

  • Ethernet transceiver device based on coaxial cable network and Ethernet transmission method
  • the invention relates to an Ethernet transmission technology, in particular to an Ethernet transceiver device based on a coaxial cable network and a transmission method of an Ethernet. Background technique
  • the television program is transmitted from the front end to the optical coaxial terminal of the television network close to the user via the optical fiber (in general, an optical coaxial terminal covers 300 to 500 peripherals).
  • the user converts the optical signal into an electrical signal at the optical coaxial terminal, and then transmits the television signal to each resident's home through the coaxial cable distribution network through the residential building.
  • new services for example, interactive digital TV, broadband services such as data, voice, and image communication on cable TV networks
  • cable television networks that can only transmit in one direction must carry out two-way services.
  • the primary problem encountered was a two-way transformation. Two-way transformation is the first threshold for the development of cable television networks from single function to multi-functional development, from radio and television networks to information networks.
  • Ethernet has the advantages of simplicity, low cost and easy expansion. It is a better choice for HFC bidirectional transformation. However, due to the transmission of the TV coaxial distribution network of broadcasting and television between the access point and the coaxial terminal and between the coaxial terminals It is a network with a large constant attenuation, which is different from a coaxial Ethernet with almost no attenuation bus type, and is different from a point-to-point twisted pair Ethernet network. The attenuation characteristics of its transmission are reflected in two aspects:
  • FIG. 1 is a schematic diagram of a network structure of a mid-floor access point to each coaxial terminal of a conventional cable television coaxial distribution network; as shown in FIG. 1, in each residential building, there is a floor amplifier.
  • the television signal is amplified to compensate for signal attenuation during transmission. I set up a 6-story residential building with 6 units, each with 12 units. Then, after the TV signal amplified by the floor amplifier, the TV signal energy is first distributed to 6 units through a 6-distributor. Through two floors on each floor within each unit The brancher then divides the TV signal into two households (coaxial terminals) on each floor.
  • the branching attenuation of each floor is different, for example, the signal is generally transmitted from the first floor to the sixth floor. , on the first floor near the signal transmission, does not need to go through the rear splitter and transmission cable, so the attenuation of the first floor brancher should be set to a large, for example, usually 14db attenuation; and the second floor branch The attenuation is slightly smaller, such as 12db, and so on.
  • the attenuation of the same television signal source through the access point to each coaxial terminal is the same.
  • the TV signal amplified by the floor amplifier is first distributed through a 6-distributor, and the energy of the TV signal is evenly distributed to 6 units. Inside each unit, there is a two-branch on each floor, and the television signal is transmitted. Divided to two households on each floor. Then the attenuation of this network is about 31dB.
  • the theoretical calculation of this attenuation value is roughly: a 6-distributor (9dB), 5 different floor splitters and a 6th floor 2 splitter (14dB) and approximately 50m (35m in the corridor and 15m in the room)
  • the coaxial cable (10dB, calculated according to the high frequency 1000MHz attenuation) adds up to 33dB. In actual engineering, it is generally less than 31dB. That is to say, the output of the floor amplifier is lOOdBuv (decibel microvolt), and the receiving range of the user terminal is 69dBuv.
  • the number of branching devices (distributors or splitters) that pass through when communicating between two coaxial terminals is different, so the attenuation amplitude is different.
  • the attenuation between each coaxial terminal can be at least 25dB or so, and can reach up to 60dB.
  • the attenuation of the two branch coaxial terminals of the same splitter is between approximately 25 dB and 30 dB.
  • the attenuation between the connected coaxial terminals of the different splitters is equivalent to a reverse isolation parameter plus a branch loss parameter, which is between 40 dB and 60 dB.
  • Ethernet transmission protocol is implemented on the coaxial cable network, especially in the MAC layer of the Ethernet, CSMA/CD (Carrier Sense Multiple Access) is implemented.
  • CSMA/CD Carrier Sense Multiple Access
  • the protocol/conflict detection protocol not only the Ethernet access point needs to communicate with each coaxial terminal, but also the coaxial terminals are interoperable. That is to say, the interconnection between the Ethernet access point and each coaxial network needs to overcome the attenuation of about 31 dB, and the interworking between the coaxial terminals needs to overcome the attenuation between 25 dB and 60 dB.
  • Ethernet physical layer access chips on the market today are 10/100M adaptive, GE (Gigabit Ethernet) and 10GE (10 Gigabit Ethernet).
  • the main functions of this type of chip are to complete the physical layer coding, digital-to-analog conversion, clock recovery, and analog amplification.
  • the structure includes an external interface (analog signal) and an interface to the MAC layer (digital signal).
  • FIG. 2 shows the structure of a physical layer device in an existing Ethernet transceiver.
  • the analog interface unit 110 is sequentially connected in series with an AD/DA (analog-to-digital) unit 120, a codec unit 130, and a MAC layer interface unit 140.
  • the received signal input from the analog interface unit 110 is first subjected to analog-to-digital conversion processing by the AD/DA unit 120, the analog signal is converted into a digital signal, and then encoded and decoded by the codec unit 130.
  • the data information of the MAC layer is extracted from the encoded data stream of the physical layer, and then sent by the MAC layer interface unit 140 for MAC layer interface processing.
  • the AD/DA unit 120 performs the analog/digital-to-analog conversion according to the IEEE 802.3 standard transmission voltage and the standard reception reference level.
  • Ethernet is based on twisted pair transmission. For example, when the transmission distance is 100 meters, the attenuation of the twisted pair at 20MHz is only 8dB.
  • the transmission level of the transceiver of the signal access point of the Ethernet does not change, if the transmitting end of the transmitting or receiving device of the access point or the coaxial terminal transmits the voltage transmitting signal according to the IEEE 802.3 standard, the receiving end also presses The standard receives the reference level receiving signal. Because the branch in the coaxial distribution network is set, the transmission attenuation between the access point and the coaxial terminal and between the coaxial terminals is large, which affects the correct decoding of the receiving end, and the receiving end cannot A signal transmitted via the coaxial distribution network is received. Therefore, the physical layer chips in the transceivers of the Ethernet access point and the coaxial terminal must be modified. Summary of the invention
  • the object of the present invention is to transmit an Ethernet baseband signal by using an existing coaxial tree network, by transmitting to the transmitting side and receiving
  • the transceiver of the side physical layer is modified to support the transmission of the baseband Ethernet in a point-to-multipoint, large-attenuation situation on the existing television coaxial network.
  • the present invention provides an Ethernet transceiver device and an implementation method thereof.
  • the device performs level amplitude detection on a received analog signal, and adaptively adjusts an amplification factor according to the detection result to enable an amplified received analog signal.
  • the output level is the same, after being subjected to analog-to-digital conversion and codec processing, it is sent to the Ethernet MAC layer; and, the signal level sent to the coaxial network is amplified and output, and the amplification factor is between the coaxial terminals. The maximum attenuation loss is determined.
  • the present invention also provides a computer device comprising software for performing the Ethernet receiving method and hardware cooperating with the software.
  • the present invention utilizes the existing coaxial tree network to transmit the baseband electrical signal of the Ethernet, adopts a new Ethernet transmission method, and supports the baseband Ethernet to make a point pair on the existing television coaxial network.
  • 1 is a schematic diagram of a network structure of an existing access point of a cable television coaxial distribution network to each coaxial terminal;
  • FIG. 2 is a structural diagram of a physical layer device (chip) in an existing Ethernet transceiver;
  • FIG. 3 is a schematic structural diagram of an embodiment of an Ethernet 4 device according to the present invention.
  • FIG. 4 is a flow chart of an embodiment of an Ethernet transmission method on a coaxial cable network (receiving direction) of the present invention. detailed description
  • Ethernet fc device The structure of the Ethernet fc device will be described in detail below with reference to the accompanying drawings, and the MAC layer of the Ethernet of the present invention can be realized by interconnecting the Ethernet access point with the coaxial terminal or the transceiver devices of the two coaxial terminals.
  • the carrier network transmits data using a carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol.
  • CSMA/CD carrier Sense Multiple Access with Collision Detection
  • Ethernet carrier sense multi-point access/collision detection protocol requires each node to be able to; detect signals sent from each other to determine whether the transmission medium is in conflict, carrier sense multiple access/conflict monitoring is to solve the network A technique for conflicting problems caused by simultaneous transmission of information.
  • the working process is as follows: Each node in the local area network (such as a workstation) listens to the carrier signal in the network transmission medium before sending the information to know if there are other stations transmitting data. If not, the signal will report the ready signal to the workstation, and the workstation will start transmitting the data: if the carrier sense signal finds that another workstation is sending data, the workstation will wait and temporarily not send the message. .
  • the coaxial terminals of the multi-television users on the coaxial distribution network can detect the signals sent from each other, it can judge whether the transmission medium collides; thus, the Ethernet MAC layer protocol CSMA/CD can be allocated coaxially on the TV. Used on the network.
  • FIG. 3 is a schematic structural diagram of an embodiment of an Ethernet transceiver device according to the present invention.
  • the analog interface unit 110 of the transceiver of the Ethernet is connected to the coaxial cable, and can be applied to an Ethernet access point in the distribution network of the coaxial cable and each coaxial terminal; similar to the structure of FIG. 2, in the transceiver device
  • the physical layer chip includes an analog interface unit 110, an AD/DA (Analog/Digital) unit 120, a codec unit 130, and a MAC layer interface unit 140, and the functions of the above units in FIG. 3 and FIG. 2 are also the same. .
  • a transmission amplifying unit 260 is inserted between the analog interface unit 110 and the AD/DA (analog-to-digital) unit 120 for amplifying the output to the analog interface unit 110.
  • the transmitting end of the transceiver of the access point or the coaxial terminal can also transmit the signal larger than the output amplitude of the transmitting voltage according to the standard of IEEE 802.3.
  • the attenuation loss between the access point and the coaxial terminal in the coaxial distribution network is a fixed value (for example, 20 dB).
  • the coaxial terminals are connected.
  • the attenuation between the in points is also 20 dB; the transmission attenuation between the coaxial terminals is different (for example, 25 dB to 60 dB). Therefore, if an Ethernet access point and each coaxial terminal and each coaxial terminal are to be interconnected, data must be received in a large dynamic range in the receiving direction.
  • the dynamic range of the reception is calculated as follows: according to the attenuation minimum between the two coaxial terminals of the same splitter (ie, the data transmitted between the two coaxial terminals can be received from each other) and the respective coaxial terminals and accesses
  • the attenuation values between the points are compared to obtain the upper limit of the dynamic receiving range, and the lower limit of the dynamic receiving range is obtained according to the attenuation between different coaxial terminals of different branches, and the upper and lower limits of the two dynamic receiving ranges
  • the difference in values represents the dynamic range of reception of the received signal.
  • the upper limit of the dynamic receiving range of this embodiment is 25 dB of input voltage attenuation
  • the lower limit is 60 dB of input voltage attenuation
  • the dynamic receiving range is 35 dB.
  • Voltage attenuation amplitude 201g (Vx/Vo) Equation 1 where Vx is the input voltage and Vo is the output voltage.
  • the output voltage 0.79V in the case of 2dB; similarly, in the case of 20dB, the output voltage is 0.1V; in the case of 60dB, the output voltage is 0.001V.
  • the amplification factor of the transmission amplifying unit 260 is the largest between the coaxial terminals.
  • the attenuation loss is determined so that the receiving end can receive the most attenuated signal (for example, 60 dB) transmitted through the coaxial distribution network.
  • the determined amplification factor of the transmission amplifying unit 260 enables the receiving end to receive the voltage signal according to the IEEE 802.3 standard without affecting the correct decoding of the receiving end.
  • a receiving processing unit 200 In the receiving direction of the signal, a receiving processing unit 200, a receiving signal detecting unit 210, and a receiving automatic amplifying unit 220 are sequentially inserted between the analog interface unit 110 and the AD/DA (modulo: digital/digital) unit 120.
  • AD/DA modulo: digital/digital
  • Receive processing unit 200 which selectively receives signals from analog interface unit 110 by setting a level threshold of the received signal.
  • the level threshold of the received signal is determined by the maximum attenuation characteristic parameter between the coaxial terminals; and the voltage value lower than the maximum attenuation loss between the coaxial terminals is filtered to avoid unnecessary interference.
  • the received signal detecting unit 210 detects the level of the received signal from the analog interface unit 110. Since the signal amplitudes of different transmitting nodes (Ethernet access points or coaxial terminals) received by the receiving end of the Ethernet access point or the coaxial terminal are different, the dynamic range of the receiving can be from 20dB to 60dB, so it is required The difference in signal amplitude is amplified for different received signals.
  • the receiving automatic amplifying unit 220 is connected to the received signal detecting unit 210 in the receiving direction, and adaptively adjusts the amplification coefficient according to the detection result of the level amplitude so that the amplified received signal reaches an output level of the same amplitude.
  • the amplification factor of the receiving automatic amplifying unit 220 is adaptively adjusted.
  • the receiving end of the present invention first detects the input signal level amplitude of the input signal received from the analog port 110, and then determines the amplification factor of the subsequent receiving automatic amplifying unit 220 according to the input signal amplitude, so that the receiving device is in the receiving device.
  • the subsequent units inside the physical layer chip for example, the analog/digital to analog conversion unit 120
  • the signal output by the receiving automatic amplifying unit 220 is input to the analog/digital-to-analog converting unit 120 for converting between the analog signal and the digital signal.
  • the received signal is sent by an Ethernet access point to a coaxial terminal, and the input voltage amplitude of the signal access point of the Ethernet is 5V, then the attenuation reaches 20dB, and the coaxial terminal is reached.
  • the signal amplitude should be 0.5V, and when the reference level of the analog-to-digital conversion unit 120 at the receiving end (the reference of the decision 0, 1) is 0.5V, the analog/digital-to-analog conversion unit 120 can correctly handle the voltage amplitude of 0.5.
  • the signal of V, the magnification of the receiving end is 2, can meet the requirements.
  • the signal transmitted by the Ethernet access point can be attenuated by the coaxial distribution network, and the amplification of the automatic amplification unit 220 is received, and the reference reference level of the AD/DA (analog-to-digital) unit 120 is not changed.
  • the analog signal of the lower amplitude is converted into the correct digital signal.
  • FIG. 4 is a flowchart of Embodiment 1 of a method for performing Ethernet transmission on a coaxial cable network (receiving direction).
  • the transmission method in this embodiment includes the following steps:
  • Step S11 setting a level threshold of the received signal to selectively receive a signal from the analog interface unit;
  • Step S12 detecting a level of the received signal
  • Step S13 adaptively adjust the amplification factor according to the detection result of the level amplitude, so that the amplified received signal reaches the same output level amplitude.
  • step S13 the method further includes:
  • Step S14 Perform analog-to-digital conversion on the received signal according to the reference level
  • Step S15 Eliminate the crosstalk signal in the received signal after analog-to-digital conversion.
  • the inter-symbol interference canceling unit 240 is connected to the modulo/digital-to-analog conversion unit 120. It is used to reject the crosstalk signal in the received signal after analog-to-digital conversion.
  • the inter-code interference cancellation unit 240 technology belongs to the prior art and will not be described herein.
  • the coaxial cable is a single The load is 75 ohms, so in the design of the PHY chip, the load needs to be changed to 75 ohms.
  • the analog interface unit 110 is connected to a coaxial cable through a resistance adjusting unit 100, and the resistance adjusting unit 100 adjusts the load of the physical layer to 75 ohms.
  • the resistance adjustment unit 100 can also be designed after the analog interface unit 110.
  • the present invention can be implemented by means of software plus a necessary general hardware platform, and of course, can also be through hardware, but in many cases, the former is a better implementation. the way.
  • the technical solution of the present invention which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium, including a plurality of instructions for making a A computer device (which may be a personal computer, server, or network device, etc.) performs the methods described in various embodiments of the present invention.

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  • Computer Networks & Wireless Communication (AREA)
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Description

基于同轴电缆网上的以太网收发装置及以太网传输方法 技术领域
本发明涉及以太网传输技术， 特别涉及一种基于同轴电缆网上的 以太网收发装置及以太网的传输方法。 背景技术
在现有的有线电视光纤同轴网络（HFC )中， 电视节目由前端经 光歼传送到电视网络靠近用户的光同轴终端（一般情况下， 一个光同 轴终端覆盖周边的 300 ~ 500个用户） ， 在光同轴终端处将光信号转 换为电信号后，再通过同轴电缆分配网络将电视信号经居民楼传送到 各个居民家中。 随着人们对双向传输新业务（例如， 交互数字电视、 在有线电视网上实现数据、语音、 图像等多媒体通信等宽带业务）需 求的增长，只能单向传输的有线电视网要开展双向业务， 所遇到的首 要问题就是双向改造。 双向改造是有线电视网从单功能向多功能发 展， 从广播电视网向信息网发展的第一道门槛。
以太网具有简单、 低成本和易扩展的优势成为 HFC双向改造的 较佳选择， 然而， 由于广电的电视同轴分配网络在接入点和同轴终端 之间以及各同轴终端之间的传输，是一个有较大恒定衰减的网络， 不 同于几乎无衰减总线型的同轴以太网，也不同于点对点双绞线以太网 网络。 其传输的衰减特征体现在两个方面：
L )接入点和同轴终端之间的衰减特征
请参阅图 1 , 图 1为现有的有线电视同轴分配网中楼接入点到各 同轴终端的网络结构示意图； 如图 1所示， 在每一个居民楼内， 有一 个楼头放大器，对电视信号进行放大，以弥补传输过程中的信号衰減。 I设， 一个 6层居民楼有 6个单元， 每一个单元有 12户， 那么经过 楼头放大器放大后的电视信号， 首先经过一个 6分配器，将电视信号 能量平均分配到 6个单元， 然后， 通过在每个单元内的每层楼上的二 分支器， 再将电视信号分到每层楼的两户居民家（同轴终端）中。 为 了保证电视信号到各家各户的信号幅度一致（因为各家的电视机接收 信号的幅度要一致）， 所以各层楼的分支器衰减幅度不同， 比如信号 一般是从一楼传送到六楼， 处于信号传输近端的一楼， 不需要经过后 面的分支器和传输电缆， 因此需将一楼分支器的衰减幅度设置为较 大， 例如， 通常为 14db的衰减； 而二楼分支器的衰减幅度稍小， 例 如 12db, 以此类推。 这样， 在电视信号源通过同一个同轴分配网络 传输到 12家的传输过程中， 虽然传输距离和传输路径不同， 但同一 电视信号源经接入点到各同轴终端的衰减是相同的。
具体地说，经过楼头放大器放大后的电视信号首先经过一个 6分 配器， 经电视信号能量平均分配到 6个单元， 在每一个单元内部， 在 每层楼有一个二分支器，将电视信号分到每层楼的两户。 那么这个网 络的衰减为大约 31dB。 该衰减值在理论上的计算大致为： 一个 6分 配器（ 9dB ) 、 5个不同楼层的分支器和一个 6楼的 2分配器（ 14dB ) 和大约 50米（楼道 35米加室内 15米） 的同轴电缆线 （10dB， 按照 高频 1000MHz的衰减计算）， 一共加起来为 33dB。 实际工程中一般 小于 31dB。 也就是说， 楼头放大器的输出为 lOOdBuv (分贝微伏） , 而用户端电柳」机的接收幅度为 69dBuv。
2 )各同轴终端之间的衰减特征
在有线电视同轴分配网中的不同同轴终端之间，由于两个同轴终 端之间进行通信时， 所经过的分支设备（分配器或分支器）的个数不 同， 因此衰减幅度不同。 各个同轴终端之间的衰减， 至少在 25dB以 上， 最大可以到达 60dB 左右。 具体地说， 同一个分支器的两个分支 同轴终端的衰减（相当于分支器的相互隔离度参数） ， 大约在 25dB 到 30dB之间。 不同分支器的所接的同轴终端之间的衰减， 相当于是 一个反向隔离度参数再加上一个分支损耗参数，大约在 40dB到 60dB 之间。
从上述两条衰减特征来看，如果在同轴电缆网上实现以太网传输 协议， 特别是在以太网的 MAC层实现 CSMA/CD (载波监听多路访 问 /冲突检测）协议的情况下， 不仅需要以太网接入点与各个同轴终 端互通， 还要做到各个同轴终端之间是互通的。 也就是说， 以太网接 入点与各个同轴网络互通需要克服 31dB左右的衰減， 各个同轴终端 之间的互通需要克服 25dB到 60dB之间的衰减。
现在市场上的以太网物理层接入芯片的规格有 10/100M自适应、 GE (千兆以太网）和 10GE (万兆以太网）等。 这类芯片的主要功能 是完成物理层的编码、 数模转换、 时钟恢复以及模拟的放大等， 其结 构上包括对外的接口（模拟信号）以及对 MAC层的接口（数字信号）。
请参阅图 2,图 2为现有以太网收发装置中的物理层设备的结构。 如图 2所示， 模拟接口单元 110与 AD/DA (模 数模）单元 120、 编解码单元 130、 MAC层接口单元 140依次串接。 在接收方向， 从 模拟接口单元 110输入的接收信号 , 首先经过 AD/DA单元 120进行 模拟至数字的变换处理，将模拟信号转换为数字信号， 然后再由编解 码单元 130进行编码解码处理，从物理层的编码数据流中提取出 MAC 层的数据信息， 再经过 MAC层接口单元 140进行 MAC层接口处理 后送出。 其中， AD/DA单元 120按照 IEEE 802.3的标准发送电压和 标准接收参考电平进行模 ¾ /数模转换。
以太网是基于双绞线传输的， 以传输距离是 100米时为例， 双绞 线在 20MHz 时的衰减仅为 8dB。 在以太网的信号接入点的收发装置 的发送电平不改变的情况下，如果使接入点或同轴终端的收发装置的 发送端按照 IEEE 802.3的标准发送电压发送信号， 接收端同样按标 准接收参考电平接收信号，由于同轴分配网中的分支设 吏接入点与 同轴终端之间以及各同轴终端之间的传输衰减较大，影响到接收端的 正确解码，接收端不能接收到经同轴分配网传输来的信号。 因此必须 对以太网接入点和同轴终端的收发装置中的物理层芯片进行改造。 发明内容
针对上述需解决的物理层信号的传输问题，本发明的目的在于借 用现有的同轴树状网络传输以太网的基带信号，通过对发送侧和接收 侧物理层的收发装置进行改造，从而达到支持基带以太网在现有电视 同轴网络上作点对多点的、 大衰减情况下的传输。
基于上述目的， 本发明提供一种以太网的收发装置及实现方法， 该装置对接收的模拟信号进行电平幅度检测，根据该检测结果， 自适 应地调整放大系数， 使放大后的接收模拟信号的输出电平幅度相同， 经过模数转换和编解码处理后， 发送到以太网 MAC层； 并且， 对向 同轴网络发送的信号电平进行放大输出，放大系数由各同轴终端之间 的最大衰减损耗确定。
本发明还提供了一种计算机设备，包括用以执行所述的以太网接 收方法的软件及与软件配合的硬件。
从上述技术方案可以看出，本发明利用现有的同轴树状网络传输 以太网的基带电信号， 采用新的以太网传输方法， 支持基带以太网在 现有电视同轴网络上作点对多点的、 过同轴分支分配器衰减的传输； 实现了以太网的接入点与各同轴终端之间以及各同轴终端之间互通， 从而使以太网的 CSMA/CD MAC层能够使用在广电同轴网络应用环 扰造成的信号失真。
因此， 为广播电视增值业务的开拓和现有网络资源的增值创造了 广阔的机会， 特别是这种双向改造的成本很低。 附图说明
图 1 为现有的有线电视同轴分配网中楼接入点到各同轴终端的 网絡结构示意图；
图 2为现有以太网收发装置中的物理层设备（芯片） 的结构； 图 3为本发明以太网 4 装置实施例的结构示意图；
图 4为本-发明在同轴电缆网上（接收方向）的以太网传输方法实 施例的流程图。 具体实施方式
下面将结合附图详细介绍以太网的 fc 装置的结构 ,及通过将以 太网接入点与同轴终端或两个同轴终端的收发装置互连，可以实现本 发明的以太网的 MAC层在同轴电缆网上采用载波侦听多点接入 /冲 突检测 ( Carrier Sense Multiple Access with Collision Detection简称 CSMA/CD ) 的协议传输数据。 图 4中的 S表示步骤。
以太网的载波侦听多点接入 /冲突检测的协议， 要求各个节点都 能够; 测到彼此发出的信号， 以判断传输介质是否冲突， 载波侦听多 路访问 /冲突监测是为了解决网络上同时传输信息而引起的冲突问题 的一种技术。 其工作过程为： 局域网中的各个节点（例如工作站）在 发送信息前都通过侦听网络传输介质中的载波信号，以了解是否有其 他工作站在发送数据。如果没有， 那么该信号就会给工作站报告一切 就绪的信号， 该工作站就开始传输凝:据，如果载波侦听信号发现有另 一台工作站在发送数据，该工作站就会等待，暂时不发送信息。因此， 同轴分配网络上的多电视用户的同轴终端之间只要能够检测到彼此 发出的信号， 才能判断传输介质是否沖突； 从而使以太网 MAC层协 议 CSMA/CD能在电视同轴的分配网络上使用。
请参阅图 3,图 3为本发明以太网收发装置实施例的结构示意图。 该以太网的收发装置的模拟接口单元 110与同轴电缆相连，可适用于 同轴电缆的分配网中的以太网接入点以及各同轴终端中；与图 2的结 构相似， 收发装置中的物理层芯片包括， 模拟接口单元 110、 AD/DA (模数 /数模）单元 120、编解码单元 130、以及 MAC层接口单元 140, 并且图 3 与图 2中上述单元的功能也是相同的。
与图 2中不同的是， 在信号的发送方向， 在模拟接口单元 110与 AD/DA (模 数模）单元 120之间插接有发送放大单元 260用来放 大输出到所述模拟接口单元 110的发送信号电平。并且接入点或同轴 终端的收发装置的发送端， 还可以大于按照 IEEE 802.3的标准的发 送电压的输出幅度发送信号。 再请参阅图 1 , 根据背景技术部分的计算， 同轴分配网中的接 入点与同轴终端之间的衰减损耗是一个固定值（例如为 20dB ) ， 同 理， 各个同轴终端与接入点之间的衰减也为 20dB; 而各同轴终端之 间的传输衰减是不同的（例如为 25dB到 60dB )。 因此， 如果要实现 以太网接入点与各个同轴终端之间、 以及各个同轴终端之间互通，在 接收方向必须在一个较大的动态范围内均能接收数据。
接收的动态范围计算如下：根据将同一个分支器的两个同轴终端 之间（即两个同轴终端之间能接收到彼此发送的数据）的衰減最小值 与各个同轴终端与接入点之间的衰减值进行比较，得到动态接收范围 的上限值，根据不同分支器的不同同轴终端之间的衰减得到动态接收 范围的下限值， 以及这两个动态接收范围的上下限数值的差值， 就代 表了接收信号的动态接收范围。例如， 本实施例的动态接收范围的上 限值为输入电压衰减 25dB, 下限值为输入电压衰减 60dB, 动态接收 范围为 35 dB。
按照基于电压的衰減计算公式（以 dB为单位） ：
电压衰减幅度 = 201g ( Vx/Vo ) 公式 1 其中， Vx为输入电压， Vo为输出电压。
通过上述计算公式可以得出，在电压衰减幅度为 20dB的情况下， VxA/o-10; 在电压衰减幅度为 60dB 的情况下， Vx/Vo=1000。 而在 无分支器衰减的 50米同轴电缆分配网的电缆传输情况下， 因其网络 电压衰减幅度仅为 2dB左右， 对应的 Vx/Vo=1.25。
因此， 假设信号接入点的输入电压 Vx = IV, 那么在 2dB的情况 下， 输出电压为 0.79V; 同样， 在 20dB的情况下， 输出电压为 0.1V; 在 60dB的情况下， 输出电压为 0.001V。
在上述情况下，如果以太网的信号接入点的输入电压幅度为 IV, 那么到达各个同轴终端的信号幅度应为 0.1V。 同样， 各个同轴终端 发出来的输出幅度为 IV的信号， 到达以太网的输入幅度也为 0.1 V； 但到其它同轴终端的信号， 输出幅度最大为 0.056V， 最小为 0.001V。 因此，所述的发送放大单元 260的放大系数由各同轴终端之间的最大 衰减损耗确定，使接收端能接收到经同轴分配网传输来的衰减最大的 信号 （例如 60dB ) 。 较优地， 所确定的发送放大单元 260的放大系 数能使接收端按照 IEEE 802.3的标准接收电压信号， 从而不影响到 接收端的正确解码。
如果物理层芯片只能识别最小幅度为 0.5V的信号， 那么按照在 电压衰减幅度为 60dB的情况下 Vx/Vo=1000计算， 需要在输入端将 物理层芯片的输出电压放大到 500V, 因此， 需要在接入点和同轴终 端的物理层芯片输出端加放大器提升信号的传送幅度。
在信号的接收方向，在模拟接口单元 110与 AD/DA (模凝： /数模 ) 单元 120之间依次插接有接收处理单元 200、 接收信号检测单元 210 以及接收自动放大单元 220。
接收处理单元 200, 其通过设置接收信号的电平阈值, 选择性地 接收来自模拟接口单元 110的信号。该接收信号的电平阈值由各同轴 终端之间的最大衰减特性参数确定；并且使低于各同轴终端之间的最 大衰减损耗的电压值过滤掉， 以避免不必要的干扰。
接收信号检测单元 210， 对来自模拟接口单元 110的接收信号进 行电平幅度的检测。由于以太网接入点或同轴终端的接收端所接收的 来自不同发送节点（以太网接入点或同轴终端）的信号幅度不同， 其 接收的动态范围可以为从 20dB到 60dB,因此需要对不同的接收信号 进行信号幅度的差异放大。
接收自动放大单元 220, 在接收方向与所述的接收信号检测单元 210连接， 其根据电平幅度的检测结果， 自适应地调整放大系数， 使 放大后的接收信号达到相同幅度的输出电平。 自适应地调整接收自动 放大单元 220的放大系数，在现有技术中有许多方法可以实现， 在此 不再赘述。
具体地说， 本发明的接收端对从模拟端口 110接收的输入信号， 先检测该输入信号电平幅度，然后根据输入信号幅度来决定后面的接 收自动放大单元 220的放大倍数，使得接收装置中的物理层芯片内部 后续的单元（例如模数 /数模转换单元 120 ) 能够进行统一处理。 本实施例中，所述的接收自动放大单元 220输出的信号输入到了 模数 /数模转换单元 120， 用来进行模拟信号与数字信号之间的转换。
例如， 如果接收到的信号是以太网接入点发送到某同轴终端的， 以太网的信号接入点的输入电压幅度为 5V,那么在衰减为 20dB的情 况下， 到达该同轴终端的信号幅度应为 0.5V, 并且当接收端的模 数模转换单元 120的参考电平（判决 0、 1的基准）为 0.5V时， 为了 模数 /数模转换单元 120能正确处理电压幅度为 0.5V的信号， 接收端 的放大倍数为 2就可以满足要求。这样就可以使以太网接入点发送的 信号， 经过同轴分配网传输的衰减后， 通过接收自动放大单元 220的 放大， 在没有改变 AD/DA (模 数模）单元 120的基准参考电平的 情况下， 其信号满足了模¾/数模转换单元 120的处理要求， 从而将 幅度较低的模拟信号中转换出正确的数字信号。
请参阅图 4, 图 4为本发明在同轴电缆网上（接收方向）进行以 太网传输的方法实施例一的流程图； 本实施例中的传输方法， 包括以 下步骤：
步骤 S11: 设置接收信号的电平阈值， 选择性地接收来自模拟接 口单元的信号；
步驟 S12: 对接收信号进行电平幅度的检测；
步骤 S13: 根据电平幅度的检测结果， 自适应地调整放大系数， 使放大后的接收信号达到相同的输出电平幅度。
在步驟 S13之后还包括：
步骤 S14: 将处理后的接收信号按参考电平进行模数转换； 步骤 S 15： 消除模数转换后接收信号中的串扰信号。
在本实施例中，为了消除因传输线中的码间干扰和传输线间的相 互干扰造成的信号失真， 在信号的接收方向， 码间干扰抵消单元 240 连接在模¾/数模转换单元 120后， 用来剔除模数转换后接收信号中 的串扰信号。码间干扰抵消单元 240技术属现有技术，在此不再赘述。
此外， 由于双绞线是 100欧姆的差分平行负载， 而同轴电缆是单 端 75欧姆的负载， 所以在 PHY 芯片的设计中， 还需要将负载改为 75欧姆的。 如图 3所示， 所述的模拟接口单元 110通过电阻调节单 元 100与同轴电缆相连，所述的电阻调节单元 100将物理层的负载调 整成 75欧姆。 电阻调节单元 100也可以设计在模拟接口单元 110之 后。
通过以上的实施方式的描述， 本领域的技术人员可以清楚地 了解到本发明可借助软件加必需的通用硬件平台的方式来实现， 当然也可以通过硬件， 但很多情况下前者是更佳的实施方式。 基 于这样的理解， 本发明的技术方案本质上或者说对现有技术做出 贡献的部分可以以软件产品的形式体现出来， 该计算机软件产品 存储在一个存储介质中， 包括若干指令用以使得一台计算机设备 (可以是个人计算机， 服务器， 或者网络设备等）执行本发明各 个实施例所述的方法。
需要声明的是，上述发明内容及具体实施方式意在证明本发明所 提供技术方案的实际应用， 不应解释为对本发明保护范围的限定。本 领域技术人员在本发明的精神和原理内，当可作各种修改、等同替换、 或改进。 本发明的保护范围以所附权利要求书为准。

Claims

权利要求
1、 一种以太网的收发装置， 用于同轴电缆分配网中的以太网数 据的传输， 包括与同轴网络连接的模拟接口单元、 与以太网连接的 MAC层接口单元、 与所述 MAC层接口单元连接的编解码单元， 以 及与所述编解码单元连接的模¾ /数模单元， 其特征在于， 还包括： 接收信号检测单元， 与模拟接口单元连接，对来自模拟接口单元 的接收信号进行电平幅度检测；
接收自动放大单元，分别与所述的接收信号检测单元和所述模数 /数模单元连接， 其根据所述接收信号检测单元对电平幅度的检测结 果， 自适应地调整放大系数， 使放大后的接收信号的输出电平幅度相 同；
发送放大单元， 分别与所述模拟接口单元和所述模数 /数.模单元 连接， 用来放大输出到所述模拟接口单元的发送信号电平； 所述的发 送放大单元的放大系数由各同轴终端之间的最大衰减损耗确定。
2、 根据权利要求 1所述的以太网的收发装置， 其特征在于， 还 包括：
接收处理单元，其插接于所述模拟接口单元与所述接收信号检测 单元之间， 其通过设置接收信号的电平阔值， 选择来自所述模拟接口 单元的信号。
3、 根据权利要求 2所述的以太网的收发装置， 其特征在于， 所 述的电平阈值由各同轴终端之间的最大的衰减损耗确定。
4、 根据权利要求 1所述的以太网的收发装置， 其特征在于， 还 包括： 电阻调节单元， 与所述模拟接口单元连接， 所述电阻调节单元 用于调整物理层的负载。
5、 根据权利要求 1所述的以太网的收发装置， 其特征在于， 还 包括：
码间干扰抵消单元 , 连接在所述模数 /数模转换单元和所述编解 码单元之间， 用于剔除模数转换后接收信号中的串扰信号。
6、 一种以太网传输方法， 应用于包括与同轴网络连接的模拟接 口单元、 与以太网连接的 MAC层接口单元、 与所述 MAC层接口单 元连接的编解码单元， 以及与所述编解码单元连接的模数 /数模单元 的装置中， 其特征在于， 所述方法包括以下步骤：
对来自所述模拟接口单元的接收信号进行电平幅度的检测，根据 电平幅度的检测结果， 自适应地调整放大系数， 使放大后的接收信号 的输出电平幅度相同， 通过所述模数 /数模转换单元和编解码单元发 送到 MAC层接口单元；
根据所述放大系数对所述 MAC层接口单元经所述编解码单元、 模数 /数模转换单元发送的输出信号的发送电平进行放大， 并将放大 后的信号由所述模拟接口单元发送到同轴网络。
7、 如权利要求 6所述以太网传输方法， 其特征在于， 在对来自 模拟接口单元的接收信号进行电平幅度的检测之前， 该方法还包括： 通过设置接收信号的电平阈值， 选择来自模拟接口单元的信号。
8、 根据权利要求 7所述以太网传输方法， 其特征在于， 所述 的电平阈值由各同轴终端之间的最大的衰减损耗确定。
9、 根据权利要求 6所述以太网传输方法， 其特征在于， 所述接 收信号进行电平幅度的检测之前还包括： 调整物理层负载。
10、 据权利要求 6所述以太网传输方法， 其特征在于， 对接收 信号进行模数 /数模转换之后、 编解码之前还包括： 去除模数转换后 业务信号中的串扰信号。
11、 一种计算机设备， 其特征在于， 包括用以执行前述权利要求 6-10所述的以太网传输方法的软件及与软件配合的硬件。
PCT/CN2007/002153 2007-01-15 2007-07-13 Dispositif de réception et d'émission par ethernet à base de réseau à câble coaxial et procédé de transmission par ethernet WO2008086670A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2154829A1 (en) * 2008-08-15 2010-02-17 Thomson Licensing Method for the adjustment of a transmission characteristic for a data transfer in a network of stations and first and second network station for the use in said method

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009124389A1 (en) * 2008-04-11 2009-10-15 Gennum Corporation System and method for programmable pre-amplification of a signal
CN101447948A (zh) * 2008-12-29 2009-06-03 杭州华三通信技术有限公司 一种数据传输方法和一种以太网终端
CN101795385B (zh) * 2009-02-03 2012-04-18 厦门Abb振威电器设备有限公司 一种自动预放大和补偿的双绞线视频传输方法和系统
US8867352B2 (en) * 2009-12-31 2014-10-21 Broadcom Corporation Receiver based power efficient transmitter for ethernet
CN108847946A (zh) * 2018-05-23 2018-11-20 新华三信息安全技术有限公司 一种信号传输方法和pcb

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1373606A (zh) * 2001-03-06 2002-10-09 北京融通天网网技术有限公司 一种基于有线电视同轴电缆的双向数据网络传输系统
CN1719891A (zh) * 2005-07-28 2006-01-11 上海大学 用于有线电视网络的可控型自动增益控制电路

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6662135B1 (en) * 1998-12-09 2003-12-09 3Com Corporation Method and apparatus for reflective mixer testing of a cable modem
US6795494B1 (en) * 2000-05-12 2004-09-21 National Semiconductor Corporation Receiver architecture using mixed analog and digital signal processing and method of operation
US6512416B2 (en) * 2000-07-03 2003-01-28 Broadcom Corporation Extended range variable gain amplifier
KR100618388B1 (ko) * 2000-09-19 2006-09-04 삼성전자주식회사 모뎀 및 그 제어방법
WO2002093758A2 (en) * 2001-05-17 2002-11-21 Broadcom Homenetworking, Inc. Apparatus for transporting home networking frame-based communications signals over coaxial cables
US20020172290A1 (en) * 2001-05-18 2002-11-21 Chorpenning Jack S. Method and system for transmitting signals between a high speed serial bus and a coaxial cable
CN1173544C (zh) * 2001-07-09 2004-10-27 北京艺盛网联科技有限公司 同轴长距离以太网接入方法及其设备
US20030162518A1 (en) * 2002-02-22 2003-08-28 Baldwin Keith R. Rapid acquisition and tracking system for a wireless packet-based communication device
US7522549B2 (en) * 2004-04-16 2009-04-21 Broadcom Corporation Registering access device multimedia content via a broadband access gateway
WO2007027667A2 (en) * 2005-09-01 2007-03-08 Optimal Licensing Corporation Media access control architecture
JP5458744B2 (ja) * 2009-08-25 2014-04-02 沖電気工業株式会社 プレゼンス情報提供方法及びシステム

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1373606A (zh) * 2001-03-06 2002-10-09 北京融通天网网技术有限公司 一种基于有线电视同轴电缆的双向数据网络传输系统
CN1719891A (zh) * 2005-07-28 2006-01-11 上海大学 用于有线电视网络的可控型自动增益控制电路

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2154829A1 (en) * 2008-08-15 2010-02-17 Thomson Licensing Method for the adjustment of a transmission characteristic for a data transfer in a network of stations and first and second network station for the use in said method

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