[問題] 請問有人用NIST的802.16 Module嗎
有點問題想請教各位
我裝了NIST的802.16 module for ns-2.31
現在想模擬wireless node1送cbr data到wireless node2
然後透過調整node的diuc來控制modulation (64QAM 3/4, 16QAM 1/2...etc)
但是有點問題
當我把cbr data rate設低一點的時候(ex. 1mb)
64QAM跟16QAM的throughput都是1mb左右
如果把cbr data rate設高的話( ex. 10mb)
那反而64QAM比16QAM的throughput還低
大概是64QAM = 5mb/s, 16QAM = 7mb/s
若把frequency bandwidth調高
則64QAM與16QAM的throughput同時上升
但仍然是16QAM比64QAM的throughput高
而64QAM的throughput較低
由trace file中來看
一直drop packet的原因為RTR QWI
官網的document說明為
- QWI: each connection has a queue to store pending frames. When
the queue is full, thepacket is dropped using this reason code.
另外官網的FAQ中data rate的說明為
Q: How to set the datarate?
A: Unlike the 802.11 implementation, the datarate is not something
set in TCL. Since each burst can use a different modulation and
therefore have different datarates, we opted for a dynamic calculation
of the datarate. By setting the frequency bandwidth, cyclic prefix and
the modulation, the datarate will change. Other parameters such as
number of contention slots for initial ranging and bandwidth requests
or the downlink/uplink ratio affect the maximum amount of data that
can be transferred during a frame.
調滿多參數了還是無法讓64QAM比16QAM的throughput高
請問是否還有哪裡需要設定呢
感激不盡
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