ericssonhistory.com

More documents

Recommendations

Info

Figure 3An example of a cell pattern for a 4/12time and frequency-reuse pattern.though the radio network uses three carriersin a 1/3 frequency-reuse pattern, itachieves an effective 3/9 or 4/12 frequencyreusepattern for the control channels by employingtime groups obtained through thesynchronization of base stations.The three carriers carry data traffic,packet-associated signaling, and packetcommon control signaling according to theGPRS standard with EDGE additions. Thesynchronization of base stations makes itpossible to allocate packet common controlchannels and packet broadcast control channelsin a way that prevents simultaneoustransmission in the cluster. Thus, it createsan effective reuse for control signaling of,say, 3/9 or 4/12. Synchronization is requiredat the symbol level and can be achieved bymeans of global positioning system (GPS)receivers.Each base-station sector is assigned onetime group. A different time group is usedin a neighboring site sector that uses thesame frequency. Figure 3 illustrates the distributionof frequencies and time groupsover cells and sectors.COMPACT includes modifications of allpacket common control channels defined forGPRS, including• COMPACT packet paging channel(CPPCH);• COMPACT packet access-grant channel(CPAGCH);• COMPACT packet random-access channel(CPRACH);• COMPACT packet broadcast channel(CPBCCH); and• packet timing-advance control channel(PTCCH).The packet-data traffic channels (PDTCH)and packet-associated control channels areidentical to those defined for Classic.Different time groups share the same frequency,but split the timeslots for controlsignaling. Figure 4 shows multiframe structuresfor an effective 4/12 frequency-reusepattern. The 52 multiframe structure is illustrated.The time-group division between sitesdoes not affect the timeslots and blocks thatcarry data traffic; that is, the data traffic continuesto employ a 1/3 frequency-reuse pattern.It should be noted, however, thatblocks which coincide with a neighboringsite's control block using another timegroup are not used. In Figure 4, these blocksare shaded. If an effective 3/9 frequencyreusepattern is employed for control signaling,only three time groups are used withcontrol blocks.The number of blocks allocated for CPBCCH and CPCCCH is flexible—from 4 toEricsson Review No. 2, 2000
12 blocks per timeslot in each 52 multiframe."Figure 4 shows a feasible block configuration,where one block is allocated forCPBCCH and three blocks for CPCCCH.A synchronization burst designed forCOMPACT, called the COMPACT SCH,or CSCH, features unique coding of theframe numbers, an indication of time group,and an extended training sequence. Thisburst is transmitted in the last GSM frameof every 52 multiframe. The COMPACTfrequency correction channel (CFCCH) is allocatedin GSM frame 25. The bit patternof the CFCCH differs from the frequencycorrection channel (FCCH) found on thebroadcast control channel (BCCH) carrier inGSM.System performanceGeneral assumptionsThe simulations described in this article assumethat 6.67 TS are available for traffic inthe COMPACT mode (1/3 frequency-reusepattern). This corresponds to four blocks allocatedfor CPBCCH and CPCCCH in aneffective 4/12 frequency-reuse pattern. TheClassic mode has 7 TS available for traffic(4/12 frequency-reuse pattern)—one timeslotis always assigned for broadcast andcommon control. Table 2 summarizes certainbasic characteristics of the two modes.The simulations described share the followingassumptions:• EDGE radio interface with incrementalredundancy.• The channel model used is ETSI typicalurban for 3 kmlh (TU3).• No frequency hopping—minimum deploymentis emphasized and only one carrieris used per sector.• Downlink—due to asymmetrical usage,the downlink is anticipated to be the re-Figure 4A 52 multi-frame structure showing 4 time groups. B(0) shows the position of CPBCCHwhereas C(i) is the position of CPCCCH in block /'.stricting link for packet data. The uplinkperformance is expected to be similar tothat of the downlink.No receiver antenna diversity in the mobileterminal.TABLE 2. SOME BASIC CHARACTERISTICS FOR CLASSIC AND COMPACTClassic Mode• All control and packet traffic channels on200 kHz• 4/12 reuse• 2.4 MHz + guard band• No requirement for synchronized BS• 7 TS available for traffic• Carrier transmits constantlyCOMPACT Mode• All control and packet traffic channels on 200 kHz• 1/3 reuse• 0.6 MHz + guard band• Synchronized BS providing 4/12 reuse forPBCCH, PCCCH, PSCH, PFCCH• 6.67 TS available for traffic• No transmission in idle slotsEricsson Review No. 2, 2000 73
Page 1: Ericsson 2/2000REVIEWTHE TELECOMMUN
Page 4 and 5: ContributorsIn this issueLuis Barri
Page 6 and 7: Ericsson Review is also published o
Page 8 and 9: Evolving from cdmaOne to third-gene
Page 10 and 11: Figure 2Operators Harmonization Agr
Page 12 and 13: more features, and greater reliabil
Page 14 and 15: Figure 7Ericsson's third-generation
Page 16 and 17: Figure 11Ericsson's timeline for ev
Page 18 and 19: Third-generation TDMAChristofer Lin
Page 20 and 21: TABLE 1 MODULATION AND CODING SCHEM
Page 24 and 25: Figure 5Curves illustrating maximum
Page 26 and 27: TABLE 3. DYNAMIC PACKET DATA SIMULA
Page 28 and 29: erage can be achieved in existing c
Page 30 and 31: Business solutions for mobile e-com
Page 32 and 33: Figure 2Comparison of traditional a
Page 34 and 35: BOX B, THE E-COMMERCE TIMELINE1999E
Page 36 and 37: Figure 6Mobile e-Pay end-user servi
Page 38 and 39: Figure 8Access features with push-a
Page 40 and 41: AuthenticationTo verify that end-us
Page 42 and 43: BOX C, MARKET HARMONIZATIONOn Tuesd
Page 44 and 45: Figure 2The footprint of the RBS 22
Page 46 and 47: Communications security in an all-I
Page 48 and 49: BOX B, SYMMETRIC KEY SYSTEMSGood sy
Page 50 and 51: Figure 4Construction of an ESP-prot
Page 52 and 53: Figure 7An X.500 database structure
Page 54 and 55: Figure 9GPRS VPN scenarios.Figure 1
Page 56 and 57: TRADEMARKSRC4 and RC4 are registere
Page 58 and 59: HIPERLAN type 2 for broadband wirel
Page 60 and 61: Figure 3Typical usage of communicat
Page 62 and 63: Figure 6Mapping of higher layer pac
Page 64 and 65: TABLE 1PHYSICAL LAYER MODES OF HIPE
Page 66 and 67: Queen City WaterfrontEMERGING PROJE
Page 68 and 69: TABLE 2. IMPORTANT PARAMETERS FOR N
Page 70: Previous issuesNo. 1,2000IPv6—The

ericssonhistory.com

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?