How to improve xbee throughput? Am using 115200 baud rate on end point.currently am getting only 8Kbps.

*Xbee as end point connected to Arduino nano
*Xbee as co ordinator connected to Raspberry Pi
*Used baud rate is 115200

Sending data from end point to co ordinator.
Am only getting througput of 8Kbps.
Endpoint and co ordinator is in below 1 meter range.
My payload size is 45 bytes.

How to improve throughput?
Kindly help me. Thanks in advance!