Latency reduction by fast forward in multi-hop communication systems
Latency reduction by fast forward (FF) in multi-hop communication device and/or systems is disclosed. Packets may be received and forwarded using a codeword (CW)-based approach with and/or without per-CW CRC. A FF session may have a flow ID and packets may have sequence numbers. Packets targeted for FF may be divided into independently decodable CWs that may be transmitted in the next hop, for example, as soon as the destination is determined without waiting for an entire packet's arrival and/or for CRC verification. Low latency (e.g. FF) traffic may be indicated. CW-based FF may be extensible for an e2e RAN path from a WTRU to the last access node in a RAN. Intermediate metrics, a packet CRC and/or a per-CW CRC may be utilized for data integrity. HARQ and/or CW retransmission procedures may be implemented between network nodes for error handling.
1. A base station in communication with a communication network, the base station comprising:
a memory;
a receiver, the receiver configured at least to:
receive a transmission of a packet from a first node, wherein the packet comprises a first codeword (CW) and a second CW;
a processor, the processor configured at least to:
determine an error associated with the first CW; and
a transmitter, the transmitter configured at least to:
transmit a null CW based on the determined error, wherein the null CW is transmitted as a replacement for the first CW, wherein the null CW is transmitted to a second node before the second CW is decoded, and the first node and the second node are different.
2. The base station of claim 1 , wherein the first CW comprises Low Density Parity Check (LDPC) codes.
3. The base station of claim 1 , wherein the packet comprises a plurality of CWs, the plurality of CWs comprising the first CW and the second CW, and the processor is further configured such that the null CW has a largest hamming distance from non-erroneous CWs of the plurality of CWs.
4. The base station of claim 1 , wherein the packet comprises a header comprising an indication that the packet is eligible for fast forwarding.
5. The base station of claim 4 , wherein the header is at least one of: a Physical (PHY) header, or a Medium Access Control (MAC) header.
6. The base station of claim 4 , wherein the packet comprises a plurality of CWs, the header is a Physical (PHY) header, and the receiver is further configured to receive a transmission Physical (Tx PHY) header for the plurality of CWs prior to receiving the plurality of CWs.
7. The base station of claim 1 , wherein the packet comprises a plurality of CWs, and a cyclic redundancy check (CRC) is associated with the plurality of CWs for a per-packet-based integrity determination.
8. The base station of claim 1 , wherein the second CW is independently verifiable without a cyclic redundancy check (CRC).
9. The base station of claim 1 , wherein the second CW is independently decodable, and the second CW is not cyclic redundancy check (CRC) verified.
10. The base station of claim 1 , wherein the second CW is cyclic redundancy check (CRC) verified.
11. The base station of claim 1 , wherein the packet comprises a plurality of CWs, and the processor is further configured to:
initiate a decoding of the plurality of CWs; and
determine that the first CW is a first erroneous CW of the plurality of CWs, wherein each CW of the plurality of CWs that is decoded before the first CW is non-erroneous.
12. The base station of claim 1 , wherein the packet comprises a plurality of CWs, and the processor is further configured to record a location of the first CW relative to remaining CWs of the plurality of CWs.
13. The base station of claim 1 , wherein the processor is further configured to initiate the transmission of the null CW to the second node as the replacement for the first CW associated with the error.
14. The base station of claim 1 , wherein the processor is further configured to initiate a transmission of a negative acknowledgement (NACK) to the first node for the first CW associated with the error, and the transmitter is further configured to transmit the NACK to the first node.
15. The base station of claim 1 , wherein the communication network is at least one of: an access network, a front-haul network, or a backhaul network.
16. A method performed by a base station, comprising:
receiving a transmission of a packet from a first node, wherein the packet comprises a first codeword (CW) and a second CW;
determining an error associated with the first CW; and
transmitting a null CW based on the determined error, wherein the null CW is transmitted as a replacement for the first CW, wherein the null CW is transmitted to a second node before the second CW is decoded, and the first node and the second node are different.
17. The method of claim 16 , wherein the second CW is independently decodable, and the second CW is not cyclic redundancy check (CRC) verified.
18. The method of claim 16 , wherein the second CW is cyclic redundancy check (CRC) verified.