From d1db79ea46f120641b9dceadbf64fcb1e4f5224f Mon Sep 17 00:00:00 2001 From: Nicola Baldo Date: Thu, 18 Apr 2013 16:17:08 +0200 Subject: [PATCH 1/3] moved LTE UE PHY measurement docs into LTE PHY section --- src/lte/doc/source/lte-design.rst | 105 +++++++++++++----------------- 1 file changed, 47 insertions(+), 58 deletions(-) diff --git a/src/lte/doc/source/lte-design.rst b/src/lte/doc/source/lte-design.rst index df16165ff..0016222e1 100644 --- a/src/lte/doc/source/lte-design.rst +++ b/src/lte/doc/source/lte-design.rst @@ -725,6 +725,53 @@ According to the considerations above, a model more flexible can be obtained con Therefore the PHY layer implements the MIMO model as the gain perceived by the receiver when using a MIMO scheme respect to the one obtained using SISO one. We note that, these gains referred to a case where there is no correlation between the antennas in MIMO scheme; therefore do not model degradation due to paths correlation. +UE Measurements Model ++++++++++++++++++++++ + +According to [TS36214]_, the UE has to report a set of measurements of the eNBs that the device is able to perceive: the the reference signal received power (RSRP) and the reference signal received quality (RSRQ). The former is a measure of the received power of a specific eNB, while the latter includes also channel interference and thermal noise. +The UE has to report the measurements jointly with the physical cell identity (PCI) of the cell. Both measurements are performed during the reception of the RS, while the PCI is obtained with the Primary Synchronization Signal (PSS). The PSS is sent by the eNB each 5 subframes and in detail in the subframes 1 and 6. According to [TS36133]_ sections 9.1.4 and 9.1.7, RSRP is reported by PHY layer in dBm while RSRQ in dB. The values of RSRP and RSRQ are provided to higher layers through the C-PHY SAP (by means of ``UeMeasurementsParameters`` struct) every 200 ms as defined in [TS36331]_. Layer 1 filtering is performed by averaging the all the measurements collected during the last window slot. The periodicity of reporting can be adjusted for research purposes by means of the ``LteUePhy::UeMeasurementsFilterPeriod`` attribute. + +The formulas of the RSRP and RSRQ can be simplified considering the assumption of the PHY layer that the channel is flat within the RB, the finest level of accuracy. In fact, this implies that all the REs within a RB have the same power, therefore: + +.. math:: + + RSRP = \frac{\sum_{k=0}^{K-1}\frac{\sum_{m=0}^{M-1}(P(k,m))}{M}}{K} + = \frac{\sum_{k=0}^{K-1}\frac{(M \times P(k))}{M}}{K} + = \frac{\sum_{k=0}^{K-1}(P(k))}{K} + +where :math:`P(k,m)` represents the signal power of the RE :math:`m` within the RB :math:`k`, which, as observed before, is constant within the same RB and equal to :math:`P(k)`, :math:`M` is the number of REs carrying the RS in a RB and :math:`K` is the number of RBs. It is to be noted that, :math:`P(k)`, and in general all the powers defined in this section, is obtained in the simulator from the PSD of the RB (which is the standard value returned from the ``LteInterferencePowerChunkProcessor``), in detail: + +.. math:: + + P(k) = PSD_{RB}(k)*180000/12 + +where :math:`PSD_{RB}(k)` is the power spectral density of the RB :math:`k`, :math:`180000` is the bandwidth in Hz of the RB and :math:`12` is the number of REs per RB in an OFDM symbol. +Similarly, for RSSI we have + +.. math:: + RSSI = \sum_{k=0}^{K-1} \frac{\sum_{s=0}^{S-1} \sum_{r=0}^{R-1}( P(k,s,r) + I(k,s,r) + N(k,s,r))}{S} + +where :math:`S` is the number of OFDM symbols carrying RS in a RB and :math:`R` is the number of REs carrying a RS in a OFDM symbol (e.g., which is fixed to :math:`2`) while :math:`P(k,s,r)`, :math:`I(k,s,r)` and :math:`N(k,s,r)` represent respectively the perceived power of the serving cell, the interference power and the noise power of the RE :math:`r` in symbol :math:`s`. As for RSRP, the measurements within a RB are always equals among each others according to the PHY model; therefore :math:`P(k,s,r) = P(k)`, :math:`I(k,s,r) = I(k)` and :math:`N(k,s,r) = N(k)`, which implies that the RSSI can be calculated as: + +.. math:: + RSSI = \sum_{k=0}^{K-1} \frac{S \times 2 \times ( P(k) + I(k) + N(k))}{S} + = \sum_{k=0}^{K-1} 2 \times ( P(k) + I(k) + N (k)) + +Considering the constraints of the PHY reception chain implementation and, in order to maintain the level of computational complexity low, only RSRP can be directly obtained for all the cells. This is due to the fact that ``LteSpectrumPhy`` is designed for evaluating the interference only respect to the signal of the serving eNB. This implies that the PHY layer is optimized for managing the power signals information with the serving eNB as a reference. However, RSRP and RSRQ of neighbor cell :math:`i` can be extracted by the current information available of the serving cell :math:`j` as detailed in the following: + +.. math:: + + RSRP_i = \frac{\sum_{k=0}^{K-1}(P_i(k))}{K} + + RSSI_i = RSSI_j = \sum_{k=0}^{K-1} 2 \times ( I_j(k) + P_j(k) + N_j(k) ) + + RSRQ_i^j = K \times RSRP_i / RSSI_j + +where :math:`RSRP_i` is the RSRP of the neighbor cell :math:`i`, :math:`P_i(k)` is the power perceived at any RE within the RB :math:`k`, :math:`K` is the total number of RBs, :math:`RSSI_i` is the RSSI of the neighbor cell :math:`i` when the UE is attached to cell :math:`j` (which, since it is the sum of all the received powers, coincides with :math:`RSSI_j`), :math:`I_j(k)` is the total interference perceived by UE in any RE of RB :math:`k` when attached to cell :math:`i` (obtained by the ``LteInterferencePowerChunkProcessor``), :math:`P_j(k)` is the power perceived of cell :math:`j` in any RE of the RB :math:`k` and :math:`N` is the power noise spectral density in any RE. The sample is considered as valid in case of the RSRQ evaluated is above the ``LteUePhy::RsrqUeMeasThreshold`` attribute. + + + + ---------- HARQ ---------- @@ -769,64 +816,6 @@ Finally, the HARQ engine is always active both at MAC and PHY layer; however, in Interaction between HARQ and LTE protocol stack -.. only:: latex - - .. raw:: latex - - \clearpage - - ---------------- -UE Measurements ---------------- - -According to [TS36214]_, the UE has to report a set of measurements of the eNBs that the device is able to perceive: the the reference signal received power (RSRP) and the reference signal received quality (RSRQ). The former is a measure of the received power of a specific eNB, while the latter includes also channel interference and thermal noise. -The UE has to report the measurements jointly with the physical cell identity (PCI) of the cell. Both measurements are performed during the reception of the RS, while the PCI is obtained with the Primary Synchronization Signal (PSS). The PSS is sent by the eNB each 5 subframes and in detail in the subframes 1 and 6. According to [TS36133]_ sections 9.1.4 and 9.1.7, RSRP is reported by PHY layer in dBm while RSRQ in dB. The values of RSRP and RSRQ are provided to higher layers through the C-PHY SAP (by means of ``UeMeasurementsParameters`` struct) every 200 ms as defined in [TS36331]_. Layer 1 filtering is performed by averaging the all the measurements collected during the last window slot. The periodicity of reporting can be adjusted for research purposes by means of the ``LteUePhy::UeMeasurementsFilterPeriod`` attribute. - -The formulas of the RSRP and RSRQ can be simplified considering the assumption of the PHY layer that the channel is flat within the RB, the finest level of accuracy. In fact, this implies that all the REs within a RB have the same power, therefore: - -.. math:: - - RSRP = \frac{\sum_{k=0}^{K-1}\frac{\sum_{m=0}^{M-1}(P(k,m))}{M}}{K} - = \frac{\sum_{k=0}^{K-1}\frac{(M \times P(k))}{M}}{K} - = \frac{\sum_{k=0}^{K-1}(P(k))}{K} - -where :math:`P(k,m)` represents the signal power of the RE :math:`m` within the RB :math:`k`, which, as observed before, is constant within the same RB and equal to :math:`P(k)`, :math:`M` is the number of REs carrying the RS in a RB and :math:`K` is the number of RBs. It is to be noted that, :math:`P(k)`, and in general all the powers defined in this section, is obtained in the simulator from the PSD of the RB (which is the standard value returned from the ``LteInterferencePowerChunkProcessor``), in detail: - -.. math:: - - P(k) = PSD_{RB}(k)*180000/12 - -where :math:`PSD_{RB}(k)` is the power spectral density of the RB :math:`k`, :math:`180000` is the bandwidth in Hz of the RB and :math:`12` is the number of REs per RB in an OFDM symbol. -Similarly, for RSSI we have - -.. math:: - RSSI = \sum_{k=0}^{K-1} \frac{\sum_{s=0}^{S-1} \sum_{r=0}^{R-1}( P(k,s,r) + I(k,s,r) + N(k,s,r))}{S} - -where :math:`S` is the number of OFDM symbols carrying RS in a RB and :math:`R` is the number of REs carrying a RS in a OFDM symbol (e.g., which is fixed to :math:`2`) while :math:`P(k,s,r)`, :math:`I(k,s,r)` and :math:`N(k,s,r)` represent respectively the perceived power of the serving cell, the interference power and the noise power of the RE :math:`r` in symbol :math:`s`. As for RSRP, the measurements within a RB are always equals among each others according to the PHY model; therefore :math:`P(k,s,r) = P(k)`, :math:`I(k,s,r) = I(k)` and :math:`N(k,s,r) = N(k)`, which implies that the RSSI can be calculated as: - -.. math:: - RSSI = \sum_{k=0}^{K-1} \frac{S \times 2 \times ( P(k) + I(k) + N(k))}{S} - = \sum_{k=0}^{K-1} 2 \times ( P(k) + I(k) + N (k)) - -Considering the constraints of the PHY reception chain implementation and, in order to maintain the level of computational complexity low, only RSRP can be directly obtained for all the cells. This is due to the fact that ``LteSpectrumPhy`` is designed for evaluating the interference only respect to the signal of the serving eNB. This implies that the PHY layer is optimized for managing the power signals information with the serving eNB as a reference. However, RSRP and RSRQ of neighbor cell :math:`i` can be extracted by the current information available of the serving cell :math:`j` as detailed in the following: - -.. math:: - - RSRP_i = \frac{\sum_{k=0}^{K-1}(P_i(k))}{K} - - RSSI_i = RSSI_j = \sum_{k=0}^{K-1} 2 \times ( I_j(k) + P_j(k) + N_j(k) ) - - RSRQ_i^j = K \times RSRP_i / RSSI_j - -where :math:`RSRP_i` is the RSRP of the neighbor cell :math:`i`, :math:`P_i(k)` is the power perceived at any RE within the RB :math:`k`, :math:`K` is the total number of RBs, :math:`RSSI_i` is the RSSI of the neighbor cell :math:`i` when the UE is attached to cell :math:`j` (which, since it is the sum of all the received powers, coincides with :math:`RSSI_j`), :math:`I_j(k)` is the total interference perceived by UE in any RE of RB :math:`k` when attached to cell :math:`i` (obtained by the ``LteInterferencePowerChunkProcessor``), :math:`P_j(k)` is the power perceived of cell :math:`j` in any RE of the RB :math:`k` and :math:`N` is the power noise spectral density in any RE. The sample is considered as valid in case of the RSRQ evaluated is above the ``LteUePhy::RsrqUeMeasThreshold`` attribute. - -.. only:: latex - - .. raw:: latex - - \clearpage - ------ MAC From a0c2d78fcfef6dfd9f470d7b0de40933f545dc72 Mon Sep 17 00:00:00 2001 From: Nicola Baldo Date: Thu, 18 Apr 2013 16:21:59 +0200 Subject: [PATCH 2/3] minor changes to PHY UE measurement docs --- src/lte/doc/source/lte-design.rst | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/lte/doc/source/lte-design.rst b/src/lte/doc/source/lte-design.rst index 0016222e1..a1744893b 100644 --- a/src/lte/doc/source/lte-design.rst +++ b/src/lte/doc/source/lte-design.rst @@ -739,7 +739,7 @@ The formulas of the RSRP and RSRQ can be simplified considering the assumption o = \frac{\sum_{k=0}^{K-1}\frac{(M \times P(k))}{M}}{K} = \frac{\sum_{k=0}^{K-1}(P(k))}{K} -where :math:`P(k,m)` represents the signal power of the RE :math:`m` within the RB :math:`k`, which, as observed before, is constant within the same RB and equal to :math:`P(k)`, :math:`M` is the number of REs carrying the RS in a RB and :math:`K` is the number of RBs. It is to be noted that, :math:`P(k)`, and in general all the powers defined in this section, is obtained in the simulator from the PSD of the RB (which is the standard value returned from the ``LteInterferencePowerChunkProcessor``), in detail: +where :math:`P(k,m)` represents the signal power of the RE :math:`m` within the RB :math:`k`, which, as observed before, is constant within the same RB and equal to :math:`P(k)`, :math:`M` is the number of REs carrying the RS in a RB and :math:`K` is the number of RBs. It is to be noted that :math:`P(k)`, and in general all the powers defined in this section, is obtained in the simulator from the PSD of the RB (which is provided by the ``LteInterferencePowerChunkProcessor``), in detail: .. math:: @@ -751,13 +751,13 @@ Similarly, for RSSI we have .. math:: RSSI = \sum_{k=0}^{K-1} \frac{\sum_{s=0}^{S-1} \sum_{r=0}^{R-1}( P(k,s,r) + I(k,s,r) + N(k,s,r))}{S} -where :math:`S` is the number of OFDM symbols carrying RS in a RB and :math:`R` is the number of REs carrying a RS in a OFDM symbol (e.g., which is fixed to :math:`2`) while :math:`P(k,s,r)`, :math:`I(k,s,r)` and :math:`N(k,s,r)` represent respectively the perceived power of the serving cell, the interference power and the noise power of the RE :math:`r` in symbol :math:`s`. As for RSRP, the measurements within a RB are always equals among each others according to the PHY model; therefore :math:`P(k,s,r) = P(k)`, :math:`I(k,s,r) = I(k)` and :math:`N(k,s,r) = N(k)`, which implies that the RSSI can be calculated as: +where :math:`S` is the number of OFDM symbols carrying RS in a RB and :math:`R` is the number of REs carrying a RS in a OFDM symbol (which is fixed to :math:`2`) while :math:`P(k,s,r)`, :math:`I(k,s,r)` and :math:`N(k,s,r)` represent respectively the perceived power of the serving cell, the interference power and the noise power of the RE :math:`r` in symbol :math:`s`. As for RSRP, the measurements within a RB are always equals among each others according to the PHY model; therefore :math:`P(k,s,r) = P(k)`, :math:`I(k,s,r) = I(k)` and :math:`N(k,s,r) = N(k)`, which implies that the RSSI can be calculated as: .. math:: RSSI = \sum_{k=0}^{K-1} \frac{S \times 2 \times ( P(k) + I(k) + N(k))}{S} = \sum_{k=0}^{K-1} 2 \times ( P(k) + I(k) + N (k)) -Considering the constraints of the PHY reception chain implementation and, in order to maintain the level of computational complexity low, only RSRP can be directly obtained for all the cells. This is due to the fact that ``LteSpectrumPhy`` is designed for evaluating the interference only respect to the signal of the serving eNB. This implies that the PHY layer is optimized for managing the power signals information with the serving eNB as a reference. However, RSRP and RSRQ of neighbor cell :math:`i` can be extracted by the current information available of the serving cell :math:`j` as detailed in the following: +Considering the constraints of the PHY reception chain implementation, and in order to maintain the level of computational complexity low, only RSRP can be directly obtained for all the cells. This is due to the fact that ``LteSpectrumPhy`` is designed for evaluating the interference only respect to the signal of the serving eNB. This implies that the PHY layer is optimized for managing the power signals information with the serving eNB as a reference. However, RSRP and RSRQ of neighbor cell :math:`i` can be extracted by the current information available of the serving cell :math:`j` as detailed in the following: .. math:: From 4f16a0636a2d7941f87fc638621a2d4f157d5b36 Mon Sep 17 00:00:00 2001 From: Manuel Requena Date: Fri, 19 Apr 2013 17:51:58 +0200 Subject: [PATCH 3/3] Add automatic handover documentation --- src/lte/doc/Makefile | 4 +- .../source/figures/lte-handover-algorithm.dot | 21 ++++++ src/lte/doc/source/lte-design.rst | 68 ++++++++++++++++--- src/lte/doc/source/lte-testing.rst | 47 ++++++++++++- src/lte/doc/source/lte-user.rst | 29 +++++++- 5 files changed, 158 insertions(+), 11 deletions(-) create mode 100644 src/lte/doc/source/figures/lte-handover-algorithm.dot diff --git a/src/lte/doc/Makefile b/src/lte/doc/Makefile index f4cc0e217..b4ba1391e 100644 --- a/src/lte/doc/Makefile +++ b/src/lte/doc/Makefile @@ -79,6 +79,7 @@ $(FIGURES)/lte-subframe-structure.pdf_width = 2in $(FIGURES)/mac-random-access-contention.pdf_width = 10cm $(FIGURES)/mac-random-access-noncontention.pdf_width = 15cm $(FIGURES)/lte-ue-rrc-states.pdf_width = 7cm +$(FIGURES)/lte-handover-algorithm.pdf_width = 10cm $(FIGURES)/helpers.pdf_width = 8cm IMAGES_SEQDIAG = \ @@ -93,7 +94,8 @@ IMAGES_SEQDIAG = \ IMAGES_DOT = \ $(FIGURES)/lte-enb-rrc-states.dot \ - $(FIGURES)/lte-ue-rrc-states.dot + $(FIGURES)/lte-ue-rrc-states.dot \ + $(FIGURES)/lte-handover-algorithm.dot IMAGES_NOBUILD = $(FIGURES)/fading_pedestrian.png \ $(FIGURES)/fading_vehicular.png \ diff --git a/src/lte/doc/source/figures/lte-handover-algorithm.dot b/src/lte/doc/source/figures/lte-handover-algorithm.dot new file mode 100644 index 000000000..9b7cfe2dc --- /dev/null +++ b/src/lte/doc/source/figures/lte-handover-algorithm.dot @@ -0,0 +1,21 @@ +digraph LteHandoverAlgorithm { + +size = "30,30" + +GET_MEASUREMENTS [shape = box, + label = "Get measurements from UE\n(The eNB receives events A2 and A4 with UE measurements)"] +CHECK_SERVING_RSRQ [shape = diamond, fixedsize = true, width = 8, height = 1.0, + label = "serving cell RSRQ <= servingHandoverThreshold"] +LOOK_BEST_NEIGHBOUR [shape = box, + label = "Look for the neighbour cell with the best RSRQ"] +CHECK_BEST_NEIGHBOUR [shape = diamond, fixedsize = true, width = 9, height = 1.0, + label = "best neighbour RSRQ - serving cell RSRQ >= neighbourHandoverOffset"] +TRIGGER_HANDOVER [shape = box, + label = "Trigger Handover procedure for this UE"] + +GET_MEASUREMENTS -> CHECK_SERVING_RSRQ +CHECK_SERVING_RSRQ -> LOOK_BEST_NEIGHBOUR +LOOK_BEST_NEIGHBOUR -> CHECK_BEST_NEIGHBOUR +CHECK_BEST_NEIGHBOUR -> TRIGGER_HANDOVER + +} diff --git a/src/lte/doc/source/lte-design.rst b/src/lte/doc/source/lte-design.rst index 69400363e..c58a9e6d8 100644 --- a/src/lte/doc/source/lte-design.rst +++ b/src/lte/doc/source/lte-design.rst @@ -1833,16 +1833,16 @@ UE Measurements UE RRC measurements support --------------------------- -The UE RRC entities provides support for UE measurements; in +The UE RRC entity provides support for UE measurements; in particular, it implements the procedures described in Section 5.5 of [TS36331]_, with the following simplifying assumptions: - only E-UTRA intra-frequency measurements are supported; - - meausrement gaps are not needed to perform the measurements; + - measurement gaps are not needed to perform the measurements; - only event-driven measurements are supported; the other type of - measurements are not supported; + measurements are not supported; - only the events A2 and A4 are to be supported; @@ -1860,16 +1860,68 @@ particular, it implements the procedures described in Section 5.5 of eNB RRC measurement configuration --------------------------------- +The eNB RRC entity configures the UE measurements. The eNB RRC entity +sends the configuration parameters to the UE RRC entity in the +MeasConfig IE of the RRC Connection Reconfiguration message when the UE +attaches to the eNB or the RRC Handover Request message when the target +eNB initiates the handover procedure. + +The eNB RRC entity implements the configuration parameters and procedures +described in Section 5.5 of [TS36331]_, with the following simplifying +assumptions: + + - only E-UTRA intra-frequency measurements are configured, so only the + downlink carrier frequency of the serving cell is configured as + measurement object; + + - only the events A2 and A4 are configured; + + - only the RSRQ threshold is configured for both events; + + - the reportInterval parameter is configured to 480 ms, so once the + events are triggered, the UE will send the measurement reports with + this periodicity; + + - the filterCoefficientRSRQ parameter is configured to fc4, it is the + default value specified in the protocol specification [TS36331]_; + + - the hysteresis and timeToTrigger parameters are configured with + values equal to zero; + Handover ++++++++ -The RRC model support the execution of an X2-based handover -procedure. The handover needs to be triggered explicitly by the -simulation program by scheduling an execution of the method -``LteEnbRrc::SendHandoverRequest ()``. The automatic triggering of the -handover based on UE measurements is not supported at this stage. +The RRC model support the execution of an X2-based handover procedure. +There are 2 ways to trigger the handover procedure: + - the handover could be triggered explicitly by the simulation program + by scheduling an execution of the method ``LteEnbRrc::SendHandoverRequest ()`` + + - the handover could be triggered automatically by the eNB RRC entity. + The eNB executes the following algorithm :ref:`fig-lte-handover-algorithm` + to trigger the handover procedure for a UE providing measurements in its + serving cell and the neighbour cells the UE measures: + +.. _fig-lte-handover-algorithm: + +.. figure:: figures/lte-handover-algorithm.* + :align: center + + Algorithm to automatically trigger the Handover procedure + +The simulation user can set two parameters to control the handover decision: + + - servingHandoverThreshold, if the RSRQ value measured by the UE in its + serving cell is less or equal to the servingHandoverThreshold parameter + (i.e. the conditions of the UE in the serving cell are getting bad or + not good enough), then the eNB considers this UE to hand it over to a new + neighbour eNB. The handover will really triggered depending on the + measurements of the neighbour cells. + + - neighbourHandoverOffset, if the difference between the best neighbour RSRQ + and the serving cell RSRQ is greater or equal to the neighbourHandoverOffset + parameter, then the handover procedure is triggered for this UE. RRC sequence diagrams diff --git a/src/lte/doc/source/lte-testing.rst b/src/lte/doc/source/lte-testing.rst index 1909a7f51..e60e308cb 100644 --- a/src/lte/doc/source/lte-testing.rst +++ b/src/lte/doc/source/lte-testing.rst @@ -693,7 +693,7 @@ The test suite ``lte-x2-handover`` checks the correct functionality of the X2 ha - a boolean flag indicating whether the ideal RRC protocol is to be used instead of the real RRC protocol - the type of scheduler to be used (RR or PF) -Each test cases passes if the following conditions are true: +Each test case passes if the following conditions are true: - at time 0.06s, the test CheckConnected verifies that each UE is connected to the first eNB - for each event in the handover list: @@ -716,3 +716,48 @@ The condition "UE is connected to eNB" is evaluated positively if and only if al - for each Data Radio Bearer, the following identifiers match between the UE and the eNB: EPS bearer id, DRB id, LCID + +Automatic X2 handover +--------------------- + +The test suite ``lte-x2-handover-measures`` checks the correct functionality of the handover +algorithm. The scenario being tested is a topology with two, three or four eNBs connected by +an X2 interface. The eNBs are located in a straight line in the X-axes. A UE moves along the +X-axes going from the neighbourhood of one eNB to the next eNB. Each test case is a particular +instance of this scenario defined by the following parameters: + + - the number of eNBs in the X-axes + - the number of EPS bearers activated for the UE + - a list of check point events to be triggered, where each event is defined by: + + the time of the first check point event + + the time of the last check point event + + interval time between two check point events + + the index of the UE doing the handover + + the index of the eNB where the UE must be connected + - a boolean flag indicating whether the ideal RRC protocol is to be used instead of the + real RRC protocol + - the type of scheduler to be used (RR or PF) + +Each test case passes if the following conditions are true: + + - at time 0.08s, the test CheckConnected verifies that each UE is connected to the first eNB + - for each event in the check point list: + + + at the indicated check point time, the indicated UE is connected to the indicated eNB + + 0.5s after the check point, for each active EPS bearer, the uplink and downlink sink + applications of the UE have achieved a number of bytes which is at least half the number + of bytes transmitted by the corresponding source applications + +The condition "UE is connected to eNB" is evaluated positively if and only if all the following conditions are met: + + - the eNB has the context of the UE (identified by the RNTI value + retrieved from the UE RRC) + - the RRC state of the UE at the eNB is CONNECTED_NORMALLY + - the RRC state at the UE is CONNECTED_NORMALLY + - the UE is configured with the CellId, DlBandwidth, UlBandwidth, + DlEarfcn and UlEarfcn of the eNB + - the IMSI of the UE stored at the eNB is correct + - the number of active Data Radio Bearers is the expected one, both + at the eNB and at the UE + - for each Data Radio Bearer, the following identifiers match between + the UE and the eNB: EPS bearer id, DRB id, LCID diff --git a/src/lte/doc/source/lte-user.rst b/src/lte/doc/source/lte-user.rst index 6ac1cae25..36d53d6f6 100644 --- a/src/lte/doc/source/lte-user.rst +++ b/src/lte/doc/source/lte-user.rst @@ -892,9 +892,36 @@ otherwise the simulation will terminate with an error message. Automatic handover trigger ************************** -add description of how to setup/configure automatic handover +Handover procedure can be triggered "automatically" by the serving eNB of +the UE. It is also known as the source eNB in the handover procedure. In +order to control when the handover procedure is initiated, you can configure +the parameters of the handover algorithm in your simulation program +through the ns-3 attributes of the eNB RRC entity:: + Config::SetDefault ("ns3::LteEnbRrc::ServingCellHandoverThreshold", + UintegerValue (30)); + + Config::SetDefault ("ns3::LteEnbRrc::NeighbourCellHandoverOffset", + UintegerValue (1)); + + +The UE measurements are used in the automatic handover algorithm. You can +configure the parameters of the UE measurements in your simulation program +through the ns-3 attributes of the eNB RRC entity. You can set the thresholds +of events A2 and A4:: + + + Config::SetDefault ("ns3::LteEnbRrc::EventA2Threshold", + UintegerValue (32)); + + Config::SetDefault ("ns3::LteEnbRrc::EventA4Threshold", + UintegerValue (2)); + + +You can find more info about events A2 and A4 in Subsections 5.5.4.3 and 5.5.4.5 +of [TS36331]_. + Handover traces ***************