计算机中英文对照专业时文选读之十八

Wireless PANs(2)

The 802.15 working group is defining different versions for devices that have different requirements. 802.15.3 focuses on high-bandwidth (about 55M bit/sec), low-power MAC and physical layers, while 802.15.4 deals with low-bandwidth (about 250K bit/sec), extra-low power MAC and physical layers.

The emphasis on minimizing cost, complexity and chip size is permeating all aspects of the standardization process. The selection criteria for power management, security algorithms and QoS all include consideration of these features. The short-range nature of communication in a wireless PAN also means reduced transmission power and cost.

The security requirements for 802.15 networks are different from more static networks because of the dynamic nature of wireless PANs. As a result, the working group is looking into specifying public-key solutions for authentication and key exchange, letting devices that have not been in contact previously establish secure communications without revealing any secret keying material.

Once the devices have been authenticated, each device in the wireless PAN shares common group (symmetric) payload protection keys for encryption and data integrity. Devices also may use the authentication mechanism to establish two-party secure subnetworks.

Another issue still facing the working group before completion of the standards is coexistence with other types of wireless devices and among the different types of 802.15 devices. There are several wireless standards that specify transmission in the 2.4-GHz range, and in some cases they interfere with each other.

Despite the remaining challenges, the working group expects to resolve the outstanding issues and provide complete, cost-effective, low-power solutions in the wireless device market.

The standards are scheduled to be completed in the third quarter of this year.

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无线个人区域网 (2)

802.15工作组正在为有不同要求的设备定义不同的版本。802.15.3针对大带宽(约55M位/秒)、低功率MAC和物理层，而802.15.4针对小带宽(约250K位/秒)和极低功率的MAC和物理层。

在此标准化过程的方方面面都贯穿着对降低成本、复杂度和芯片尺寸的强调。用电管理、安全算法和 QoS的选择标准全都考虑到这些特点。无线PAN的短距离通信的本质也意味着降低了发射功率和成本。

由于无线 PAN具有动态的本质，802.15网络的安全要求不同于更多的静态网络。因此，该工作组正在为认证和密钥交换的公开密钥方案做深入的研究，以便让以前没有接触过的设备在不暴露任何密钥材料的情况下建立安全的通信。

一旦设备得到认证，无线 PAN中的每台设备就共享用于加密和数据完整性的公共组(对称)有效负荷保护密钥。设备也能使用认证机制，建立两方的安全子网。

工作组在完成此标准之前还面临着另一个问题，即与其他类型的无线设备和在不同类型的 802.15设备之间的共处问题。在2.4GHz波段已有几个阐明发射的无线标准，在某些情况下，这些标准互相有干扰。

尽管还存在着挑战，但工作组期待着解决这些突出的问题，为无线设备市场提供完整的、有效的、低功率的解决方案。

此标准预定在今年第三季度完成。