Need to add a separate scope for our Cisco Wireless Connections

[IT-LDI]

In our network we have our Router, DC, DNS, DHCP, server setup. Our DHCP is currently setup using 10.110.0.0/16 and I tried setting up a DHCP scope for the Cisco Wireless, but the Scope was not handing out any leases. I did create a DHCP server on the Cisco 3650 WLAN Controller, which there are some other DHCP issues that I would like to rule out and have this on its own scope.

I have not ever created a scope before and notice that there are some entries on the router in relation to the scope, so I'm in need of some assistance here so I do things right. 

Since it's a /16 network what IP Address range would work. ie; 10.110.20.0/16

The router is a C2921-CME-SRST/K9

Then will this need to be added to the router for it to be able to hand out the IP addresses. If so I notice that they are setup using Port-channel configuration and would that be something that I need to do for this. I did try this previously, but it came up with an overlap error. Here is how our scope information is in the router, minus the real values.

!
interface Port-channel1.3
description Data Network Interface
encapsulation dot1Q 3
ip address 10.110.x.xxx 255.255.0.0 secondary
ip address 10.110.x.xxx 255.255.0.0
ip helper-address 10.110.x.xxx
!
interface Port-channel1.5
description Interface for Internet Only SSID DHCP
encapsulation dot1Q 5
ip address 192.168.110.1 255.255.255.0
ip access-group Guest-Wireless
ip helper-address 10.110.x.xxx
!
interface Port-channel1.10
description Voice Network Interface
encapsulation dot1Q 10
ip address 192.168.1.10 255.255.255.0
ip pim sparse-dense-mode

Thank you,

[pieterh]

first remark: /16 is a very large scope, !!!

if you are using 10.110.0.0/16 as the current scope then 10.110.20.0/16 will not work!
/16 means all addresses from 10.110.0.0 through 10.110.255.255 are included also 10.110.20.0

normally you try to limit the number of hosts within a scope to about 1024 or maybe 4096 but not /16 (65000+ hosts)
-> you need to use something like 10.111.0.0/16 (or /24 or /22)
or do a redisign of your adress assignement so you use smaller scopes.

as Port-channel1.3 allready has an ip-address in the 10.110.0.0/16 network, it can reach the DHCP-server directly
the ip-helper address here has no function, the router does not need to forward dhcp packets to another network
In my opinion the secondary address has no function either or at least does not function as you intended!