MU886 System Description 无线宽带MU886系统描述 November 2003 2003年11月

1. System Overview

1.1 IEEE 802.16a Compliance

1. 系统总揽

1.1 符合IEEE 802.16a标准（电气电子工程师协会）

The Xxx MU886 system is a carrier class high-speed IEEE 802.16a compliant wireless switch for Point-to-Point and Point-to-Multipoint deployment. The system is initially available in the 3.5GHz band.

Xxx公司的MU886系统是一种高速点对点及一点对多点的载波无线交换应用设备，符合IEEE 802.16a标准，其初始化的有效波段为3.5G赫。

The IEEE 802.16 Air Interface Specification describes a point-to-multipoint broadband wireless access standard for systems in the frequency range of 2-11 GHz, and 10-66 GHz (licensed and unlicensed bands). This standard includes descriptions for both the Media Access Control (MAC) and the physical (PHY) layers.

IEEE 802.16标准的空中接口规范描述了一种单点对多点的无线宽带接入标准，其系统频率范围为2-11G赫，以及10-66G赫（已获授权及未授权的波段）。此标准包括对媒介存取控制(MAC)和物理层(PHY)的描述。

The 802.16 specification is designed to cover the fixed broadband wireless access needs for a variety of applications, and includes allowances for different physical layers, frequency bands, and frequency use restrictions worldwide. The specification includes descriptions covering both IP and ATM centric systems, and for markets ranging from business users requiring very high bandwidth to SOHO and residential users.

802.16规范是为了可涵盖多种应用需求的固定式宽带无线接入而设计的，并包括不同的物理层、频率波段，以及全球的频率使用限定。该规范的描述包括了网际协议（IP）以及异步传输模式（ATM）的中心系统，其市场范围可涵盖对于带宽要求很高的商业用户，到SOHO一族，以及住宅用户等。

The 802.16 working group recognized that it might be impractical for vendors to implement system features that are unrelated to the requirements of their customer. The 802.16 specification includes a chapter describing system profiles, specifying both mandatory and optional features for the MAC and PHY, based on projected requirements for deployment of real systems. Use of these profiles is intended to insure that vendor products for a specified market sector will be interoperable (without requiring implementation of every feature in the specification).

802.16工作组认识到，让零售商来实施那些与客户需求并不相关的系统性能往往是不切实际的。802.16规范中有一章是对系统的简要描述，该章根据系统在实际部署时的计划要求、详细规定了对MAC和PHY系统的强制性能事项及可选性能事项，其目的是为了确保在指定市场范围内的零售产品可以互换使用（不需要同时实施规范中的每一个性能）。

The MU886 system is designed to meet the interoperability profile established by Wimax for 2-11 GHz operation. WiMAX (http://www.wimaxforum.org) promotes deployment of broadband wireless access networks by using global standards and certifying interoperability of products and technologies.

MU886系统的设计满足了由Wimax组织提出的2-11G赫波段的操作互用性要求。WiMAX组织(http://www.wimaxforum.org)通过使用全球化标准以及对产品和技术的互用性进行认证，推动了无线宽带接入网络的部署。

1.2 PHY Specification

1.2 PHY规范

The MU886 system conforms to the 'WirelessMAN-OFDM PHY' definition in the IEE802.16 specification. Designed for 2 GHz to 11 GHz operation, it is initially available in the following frequencies:

MU886系统符合IEE802.16规范中有关WirelessMAN-OFDM PHY的定义，所设计的运行频率范围为2 GHz到11 GHz，其初始化的有效频率如下：

• Release R1.0 supports 3.4- 3.5 GHz in the TDD mode,
• Release R1.1 supports 3.6- 3.7 GHz in the TDD mode,

§ Release R1.2 supports 3.4- 3.6 GHz in the FDD mode,

■ R1.0版本在TDD模式下支持3.4-3.5G赫。

■ R1.1版本在TDD模式下支持3.6-3.7G赫。

■ R1.2版本在FDD模式下支持3.4-3.6G赫。

1.3 Communications

1.3 通信

The MU886 system uses a non-contention based two-way, centrally coordinated, PMP cell deployment communications strategy. The base station sector unit controls scheduling for all transmissions -- broadcasting on the downlink to all subscriber stations. Subscriber Stations are polled or granted time slots to transmit on the uplink (like TDMA) based on the service level criteria of each active Service Flow (QoS Management). Support is provided for real-time polling (rtPS), non-real-time polling (nrtPS), unsolicited grant service (USG) and best effort (BE). Mesh communication (direct subscriber-to-subscriber) is not supported.

MU886系统使用一种基于非争用模式的双向、中央协同、部署PMP单元的通讯策略。它的基站单元控制着所有传输的时序安排——向所有的下行用户站群发(如时域多路存取技术TDMA那样)。用户站都可获得轮询或被给与时隙、按每个活跃服务流(服务质量管理)的服务水平标准进行上行发送。提供的支持分为实时轮询(rtPS)、非实时轮询(nrtPS)、非申请授予(USG)，以及“尽力而为”(BE)模式。不支持网式通讯(用户与用户之间的直接通讯)。

1.4 Link performance

1.4 链接性能

MU886 is able to deliver high data rates of up to 35Mbps over the air (18Mbps net) using a 7MHz channel.

MU886系统使用一个7M赫的信道，可按无线方式(18Mbps net)传输高速率的数据流，最高达35Mbps。

The product is designed to deliver up to 10km (6Miles) in No-Line-of-Sight (NLOS) operation and up to 80km (50 miles) in Line-of-Sight (LOS) operation.

该产品的设计传送距离为非视距下(NLOS)10公里(6英里)，视距下(LOS)80公里(50英里)。

1.5 Time Division Duplexing (TDD)

1.5 分时双工技术（TDD）

The MU886 system uses Time Division Duplexing (TDD) technique to transmit and receive on the same channel. This requires no band separation and provides efficient use of the entire spectrum. Use of TDD also allows the MU886 to adaptively modify the ratio of downlink and uplink data (i.e., 70% uplink / 30% downlink).

MU886系统使用分时双工（TDD）技术，可在同一个信道内发送及接收信号。这里无需频段分离，可充分使用整个频谱段。使用了TDD技术的MU886系统还可调节下行数据和上行数据的比率（如70％上传，30％下载）。

1.6 Frequency Division Duplexing (FDD)

1.6 分频双工技术（FDD）

From Release 1.2 onwards MU886 will also be able to operate in Frequency Division Duplexing (FDD) mode. In countries the licenses are issued in paired bands where one band is used for downstream and the other band is used for upstream transmission. The paired bands are usually separated by 100MHz.

从版本1.2起，MU886还能按分频双工（FDD）的模式运行。有的国家是按成对的波段颁发使用许可的，其中一个波段用于数据下行，另一个用于数据上行，其之间的间隔通常为100兆赫。

MU886 operates in half-duplex FDD mode, i.e. it does not transmit in the upstream and downstream directions simultaneously.

MU886系统的运行模式为半双工的FDD，即它并不同时传输上行和下行数据。

1.7 OFDM (256 FFT)

1.7 正交频分复用技术(256 状态)

The MU886 uses Orthogonal Frequency Division Multiplexing (OFDM) techniques to send data by radio transmission. During each burst, data is encoded using a Fast Fourier Transform (FFT) algorithm and transmitted on sub-channels. OFDM provides high spectral efficiency, and is highly resistant to multi-path interference and frequency specific fading.

MU886系统使用正交频分复用(OFDM)技术发送无线数据，在每个脉冲中使用快速傅里叶快速变换(FFT)的算法将数据进行编码后传输到亚信道。正交频分复用提供了很高的频谱利用率，并能很好地抵御多通道干扰和频率特点衰减。

1.8 Dynamic Adaptive Modulation

1.8 动态自适应调制

The MU886 evaluates link conditions on a burst-by-burst basis. As link conditions change (half-loss, interference, seasonal) the transmission settings are adjusted independently for each active Service Flow within each burst. This maintains the highest possible data rate available while maintaining an error rate below 1x10 -6 BER.

MU886系统在一个个脉冲的基础上评估链接状况。如发现链接情况发生变化(半丢失，干扰，周期性失效等)，将按每个脉冲的情况对每一个活跃服务流的传输设置予以单独调整。这样做可在将误码率维持在1x10 –6 BER以下的同时保持尽可能高的数据传输速率。

Dynamic adaptation and error correction features include:

- Adaptive coding: ratio of redundant code to raw data (1/2, 2/3 and 3/4)

- Adaptive modulation: modulation technique (BPSK, QPSK, QAM16 and QAM64)

- ARQ: retransmission with modified modulation to improve chance of delivery

- Reed Solomon forward error correction.

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动态调整和纠错性能包括：

－ 自适应编码：冗余编码对原始数据的比率(1/2，2/3和3/4)

— 自适应调制：调制技术(BPSK, QPSK, QAM16 和 QAM64)

— 自动误差校正：优化调制后进行重新传输，以提高送达机会

— 里德所罗门正向纠错

1.9 Security

1.9 安全

The encapsulation protocol defines a set of cryptographic suites used to encrypt packet data across the fixed broadband wireless access network. The Privacy Key Management (PKM) protocol provides secure distribution of keying data (DES/3DES) from base stations to subscribers. Base stations use this protocol to enforce conditional access to network services and when synchronizing key data with subscriber stations. Subscriber authorization is based on the X.509 certificate.

封装协议定义了一套密码组，将在固定式无线宽带存取网络上传输的数据包进行加密。密钥管理(PKM)协议可将用户的密钥数据(DES/3DES)从基站安全发送到用户那里。基站使用该协议后，可在用户站提供了密钥合成数据后实现有条件地获得网络服务。用户授权建立在X.509证明的基础之上。

1.10 Powering Options

1.10 电源选购件

MU886 provides a number of power supply options.

- Single AC Power Supply (MU886)

- Single DC Power Supply (24-70VDC, +/- polarity)

- Redundant PS options– AC/AC, AC/DC, or DC/DC

- Selection of antenna types (directional or sectorized)

MU886系统有多种电源选购件

— 单一交流电源（MU886）

— 单一直流电源（24-70VDC, +/- 极）

— 备用电源选购件- AC/AC, AC/DC, 或DC/DC

— 可选天线类型（定向或分区）

If no power supply option is specified at the time of order, the product is shipped with single AC power supply.

如在订货时没有指定电源的类型，供货时将提供单一交流电源。

2. Applications and Services

2.1 Connection to Remote or Under-Serviced Area

2．应用及服务

2.1 偏远地区或落后地区的接通

Generally, the broadband access market is adequately served with wireline technologies such as xDSL and fiber. For example, fiber is available in only 5% of US office buildings and DSL is only available within 3km of a central office.

一般来说，线缆接入技术如xDSL和光纤等可以为宽带接入市场提供足够的服务。例如，在美国的写字楼中仅有5%的大楼使用了光纤，而DSL仅在中心局的3公里范围内有用。

The robustness and flexibility of the MU886 system addresses these limitations and enables organisations and service providers to quickly deploy new broadband services in under-serviced and remote areas:

- Where line-of-sight is not available

- Distances can exceed 80km (50 Miles)

强大且具灵活性的MU886系统可以应付这些限制，让公司机构和服务提供商能在落后的以及偏远地区迅速地部署新的宽带服务：

— 在尚无可视距条件的地区

— 距离超过80公里(50英里)的地区