LoRaServer 笔记 0.1.1 LoRa Server 组件功能介绍

我们先来看看 LoRa Server 的作用是什么。

LoRa Server 是个开源的 LoRaWAN network-server，是 LoRa Server project 的一部分。它的作用是对从基站接收到的上行数据做处理和去重，对下行传输的数据做 LoRaWAN mac层的处理和调度。

LoRa Server is an open-source LoRaWAN network-server, part of the LoRa Server project. The responsibility of the network-server component is the de-duplication and handling of received uplink frames received by the gateway(s), handling of the LoRaWAN mac-layer and scheduling of downlink data transmissions.

LoRa Server 功能特点

设备类型(Device classes)

• Class A

LoRa Server 全面支持 Class-A 设备。接收到的数据会做去重处理，然后转发给AS。当 接收窗口 打开时，LoRa Server 会向 AS poll 下行数据。通过 polling 这种方式，AS 可以按照 速率相应的最大载荷长度 的相关规定来安排下行数据。

• Class B

Todo

• Class C

LoRa Server 全面支持 Class-C 设备。它会记住上一次的接收参数(每个网关接收到的上行数据情况)，因此可以判断出最近的那个网关，从而下发下行数据。下行数据可以调用 NetworkServer.PushDataDown API 来处理。

带应答的上下行数据(Confirmed data up / down)

带应答的上下行数据都是 LoRa Server 来处理，特别是下行数据， LoRa Server 会一直保存着它的序列号，直到等到节点的应答。

终端加网(Node activation)

LoRa Server 支持 ABP 和 OTAA 两种加网方式。在 ABP 方式中，AS 提供给 LoRa Server 一个 node-session 。在 OTAA 方式中，LoRa Server 会调用将接收到的 join-request 发给 AS，如果准许的话，它会发送 join-accept 给节点。

速率自适应(实验阶段)(Adaptive data-rate (experimental))

LoRa Server 支持 速率自适应(ADR)。

LoRa Server has support for adaptive data-rate (ADR). In order to activate ADR, The node must have the ADR interval and installation margin configured. The first one contains the number of frames after which to re-calculate the ideal data-rate and TX power of the node, the latter one holds the installation margin of the network (the default recommended value is 5dB). From the node-side it is required that the ADR flag is set for each uplink transmission.

Important: ADR is only suitable for static devices, thus devices that do not move!

网关管理和统计(Gateway management and stats)

Gateways can be created either automatically when LoRa Server receives statistics from the gateways or by using the API. Gateway statistics will be aggregated on the given intervals and are exposed through the api API. See also gateway management.

接收窗口(Receive windows)

Through OTAA and ABP, it is possible to configure which RX window to use for downlink transmissions. This also includes the parameters like data-rate (for RX2) and the delay to use.

释放帧序号(Relax frame-counter)

A problem with many ABP devices is that after a power-cycle, the frame-counter of the device is reset. Since this reset is not known by LoRa Server it means that all payloads with a frame-counter smaller or equal than the known counter get rejected. In order to work around this issue it is possible to enable the relax frame-counter mode. Important to know, this compromises security!

ISM频段(ISM bands)

As different regions have have different regulations regarding the license-free bands, you have to specify the ISM band to operate on when starting LoRa Server. At this moment the following ISM bands have been implemented:

• AS 923
• AU 915-928
• CN 470-510
• CN 779-787
• EU 433
• EU 863-870
• IN 865-867
• KR 920-923
• US 902-928