Method and apparatus for enhancing RLC for flexible RLC PDU size
Enhancements are provided for the radio link control (RLC) protocol in wireless communication systems where variable RLC packet data unit (PDU) size is allowed. When flexible RLC PDU sizes are configured by upper layers, radio network controller (RNC)/Node B flow control, RLC flow control, status reporting and polling mechanisms are configured to use byte count based metrics in order to prevent possible buffer underflows in the Node B and buffer overflows in the RNC. The enhancements proposed herein for the RLC apply to both uplink and downlink communications.
1. A network entity comprising:
a memory; and
a processor, wherein the network entity is configured at least in part to:
receive, from a Node B, a control frame indicating a capacity allocation is a byte allocation, wherein the network entity is a radio network controller (RNC);
determine that flexible medium access control-d (MAC-d) packet data unit (PDU) size is configured;
determine a capacity allocation for a data flow by multiplying a credit by a maximum PDU size, wherein the credit is a number of PDUs, and wherein the capacity allocation is calculated as a number of octets; and
transfer a number of MAC-d PDUs without violating the capacity allocation.
2. The network entity of claim 1 , wherein the network entity is further configured, at least in part, to:
store a mapping of a PDU sequence number (SN) to an associated length in bytes; and
transmit PDUs without exceeding the number of bytes of credit.
3. The network entity of claim 1 , wherein the RNC is a serving RNC (SRNC).
4. The network entity of claim 1 , wherein the RNC is a controlling RNC (CRNC).
5. The network entity of claim 1 , herein the network entity is further configured, at least in part, to receive a specified time to transmit under the granted capacity allocation.
6. A method comprising:
receiving, from a Node B, a control frame indicating that a capacity allocation is a byte allocation, wherein the receiving is performed by a network entity, and wherein the network entity is a radio network controller (RNC);
determining that flexible medium access control-d (MAC-d) packet data unit (PDU) size is configured;
determining a capacity allocation for a data flow by multiplying a credit by a maximum PDU size, wherein the credit is a number of PDUs, and wherein the capacity allocation is calculated as a number of octets; and
transferring a number of MAC-d PDUs without violating the capacity allocation.
7. The method of claim 6 , wherein the method further comprises:
storing a mapping of a PDU sequence number (SN) to an associated length in bytes; and
transmitting PDUs without exceeding the number of bytes of credit.
8. The method of claim 6 , wherein the RNC is a serving RNC (SRNC).
9. The method of claim 6 , wherein the RNC is a controlling RNC (CRNC).
10. The method of claim 6 , further comprising receiving a specified time to transmit under the granted capacity allocation.
11. A device comprising:
a processor; and
a memory comprising instructions that when executed by the processor cause the device to:
maintain a byte count mechanism, wherein flexible packet data unit size is configured; and
on a condition that a count is determined to be equal to or exceed a Poll_Bytes value, configure a packet data unit for transmission to include a poll, wherein the packet data unit is configured by setting a polling bit in the packet data unit.
12. The device of claim 11 , wherein the packet data unit is an acknowledged mode data packet data unit.
13. The device of claim 11 , wherein the count includes a packet data unit transmitted in an original transmission.
14. The device of claim 11 , wherein the count includes a packet data unit transmitted in an original transmission and a packet data unit transmitted in a retransmission.