WI-FI Speed limit Issues on BCM943362WCD4_EVB

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Anonymous
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Hello all - I have been using the demo console example program on 2 separate eval boards (DEV A and DEV B). I start Soft AP on DEV A and join the AP on DEV B. I set the data rate on both to 54. Using iperf -s on DEV A and iperf-c on DEVB the max rate I can achieve is 5.8Mbits/sec. I'm not sure but that data rate seems really low. I also tried UDP and the results where much worse.

That said is there way a way to get the data rate between the two devices up to somewhere around 50Mbits/sec. Is there a variable/constant/PCB jumper to jack the rate up? Is there a way to get more concurrent channels open between the two devices.

I plan on using TCP/IP in our upcoming design, and our requirements for throughput is in the 100Mbits/sec area.

Thanks in advance

Scott

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1 Solution
Anonymous
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The 43362 is a 1x1 802.11n device with a theoretical maximum rate of 72 mbps (assuming short guard interval) or 65mbps otherwise. As Greg already mentioned environment and protocol overheads reduce that significantly.

Our testing has shown that, for ThreadX-NetX_Duo, the following throughputs are achievable from a BCM943362WCD4 device to a laptop via a router:

  

UDP Tx28.6 mbps
UDP Rx

39.6 mbps

  

TCP Tx 27.7 mbps
TCP Rx13.3 mbps

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14 Replies
GregG_16
Employee
Employee
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Hi,

You need 100mbps? Or do you mean 10mbps?

The best theoretical max is about 60 percent of your max phy rate. So if your phy is 54 you are looking at 30mbps tcp. I may be off here since there are tricks to play to optimize this.

Did you try to replace cards with a laptop running iperf and associate to a 2.4G router?

How is your environment?  Clean from other wifi noise or open air? You can also try laptop to laptop to see what your best case over the air can be.

You can increase your tcp window size in iperf with -w command. For exampie -w 256K in command line. This may help, but not that much.

Send me your exact setup and commands I'll see what I get in the chamber.

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Anonymous
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Thanks Gangi - Yes I did mean 100Mbits/sec or the same speed as ethernet but over wifi- Is there a way to multiplex and use more channels with WICED.  If I can't acheive 100Mbit/Sec with WICED, does Broadcom offer  a 802.11/ac module available for embedded development activities.

Heres my setup

1. Laptop with 2 BCM943362WCD4 Eval boards connect via USB Com 12 and Com 14

2  Two Sessions of PutTTY running connected to the dev boards with these settings

2014-05-01 06:59:38 Opening serial device COM14

2014-05-01 06:59:38 Configuring baud rate 115200

2014-05-01 06:59:38 Configuring 8 data bits

2014-05-01 06:59:38 Configuring 1 data bits

2014-05-01 06:59:38 Configuring no parity

2014-05-01 06:59:38 Configuring XON/XOFF flow control

3. Each Device has the " test.console-BCM943362WCDR download run"  target on the device. Devices are 1 meter apart.

4. iperf -s on Device A and iperf-c 192.168.0.1 on Device B. Log files are below

5. Log files for  iperf server

> start_ap doogie wpa2 password 1

Setting IPv6 link-local address

IPv4 network ready IP: 192.168.0.1

> set_data_rate 54

> iperf -s

Spawning a listener.

------------------------------------------------------------

Server listening on TCP port 5001

TCP window size: 8.00 KByte (default)

------------------------------------------------------------

Spawning a server.

[ ID] Interval       Transfer     Bandwidth

[  0]  0.0-10.0 sec  6.98 MBytes  5.85 Mbits/sec

Spawning a server.

[  0]  0.0-10.0 sec  7.49 MBytes  6.28 Mbits/sec

6. Log file for iperf client

> join doogie wpa2 password

Joining : doogie

Successfully joined : doogie

Obtaining IPv4 address via DHCP

Setting IPv6 link-local address

IPv4 network ready IP: 192.168.0.2

> set_data_rate 54

> iperf -c 192.168.0.1

------------------------------------------------------------

Client connecting to 192.168.0.1, TCP port 5001

TCP window size: 8.00 KByte (default)

------------------------------------------------------------

[ ID] Interval       Transfer     Bandwidth

[  0]  0.0-10.0 sec  6.98 MBytes  5.86 Mbits/sec

> iperf -c 192.168.0.1 -w 256k

------------------------------------------------------------

Client connecting to 192.168.0.1, TCP port 5001

TCP window size: 8.00 KByte (WARNING: requested  256 KByte)

------------------------------------------------------------

[  0]  0.0-10.0 sec  7.49 MBytes  6.28 Mbits/sec

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Hi Scott,

WICED does not target bandwidth you are asking at this time. You may consider Broadcom WiFi radios with different CPUs.

- Seyhan

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Anonymous
Not applicable

The 43362 is a 1x1 802.11n device with a theoretical maximum rate of 72 mbps (assuming short guard interval) or 65mbps otherwise. As Greg already mentioned environment and protocol overheads reduce that significantly.

Our testing has shown that, for ThreadX-NetX_Duo, the following throughputs are achievable from a BCM943362WCD4 device to a laptop via a router:

  

UDP Tx28.6 mbps
UDP Rx

39.6 mbps

  

TCP Tx 27.7 mbps
TCP Rx13.3 mbps

Hi nikvh,

Could you clarify the test setup to achieve the throughput listed in your post?

Is the measure performed at the application processor level using the WICED API?

When you do the transmission of packets, are you generating traffic from a WICED application running on the application processor? (I believe yes, just want to make sure).

Thanks

Anonymous
Not applicable

Hi

Did you got the result as mentioned above ?

with stm32f429 mcu + sn800 i'm getting 1Mbits/s only

Any suggestion?

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Which interface SDIO/SPI  to connect WIFI ?

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Anonymous
Not applicable

I'm using SDIO interface

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How fast your SDIO clock ?

How to connect your WIFI via SDIO of MCU ? jump wiring or have custom PCB ?

SDIO interface is running in one-bit or 4-bit mode ? HighSpeed enable or not ?

If you connect your MCU SDIO to WiFi via jump wiring ! The throughput will NOT Good !

And you should running the throughput test in chamber !

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Anonymous
Not applicable

Actally I replcated the same behaviour on SN8000x Evaluation board from Murata. Which has support on Wiced.

SDIO 25Mhz, In EVB & my custom board its connected on PCB , I suppose 4 bit mode & high speed is enabled may be that's why I'm getting 25Mhz

I should be able to get a throughtput of at least 4-8Mb/s right?

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Suppose 4Mb/s is reasonable number!

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Anonymous
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But as per now I only get 1Mb/s (UDP packet creation+sending of 8ms).

How can I improve this?

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Did you run throughput test via iperf in  test.console ?

We are talking throughput  result via iperf!

If you did not done it yet, You should do it now!

If you got the same low throughput! I guess your system is not well design in H/W!

You should review your H/W first!

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Anonymous
Not applicable

Ok, i sorted it out .

I was using debug alongwith the build string which caused high duration of packet creation + sending, (not clear why is this)

When I removed it I got creation+sending under 200-400microseconds, which is a good throughput

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