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5692480e365e21a881d790cc4eaea394 | 45.912 | 6.4.2.1 Voice Capacity | This subclause provides results of system level simulations from [7], [12] evaluating the potential gains in voice capacity when introducing MS receive diversity. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.4.2.1.1 Link to System Mapping | The link-to-system mapping was validated by comparing the actual link simulator to a "mapped link simulator". The "mapped link simulator" read the desired and interfering signal levels from the actual link simulator on every burst and translated them to estimated BEP and FEP with the stage-1 and stage-2 maps. The actua... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.4.2.2 Mixed Voice and HTTP traffic | Voice and HTTP traffic were generated in a static simulation in accordance with the system configuration description in table 17 and the HTTP traffic model in table 18. The HTTP traffic model is similar to that in [27], with minor changes. A dedicated 32 kbps backhaul resource was assumed for each user, and as a conseq... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.5 Impacts to the Mobile Station | MS receiver diversity has significant impacts to the MS design. The additional antenna and corresponding RF module is likely to increase the size and thus also the cost of the MS. Assuming a parallel receiver structure, MS Diversity can in terms of signal processing be considered as somewhat comparable to twice the com... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.6 Impacts to the BSS | The introduction of MS receiver diversity is likely to require the optimisation of BSS algorithms such as link adaptation and power control. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.7 Impacts to the Core Network | As with SAIC/DARP it is desirable that the network is able to take the improvement in link level performance into account. That is, it should be possible for the MS to signal its capabilities to the network. This could be implemented as a DARP phase 2.
The network should be able to signal the MS how to use the dual rec... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.8 Impacts to the Specification | As was the case with SAIC/DARP, MS receiver diversity can be implemented with limited impacts to the 3GPP specifications.
Table 19: Impacted 3GPP specifications
Specification
Description
3GPP TS 45.005
Radio transmission and reception
3GPP TS 24.008
Mobile radio interface Layer 3 specification; Core network protocols; ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 6.9 References | [1] 3GPP TR 45.903: "Feasibility study on Single Antenna Interference Cancellation (SAIC) for GSM networks (Release 6)".
[2] 3GPP TS 25.101: "User Equipment (UE) radio transmission and reception (FDD) (Release 6)".
[3] IEEE Journal on Selected Areas in Communications, Vol. 20, No., 6 August 2002: "A Stochastic MIMO Rad... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7 Dual-carrier and multi-carrier | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.1 Introduction | Multi-carrier GERAN is a performance-enhancing feature aimed at improving peak and average user throughput, increase trunking gain, and to reduce latency. Currently, the theoretical peak data rate of EGPRS is 473.6 kbps. In a real network, bit rates in the order of 100 kb/s to 200 kb/s are feasible on four timeslots. W... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.2 Concept description | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.2.1 Basic concept | Multi-carrier GERAN means that multiple GERAN carriers on independent carrier frequencies (or MAIO:s in the frequency hopping case) are received or are transmitted by the same terminal. A straightforward solution would be to split the data flow of one user onto multiple carriers below RLC/MAC, reusing the current physi... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.3 Modelling assumptions and requirements | There are no special requirements for the modelling of the multi-carrier concept. The same principles as with EGPRS can be used. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4 Performance characterization | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.1 Peak data rates | The peak data rates for EGPRS for different number of carriers are shown in table 20. The increase in average data rate is also proportional to the number of carriers. Since there are also some additional degrees of freedom in the channel allocation and link adaptation (trunking gain), the improvement can be somewhat l... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.2 Window size limited TCP throughput | The high latency is a potential problem for the transport layer protocol. In particular, the throughput and RTT should satisfy the "throughput x RTT = TCP window size" limit, which gives the maximum throughput for a given TCP round trip delay and TCP window size. This relation is illustrated in figure 22, which shows t... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.3 Error-limited TCP throughput | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.3.1 Introduction | The TCP throughput may also be limited by the segment error rate and by the delay. This is generally referred to as the error-limited TCP throughput. In this subclause, the performance of TCP is considered as not limited by the TCP window. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.3.2 TCP modelling | The error-limited TCP throughput has been analyzed in the literature, and is modelled by the following empiric formula (see [1] in clause 2):
Where the following parameters are defined.
Table 21: TCP modelling parameters
Parameters
Description
MSS
IP segment size (bits)
RTT
Round-trip time
T0
Timeout (assumed = 5 * RTT... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.3.3 Multi-carrier GERAN modelling | Air Interface
The air interface peak data rate for Multi-carrier GERAN has been computed as the simple multiplication of the per-carrier peak data rate times the number of carriers. Two cases have been considered: the ideal case of 8 allocated slots per carriers, and the more realistic case of 4 allocated slots per car... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.4.3.4 Results | The plots provided in annex A show how the error-limited TCP throughput may turn into a performance upper bound, no matter how many carriers are combined for MC GERAN.
When the two curves (i.e. the air interface peak data rate and the TCP error-limited throughput) cross, it means that the increase of air interface peak... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5 Impacts to protocol architecture | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.1 Physical Layer | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.1.1 Modulation, multiplexing, and radio transmission | No changes are expected. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.1.2 Channel coding | The channel coding of the basic multi-carrier concept (without inter-carrier interleaving) can be carried out with the existing modulation and coding schemes of EGPRS (MCS 1-9). |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.1.3 Mobile capabilities | The multi-carrier capability could be defined either as a simple indication, or as a set of dedicated multi-slot classes for multi-carrier. The first option implies that the multi-carrier mobile would act like a time-slot multiplier, the time and frequency domains being fully independent from each other. With the latte... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.1.4 Channel quality measurements | The current EGPRS mobiles are required to support the reporting of four different types of measurements: MEAN_BEP measurements, CV_BEP measurements, interference measurements (CH), and slot-wise MEAN_BEP measurements (MEAN_BEP_TS).
For multi-carrier mobiles, the MEAN_BEP and CV_BEP reporting could be done either in a ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2 RLC/MAC | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.1 Multiplexing with legacy MSs | The same principles apply for multiplexing on multiple carriers as on a single carrier. There is no radio resource segregation: provided that the intra-carrier interleaving is not used, the multi-carrier data flows can be multiplexed with the single carrier data flows on the same timeslots. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.2 Multiplexing data on multiple carriers | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.2.1 Simultaneous transmission over multiple carriers | The most straightforward way to allow for transmission over multiple carriers is to allow a TBF to span over two carriers, like it would span over several timeslots. The same TFI can be used over all carriers (even a different TFI could be used per carrier, if deemed necessary). However RLC limitations (window size) ma... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.2.2 Time-divided transmission over multiple carriers | Uplink transmission is ruled by dynamic allocation i.e. through USF. RRBP is also used for reserving uplink radio blocks for transmission of RLC/MAC control blocks by the mobile station.
With multi-carrier on the downlink, receiving over multiple carriers brings about the transmission over multiple carriers (distinctiv... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.3 Segmentation / reassembly | Reassembly in multi-carrier case is comparable to reassembly in multi-slot case; additional timeslots are monitored on the allocated carriers. Note that additional requirement is put on mobile station side given all carriers have to be monitored simultaneously: the MS has to monitor all allocated timeslots on both carr... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.4 RLC window size | The RLC window size needs to cope with the maximum amount of outstanding RLC data blocks within RLC roundtrip time. Otherwise too small a window starts to limit the peak throughput. This amount is given as follows when N carriers, all timeslots (8 per carrier) and two RLC data blocks per radio block (20ms) are used:
(4... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.5 Incremental redundancy | In order to retain full retransmission flexibility, the incremental redundancy (IR) within all carriers should be supported. This feature would be mandatory for MS and optional for BSS. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.6 Link adaptation | Link quality measurements are reported in acknowledgement message, upon request from the network. As described in subclause 7.5.1.4, it would be beneficial to report the measurements separately for all carriers. In order to avoid reporting a large amount of measurement data in a single EGPRS channel quality report, the... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.2.7 Signalling | The allocation of multiple carriers needs to be supported through signalling (assignment, reconfiguration of resources) between the network and the mobile station. This will increase the likelihood for segmentation of the corresponding RLC/MAC control messages. Note however that extended RLC/MAC control message segment... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.5.3 Higher layers | The support of multi-carrier by the mobile station needs to be indicated with sufficient flexibility as part of the mobile station's capabilities.
It is assumed that the indication (broadcast) of the network support for multi-carrier is not needed, given no need is identified for the MS to request a multi-carrier trans... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6 Downlink Dual Carrier | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.1 Overall throughput considerations for dual carrier on the downlink | A preliminary assessment is that multi-carrier is most feasible for the downlink. Whether is can be applied also to the uplink depends on MS implementation constraints which are studied in further subclauses. However, even by just allowing multi-carrier reception in the downlink, it is possible to increase the uplink d... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.2 Inter-carrier interleaving | This is investigated in clause 10. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.3 Dual-carrier diversity | The same baseband signal is transmitted over two carrier frequencies. At the receiver, the signals on the two carriers are converted to baseband, providing two diversity branches. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.4 Adaptation between dual carrier and receive diversity | In many cases, the dual-carrier on the downlink would be deployed in a network that already supports the MS RX diversity. In order to guarantee the most optimal utilization of network resources, it should be possible to switch between the two modes. The performance evaluation of this scheme is studied in clause 12. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5 Impacts to the mobile station | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.1 Multiple narrowband receivers | There are different options for the implementation of the multi-carrier RF in the MS receiver. One option, suitable mainly for a small number of carriers (e.g. dual-carrier), is to have separate receiver chains for each carrier. This means that the multi-carrier terminals exploit an architecture, where the receiver bra... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.2 Wideband receiver | Another option, mainly suitable for a larger number of carriers, is a wideband receiver. This option may have additional impacts to the network since it may be necessary to limit the carrier spacing of the multi-carrier assignment. Also, blocking requirements may be an issue. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.2.1 Larger bandwidth | Simultaneous reception of n carriers would obviously imply larger bandwidth for the receiver front-end. This is in itself a source for additional complexity. However, it is difficult to assess such complexity without a clear requirement on the width of the wideband front-end.
Given that most, if not all, of the GERAN c... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.2.2 Channel separation | As mentioned in a previous contribution (see [2] in subclause 7.12), channel separation may be performed with known techniques, e.g. digitally.
However, it is important to note that the complexity of digital channel separation is also dependent on the width of the wideband receiver, which shall maintain the same C/N ap... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.2.3 Blocking requirements | Blocking requirements are described in 3GPP TS 45.005.
In-band blocking requirements are obviously defined assuming that there is one "useful" carrier, and the receiver has to fulfil some blocking requirements towards all frequencies higher and lower than the "useful" carrier.
This can be illustrated pictorially by fig... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.6.5.3 Baseband | On baseband, the receiver is required to process multiple RLC/MAC blocks per time slot. This requirement may have an impact on meeting the timing requirements of baseband processing. The baseband complexity is directly proportional to the number of carriers.
The support for multi-carrier incremental redundancy may have... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7 Uplink Dual Carrier | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.1 Concept description for dual carrier on the uplink | Dual Carrier in the Uplink shall be operated in such a way that it is compatible with legacy network operation. Multiplexing with existing GSM/EDGE bearers and a minimized BSS impact should therefore be ensured according to the objectives of the Feasibility Study.
It may be applied on non-hopping carriers as well as on... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.2 Mobile Station Capabilities | The mobile station is required to include a second transmitter for Dual Carrier in the Uplink. It is also possible that a second transmit antenna at the mobile station might be necessary in order to avoid additional insertion loss. The impacts on the mobile station are described in subclause 7.6.1. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.3 Increase in Peak Data Rate | The performance gain in peak data rate can be up to 100 % for dual carrier. Specifically, in interference limited scenarios which are typical for high traffic densities, it is expected that dual carrier leads to a doubled average data rate on UL. In sensitivity limited scenarios the average data rate may be doubled for... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.4 Decrease of Latency | The main impact on latency would be the decrease in delays due to the higher bit rates that would be possible with dual carrier in the uplink. However, a reduced TTI could also be implemented, bringing additional improvements for the latency of small amounts of data. By using dual carrier on uplink with inter carrier i... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.5 Impact on Cell Coverage | The cell coverage is dependent on the propagation conditions, the cell overlap and the required Eb/No for a particular service.
At cell edges when 8PSK can not be supported, the GMSK transmission can be used on two carriers with appropriate back off as pointed out in subclause 7.7.1 and thus data rates even at the cell... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6 Impacts to the mobile station | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.1 RF Architecture options | Dual carrier requires duplication of the whole TX path e.g. from DSP to PA including own VCOs for both carriers. The architecture for a Dual Carrier RF in UL could be based on the following options:
A) Combined single carrier transmitters with single antenna.
B) Single carrier transmitters with separate antennas.
C) Wi... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2 Evaluation of option A and option B (Taken from GP-060188) | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.1 Combining loss | With single antenna option A) a combiner is needed. Insertion loss of hybrid combiner is about 3 dB to 3.5dB, and that loss should be included to the RF loss budget in the architecture option A). |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.2 Intermodulation (IM) | Intermodulation products, due to various mechanisms are a challenge for systems with multiple carriers. Good isolation between transmitters is essential to avoid IM products. In this subclause, so called reverse intermodulation is assumed to have highest IM contribution.
Typically 3rd order IM results are dominating an... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.2.1 Reverse Inter Modulation (RIM) | Reverse intermodulation products are generated in the transmitter by wanted signal and external signal coming to transmitter's output port e.g. from an adjacent transmitter. Typically the reverse IM is tested at -40 dBc level of external signal thereby indicating needed level of isolation between transmitters. With tha... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.2.1.1 Isolators | This ~30 dB isolation requirement between transmitters should be taken into account with both architecture options A) and B). It would mean e.g. to use isolators at the transmitter output. Isolators are narrow band devices, thus multiband MS should have separate isolators on lower and upper bands. Furthermore 2 to 4 is... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.2.1.2 RX band rejection of TX filter | Assuming IM level of -70dBc and spurious requirement of < -79 dBm at 900 RX band and assuming also that number of allowances (5) up to -39 dBm is exceeded with frequency hopping, the TX filtering of dual carrier transmitter with 27 dBm output should have ~37 dB rejection at RX band. This may not be obtained by the exis... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.3 Decreased efficiency due to reduced output power | The efficiency of a transistor gets smaller when a smaller part of the supply voltage is used for the actual signal. Thus the efficiency of the PA is reduced due back-off. It's assumed that dual carrier transmitter should not have higher total transmitter power than single carrier transmitter. This will introduce 3dB b... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.2.4 Peak power consumption | The efficiency of MS transmitter has high impact on the MS design, e.g. in size and battery life. It needs to be noted that the whole TX path need to be duplicated, and not only PA, which may further increase power consumption and also in idle mode. In table 24 peak power consumption for options A) and B) are compared.... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.3 Evaluation of option B (Taken from GP-052723) | For uplink transmission the dual carrier approach requires the implementation of one further transmitter in the MS. This will cause an increase both of thermal power and battery peak current consumption, if appropriate countermeasures are not followed.
Due to the prerequisite of independent frequency hopping on both ca... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.3.1 PA and battery considerations | Current PA technologies are not yet optimised for dual carrier transmission. A second state-of-the-art power amplifier will double peak current consumption in the mobile. Even if a power amplifier is backed off by 3 dB, the power consumption is decreased by only about 25 %. Hence if two power amplifiers are operated wi... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.3.2 Antenna considerations | For dual carrier transmission in the UL it is required to implement a second transmit antenna at the MS in order to isolate both transmitters and at the same time avoid an insertion loss due to a combiner. None of the antennas should be covered by the user's hand. This can be achieved e.g. by the combination of a conve... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4 Evaluation of option C (Taken from GP-060609) | This subclause presents a third implementation option for the uplink, with the dual carrier generation at baseband utilizing a common PA and transmitter antenna. Some possibilities such as introducing restrictions on the frequency allocation are investigated to improve implementation feasibility. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.1 Concept Description | Possible architectures based on a single TX path are proposed and illustrated in figures 58 and 59. These possibilities avoid the drawbacks associated with fully duplicated TX paths.
Figure 58: Architecture with separate modulators and common wideband transmitter
For the architecture in figure 58, the bandpass filter b... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.2 System Impacts | The uplink "digital" dual carrier proposals only affect part of the baseband and the TX chain. Therefore, impacts to higher layers (RLC/MAC) are very similar to the generic downlink dual carrier architecture and are not addressed. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.3 Output Power | The output power generated by the single PA is divided between the two carriers. Depending on the frequency separation of the two carriers the fading profile of the associated radio channels will be more or less identical. However the interference profile seen by each of the carriers could vary significantly. The abili... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.4 Power Efficiency | The peak to average power ratio (PAR) of a single 8-PSK carrier is approximately 3.2 dB. Adding a second carrier increases the PAR to approximately 6.2 dB. Therefore, in digital dual carrier mode with a single PA and two 8-PSK modulated carriers, the power level into the PA would need to be 3 dB lower than in the singl... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.5 Coverage | The increased back-off to compensate for the higher PAR can potentially impact coverage. Applying the reduction of MS maximum output power specified in 3GPP TS 45.005 to an uplink dual carrier transmission, no significant changes to cell coverage is expected compared to a single-carrier multislot transmission with the ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.6 Frequency Planning, Frequency Hopping | The carrier spacing for uplink digital dual carrier is assumed to be fixed within each cell. For non-hopping scenarios this does not impose any restrictions other than that both carriers have to be available.
In the case of frequency hopping, the carrier spacing has to be preserved, i.e. the two carriers have to hop in... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.4.7 Intermodulation Interference | Restricting the maximum permitted frequency distance between the carriers makes it possible to reuse the technique and experience from WCDMA transmitters. This may make it possible to reduce the unwanted intermodulation products to acceptable levels, provided that these products fall into the active bandwidth of the er... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.5 Observations on the implementation options (Taken GP-060732) | The three possible implementation approaches described in subclause 7.7.6.1 can be summarised as follows:
a) dual, single-carrier PA's, driving either one of the two antennas, post-combining;
b) dual, single-carrier PA's, with each PA coupled to one of two antennas; or
c) a single wideband PA supporting dual carriers, ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.5.1 Base Station Architecture Impact | One of the advantages of DCU is the potential for low impact on the BTS hardware, and constrained DCU can be viewed similarly. One important consideration, however, is the effect of a continuous adjacent companion carrier on achievable per-carrier receiver CINR, and the corresponding impact on reception of logical chan... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.5.2 Dual Carrier Interleaving and Constrained Dual Carrier Uplink | Constraining uplink dual-carriers to be immediately adjacent in frequency also has the potential to reduce any additional frequency diversity gain achieved through intra-burst interleaving beyond that attributable to conventional frequency hopping.
Table 27 provides guidance on Eb/N0 values (reference to the coded bit ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.6.5.3 System Frequency Re-Use Impact | The availability of sufficiently large cell allocations to support constrained DCU re-use patterns of the same dimension as traditional (3,3,9) or (4,3,12) BCCH patterns may be unlikely except in deployments with unusually rich resources. Accordingly, use of CDCU may often be limited to frequency hopping pairs. In this... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7 Impact of reduced MS power | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.1 Introduction | The major problem of the uplink DC is the increased power consumption, which is a direct consequence of the simultaneous transmission on two uplink carriers. To maintain the same total transmitted power, both transmitters of a dual-carrier terminal need to be backed off by 3 dB. Unfortunately, the backoff decreases the... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.2 Simulation setup | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.2.1 Network | Two network scenarios are considered:
- Network 1: Interference-limited.
- Network 2: Coverage-limited.
The main parameters of these scenarios are listed in table 28.
Table 28: Network scenarios
Parameter
Interference limited scenario
Coverage limited scenario
Site separation
2.25 km
12 km
Bandwidth
2.4 MHz (BCCH), 2.4... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.2.2 Dual-carrier Deployment | Two dual-carrier deployment scenarios are considered:
- Deployment scenario 1: BCCH / Hopping.
- Deployment scenario 2: Hopping / Hopping.
In the first case it is assumed that the PS traffic originally resides on the BCCH TRX. When deploying dual-carrier, one hopping TRX is reserved for the dual-carrier traffic. In the... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.2.3 Backoff | Three different backoff scenarios are considered (powers relative to 33 dBm):
- Reference: 0 dB backoff for GMSK, 6 dB backoff for 8PSK.
- Backoff case 1: 3 dB backoff for GMSK, 6 dB backoff for 8PSK.
- Backoff case 2: 3 dB backoff for GMSK, 9 dB backoff for 8PSK.
In the first case (backoff case 1), the GMSK power is b... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.3 Results | This subclause summarizes the results from the dynamic network simulations. The throughput is given as net session throughput per user, which means that only the times when the mobile has had a TBF or it has been in the TBF establishment procedure are included. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.3.1 Coverage limited network | The results from the coverage limited simulations (BCCH/hopping deployment scenario) are shown in figure 66.
Figure 66: Dual-carrier UL performance in the coverage limited network
As can be seen from the results, there is no performance loss due to the GMSK backoff. This is due to the fact that in this scenario only a ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.7.3.2 Interference limited network | The results from the interference limited simulations (hopping/hopping deployment scenario) are shown in figure 67.
Figure 67: Dual-carrier UL performance in the interference limited network
As can be seen, the impact of the additional backoff is less severe in an interference-limited environment. This is largely due t... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8 Modified Concept for Dual Carrier in the Uplink | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.1 Introduction | It is stated in subclause 7.7.6.2 that additional TX filtering is required in the TX paths of the mobile station to counteract the generation of 3rd order intermodulation products, falling into the RX band. This filter is estimated to have at least a 37 dB RX band rejection, which is judged difficult for a small MS. In... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.2 Modified Concept | In order to avoid such interference injection into RX band of the mobile station, the dual carrier in UL concept is modified below.
In fact most relevant are 3rd order intermodulation products of the form 2*f1 - f2 and 2*f2 - f1 as well as 5th order intermodulation products of the form 3*f1 - 2*f2 and 3*f2 - 2*f1 . The... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.3 Intermodulation measurements | In this subclause, measurements related to the most relevant impact from 3rd order and 5th order intermodulation products due to dual carrier implementation are presented.
Note that IM products due to near-far scenarios have not been considered. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.3.1 Measurement setup | All the measurements are made with an EDGE mobile station module. Three different setups shown below are used for the measurements. The interference signal is generated using a separate signal generator. At this point a continuous wave signal is used to simulate the interference signal from the other antenna. An isolat... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.3.2 Analysis of IM3 measurements | The measurements shown in figure 69 are made using setup 1. IM3 occurs at:
2 x 914.8 - 880.2 = 949.4 MHz
Figure 69: Measurements for IM3 in GMSK mode - f1 at 32 dBm - Setup 1
It can be seen from the figure that in order to satisfy the requirement for the IM3 falling in uplink band (i.e. < -36 dBm), the power of the int... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.3.3 Analysis of IM5 measurements | IM5 is investigated with both setup 2 and setup 3.
Figure 72: IM5 Measurements for 8-PSK 27 dBm mode - Setup 2
For IM5, it is assumed that a level of up to -79 dBm is allowed (downlink band requirements). Since at approximately ‑2 dBm interferer level there is an IM5 of approximately -76 dBm, we can assume that up to -... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.3.4 Analysis of IM2 | There were concerns that there could be some impact of IM2 products from GSM900 band falling into the DCS1800 downlink band. Hence the impact of IM2 was also investigated. Setup 3 is reused for this purpose. Figure 74 shows the measurement results.
Figure 74: IM2 measurement for 8-PSK 27 dBm mode - Setup 3
At an interf... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.4 Dual carrier architecture with minimal single-carrier operation impact | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 7.7.8.4.1 Introduction | In subclause 7.7.8.4, measurement results for uplink dual carrier were shown and it has been shown that to satisfy the requirements for emissions in TX and RX bands two isolators are needed in series in the TX paths of an uplink dual carrier mobile with two PAs. In this subclause, a possible architecture for the new du... |
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