7.3.6 PDCP RoHC performance testing

34.123-13GPPPart 1: Protocol conformance specificationRelease 15TSUser Equipment (UE) conformance specification

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

7.3.6.1 General

IETF RFC3095 "RObust Header Compression (ROHC)" [40] and RFC 4815: "RObust Header Compression (ROHC): Corrections and Clarifications to RFC 3095” [41] is the IP header compression method specially designed for real time IP services over wireless links. ROHC is specified as part of the Rel-4 of UTRAN as one of the compression schemes to be provided by the PDCP sublayer in the RNC. If the UE supports IMS, as described in 3GPP 23.228 [42], the UE shall support header compression according to RFC 3095 as defined in 3GPP 25.323 [30].

ROHC performance requirements have been specified in Rel-5 of the 3GPP 25.323 [30]. The ROHC performance requirements and the corresponding test cases in this clause are specified for profile 0x0001 for compression of RTP/UDP/IP headers.

7.3.6.1.1 Generic ROHC performance test procedure

Step	Direction		Message	Comments
Step	UE	SS	Message	Comments
1	<–		SYSTEM INFORMATION (BCCH)	Broadcast
2	<–		PAGING TYPE 1 (PCCH)	Paging (PS domain, P-TMSI)
3	–>		RRC CONNECTION REQUEST (CCCH)	RRC
4	<–		RRC CONNECTION SETUP (CCCH)	RRC
5	–>		RRC CONNECTION SETUP COMPLETE (DCCH)	RRC
6a	–>		SERVICE REQUEST (DCCH)	GMM
6b	<–		SECURITY MODE COMMAND	RRC see note 1
6c	–>		SECURITY MODE COMPLETE	RRC see note 1
7	<–		ACTIVATE RB TEST MODE (DCCH)	TC
8	–>		ACTIVATE RB TEST MODE COMPLETE (DCCH)	TC
9	<–		RADIO BEARER SETUP (DCCH)	RRC.
10	–>		RADIO BEARER SETUP COMPLETE (DCCH)	RRC
11	<–		CLOSE UE TEST LOOP (DCCH)	TC UE test mode 1 RLC SDU size is set to TBD
12	–>		CLOSE UE TEST LOOP COMPLETE (DCCH)	TC
13	<–>		ROHC performance test execution	Execute the actual ROHC performance test case
14	<–		OPEN UE TEST LOOP (DCCH)	TC
15	–>		OPEN UE TEST LOOP COMPLETE (DCCH)	TC
16	<–		RRC CONNECTION RELEASE	RRC
17	–>		RRC CONNECTION RELEASE COMPLETE	RRC

NOTE 1 In addition to activate integrity protection Step 6b and Step 6c are inserted in order to stop T3317 timer in the UE, which starts after transmitting SERVICE REQUEST message.

Specific Message Contents

RADIO BEARER SETUP message (Step 9)

Use the same message as specified for "Packet to CELL_DCH from CELL_DCH in PS" in TS34.108 clause 9 Default Message Contents to setup 6.11.4e Interactive or background / UL:64 DL: 64 kbps / PS RAB + UL:3.4 DL:3.4 kbps SRBs for DCCH, with the following exceptions:

Information Element	Value/remark
RAB information for setup
– RAB info
– RAB identity	TBD
– CN domain identity	PS domain
– RB information to setup
– RB identity	TBD
– PDCP info
– Support of lossless SRNS relocation	FALSE
– Max PDCP SN window size	sn255
– PDCP PDU header	present
– Header compression information	present
CHOICE algorithm type
– RFC3095
– Profiles	2
– Profile instance	1
– Uplink
– Max_CID	15
– Downlink
– Max_CID	15
– Reverse_Decompression_Depth	0
– PDCP ROHC target mode	depends on test case

7.3.6.2 Base test of ROHC RTP O-mode compressor

7.3.6.2.1 Definition and applicability

The purpose of the base test is to verify that the compressor implements an active and efficient compression for a regular IP/UDP/RTP packet stream, i.e. that it makes use of the most efficient compressed packet formats provided by ROHC RTP [40] for O-mode.

7.3.6.2.2 Conformance requirement

This subclause defines performance test cases for ROHC. The ROHC profile within scope is profile 0x0001 for compression of RTP/UDP/IP headers only. This subclause is not meant to bring incoherent limitations to implementations, and is not meant to create a sub-specification of RFC 3095 [40] either, as a consequence of the requirements on performance that it defines.

…

Compressor implementations are expected to implement robustness algorithms according to the optimistic approach for the U/O-modes of operation. The optimistic approach is the part of the selection of the packet format where a format that contains the necessary information to update a field is used a number N time, starting from the packet for which a new value has to be established in the decompressor context. While N is an implementation parameter, the metrics for each sequence in U/O-mode is expressed in terms of this parameter. Implementation should use the value N as an input parameter for the testing, to adapt to the expected robustness level required for the testing. The value of the parameter N is defined in test case definition separately (informative value is given in Annex B.2.3.). Similarly, R-mode operation requires that an update be conveyed to the decompressor until it gets acknowledged; however for R-mode, relevant test cases provide explicit feedback messages when necessary.

…

The feedback messages used in the test cases, when applicable, are artificially generated and interspersed with the input sequence of uncompressed packets. Feedback messages are generated according to the following format:

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set as defined by the test case

– SN is set as defined by the test case

– CRC is the 8-bit CRC computed over the entire feedback payload including any CID fields but excluding the packet type, the ‘Size’ field and the ‘Code’ octet, using the polynomial defined in RFC 3095.

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

…

The purpose of the base test case is to verify that the compressor properly implements compression for a well-behaved IP/UDP/RTP packet flow, i.e. that t it makes use of efficient compressed packet formats available to ROHC RTP [40] when operating in O-mode.

A sequence consisting of 70 packets in total is used where all header fields are set according to the basic test packet structure, as described in subclause A.3, with addition of the following:

1. The RTP Sequence Number is a linearly increasing counter with a packet-to-packet delta of 1, set to 0x0000 for the first packet and thus ending with 0x0045 (69) in the last packet of the sequence

2. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet and thus ending with 0x00002B20 (11040) in the last packet of the sequence.

3. The IP Identification is set to the same value as the RTP Sequence Number; this means that for IPv4 the IP-ID behaviour is not random, thus value(RND)=0 defined in [40] for both IPv4 and IPv6.

Between the 6th and 7th packets (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is to be given to the ROHC compressor to trigger an immediate transition to O-mode operation. The format of that packet is as follows:

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

Reference(s)

3GPP TS 25.323 clauses A.1, A.1.1, A.2.1.

7.3.6.2.3 Test purpose

To verify that the ROHC compressor successfully transfers to O-mode operation and makes use of efficient compressed packet formats available to ROHC RTP.

7.3.6.2.4 Method of test

Initial conditions

User Equipment:

The UE is in Idle mode (state 3 or state 7) as specified in clause 7.4 of TS 34.108. Execute the generic ROHC performance test procedure for a mobile terminating packet switched session according to clause 7.3.6.1.1.

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

After the session setup the UE ROHC compressor is in the U-mode operation in accordance with RFC3095 and in the IR state. The SS starts to send IP packets to the UE, the test sequence consists of 70 packets. The UE returns the IP packets in ROHC U-mode using the test loop function. Between the 6^th and 7^th packets (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is sent to the UE ROHC compressor to trigger an immediate transition to O-mode operation. When all the expected compressed headers have been received by the SS, the SS disconnects the session. The SS calculates the Average Compressed Header Size and checks if it meets the test requirements for the IP version used.

1. The RTP Sequence Number is a linearly increasing counter with a packet-to-packet delta of 1, set to 0x0000 for the first packet and thus ending with 0x0045 (69) in the last packet of the sequence.

3. The IP Identification is set to the same value as the RTP Sequence Number; this means that for IPv4 the IP-ID behaviour is not random, thus value(RND)=0 defined in RFC3095 for both IPv4 and IPv6.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		70 test packets	The SS starts sending test packets
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th packet (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is sent to the ROHC compressor to trigger an immediate transition to O-mode operation.
5	UE			The UE changes immediately to O-mode operation and continues to send the test packets
6			Test packets in O-mode operation.
7	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Use the same message as specified for "Packet to CELL_DCH from CELL_DCH in PS" in TS 34.108 clause 9 Default Message Contents, with the exceptions defined in clause 7.3.6.1.1 and the following exception:

Information Element	Value/remark
– PDCP ROHC target mode	O-mode

ROHC feedback packet of feedback type 2 (Step 3)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

7.3.6.2.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.2.

Table 7.3.6.2: Test Requirement for ROHC RTP O-mode compressor

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= N-1	44 octets	68 octets
SN >= N	5 octets	5 octets

With N value equal to 4 (which is smaller than 8).

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.2: Expected outcome for ROHC RTP O-mode compressor test

7.3.6.3 Base test of ROHC RTP R-mode compressor

7.3.6.3.1 Definition and applicability

The purpose of the base test case is to verify that the compressor properly implements compression for a well-behaved IP/UDP/RTP packet flow, i.e. that it makes use of efficient compressed packet formats available to ROHC RTP [40] when operating in R-mode.

7.3.6.3.2 Conformance requirement

…

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set as defined by the test case

– SN is set as defined by the test case

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

…

A sequence consisting of 70 packets in total is used where all header fields are set according to the basic test packet structure, as described in subclause A.3, with addition of the following:

1. The RTP Sequence Number is a linearly increasing counter with a packet-to-packet delta of 1, set to 0x0000 for the first packet and thus ending with 0x0045 (69) in the last packet of the sequence.

3. The IP Identification is set to the same value as the RTP Sequence Number; this means that for IPv4 the IP-ID behaviour is not random, thus value(RND)=0 defined in [40] for both IPv4 and IPv6.

Between the 6th and 7th (SN=5 and SN=6) packet of the sequence, the first ROHC feedback packet of feedback type 2 is to be given to the ROHC compressor to initiate transition to R-mode operation. The format of that packet is as follows:

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x3 (means R-mode)

– SN is set to 0x000

Reference(s)

3GPP TS 25.323 clauses A1, A.2.2, A.3 and B.2.3.

7.3.6.3.3 Test purpose

To verify that the ROHC compressor successfully transfers to R-mode operation and makes use of efficient compressed packet formats available to ROHC RTP.

7.3.6.3.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

After the session setup the ROHC compressor is in the U-mode operation in accordance with RFC3095 and in the IR state. The SS starts to send IP packets to the UE, the test sequence consists of 70 packets. The UE returns the IP packets in ROHC U-mode using the test loop function. Between the 6^th and 7^th packets (SN=5 and SN=6) of the sequence, the first ROHC feedback packet of feedback type 2 is sent to the UE ROHC compressor to trigger an immediate transition to R-mode operation. When all the expected compressed headers have been received by the SS, the SS disconnects the session. The SS calculates the Average Compressed Header Size and checks if it meets the test requirements for the IP version used.

1. The RTP Sequence Number is a linearly increasing counter with a packet-to-packet delta of 1, set to 0x0000 for the first packet and thus ending with 0x0045 (69) in the last packet of the sequence.

3. The IP Identification is set to the same value as the RTP Sequence Number; this means that for IPv4 the IP-ID behaviour is not random, thus value(RND)=0 defined in RFC3095 for both IPv4 and IPv6.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		70 test packets	The SS starts sending test packets
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th (SN=5 and SN=6) packet of the sequence the SS initiates a transition to R-mode operation.
5	UE			The UE changes immediately to R-mode operation and continues to send the test packets
6			Test packets in R-mode operation.	The UE returns test packets in R-mode operation using the test loop function.
6a	ß		ROHC feedback packet of feedback type 2	During the test case the SS generates a feedback message when the ROHC packet type octet of the received compressed header matches any of the values as described in the table 7.3.6.3.1.
7	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	R-mode

ROHC feedback packet of feedback type 2 (Step 4 and 6a)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x3 (means R-mode)

– SN is set to 0x000

The test equipment waits for a UOR-2, IR-DYN or IR packet from the RoHC compressor with the mode transition parameter set to R. The value of x is the RTP SN of this received packet for which the test equipment generates the second feedback packet of type 2.

The SS shall generate a feedback message when the ROHC packet type octet of the received compressed header matches any of the values as described in the table 7.3.6.3.1. The compressed header type can be identified by inspecting the packet type octet of the compressed header, i.e. the first octet of the ROHC base header.

Table 7.3.6.3.1: Bitmasks for feedback generation

Compressed Header Type (binary mask)	Packet Type	Outcome
01xxxxxx	R-0-CRC	Send feedback
110xxxxx	UOR-2*	Send feedback
1111110x	IR	Send feedback
11111000	IR-DYN	Send feedback
Other values	Other packets	No feedback

where ‘x’ means ‘any value’.

In the feedback message:

– Mode is set to 0x3 (means R-mode)

– SN is set to the RTP SN corresponding to the received compressed header

The SS shall index the input sequence of uncompressed headers using the RTP Sequence Number, and it shall associate the correct RTP SN to each compressed header that it receives back from the compressor. The SS can derive the RTP SN by counting the number of received compressed headers.

NOTE: The purpose of this mechanism is only to provide feedback to the compressor when operating in R-mode; it is not meant to make further verifications of any specific ROHC functionality and applies only to the test cases defined in this annex.

7.3.6.3.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.3.2

Table 7.3.6.3.2: Test Requirement for ROHC RTP R-mode compressor

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= N-1	44 octets	68 octets
N <= SN <= 5	5 octets	5 octets
6 <= SN <= x	9 octets	9 octets
SN >= x+1	5 octets	5 octets

N shall be equal to 4 in the test case.

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.3: Expected outcome for ROHC RTP R-mode compressor test

7.3.6.4 Re-establishment of TS function after DTX in O-mode

7.3.6.4.1 Definition and applicability

The purpose of the TS re-establishment test case is to verify that the compressor re-establishes the proper TS value after a DTX period, i.e. that it uses efficient header formats available to ROHC RTP [40] when operating in O-mode.

7.3.6.4.2 Conformance requirement

The outline of each test case follows the same format with respect to the input sequences and the requirements Test 1a and 1b are base tests using a well-behaving flow of packets as one of the inputs. All subsequent tests are based on test 1a or test 1b, each with specific test events added to the packet flow of the base tests.

…

The test sequence is the same as in subclause A.2.1, with the following exception:

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

2. For packet with SN= 20, TS is increased to represent a 32 (0.64 seconds) packet skip (32×160) and is thus set to (20+32)x160=8320 (0x00002080). Then TS continues to grow as stated in 1 above.

3. For packet with SN= 30, TS is increased to represent a 128 (2.56 seconds) packet skip (128×160) and is thus set to (30+32+128)x160=30400 (0x000076C0). Then TS continues to grow as stated in 1 above.

4. For packet with SN= 40, TS is increased to represent a 2048 (40.96 seconds) packet skip (2048×160) and is thus set to (40+32+128+2048)x160=359680 (0x00057D00). Then TS continues to grow as stated in 1 above.

5. TS thus ends at 364320 (0x00058F20) in the last packet of the sequence with RTP sequence number 69.

Reference(s)

3GPP TS 25.323 clauses A1.2, A.2.5, A.2.1, A.3, B.2.3.

7.3.6.4.3 Test purpose

To verify that the ROHC compressor re-establishes the proper TS value after a DTX period, i.e. that it uses efficient header formats available to ROHC RTP when operating in O-mode.

7.3.6.4.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

The SS calculates the Average Compressed Header Size and checks if it meets the test requirements as in clause 7.3.6.4.2, for the IP version used with the following exceptions:

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

2. For packet with SN= 20, TS is increased to represent a 32 (0.64 seconds) packet skip (32×160) and is thus set to (20+32)x160=8320 (0x00002080). Then TS continues to grow as stated in 1 above.

5. TS thus ends at 364320 (0x00058F20) in the last packet of the sequence with RTP sequence number 69.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		70 test packets	The SS starts sending test packets
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th packet (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is sent to the ROHC compressor to trigger an immediate transition to O-mode operation.
5	UE			The UE changes immediately to O-mode operation and continues to send the test packets
6			Test packets in O-mode operation.
7	SS			For packet with SN= 20, the SS increases TS to represent a 32 packet skip and sets it to (20+32)x160=8320.
8	SS			For packet with SN= 30, the SS increases TS to represent a 128 packet skip and sets it to (30+32+128)x160=30400.
9	SS			For packet with SN= 40, the SS increases TS to represent a 2048 packet skip and sets it to (40+32+128+2048)x160=359680.
10	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	O-mode

ROHC feedback packet of feedback type 2 (Step 3)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

7.3.6.4.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.4.

Table 7.3.6.4: Test Requirement for ROHC Test 7.3.6.4

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= 19	See Test 1a (Test 7.3.6.2 in TS 34.123-1)
20 <= SN <= 19 + N 30 <= SN <= 29 + N	10 octets	10 octets
40 <= SN <= 39 + N	10 octets	10 octets
Other SN values	5 octets	5 octets

With N value equal to 4.

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.4: Expected outcome for ROHC Test 7.3.6.4

7.3.6.5 Re-establishment of TS function after DTX in R-mode

7.3.6.5.1 Definition and applicability

The purpose of the TS (Timestamp) re-establishment test case is to verify that the compressor re-establishes the proper TS value after a DTX period, i.e. that it uses the efficient header formats available to ROHC RTP [40] when operating in R-mode.

- - - 1. Conformance requirement

…

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set as defined by the test case

– SN is set as defined by the test case

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

…

The test sequence is the same as in subclause A.2.2, with the following exception:

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

2. For packet with SN= 20, TS is increased to represent a 32 (0.64 seconds) packet skip (32×160) and is thus set to (20+32)x160=8320 (0x00002080). Then TS continues to grow as stated in 1 above.

5. TS thus ends at 393120 (0x0005FFA0) in the last packet of the sequence with RTP sequence number 69.

Reference(s)

3GPP TS 25.323 clauses A.1, A.2.6, A.3 and B.2.3.

7.3.6.5.3 Test purpose

To verify that the compressor re-establishes the proper TS value after a DTX period, i.e. that it uses the efficient header formats available to ROHC RTP when operating in R-mode.

7.3.6.5.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

For packet with SN= 20, the SS increases TS to represent a 32 (0.64 seconds) packet skip (32×160) and sets it to (20+32)x160=8320 (0x00002080). Then TS continues to grow linearly with a packet-to-packet delta of 160.

For packet with SN= 30, the SS increases TS to represent a 128 (2.56 seconds) packet skip (128×160) and sets it to (30+32+128)x160=30400 (0x000076C0). Then TS continues to grow linearly with a packet-to-packet delta of 160.

For packet with SN= 40, the SS increases TS to represent a 2048 (40.96 seconds) packet skip (2048×160) and sets it to (40+32+128+2048)x160=359680 (0x00057D00). Then TS continues to grow linearly with a packet-to-packet delta of 160.

The test sequence ends with TS at 393120 (0x0005FFA0) in the last packet of the sequence with RTP sequence number 69.

When all the expected compressed headers have been received by the SS, the SS disconnects the session. The SS calculates the Average Compressed Header Size and checks if it meets the test requirements for the IP version used.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		Test packets	The SS starts sending test packets. The test sequence consists of 70 packets.
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th (SN=5 and SN=6) packet of the sequence the SS initiates a transition to R-mode operation.
5	UE			The UE changes immediately to R-mode operation and continues to send the test packets
6			Test packets in R-mode operation.	The UE returns test packets in R-mode operation using the test loop function.
6a	ß		ROHC feedback packet of feedback type 2	During the test case the SS generates a feedback message when the ROHC packet type octet of the received compressed header matches any of the values as described in the table 7.3.6.3.1.
7	SS			For packet with SN= 20, the SS increases TS to represent a 32 packet skip and sets it to (20+32)x160=8320.
8	SS			For packet with SN= 30, the SS increases TS to represent a 128 packet skip and sets it to (30+32+128)x160=30400.
9	SS			For packet with SN= 40, the SS increases TS to represent a 2048 packet skip and sets it to (40+32+128+2048)x160=359680.
10	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	R-mode

ROHC feedback packet of feedback type 2 (Step 4 and 6a)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x3 (means R-mode)

– SN is set to 0x000

7.3.6.5.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.5.1

Table 7.3.6.5.1: Test Requirement for Re-establishment of TS function after DTX in R-mode

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= 19	See Test 1b (Test case 7.3.6.3 in TS 34.123-1)
20 <= SN <= 19 + x 30 <= SN <= 29 + x	10 octets	10 octets
40 <= SN <= 39 + x	10 octets	10 octets
Other SN values	5 octets	5 octets

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.5: Expected outcome for Re-establishment of TS function after DTX in R-mode test

7.3.6.6 Compressor response to single lost packets in O-mode

7.3.6.6.1 Definition and applicability

Same as in 34.123-1 clause 7.3.6.2.1.

7.3.6.6.2 Conformance requirement

Same as in 34.123-1 clause 7.3.6.2.2.

7.3.6.6.3 Test purpose

The purpose of this test is to verify that the compressor does not panic just because there is a single missing packet, i.e. the compressed packet size should not increase due to such events.

7.3.6.6.4 Method of test

The method is the same as in 34.123-1 clause 7.3.6.2.4 except that test packets with SN 20, 30 and 40 are removed from the sequence.

7.3.6.6.5 Test requirements

The maximal compressed header overhead shall be the same as in 34.123-1 clause 7.3.6.2.5.

7.3.6.7 Compressor response to single lost packets in R-mode

7.3.6.7.1 Definition and applicability

Same as in 34.123-1 clause 7.3.6.3.1.

7.3.6.7.2 Conformance requirement

Same as in 34.123-1 clause 7.3.6.3.2.

7.3.6.7.3 Test purpose

The purpose of this test is to verify that the compressor does not panic just because there is a single missing packet, i.e. the compressed packet size should not increase due to such events

7.3.6.7.4 Method of test

The method is the same as in 34.123-1 clause 7.3.6.3.4 except that test packets with SN 20, 30 and 40 are removed from the sequence.

7.3.6.7.5 Test requirements

The maximal compressed header overhead shall be the same as in 34.123-1 clause 7.3.6.3.5.

7.3.6.8 TS function during DTX with varying delta in O-mode

7.3.6.8.1 Definition and applicability

The purpose of this test case is to verify that the compressor properly handles variations in the function between the TS value and the SN during and after a DTX period, during which SID packets are sent periodically, i.e. that it uses efficient header formats available to ROHC RTP [40] when operating in O-mode.

7.3.6.8.2 Conformance requirement

…

The test sequence is the same as in subclause A.2.1, with the following exception:

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

2. For packets SN = 20, 21 and 22, TS is increased to represent a 7 (0.14 seconds) packet skip (7×160) and is thus set to (20+7)x160=4320 (0x000010E0), (21+7+7)x160=5600(0x000015E0) and (22+7+7+7)x160=6880(0x00001AE0), respectively.

3. For packets SN = 30, 31, 32, 33 and 34, TS is increased to represent a 7 (0.14 seconds) packet skip (7×160) and is thus set to 9280 (0x00002440), 10560 (0x00002940), 11840 (0x00002E40), 13120 (0x00003340) and 14400 (0x00003840) respectively.

4. For packets SN = 40, 41, 42, 43, 44, 45, and 46, TS is increased to represent a 7 (0.14 seconds) packet skip (7×160) and is thus set to 16480 (0x00004060), 17760 (0x00004560), 19040 (0x00004A60), 20320 (0x00004F60), 21600 (0x00005460), 22880 (0x00005960) and 24160 (0x00005E60) respectively.

5. TS thus ends at 27840 (0x00006CC0) in the last packet of the sequence with RTP sequence number 69

Reference(s)

3GPP TS 25.323 clauses A.1.2,A.2.11, A.2.1, A.3, B.2.3.

7.3.6.8.3 Test purpose

To verify that the ROHC compressor properly handles variations in the function between the TS value and the SN during and after a DTX period, during which SID packets are sent periodically, i.e. that it uses efficient header formats available to ROHC RTP when operating in O-mode.

7.3.6.8.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

2. For packets SN = 20, 21 and 22, TS is increased to represent a 7 (0.14 seconds) packet skip (7×160) and is thus set to (20+7)x160=4320 (0x000010E0), (21+7+7)x160=5600 (0x000015E0) and (22+7+7+7)x160=6880 (0x00001AE0), respectively.

5. TS thus ends at 27840 (0x00006CC0) in the last packet of the sequence with RTP sequence number 69.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		70 test packets	The SS starts sending test packets
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th packet (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is sent to the ROHC compressor to trigger an immediate transition to O-mode operation.
5	UE			The UE changes immediately to O-mode operation and continues to send the test packets
6			Test packets in O-mode operation.
7	SS			For packets SN = 20, 21 and 22, the SS increases TS to represent a 7 packet skip and sets TS to (20+7)x160=4320, (21+7+7)x160=5600 and (22+7+7+7)x160=6880 respectively.
8	SS			For packets SN = 30, 31, 32, 33 and 34, the SS increases TS to represent a 7 packet skip and sets TS to 9280, 10560, 11840, 13120 and 14400 respectively.
9	SS			For packets SN = 40, 41, 42, 43, 44, 45, and 46, the SS increases TS to represent a 7 packet skip and sets TS to 16480, 17760, 19040, 20320, 21600, 22880 and 24160 respectively.
10	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	O-mode

ROHC feedback packet of feedback type 2 (Step 3)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

7.3.6.8.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.8.

Table 7.3.6.8: Test Requirement for ROHC Test 7.3.6.8

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= 19	See Test 1a (Test 7.3.6.2 in TS 34.123-1)
20 <= SN <= 22 + N 30 <= SN <= 34 + N 40 <= SN <= 46 + N	15 octets	15 octets
Other SN values	5 octets	5 octets

With N value equal to 4.

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.8: Expected outcome for ROHC Test 7.3.6.8

7.3.6.9 TS function during DTX with varying delta in R-mode

7.3.6.9.1 Definition and applicability

The purpose of this test case is to verify how efficiently the compressor handles variations in the function between the TS value and the SN during and after a DTX period, during which SID packets are sent periodically, i.e. that it uses the efficient header formats available to ROHC RTP [40] when operating in R-mode.

- - - 1. Conformance requirement

…

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set as defined by the test case

– SN is set as defined by the test case

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

…

The test sequence is the same as in subclause A.2.2, with the following exception:

1. The RTP Time Stamp is a linearly increasing counter with a packet-to-packet delta of 160, set to 0x00000000 for the first packet.

5. TS thus ends at 27840 (0x00006CC0) in the last packet of the sequence with RTP sequence number 69.

Reference(s)

3GPP TS 25.323 clauses A.1, A.2.12, A.3 and B.2.3.

7.3.6.9.3 Test purpose

To verify how efficiently the compressor handles variations in the function between the TS value and the SN during and after a DTX period, during which SID packets are sent periodically, i.e. that it uses the efficient header formats available to ROHC RTP when operating in R-mode.

7.3.6.9.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

For packets SN = 20, 21 and 22, the SS increases TS to represent a 7 (0.14 seconds) packet skip (7×160) and sets TS to (20+7)x160=4320 (0x000010E0), (21+7+7)x160=5600 (0x000015E0) and (22+7+7+7)x160=6880 (0x00001AE0), respectively.

For packets SN = 30, 31, 32, 33 and 34, the SS increases TS to represent a 7 (0.14 seconds) packet skip (7×160) and sets TS to 9280 (0x00002440), 10560 (0x00002940), 11840 (0x00002E40), 13120 (0x00003340) and 14400 (0x00003840) respectively.

For packets SN = 40, 41, 42, 43, 44, 45, and 46, the SS increases TS to represent a 7 (0.14 seconds) packet skip (7×160) and sets TS to 16480 (0x00004060), 17760 (0x00004560), 19040 (0x00004A60), 20320 (0x00004F60), 21600 (0x00005460), 22880 (0x00005960) and 24160 (0x00005E60) respectively.

The test sequence ends with TS at 27840 (0x00006CC0) in the last packet of the sequence with RTP sequence number 69.

Expected sequence

Step	Direction		Message	Comments
	UE	SS
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		Test packets	The SS starts sending test packets. The test sequence consists of 70 packets.
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th (SN=5 and SN=6) packet of the sequence the SS initiates a transition to R-mode operation.
5	UE			The UE changes immediately to R-mode operation and continues to send the test packets
6			Test packets in R-mode operation.	The UE returns test packets in R-mode operation using the test loop function.
6a	ß		ROHC feedback packet of feedback type 2	During the test case the SS generates a feedback message when the ROHC packet type octet of the received compressed header matches any of the values as described in the table 7.3.6.3.1.
7	SS			For packets SN = 20, 21 and 22, the SS increases TS to represent a 7 packet skip and sets TS to (20+7)x160=4320, (21+7+7)x160=5600 and (22+7+7+7)x160=6880 respectively.
8	SS			For packets SN = 30, 31, 32, 33 and 34, the SS increases TS to represent a 7 packet skip and sets TS to 9280, 10560, 11840, 13120 and 14400 respectively.
9	SS			For packets SN = 40, 41, 42, 43, 44, 45, and 46, the SS increases TS to represent a 7 packet skip and sets TS to 16480, 17760, 19040, 20320, 21600, 22880 and 24160 respectively.
10	SS		After the SS has received all 70 packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	R-mode

ROHC feedback packet of feedback type 2 (Step 4 and 6a)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x3 (means R-mode)

– SN is set to 0x000

7.3.6.9.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.9.1

Table 7.3.6.9.1: Test Requirement for TS function during DTX with varying delta in R-mode

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= 19	See Test 1b (Test case 7.3.6.3 in TS 34.123-1)
20 <= SN <= 22 + x 30 <= SN <= 34 + x 40 <= SN <= 46 + x	15 octets	15 octets
Other SN values	5 octets	5 octets

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.9: Expected outcome for TS function during DTX with varying delta in R-mode test

7.3.6.10 SRNS relocation for ROHC RTP O-mode compressor

7.3.6.10.1 Definition and applicability

The purpose of this test case is to verify that the compressor does not interrupt efficient header compression upon reception of the indication about SRNS relocation being performed, i.e. that it makes use of efficient compressed packet formats available to ROHC RTP [40] when operating in O-mode when data transmission is resumed after SRNS relocation.

7.3.6.10.2 Conformance requirement

The header compression context relocation is performed by the decision of upper layers in source RNC based on the UE radio capabilities. The decision is done independently every time the SRNS relocation occurs and is specific for each header compression protocol. It is indicated to UE as a part of the SRNS relocation signalling of the upper layer and the selected relocation method is configured to UE PDCP by the upper layer.

The header compression context relocation shall not be performed if the radio bearer is configured to support the lossless SRNS Relocation.

In the UE, upon reception of the indication about SRNS relocation being performed:

– the upper layer configures PDCP (CPDCP-CONFIG.Req) to perform either re-initialisation (R) or the context relocation (C) of header compression protocols;

– if the context relocation is to be applied for RFC3095 header compression protocol:

– if the compressor (M-HC) is operating in R mode:

– uplink data may be compressed and transmitted normally.

– if the compressor (M-HC) is operating in O mode:

– compress and transmit uplink data as specified in [8] using the assumption that all ROHC uplink packets transmitted are likely to be lost. When SRNS relocation is completed, M-HC should return to normal operation.

NOTE: When the M-HC is using the assumption that all ROHC uplink packets transmitted are likely to be lost:
– the M-HC can not transit to a higher compression state;
– for W-LSB encoding, the M-HC updates the set of candidate reference values used by the decompressor by adding newly transmitted values but not removing old values.

…

A sequence consisting of 70 packets in total is used where all header fields are set according to the basic test packet structure, as described in subclause A.3, with addition of the following:

1. The RTP Sequence Number is a linearly increasing counter with a packet-to-packet delta of 1, set to 0x0000 for the first packet and thus ending with 0x0045 (69) in the last packet of the sequence

3. The IP Identification is set to the same value as the RTP Sequence Number; this means that for IPv4 the IP-ID behaviour is not random, thus value(RND)=0 defined in [40] for both IPv4 and IPv6.

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

NOTE: If compressor uses CID field in compressed packet, the CID field should be included in the feedback packet and the Code and CID should be set as defined in [40].

…

The test sequence is the same as in subclause A.2.1, with the following exceptions:

Packets with SN = 10 to SN = 59 are removed from the sequence.

SRNS relocation occurs between packet with SN = 9 and packet with SN = 60, thus simulating a 1s long SRNS relocation that affects compression of the IP/UDP/RTP packet flow.

NOTE: The operation of the ROHC compressor is not affected by the time interval between packets with SN = 9 and SN = 60 (timer-based compression is not allowed because no appropriate feedback is provided).

Reference(s)

3GPP TS 25.323 clauses 5.4.2, A.1.2, A.2.1, A.2.13.

7.3.6.10.3 Test purpose

To verify that the compressor does not interrupt efficient header compression upon reception of the indication about SRNS relocation being performed, i.e. that it makes use of efficient compressed packet formats available to ROHC RTP [40] when operating in O-mode when data transmission is resumed after SRNS relocation.

To verify the ROHC compressor shall normally add information to the compression context as new uplink data are compressed, but not remove any existing information from the compression context upon reception of the indication about SRNS relocation being performed and if the context relocation is to be applied for RFC3095 header compression protocol when operating in O-mode.

To verify that normal operation is applied when SRNS relocation with header compression context relocation is completed.

7.3.6.10.4 Method of test

Initial conditions

User Equipment:

Profile 0x0001 for compression of RTP/UDP/IP headers only is used

N=4

Related ICS/IXIT Statement(s)

Support of PS Yes/No

Support of ROHC Yes/No

Support of context relocation Yes/No

UE Supports IPv4 Yes/No

UE Supports IPv6 Yes/No

Test procedure

The SS transmits a RADIO BEARER RECONFIGURATION message. Packets with SN = 10 to SN = 59 are removed from the sequence.

The UE performs a combined hard handover and SRNS relocation with header compression context relocation and then transmits a RADIO BEARER RECONFIGURATION COMPLETE message in the new cell. The SS resumes the transmission of IP packets and checks that all transmitted IP Packets are sent back by the UE.

Expected sequence

Step	Direction		Message	Comments
Step	UE	SS	Message	Comments
1				After the PS session setup the UE is in ROHC U-mode operation and in the IR state.
2	ß		Test packets	The SS starts sending test packets
3			Test packets in U-mode operation.	The UE starts returning test packets in U-mode operation using the test loop function.
4	ß		ROHC feedback packet of feedback type 2	Between the 6^th and 7^th packet (SN=5 and SN=6) of the sequence, a ROHC feedback packet of feedback type 2 is sent to the ROHC compressor to trigger an immediate transition to O-mode operation.
5	UE			The UE changes immediately to O-mode operation and continues to send the test packets
6			Test packets in O-mode operation.
7			RADIO BEARER RECONFIGURATION
				The SS stop sending test packets
8			RADIO BEARER RECONFIGURATION COMPLETE
9	ß		Test packets	The SS resumes sending test packets.
10			Test packets in O-mode operation.
11	SS		After the SS has received all the packets in the test sequence the SS disconnects the PS session.

Specific Message Contents

RADIO BEARER SETUP message (during Generic ROHC performance test procedure in clause 7.3.6.1.1)

Information Element	Value/remark
– PDCP ROHC target mode	O-mode

ROHC feedback packet of feedback type 2 (Step 4)

0 1 2 3 4 5 6 7

+—+—+—+—+—+—+—+—+

| 1 1 1 1 0 | Code | feedback type octet

+—+—+—+—+—+—+—+—+

|Acktype| Mode | SN |

+—+—+—+—+—+—+—+—+

| SN |

+—+—+—+—+—+—+—+—+

| 0 0 0 1 | 0 0 0 1 |

+—+—+—+—+—+—+—+—+

| CRC |

+—+—+—+—+—+—+—+—+

Where:

– Code is set to 0x4 (indicates that feedback data above the type octet is 4 octets)

– Acktype is set to 0x0 (means ACK)

– Mode is set to 0x2 (means O-mode)

– SN is set to 0x000

RADIO BEARER RECONFIGURATION (Step 7)

Use the same message sub-type found in [9] TS 34.108 clause 9, which is entitled “Packet to CELL_DCH from CELL_DCH in PS”, with the following exceptions:

Information Element	Value/remark
RB information to reconfigure list
– RB information to reconfigure
– RB identity	TBD
– PDCP info
– Support for lossless SRNS relocation	FALSE
– PDCP PDU header	Present
– Header compression information	present
CHOICE algorithm type
– RFC3095
– RLC info
– CHOICE Uplink RLC mode	UM RLC
– CHOICE Downlink RLC mode	UM RLC
RB with PDCP context relocation info list
– PDCP context relocation info
– RB identity	TBD
– Downlink RFC 3095 context relocation indication	TRUE
– Uplink RFC 3095 context relocation indication	TRUE

7.3.6.10.5 Test requirements

The average compressed header size shall not exceed the limits specified in Table 7.3.6.10.

Table 7.3.6.10: Test Requirement for SRNS relocation for ROHC RTP O-mode compressor

	Average Compressed Header Size, IPv4	Average Compressed Header size, IPv6
SN <= N-1	44 octets	68 octets
N <= SN <= 9	5 octets	5 octets
60 <= SN <= 59+N	8 octets	8 octets
SN >= 60+N	5 octets	5 octets

With N value equal to 4.

The sequence of expected compressed headers can be illustrated as follow (informative):

Figure 7.3.6.10: Expected outcome for SRNS relocation for RTP O-mode compressor test