OT: Wireless Network Strength Dependent On Wired Network?

Sat Jun 20 20:11:02 UTC 2009

On Jun 20, 2009, at 2:47 AM, Neil wrote:

> Okay, a small, offtopic question. (I figured you guys were a far more
> reliable source than my local ${electronics_store} salesperson...)
>
> Consider the following setup:
> internet pipe -> wired network -> (wireless router) wireless network  
> ->
> computer1, computer2
>
> Suppose the signal coming in on the pipe is good, but the signal
> deteriorates rapidly in wired network (old & bad wiring). Now, the two
> computers are connected via the wireless network only. computer1 has  
> a great
> connection (it's in the same room as the wireless router), but  
> computer2 is
> far away and drops the wireless connection frequently.
>
> Now, a former electrical engineer is claiming that if we improve the  
> wired
> network so that the signal comes across better, then computer2 won't  
> drop
> the wireless connection so frequently. (He says that the signal  
> emitted by
> the wireless router will be improved by feeding it a better source  
> signal.)
>

If you are running a digital network, no. Digital doesn't work like  
that. The
packets get through intact, or they are dropped. Dropping the wireless  
connection means that
you are having trouble communicating between the wireless router and  
computer 2.
Since computer 1 is close and works and computer 2 is far away, that  
strongly suggests that you have
a SNR problem. To fix that, you need either a stronger
access point (wireless router), another access point closer to  
computer 2, or a wireless repeater. Note that the AP also has
to receive the signal from computer 2, and you probably can't boost  
computer 2's power, so you may
not be able to fix this by just boosting the access point's power.

There is a possibility that the problem is with computer 2. You might  
try swapping
computer 1 and 2 to  confirm that the problem is distance related, or  
(what I generally do)
use a laptop as a test probe to confirm a good signal at computer 1,  
and a poor one at computer 2.

> I argue that there are two separate signals: the internet connection  
> signal
> coming in on the pipe, and then the wireless network signal being  
> emitted
> from the wireless router; and their strengths are independent. In  
> other
> words, if we improve the wiring, the wireless signal will not get any
> stronger.
>

In the spacecraft world, what the wireless router is doing is called  
regeneration. It is
not just amplifying the wireline signal it receives, it receives it,  
decodes it, turns it into
bits, and then puts those bits out as a radio encoding. Any noise in  
the signal
received is irrelevant, as long as it is not enough to cause the  
entire packet to be dropped.

Regards
Marshall

> So...basically, who's right? (Or are neither of us?) Any thoughts,  
> comments,
> corrections?
>