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马祖长在通信学报上无线传感器网综述一文抄袭举例

作者：BerkeleyWolf

中文：马祖长等，《无线传感器网络综述》，通信学报， 2004.4.
英文：Ian Akyildiz etc. A survey on Sensor Networks, IEEE 
Communication Magazine. Aug. 2002.


5.3.1.3

SPIN 通过协商和资源调整，可以克服经典的扩散法（Flooding）的缺点。
(SPIN) [15] is designed to address the deficiencies of classic 
flooding by negotiation and resource adaptation.

SPIN 通过发送描述传感器数据的信息，而不是发送所有的数据（例如图象）来
节省能量。
Sensor nodes operate more efficiently and conserve energy by sending 
data that describe the sensor data instead of sending all the data; 
for example, image


SPIN 有三种信息，ADV、REQ 和DATA，在发送一个信息之前，传感器节点广播一
个
ADV 信息，信息中包括对自己即将发送数据的描述。
SPIN has three types of messages, that is, ADV, REQ, and DATA. Before 
sending a
DATA message, the sensor node broadcasts an ADV message containing a 
descriptor (i.e.,
meta-data) of the DATA


如果某个邻居对这个信息感兴趣，它就发送REQ消息来请求DATA，数据就向这个
节点发送。
If a neighbor is interested in the data, it sends a REQ message for 
the DATA and DATA
is sent to this neighbor sensor node

这个过程一直重复下去，直到网络中所有对这个信息感兴趣的节点都获得了这个
信息的一个拷贝。

The neighbor sensor node then repeats this process, as illustrated in 
steps 4, 5, and 6 of Fig. 4c. As a result, the sensor nodes in the 
entire sensor network that are interested in the data will get a
copy.


5.3.2.1

LEACH 是以群为基础的路由协议，
Low-Energy Adaptive Clustering Hierarchy (LEACH) is a clustering-based 
protocol

自选择的群头节点从它所在群中的所有传感器节点收集数据，将这些数据进行初
步的处理，然后向网关发送。
The purpose of LEACH is to randomly select sensor nodes as clusterheads, 
so the high
energy dissipation in communicating with the base station is spread to 
all sensor nodes in the sensor network.

LEACH 以“轮（round）”为工作时间单位，每一轮分为两个阶段： 启动阶段和
稳定阶段。

The operation of LEACH is separated into two phases, the setup phase 
and the steady phase.

在启动阶段，主要是传送控制信息，建立节点群，并不发送实际的传感数据。
为了提高电源效率，稳定阶段应该比启动阶段有着更长的持续时间。
The duration of the steady phase is longer than the duration of the 
setup phase in order to minimize overhead.

在每一轮的启动阶段，传感器节点在0 和1 之间选择一个随机数来决定是否成为
群头。
During the setup phase, a sensor node chooses a random number between 
0 and 1.

如果选择的随机数小于T（n），该节点就是一个群头，T（n）的计算如下：
If this random number is less than the threshold T(n), the sensor node 
is a clusterhead.

其中，P 是群头节点占总节点数的百分比，
where P is the desired percentage to become a clusterhead,

对于不同的网络，P 的最佳取值也不同。r是当前轮，G 是前面1/P 轮中，没有
被选择作为群头的节点集。
r is the current round, and G is the set of nodes that have not being 
selected as a clusterhead in the last 1/P rounds.

采用这样的计算公式，可以保证每个节点都可以在连续1/P 轮中的某一轮中成为
群头。

群头节点产生后，向网络中所有的节点宣布它们是新的群头节点，
After the clusterheads are selected, the clusterheads advertise to all 
sensor nodes in the network that they are the new clusterheads.

未被选择作为群头的传感器节点接收到这样的广播信息，根据预先设定的参数，
例如信噪比、接收信号强度等来决定自己加入哪个群。
Once the sensor nodes receive the advertisement, they determine the 
cluster to which
they want to belong based on the signal strength of the advertisement 
from the clusterheads to the sensor nodes.

节点选择加入某个群，并向该群头节点发出信息；群头节点根据群内
节点的信息，产生一个时分多址（TDMA）方案，为每个节点分配一个通信时隙，
只有在属于自己的时隙内，节点才可以向群头节点发送数据。
The sensor nodes inform the appropriate clusterheads that they will be 
a member of
the cluster. Afterward, the clusterheads assign the time on which the 
sensor nodes can send data to the clusterheads based on a TDMA approach.

在稳定阶段，传感器节点以固定的速度采集数据，并向群头节点发送，群头在向
网关发送数据之前，首先要对这些信息进行一定程度的融合。

During the steady phase, the sensor nodes can begin sensing and 
transmitting data to the
clusterheads. The clusterheads also aggregate data from the nodes in 
their cluster before sending these data to the base station.

稳定阶段经过一定的时间后，网络重 新进入启动阶段，进行下一轮的群头选择。
After a certain period of time spent on the steady phase, the network 
goes into the setup phase again and enters another round of selecting 
clusterheads.

(XYS20060214)

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