On 11/21/16 11:13 AM, Jean-Francois Mezei wrote:
On 2016-11-21 02:53, Mikael Abrahamsson wrote:
Typically it travels on another "bearer" compared to Internet traffic.
http://blog.3g4g.co.uk/2013/08/volte-bearers.html
Think of bearers as "tunnels" between the mobile core network and the device. Many thanks for the pointer. The fact that VoLTE has its own dedicated APN explains things.
I am however a bit confused on the "bearer" term.
Say a carrier has spectrum in 700Mhz bands A and B each 5mhz in each direction, bonded together as a single 10mhz (each way) channel.
The docunment states: "R.92 requires the use of a particular set of radio bearers"
Does this mean that a bearer is given specific spectrum within a block (such as a dedicated colour on a fibre) or that it is just given dedicated capacity on the single data channel formed by LTE compressing all of the spectrum into one big channel ?
I though I understood the concept when the name "tunnel" had been mentioned because I understand that a handset estabishes a "hopping" tunnel with local IP which changes as you move from tower to tower, but the tunnel itself maintains a permanent IP connection that remains unchanged as you move from tower to tower. In such a concept, I could understand each tunnel (one to the data APN, one to the IMS/VoLTE APN) having bandwidth allocations.
the radio bearers described are are the signaling radio bearers. their existence is independent of of the link/mac layer configuration. The mac layer layer (e-utra) exists below the l2 bearers. https://en.wikipedia.org/wiki/E-UTRA these are URBs they are terminated between the UE and the P-GW
But when the text brought up "radio bearer", I got confused again sicne radio implies breaking the spectrum apart, which would reduce LTE compression efficiency. SRB and URB are the l2 presentation of the tunnels established for user and signaling traffic.