Patexia seeks prior art for a US patent which allegedly describes a method of more efficiently utilizing protocol data units (PDU) when sending multiple service data units (SDU) by not requiring an entire empty PDU to mark the end of a divided SDU.

In wireless communication, a protocol data unit (PDU) is used to transfer data between two different layers as defined by the Open Systems Intercommunication (OSI) model. The data that the PDU contains is called a service data unit (SDU). In addition to the SDU, a PDU also includes a length indicator which contains an extension bit.

If an SDU is too large for transmission in one PDU, the system can divide an SDU into multiple smaller packets for transmission via multiple PDUs. In this case, the length indicator also indicates how many PDUs the system needs to collect to rebuild the entire SDU.

When this subdivision occurs, if the last segmented SDU fits exactly into the data field length of its PDU or if an entire SDU fits exactly into the data field length of its PDU, the system is forced to send an extra PDU in order to recognize that the end of the SDU (whether segmented or complete) has been reached. This means that the data field of the extra PDU is wasted and the transmission efficiency is lowered.

Figure 1. Overview of a traditional segmented SDU/PDU transmission system

As shown in Figure 1, for PDU (N) which incorporates the last part of segmented SDU, PDU (N+1) is needed to mark the end of the segmented SDU and is thus wasted. Similarly, for PDN (N+2) which incorporates an entire complete SDU, PDU (N+3) is needed to mark the end of the complete SDU and is thus also wasted.

Figure 2. Overview of the currently described data division system

The patent allegedly describes an improvement (as shown in Figure 2) to this data division process by allowing the system to recognize the end of a segmented SDU and end of a complete SDU by setting a specific value to the extension bit of the complete SDU’s PDU. Thus, instead of wasting PDU (N+1) and PDU (N+3) from Figure 1, the system can be more efficient by transmitting only PDU (K) and PDU (K+1) from Figure 2.

This Contest is related to the following Mobile Phone Connection Contests. Similar references are allowed; however, the five Contests focus on different features and have different questions. All five Contests have the same list of Known References.

1. Data Division of a Service Data Unit
2. HARQ Control of MIMO Handoff
3. Efficient Random Access Preamble Procedure
4. RLC Variable Reset
5. HARQ with TTI Bundling

Questions

1. Was the reference filed or published before May 18th, 2005?
2. Does the reference describe a system that includes both a transmitter and receiver for sending data from a service data unit (SDU) layer packaged in a protocol data unit (PDU) layer either in one packet, or in multiple packets?
3. Does the system interpret data sent via an alternate process by packaging SDU data in its PDU without a modified length indicator to mark its end, then packaging a second SDU’s data in a second PDU sent by modifying the length indicator to mark this as the end of both PDUs sent?
4. Does the system pack the first SDU in a first PDU without a modification to the length indicator to mark that the first SDU ends exactly at the last part of the first PDU?
5. After sending the first PDU, does the system pack the second SDU in a second PDU and set the extension bit of the length indicator to a specific value if the second PDU contains only the complete SDU so that it’s not a part of another SDU, a combination of SDUs, or includes empty space?
6. Does the data receiver receive the first PDU with the first SDU but without a modification to the length indicator, and then receive the second PDU with the second SDU and with the length indicator’s extension bit?
7. Does the data receiver check the length indicator of the second PDU, and keep both the first PDU and the second PDU packets for further delivery if the length indicator equals to a specific value?