Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn<\/p>\n\n\n\n
H\u1ec7 th\u1ed1ng m\u1ea1ng di \u0111\u1ed9ng ng\u00e0y c\u00e0ng ph\u00e1t tri\u1ec3n v\u1edbi s\u1ef1 xu\u1ea5t hi\u1ec7n ng\u00e0y c\u00e0ng nhi\u1ec1u ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0 GSM, WCDMA, CDMA. Tuy nhi\u00ean kh\u00f4ng ph\u1ea3i ai n\u1eafm ch\u1eafc WCDMA, CDMA hay GSM l\u00e0 g\u00ec c\u0169ng nh\u01b0 c\u00e1c th\u00f4ng tin v\u1ec1 h\u1ec7 th\u1ed1ng m\u1ea1ng to\u00e0n c\u1ea7u n\u00e0y v\u00e0 th\u01b0\u1eddng xuy\u00ean x\u1ea3y ra t\u00ecnh tr\u1ea1ng nh\u1ea7m l\u1eabn v\u1ec1 ch\u1ee9c n\u0103ng, \u00fd ngh\u0129a c\u1ee7a ch\u00fang. V\u1eady n\u00ean, trong b\u00e0i vi\u1ebft h\u00f4m nay, Vietlearn s\u1ebd cung c\u1ea5p cho b\u1ea1n nh\u1eefng th\u00f4ng tin chi ti\u1ebft nh\u1ea5t.<\/p>\n\n\n\n
GSM l\u00e0 g\u00ec? T\u1ed5ng quan c\u00e1c th\u00f4ng tin<\/p>\n\n\n\n
GSM l\u00e0 t\u00ean vi\u1ebft t\u1eaft c\u1ee7a c\u1ee5m t\u1eeb ti\u1ebfng anh Global System for Mobile Communication. C\u00f3 ngh\u0129a l\u00e0 h\u1ec7 th\u1ed1ng to\u00e0n c\u1ea7u d\u00e0nh ri\u00eang cho vi\u1ec7c li\u00ean l\u1ea1c di \u0111\u1ed9ng. M\u1ea1ng GSM \u0111\u01b0\u1ee3c h\u01a1n 2 t\u1ef7 ng\u01b0\u1eddi tr\u00ean 212 qu\u1ed1c gia v\u00e0 v\u00f9ng l\u00e3nh th\u1ed5 l\u1ef1a ch\u1ecdn s\u1eed d\u1ee5ng. C\u00e1c m\u1ea1ng th\u00f4ng tin di \u0111\u1ed9ng GSM c\u00f3 th\u1ec3 chuy\u1ec3n v\u00f9ng (roaming) v\u1edbi nhau. Do \u0111\u00f3 nh\u1eefng \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng GSM c\u1ee7a c\u00e1c m\u1ea1ng GSM kh\u00e1c nhau c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u01b0\u1ee3c \u1edf nhi\u1ec1u n\u01a1i tr\u00ean th\u1ebf gi\u1edbi.<\/p>\n\n\n\n
M\u1ea1ng GSM l\u00e0 chu\u1ea9n ph\u1ed5 bi\u1ebfn nh\u1ea5t cho \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng tr\u00ean to\u00e0n th\u1ebf gi\u1edbi. Kh\u1ea3 n\u0103ng ph\u1ee7 s\u00f3ng l\u1edbn cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng c\u1ee7a m\u00ecnh \u1edf b\u1ea5t c\u1ee9 n\u01a1i \u0111\u00e2u tr\u00ean th\u1ebf gi\u1edbi. GSM kh\u00e1c v\u1edbi c\u00e1c chu\u1ea9n ti\u1ec1n th\u00e2n v\u1ec1 c\u1ea3 t\u00edn hi\u1ec7u, t\u1ed1c \u0111\u1ed9 c\u0169ng nh\u01b0 ch\u1ea5t l\u01b0\u1ee3ng cu\u1ed9c g\u1ecdi. N\u00f3 \u0111\u01b0\u1ee3c xem nh\u01b0 l\u00e0 m\u1ed9t h\u1ec7 th\u1ed1ng m\u1ea1ng th\u00f4ng tin di \u0111\u1ed9ng th\u1ee9 hai.<\/p>\n\n\n\n
C\u1ea5u tr\u00fac m\u1ea1ng GSM<\/p>\n\n\n\n
C\u1ea5u tr\u00fac m\u1ea1ng GSM \u0111\u01b0\u1ee3c chia l\u00e0m 3 th\u00e0nh ph\u1ea7n:<\/p>\n\n\n\n
Tr\u1ea1m di \u0111\u1ed9ng (mobile station) \u0111\u01b0\u1ee3c ng\u01b0\u1eddi th\u00ea bao mang theo<\/p>\n\n\n\n
H\u1ec7 th\u1ed1ng tr\u1ea1m g\u1ed1c (Base station subsystem) \u0111i\u1ec1u khi\u1ec3n k\u1ebft n\u1ed1i v\u00f4 tuy\u1ebfn v\u1edbi tr\u1ea1m di \u0111\u1ed9ng<\/p>\n\n\n\n
H\u1ec7 th\u1ed1ng m\u1ea1ng (Network subsystem).<\/p>\n\n\n\n
B\u1ed9 ph\u1eadn ch\u00ednh \u0111\u00f3 ch\u00ednh l\u00e0 trung t\u00e2m chuy\u1ec3n m\u1ea1ch d\u1ecbch v\u1ee5 di \u0111\u1ed9ng MSC, th\u1ef1c hi\u1ec7n vi\u1ec7c chuy\u1ec3n m\u1ea1ch cu\u1ed9c g\u1ecdi gi\u1eefa c\u00e1c thu\u00ea bao di \u0111\u1ed9ng v\u00e0 gi\u1eefa c\u00e1c thu\u00ea bao di \u0111\u1ed9ng v\u1edbi thu\u00ea bao c\u1ed1 \u0111\u1ecbnh. MSC c\u0169ng th\u1ef1c hi\u1ec7n ch\u1ee9c n\u0103ng qu\u1ea3n l\u00fd di \u0111\u1ed9ng.<\/p>\n\n\n\n
Tr\u1ea1m di \u0111\u1ed9ng MS g\u1ed3m \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng v\u00e0 m\u1ed9t th\u1ebb x\u00e1c th\u1ef1c thu\u00ea bao (sim). Sim cung c\u1ea5p kh\u1ea3 n\u0103ng di \u0111\u1ed9ng c\u00e1 nh\u00e2n, v\u00ec th\u1ebf ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 l\u1eafp sim v\u00e0o b\u1ea5t c\u1ee9 m\u00e1y \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng GSM n\u00e0o \u0111\u1ec3 truy c\u1eadp c\u00e1c d\u1ecbch v\u1ee5 \u0111\u00e3 \u0111\u0103ng k\u00fd. M\u1ed7i m\u1ed9t \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng \u0111\u01b0\u1ee3c ph\u00e2n bi\u1ec7t b\u1edfi m\u1ed9t s\u1ed1 nh\u1eadn d\u1ea1ng \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng IMEI.<\/p>\n\n\n\n
H\u1ec7 th\u1ed1ng tr\u1ea1m g\u1ed1c g\u1ed3m 2 ph\u1ea7n \u0111\u00f3 l\u00e0 tr\u1ea1m thu ph\u00e1t g\u1ed1c v\u00e0 tr\u1ea1m \u0111i\u1ec1u khi\u1ec3n g\u1ed1c. Hai ph\u1ea7n n\u00e0y giao ti\u1ebfp v\u1edbi nhau qua giao di\u1ec7n Abis, cho ph\u00e9p c\u00e1c thi\u1ebft b\u1ecb c\u1ee7a nh\u00e0 cung c\u1ea5p kh\u00e1c nhau \u0111\u1ec3 c\u00f3 th\u1ec3 \u201cb\u1eaft tay\u201d nhau \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n
Tr\u1ea1m thu ph\u00e1t g\u1ed1c c\u00f3 b\u1ed9 thu ph\u00e1t v\u00f4 tuy\u1ebfn x\u00e1c \u0111\u1ecbnh l\u00e0 m\u1ed9t \u00f4 (cell) v\u00e0 thi\u1ebft l\u1eadp giao th\u1ee9c k\u1ebft n\u1ed1i v\u00f4 tuy\u1ebfn v\u1edbi tr\u1ea1m di \u0111\u1ed9ng. Trong m\u1ed9t khu \u0111\u00f4 th\u1ecb l\u1edbn th\u00ec s\u1ed1 l\u01b0\u1ee3ng BTS l\u1eafp \u0111\u1eb7t s\u1ebd r\u1ea5t l\u1edbn n\u00ean y\u00eau c\u1ea7u \u0111\u1ed1i v\u1edbi tr\u1ea1m BTS l\u00e0 ch\u1eafc ch\u1eafn, \u1ed5n \u0111\u1ecbnh v\u00e0 c\u00f3 th\u1ec3 di chuy\u1ec3n \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n
Tr\u1ea1m \u0111i\u1ec1u khi\u1ec3n g\u1ed1c l\u00e0 n\u01a1i qu\u1ea3n l\u00fd t\u00e0i nguy\u00ean v\u00f4 tuy\u1ebfn cho m\u1ed9t ho\u1eb7c v\u00e0i tr\u1ea1m BTS. N\u00f3 th\u1ef1c hi\u1ec7n ch\u1ee9c n\u0103ng thi\u1ebft l\u1eadp k\u00eanh v\u00f4 tuy\u1ebfn, ph\u00e2n b\u1ed5 t\u1ea7n s\u1ed1 v\u00e0 chuy\u1ec3n v\u00f9ng. BSC l\u00e0 n\u01a1i k\u1ebft n\u1ed1i gi\u1eefa tr\u1ea1m di \u0111\u1ed9ng v\u00e0 t\u1ed5ng \u0111\u00e0i chuy\u1ec3n m\u1ea1ch di \u0111\u1ed9ng MSC.<\/p>\n\n\n\n
Th\u00e0nh ph\u1ea7n trung t\u00e2m c\u1ee7a h\u1ec7 th\u1ed1ng m\u1ea1ng \u0111\u00f3 ch\u00ednh l\u00e0 t\u1ed5ng \u0111\u00e0i chuy\u1ec3n m\u1ea1ch di \u0111\u1ed9ng MSC. N\u00f3 ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t t\u1ed5ng \u0111\u00e0i chuy\u1ec3n m\u1ea1ch PSTN ho\u1eb7c ISDN th\u00f4ng th\u01b0\u1eddng, cung c\u1ea5p t\u1ea5t c\u1ea3 c\u00e1c ch\u1ee9c n\u0103ng c\u1ea7n thi\u1ebft \u0111\u1ed1i v\u1edbi m\u1ed9t thu\u00ea bao di \u0111\u1ed9ng nh\u01b0: \u0111\u0103ng k\u00fd, x\u00e1c th\u1ef1c, c\u1eadp nh\u1eadt v\u1ecb tr\u00ed, chuy\u1ec3n v\u00f9ng v\u00e0 \u0111\u1ecbnh tuy\u1ebfn cu\u1ed9c g\u1ecdi t\u1edbi m\u1ed9t thu\u00ea bao roaming (chuy\u1ec3n v\u00f9ng). MSC s\u1ebd cung c\u1ea5p k\u1ebft n\u1ed1i \u0111\u1ebfn m\u1ea1ng c\u1ed1 \u0111\u1ecbnh ( PSTN ho\u1eb7c ISDN). \u0110\u1ed3ng th\u1eddi, b\u00e1o hi\u1ec7u gi\u1eefa c\u00e1c th\u00e0nh ph\u1ea7n ch\u1ee9c n\u0103ng c\u00f3 trong h\u1ec7 th\u1ed1ng m\u1ea1ng s\u1eed d\u1ee5ng H\u1ec7 th\u1ed1ng b\u00e1o hi\u1ec7u s\u1ed1 7 (SS7).<\/p>\n\n\n\n
B\u1ed9 ghi \u0111\u1ecba ch\u1ec9 th\u01b0\u1eddng tr\u00fa (HLR) v\u00e0 b\u1ed9 ghi \u0111\u1ecba ch\u1ec9 t\u1ea1m tr\u00fa (VLR) v\u1edbi t\u1ed5ng \u0111\u00e0i chuy\u1ec3n m\u1ea1ch di \u0111\u1ed9ng MSC s\u1ebd cung c\u1ea5p kh\u1ea3 n\u0103ng \u0111\u1ecbnh tuy\u1ebfn cu\u1ed9c g\u1ecdi v\u00e0 roaming \u0111\u1ed1i v\u1edbi GSM. HLR s\u1ebd bao g\u1ed3m t\u1ea5t c\u1ea3 c\u00e1c th\u00f4ng tin qu\u1ea3n tr\u1ecb cho c\u00e1c thu\u00ea bao \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u0103ng k\u00fd c\u1ee7a m\u1ea1ng GSM v\u00e0 v\u1ecb tr\u00ed hi\u1ec7n t\u1ea1i c\u1ee7a thu\u00ea bao. V\u1ecb tr\u00ed c\u1ee7a thu\u00ea bao th\u01b0\u1eddng d\u01b0\u1edbi d\u1ea1ng l\u00e0 \u0111\u1ecba ch\u1ec9 b\u00e1o hi\u1ec7u c\u1ee7a VLR t\u01b0\u01a1ng \u1ee9ng v\u1edbi tr\u1ea1m di \u0111\u1ed9ng. Ch\u1ec9 c\u00f3 m\u1ed9t HLR logic cho to\u00e0n b\u1ed9 h\u1ec7 th\u1ed1ng m\u1ea1ng GSM m\u1eb7c d\u00f9 n\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c tri\u1ec3n khai d\u01b0\u1edbi d\u1ea1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u ph\u00e2n b\u1ed1.<\/p>\n\n\n\n
B\u1ed9 ghi \u0111\u1ecba ch\u1ec9 t\u1ea1m tr\u00fa (VLR) g\u1ed3m c\u00f3 c\u00e1c th\u00f4ng tin qu\u1ea3n tr\u1ecb \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn t\u1eeb HLR, c\u1ea7n thi\u1ebft cho vi\u1ec7c \u0111i\u1ec1u khi\u1ec3n cu\u1ed9c g\u1ecdi v\u00e0 cung c\u1ea5p c\u00e1c d\u1ecbch v\u1ee5 thu\u00ea bao, cho c\u00e1c di \u0111\u1ed9ng \u0111ang \u1edf v\u1ecb tr\u00ed m\u00e0 n\u00f3 qu\u1ea3n l\u00fd. M\u1eb7c d\u00f9, c\u00e1c ch\u1ee9c n\u0103ng n\u00e0y \u0111\u01b0\u1ee3c tri\u1ec3n khai v\u1edbi c\u00e1c thi\u1ebft b\u1ecb \u0111\u1ed9c l\u1eadp nh\u01b0ng c\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t t\u1ed5ng \u0111\u00e0i \u0111\u1ec1u s\u1ebd k\u1ebft h\u1ee3p VLR v\u00e0o MSC. V\u00ec th\u1ebf, vi\u1ec7c \u0111i\u1ec1u khi\u1ec3n c\u00e1c v\u00f9ng \u0111\u1ecba l\u00fd c\u1ee7a MSC v\u1edbi c\u1ee7a VLR s\u1ebd tr\u1edf n\u00ean \u0111\u01a1n gi\u1ea3n khi \u0111\u01b0\u1ee3c b\u00e1o hi\u1ec7u.<\/p>\n\n\n\n
C\u00f3 hai b\u1ed9 ghi kh\u00e1c \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho m\u1ee5c \u0111\u00edch an ninh v\u00e0 x\u00e1c th\u1ef1c. B\u1ed9 ghi nh\u1eadn d\u1ea1ng thi\u1ebft b\u1ecb (EIR) l\u00e0 m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u ch\u1ee9a danh s\u00e1ch c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c m\u00e1y \u0111i\u1ec7n di \u0111\u1ed9ng h\u1ee3p l\u1ec7 v\u1edbi m\u1ed7i m\u00e1y n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c ph\u00e2n bi\u1ec7t b\u1edfi s\u1ed1 IMEI. M\u1ed9t IMEI b\u1ecb \u0111\u00e1nh d\u1ea5u th\u00ec s\u1ebd l\u00e0 kh\u00f4ng h\u1ee3p l\u1ec7 n\u1ebfu n\u00f3 \u0111\u01b0\u1ee3c b\u00e1o l\u00e0 m\u1ea5t c\u1eafp ho\u1eb7c l\u00e0 kh\u00f4ng t\u01b0\u01a1ng th\u00edch. Trung t\u00e2m x\u00e1c th\u1ef1c (AuC) ch\u00ednh l\u00e0 m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u b\u1ea3o v\u1ec7 ch\u1ee9a b\u1ea3n sao c\u1ee7a c\u00e1c kho\u00e1 b\u1ea3o m\u1eadt c\u1ee7a card SIM, \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 x\u00e1c th\u1ef1c v\u00e0 m\u00e3 ho\u00e1 tr\u00ean k\u00eanh v\u00f4 tuy\u1ebfn.<\/p>\n\n\n\n
Ch\u1ee9c n\u0103ng c\u1ee7a GSM l\u00e0 g\u00ec?<\/p>\n\n\n\n
GSM l\u00e0 m\u1ea1ng chu\u1ea9n ph\u1ed5 bi\u1ebfn nh\u1ea5t cho \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng (\u0110TD\u0110) tr\u00ean th\u1ebf gi\u1edbi. C\u00e1c d\u00f2ng \u0111i\u1ec7n tho\u1ea1i nh\u01b0 Samsung, iphone, oppo,\u2026 \u0111\u1ec1u s\u1eed d\u1ee5ng chu\u1ea9n m\u1ea1ng n\u00e0y.<\/p>\n\n\n\n
Kh\u1ea3 n\u0103ng ph\u1ee7 s\u00f3ng r\u1ed9ng kh\u1eafp n\u01a1i gi\u00fap m\u1ea1ng GSM tr\u1edf n\u00ean ph\u1ed5 bi\u1ebfn tr\u00ean th\u1ebf gi\u1edbi, cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0110TD\u0110 c\u1ee7a h\u1ecd \u1edf nhi\u1ec1u v\u00f9ng tr\u00ean th\u1ebf gi\u1edbi.<\/p>\n\n\n\n
N\u00f3 \u0111\u01b0\u1ee3c coi l\u00e0 m\u1ed9t h\u1ec7 th\u1ed1ng m\u1ea1ng th\u00f4ng tin di \u0111\u1ed9ng th\u1ebf h\u1ec7 th\u1ee9 hai (second generation, 2G).<\/p>\n\n\n\n
GSM l\u00e0 m\u1ed9t chu\u1ea9n m\u1edf, \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n b\u1edfi 3rd Generation Partnership Project (3GPP).<\/p>\n\n\n\n
\u0110\u1ee9ng v\u1ec1 ph\u00eda kh\u00e1ch h\u00e0ng, l\u1ee3i th\u1ebf c\u1ee7a GSM ch\u00ednh l\u00e0 ch\u1ea5t l\u01b0\u1ee3ng cu\u1ed9c g\u1ecdi t\u1ed1t h\u01a1n, gi\u00e1 th\u00e0nh th\u1ea5p c\u00f9ng d\u1ecbch v\u1ee5 tin nh\u1eafn t\u1ed1t.<\/p>\n\n\n\n
M\u1ea1ng GSM cho ph\u00e9p nh\u00e0 \u0111i\u1ec1u h\u00e0nh m\u1ea1ng c\u00f3 th\u1ec3 cung c\u1ea5p d\u1ecbch v\u1ee5 \u1edf b\u1ea5t c\u1ee9 \u0111\u00e2u.<\/p>\n\n\n\n
CDMA l\u00e0 t\u00ean vi\u1ebft t\u1eaft ti\u1ebfng anh c\u1ee7a Multiple Division Access Division. Chu\u1ea9n m\u1ea1ng n\u00e0y s\u1eed d\u1ee5ng c\u00f4ng ngh\u1ec7 ph\u1ed5 li\u00ean t\u1ee5c r\u1ed9ng, cho ph\u00e9p g\u1eedi nhi\u1ec1u t\u00edn hi\u1ec7u, th\u00f4ng tin qua m\u1ed9t k\u00eanh duy nh\u1ea5t d\u1ec5 d\u00e0ng.<\/p>\n\n\n\n
V\u1edbi m\u1ea1ng CDMA, nh\u00e0 cung c\u1ea5p m\u1ea1ng s\u1ebd \u0111\u01b0a v\u00e0o m\u1ed9t s\u1ed1 danh s\u00e1ch \u0111\u1eb7c bi\u1ec7t \u0111\u1ec3 ph\u00e1t ra c\u00e1c thu\u00ea bao c\u1ee7a h\u1ecd trong v\u00f9ng ph\u1ee7 s\u00f3ng v\u00e0 kh\u00f4ng c\u1ea5p khe sim tr\u00ean \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng. Khi s\u1eed d\u1ee5ng m\u1ea1ng n\u00e0y, ng\u01b0\u1eddi d\u00f9ng s\u1ebd kh\u00f3 c\u00f3 th\u1ec3 \u0111\u1ed5i sim m\u00e0 ph\u1ea3i s\u1eed d\u1ee5ng m\u1ed9t chi\u1ebfc \u0111i\u1ec7n tho\u1ea1i kh\u00e1c c\u00f3 h\u1ed7 tr\u1ee3 CDMA t\u1eeb m\u1ed9t nh\u00e0 m\u1ea1ng ch\u1ea5p thu\u1eadn kh\u00e1c. N\u1ebfu \u0111\u01b0\u1ee3c ch\u1ea5p thu\u1eadn, th\u1ee7 t\u1ee5c chuy\u1ec3n th\u00f4ng tin t\u1eeb thu\u00ea bao m\u1edbi sang c\u0169 kh\u00e1 ph\u1ee9c t\u1ea1p.<\/p>\n\n\n\n
Tuy nhi\u00ean, hi\u1ec7n nay c\u00f3 nhi\u1ec1u nh\u00e0 m\u1ea1ng c\u0169ng \u0111\u00e3 h\u1ed7 tr\u1ee3 cho c\u00e1c d\u00f2ng thi\u1ebft b\u1ecb CDMA ch\u00fang c\u00f3 t\u00edch h\u1ee3p th\u00eam khe c\u1eafm sim \u0111\u1ec3 s\u1eed d\u1ee5ng m\u1ea1ng 4G LTE ph\u1ee5c v\u1ee5 cho vi\u1ec7c l\u01b0\u1edbt web t\u1ed1c \u0111\u1ed9 cao hay g\u1ecdi \u0111i\u1ec7n t\u1ea1i c\u00e1c qu\u1ed1c gia c\u00f3 s\u1eed d\u1ee5ng m\u1ea1ng GSM. Hi\u1ec7n t\u1ea1i Vi\u1ec7t Nam \u0111ang h\u1ed7 tr\u1ee3 tri\u1ec3n khai m\u1ea1ng 4G cho t\u1ea5t c\u1ea3 c\u00e1c nh\u00e0 m\u1ea1ng. Ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 \u0111\u0103ng k\u00fd 4G c\u1ee7a viettel, vinaphone,\u2026\u0111\u1ec3 tr\u1ea3i nghi\u1ec7m t\u1ed1c \u0111\u1ed9 cao tr\u00ean di \u0111\u1ed9ng. L\u01b0u \u00fd nh\u1ecf cho b\u1ea1n l\u00e0 khi \u0111\u0103ng k\u00fd 4G c\u1ea7n t\u00ecm hi\u1ec3u k\u1ef9 c\u00e1c th\u00f4ng tin g\u00f3i c\u01b0\u1edbc \u0111\u1ec3 tr\u00e1nh \u0111\u0103ng k\u00fd nh\u1ea7m sang c\u00e1c g\u00f3i c\u01b0\u1edbc v\u01b0\u1ee3t qu\u00e1 nhu c\u1ea7u s\u1eed d\u1ee5ng c\u1ee7a c\u00e1 nh\u00e2n.<\/p>\n\n\n\n
WCh\u1ebf \u0111\u1ed9 m\u1ea1ng WCDMA s\u1eed d\u1ee5ng m\u1ed9t c\u00f4ng ngh\u1ec7 \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 tr\u1ea3i ph\u1ed5 (spread spectrum) \u0111\u1ec3 t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c s\u1eed d\u1ee5ng b\u0103ng th\u00f4ng. N\u00f3 cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng g\u1eedi, nh\u1eadn t\u00edn hi\u1ec7u th\u00f4ng tin c\u00f9ng m\u1ed9t l\u00fac th\u00f4ng qua m\u1ed9t k\u00eanh duy nh\u1ea5t. N\u00f3i theo c\u00e1ch kh\u00e1c, ng\u01b0\u1eddi d\u00f9ng s\u1ebd chia s\u1ebb chung m\u1ed9t d\u1ea3i t\u1ea7n s\u1ed1 r\u1ed9ng chuy\u00ean d\u1ee5ng cho m\u1ee5c \u0111\u00edch truy\u1ec1n t\u1ea3i d\u1eef li\u1ec7u. M\u1ed7i m\u1ed9t cu\u1ed9c g\u1ecdi s\u1ebd \u0111\u01b0\u1ee3c m\u00e3 h\u00f3a tr\u01b0\u1edbc khi truy\u1ec1n t\u1ea3i, sau \u0111\u00f3 \u0111\u01b0\u1ee3c gi\u1ea3i m\u00e3 b\u1edfi smartphone \u0111\u00edch. Qualcomm l\u00e0 \u0111\u01a1n v\u1ecb \u0111\u1ea7u ti\u00ean ph\u00e1t tri\u1ec3n ch\u1ebf \u0111\u1ed9 m\u1ea1ng WCDMA.<\/p>\n\n\n\n
Tr\u01b0\u1edbc \u0111\u00e2y \u1edf Vi\u1ec7t Nam c\u00f3 m\u1ea1ng WCDMA do 2 nh\u00e0 m\u1ea1ng S-Fone v\u00e0 CityPhone cung c\u1ea5p, nh\u01b0ng ch\u1ec9 sau m\u1ed9t th\u1eddi gian ng\u1eafn ch\u00fang \u0111\u00e3 bi\u1ebfn m\u1ea5t tr\u00ean th\u1ecb tr\u01b0\u1eddng. V\u1eady n\u00ean c\u00e1c nh\u00e0 m\u1ea1ng l\u1edbn nh\u01b0 MobiFone, VinaPhone v\u00e0 Viettel \u0111\u1ec1u cung c\u1ea5p d\u1ecbch v\u1ee5 m\u1ea1ng GSM.<\/p>\n\n\n\n
C\u00e1c qu\u1ed1c gia \u1edf Ch\u00e2u \u00c2u th\u01b0\u1eddng d\u00f9ng m\u1ea1ng GSM, c\u00f2n \u1edf M\u1ef9 th\u00ec d\u00f9ng c\u1ea3 2 ch\u1ebf \u0111\u1ed9 m\u1ea1ng \u0111\u00f3 l\u00e0 GSM v\u00e0 WCDMA. M\u1ed7i m\u1ed9t \u0111\u01a1n v\u1ecb cung c\u1ea5p s\u1ebd c\u00f3 m\u1ed9t ch\u1ebf \u0111\u1ed9 m\u1ea1ng kh\u00e1c nhau.<\/p>\n\n\n\n
V\u1edbi c\u00e1c n\u1ed9i dung th\u00f4ng tin trong b\u00e0i vi\u1ebft \u201cM\u1ea1ng GSM l\u00e0 g\u00ec? Ph\u00e2n bi\u1ec7t ch\u1ebf \u0111\u1ed9 m\u1ea1ng GSM v\u00e0 WCDMA\u201d hy v\u1ecdng s\u1ebd gi\u00fap \u00edch cho b\u1ea1n. B\u1ea5t k\u1ef3 th\u1eafc m\u1eafc n\u00e0o c\u1ea7n \u0111\u01b0\u1ee3c gi\u1ea3i \u0111\u00e1p, qu\u00fd kh\u00e1ch h\u00e0ng h\u00e3y comment ph\u00eda d\u01b0\u1edbi, ch\u00fang t\u00f4i s\u1ebd h\u1ed7 tr\u1ee3 b\u1ea1n nhanh ch\u00f3ng v\u00e0 mi\u1ec5n ph\u00ed 100%.<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn H\u1ec7 th\u1ed1ng m\u1ea1ng di \u0111\u1ed9ng ng\u00e0y c\u00e0ng ph\u00e1t tri\u1ec3n v\u1edbi s\u1ef1 xu\u1ea5t hi\u1ec7n ng\u00e0y c\u00e0ng nhi\u1ec1u ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0 GSM, WCDMA, CDMA. Tuy nhi\u00ean kh\u00f4ng ph\u1ea3i ai n\u1eafm ch\u1eafc WCDMA, CDMA hay GSM l\u00e0 g\u00ec c\u0169ng nh\u01b0 c\u00e1c th\u00f4ng tin v\u1ec1 h\u1ec7 th\u1ed1ng m\u1ea1ng to\u00e0n c\u1ea7u n\u00e0y v\u00e0 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[1],"tags":[],"class_list":["post-3517","post","type-post","status-publish","format-standard","hentry","category-general"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/3517","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=3517"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/3517\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=3517"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=3517"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=3517"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}